==Materials and processes used to make iterative models==

==7.1a Understand that 3D iterative models can be made from a range of materials and components to create block models and working prototypes to communicate and test ideas, moving parts and structural integrity==

==7.1b Demonstrate an understanding of simple processes that can be used to model ideas using hand tools and digital tools such as rapid prototyping, or digital simulation packages.==
[[File:solidworks_example.jpg|500px|thumb|center]]
#Solidworks is an example of 3D software used to model working prototypes. This software can be used to digitally simulate models. Other software packages that can be used are Circuit Wizard.
[[File:circuit_wizard_example.gif|500px|thumb|center]]
#Materials and processes used to make final prototypes

==7.2a Understand how to select and safely use of common workshop tools, equipment and machinery to manipulate materials by methods of:==
===wasting/subtraction processes such as cutting, drilling, turning, milling===
#Cutting is the separation of a physical object, into two or more portions, through the application of an acutely directed force.
#Chip forming - sawing, drilling, milling, turning etc.
#Shearing - punching, stamping, scissoring.
#Abrading - grinding, lapping, polishing; water-jet.
#Heat - flame cutting, plasma cutting, laser cutting.
#Electrochemical - etching, electrical discharge machining (EDM).
#Drilling is a cutting process that uses a drill bit to cut a hole of circular cross-section in solid materials. The drill bit is usually a rotary cutting tool, often multi-point. The bit is pressed against the work-piece and rotated at rates from hundreds to thousands of revolutions per minute.
[[File:drilling_process.jpg|500px|thumb|center]]
#Turning is a form of machining, a material removal process, which is used to create rotational parts by cutting away unwanted material. The turning process requires a turning machine or lathe, workpiece, fixture, and cutting tool.
<center><youtube>8EsAxOnzEms</youtube></center>
#Milling is the most common form of machining, a material removal process, which can create a variety of features on a part by cutting away the unwanted material. The milling process requires a milling machine, workpiece, fixture, and cutter.
<center><youtube>eJR-G-3Kvsk</youtube></center>
===addition processes such as soldering, brazing, welding, adhesives, fasteners===
#Soldering is a process in which two or more metal items are joined together by melting and then flowing a filler metal into the joint—the filler metal having a relatively low melting point. Soldering is used to form a permanent connection between electronic components.
[[File:soldering.jpeg|500px|thumb|center]]
#Brazing is a metal-joining process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the adjoining metal.
[[File:brazing.jpg|500px|thumb|center]]
#There are many different types of welding.
[[File:welding_processes.jpg|500px|thumb|center]]
#Click on the links below to read more about the main types of welding:
##[http://www.technologystudent.com/equip_flsh/acet1.html Gas welding]
##[https://en.wikipedia.org/wiki/Arc_welding Arc welding]
##[https://en.wikipedia.org/wiki/Gas_metal_arc_welding MIG welding]
#Adhesives may be used interchangeably with glue, cement, mucilage, or paste, and is any substance applied to one surface, or both surfaces, of two separate items that binds them together and resists their separation.
##To read up on different types of glues/adhesives, click on [http://www.technologystudent.com/joints/stglu1.htm this] link to go to www.technologystudent.com to read more on this.
#A fastener is a hardware device that mechanically joins or affixes two or more objects together. In general, fasteners are used to create non-permanent joints; that is, joints that can be removed or dismantled without damaging the joining components.

[[File:fastners.jpg|500px|thumb|center]]

===deforming and reforming processes such as bending, vacuum forming===
#There are many different ways to bend different types of materials. Line bending is a common way of bending plastics. Click on [http://www.technologystudent.com/joints/desk17.htm this] link to read more about line bending.
#If you want to bend pipes or tubes, click on [http://www.technologystudent.com/equip_flsh/pipe1.html this] link to read more about it.
#Vacuum forming is a simplified version of thermoforming, where a sheet of plastic is heated to a forming temperature, stretched onto a single-surface mold, and forced against the mould by a vacuum. This process can be used to form plastic into permanent objects such as turnpike signs and protective covers. Normally draft angles are present in the design of the mould (a recommended minimum of 3°) to ease removal of the formed plastic part from the mold.
[[File:vaccuum_forming.jpg|500px|thumb|center]]
[[File:vaccuum_forming_machine.jpg|500px|thumb|center]]
<center><youtube>BqV_jsxD0UA&t</youtube></center>

==7.2b Demonstrate an understanding of the role of computer-aided manufacture (CAM) and computer-aided engineering (CAE) to fabricate parts, such as:==
===additive manufacturing (3D printing) to fabricate a usable part===
#3D printing refers to processes in which material is joined or solidified under computer control to create a three-dimensional object, with material being added together (such as liquid molecules or powder grains being fused together). 3D printing is used in both rapid prototyping and additive manufacturing (AM). Objects can be of almost any shape or geometry and typically are produced using digital model data from a 3D model or another electronic data source such as an Additive Manufacturing File (AMF) file (usually in sequential layers). Stereolithography (STL) is one of the most common file types that is used for 3D printing. Thus, unlike material removed from a stock in the conventional machining process, 3D printing or AM builds a three-dimensional object from computer-aided design (CAD) model or AMF file, usually by successively adding material layer by layer.
<center><youtube>Gwro2HzxMgw&t</youtube></center>
===subtractive CNC manufacturing such as laser/plasma cutting, milling, turning and routing===
#To read more about the world of CNC machining, click on the links below.
##[https://en.wikipedia.org/wiki/Laser_cutting Laser cutting]
##[https://en.wikipedia.org/wiki/Plasma_cutting Plasma cutting]
##[https://en.wikipedia.org/wiki/Milling_(machining) CNC milling]
##[https://en.wikipedia.org/wiki/Turning CNC turning]
##[https://en.wikipedia.org/wiki/CNC_router CNC router]

==7.2c Demonstrate an understanding of measuring instruments and techniques used to ensure that products are manufactured accurately or within tolerances as appropriate.==
#There are many instruments that can be used to measure sizes of products. The 2 most common ones you will use are the:
##Steel rule
[[File:steel_rule.jpg|500px|thumb|center]]

##Vernier Caliper
[[File:vernier.png|500px|thumb|center]]
#To read more about the vernier caliper, click on [http://www.technologystudent.com/equip1/vernier3.htm this] link to go to www.technologystudent.com to read how to use the measuring instrument.
#Other tools are available to measure products, such as a 'dial test indicator' or a 'micrometer'.

==7.2d Understand how the available forms, costs and working properties of materials contribute to the decisions about suitability of materials when developing and manufacturing their own products.==
#In every decision about manufacturing a product, the cost of the overall product is very important to a manufacturer as this will determine profits. When deciding on the materials to be used in a product, there are many decisions that will need to be made. First you would need to find as many suitable materials as possible, considering as many possibilities as you can, such as, corrosion resistance or longevity.
#Once you have selected suitable materials for your product, you will then need to consider cost, practicalities, such as manufacturing processes. This will need to be completed before deciding on the end material.
#Materials and processes used to make commercial products

==7.3a Demonstrate an understanding of the industrial processes and machinery used for manufacturing component parts in various materials, including:==
#polymer moulding methods, such as injection moulding, blow moulding, compression moulding and thermoforming.
#Injection moulding is a manufacturing process for producing parts by injecting molten material into a mould. Injection moulding can be performed with a host of materials mainly including metals, (for which the process is called die-casting), glasses, elastomers, confections, and most commonly thermoplastic and thermosetting polymers. Material for the part is fed into a heated barrel, mixed (Using a helical shaped screw), and injected (Forced) into a mould cavity, where it cools and hardens to the configuration of the cavity. After a product is designed, usually by an industrial designer or an engineer, moulds are made by a mould-maker (or toolmaker) from metal, usually either steel or aluminium, and precision-machined to form the features of the desired part. Injection moulding is widely used for manufacturing a variety of parts, from the smallest components to entire body panels of cars. Advances in 3D printing technology, using photopolymers which do not melt during the injection moulding of some lower temperature thermoplastics, can be used for some simple injection moulds.
[[File:injection_moulding.png|500px|thumb|center]]

#Blow molding is a manufacturing process by which hollow plastic parts are formed: It is also used for forming glass bottles. In general, there are three main types of blow molding: extrusion blow molding, injection blow molding, and injection stretch blow molding. The blow molding process begins with melting down the plastic and forming it into a parison or in the case of injection and injection stretch blow moulding (ISB) a preform. The parison is a tube-like piece of plastic with a hole in one end through which compressed air can pass.

[[File:blow_molding.png|500px|thumb|center]]

#Extrusion moulding is a manufacturing process used to make pipes, hoses, drinking straws, curtain tracks, rods. Plastic granules melt into a liquid which is forced through a die, forming a long 'tube like' shape. The shape of the die determines the shape of the tube. The extrusion is then cooled and forms a solid shape. The tube may be printed upon, and cut at equal intervals. The pieces may be rolled for storage or packed together. Shapes that can result from extrusion include T-sections, U-sections, square sections, I-sections, L-sections and circular sections. Extrusion is similar to injection moulding except that a long continuous shape is produced. Learn more [https://www.technologystudent.com/equip1/plasextru1.html here].

#Compression Molding is a method of molding in which the moulding material, generally preheated, is first placed in an open, heated mould cavity. The mold is closed with a top force or plug member, pressure is applied to force the material into contact with all mold areas, while heat and pressure are maintained until the molding material has cured. The process employs thermosetting resins in a partially cured stage, either in the form of granules, putty-like masses, or preforms.

[[File:compression_molding.png|500px|thumb|center]]

#Thermoforming is a manufacturing process where a plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. The sheet, or "film" when referring to thinner gauges and certain material types, is heated in an oven to a high-enough temperature that permits it to be stretched into or onto a mold and cooled to a finished shape. Its simplified version is vacuum forming.

[[File:Thermoforming.gif|500px|thumb|center]]

===metal casting methods such as sand casting and die casting===
#Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand as the mold material. The term "sand casting" can also refer to an object produced via the sand casting process. Sand castings are produced in specialized factories called foundries. Over 70% of all metal castings are produced via sand casting process.

[[File:sand_casting.png|500px|thumb|center]]

#Die casting is a metal casting process that is characterised by forcing molten metal under high pressure into a mould cavity. The mould cavity is created using two hardened tool steel dies which have been machined into shape and work similarly to an injection mould during the process. Most die castings are made from non-ferrous metals, specifically zinc, copper, aluminium, magnesium, lead, pewter and tin-based alloys. Depending on the type of metal being cast, a hot- or cold-chamber machine is used. The steps are...
##Moulds machined from HSS using a CNC milling machine.
##Molten aluminium alloy added to die casting machine.
##Molten aluminium forced into die by piston.
##Water cooling of casting.
##Split dies open and ejector pins eject the cast part.
##Finished part is 'fettled' (the rough edges are sanded/tidied) to remove flashing where the two halves of the mould came together.
##If required, the part can then be painted (e.g. by spraying or a dip-coating process)
[[File:die_casting.png|500px|thumb|center]]

===sheet metal forming methods using equipment such as punches, rollers, shears and stamping machines===
#Punching is a forming process that uses a punch press to force a tool, called a punch, through the workpiece to create a hole via shearing. Punching is applicable to a wide variety of materials that come in sheet form, including sheet metal, paper, vulcanized fibre and some forms of plastic sheet. The punch often passes through the work into a die. A scrap slug from the hole is deposited into the die in the process. Depending on the material being punched this slug may be recycled and reused or discarded.

[[File:punching.jpeg|500px|thumb|center]]

#Sheet metal rolling.
<center><youtube>1EGnHsYoKH0</youtube></center>

#Shearing, also known as die cutting, is a process which cuts stock without the formation of chips or the use of burning or melting. Strictly speaking, if the cutting blades are straight the process is called shearing; if the cutting blades are curved then they are shearing-type operations. The most commonly sheared materials are in the form of sheet metal or plates, however rods can also be sheared.

[[File:shear.jpg|500px|thumb|center]]

#Stamping (also known as pressing) is the process of placing flat sheet metal in either blank or coil form into a stamping press where a tool and die surface forms the metal into a net shape. Stamping includes a variety of sheet-metal forming manufacturing processes, such as punching using a machine press or stamping press, blanking, embossing, bending, flanging, and coining.

[[File:stamping.gif|500px|thumb|center]]

==7.3b Demonstrate an understanding of the industrial methods used for assembling electronic products, such as:==
===surface mount technology (SMT)===
#PCB assembly using solder stencils, pick-and-place machines and reflow soldering ovens.
#Watch the video below, this is a homemade machine, but it shows clearly the process of picking and placing surface mount (SMT) compinents to a PCB.

<center><youtube>CRSLbo_8nTQ</youtube></center>

#Below is a video explaining what reflow soldering is. Below that video is one explaining how the relow soldering oven work. It is selling a product, if you skip to 1:20, you will see how it works.
<center><youtube>eOUf59iut3s</youtube></center>
<center><youtube>Zw53kxy7yL0</youtube></center>

===CNC manufacturing such as laser/plasma cutting, milling, turning and routing===
#Watch the videos below to see the above CNC machines in action.
#CNC plasma cutting (the same as laser cutting)

<center><youtube>sKLdrHo2RWs</youtube></center>

#CNC milling machine.

<center><youtube>QL-K3-ODK4s</youtube></center>

#CNC turning machine.

<center><youtube>MwgobIVj4fU</youtube></center>

#CNC routing machine.

<center><youtube>txCMvRF4Bm8</youtube></center>

==7.3c Demonstrate an understanding of the benefits and flexibility of using computer-controlled machinery.==
===Automated material handling systems===
#Automated Materials Handling. Automated materials handling (AMH) refers to any automation that reduces or eliminates the need for humans to check-in, check-out, sort material, or to move totes and bins containing library material.
#Robot arms to stack, assemble, join and paint parts.
##Click [https://www.youtube.com/watch?v%3DgUWCljX7oa0 here] to watch a video of a robot being used to paint a car.
##Click [https://www.youtube.com/watch?v%3DLVtBjFUfFLE here] to watch a video of a robotic assembly line.

==7.3d Understand the necessity for manufacturers to optimise the use of materials and production processes.==
===Economical cutting and costing===

===Working to a budget through efficient manufacture===

==7.4a The methods used for manufacturing at different scales of production, including:==
===one-off, bespoke production===
#Job production, sometimes called jobbing or *one-off* production, involves producing custom work, such as a one-off product for a specific customer or a small batch of work in quantities usually less than those of mass-market products.

===Batch production===
#Batch production is a technique used in manufacturing, in which the object in question is created stage by stage over a series of workstations, and different batches of products are made.

===Mass production===
#Mass production is the manufacture of large quantities of standardized products, frequently utilizing assembly line technology. Mass production refers to the process of creating large numbers of similar products efficiently.

===lean manufacturing and just-in-time (JIT) methods===
#Lean manufacturing or lean production, often simply "lean", is a systematic method for waste minimization ("Muda") within a manufacturing system without sacrificing productivity. Lean also takes into account waste created through overburden ("Muri") and waste created through unevenness in work loads ("Mura"). Working from the perspective of the client who consumes a product or service, "value" is any action or process that a customer would be willing to pay for.
#Just-in-time (JIT) manufacturing, also known as just-in-time production or the Toyota Production System (TPS), is a methodology aimed primarily at reducing flow times within production system as well as response times from suppliers and to customers. Its origin and development was in Japan, largely in the 1960s and 1970s and particularly at Toyota.

===Fully automated manufacture===
#Lights out (manufacturing) Lights out or lights-out manufacturing is a manufacturing methodology (or philosophy), rather than a specific process. Factories that run lights out are fully automated and require no human presence on-site.
#Click [https://en.wikipedia.org/wiki/Lights_out_(manufacturing) here] to read more about 'lights out' manufacturing.

==7.4b Understanding how ICT and digital technologies are changing modern manufacturing.==
===Customised manufacture systems===
#In the custom manufacturing system, each item is produced by a single craftsperson, who works solely by hand or with the help of a machine. ... As a result, custom-manufactured products are of the highest quality but are also the most expensive products in the market.

===Rapid prototyping===
#Rapid prototyping is a group of techniques used to quickly fabricate a scale model of a physical part or assembly using three-dimensional computer aided design (CAD) data. Construction of the part or assembly is usually done using 3D printing or "additive layer manufacturing" technology.

===Additive and digital manufacture methods===
#Additive Manufacturing refers to a process by which digital 3D design data is used to build up a component in layers by depositing material. The term "3D printing" is increasingly used as a synonym for Additive Manufacturing. However, the latter is more accurate in that it describes a professional production technique which is clearly distinguished from conventional methods of material removal. Instead of milling a workpiece from solid block, for example, Additive Manufacturing builds up components layer by layer using materials which are available in fine powder form. A range of different metals, plastics and composite materials may be used.

===Stock control, monitoring logistics in industry===
#Stock control, monitoring logistics is the fact or process of ensuring that appropriate amounts of stock are maintained by a business, so as to be able to meet customer demand without delay while keeping the costs associated with holding stock to a minimum.

==7.5a Understanding the process that needs to be undertaken to ensure products meet legal requirements and are high quality.==
#Total Quality management (TQM) is the continual process of detecting and reducing or eliminating errors in manufacturing, streamlining supply chain management, improving quality and customer experience. This is implemented through three areas:

===Management===
#ISO9000 certification process to appreciate quality in house and from suppliers.
#BS 7850 as a standard for effective management of human resources and materials.
#Poke-Yokes as a simple checking strategy to eliminate errors arising for relative labour-intensive tasks.
#Implementation of Kaizen as a method of continuous improvement as workers are best placed to suggest improvements to processes and feel empowered and wanted within their jobs.

===Quality Assurance===
#Check for quality raw materials / components from suppliers.
#Checking every stage of the manufacturing process.
#Induction / ongoing training for staff to ensure they understand how to achieve quality.
#Checking against the specification to ensure customer requirements.

===Quality Control===
#Random Sampling of parts and components as they are being manufactured.
#Tolerances in place to ensure upper and lower dimensional allowances.

==QA Vs QC==
#During the manufacturing process, QC and QA are vital to ensure a high-quality end product which is safe, and meets client expectation. In the areas such as aeronautical, automotive and medical industries, getting this right can have life or death implications.
#QC is like checking from time to time that your goldfish is still alive. With QA, you would also aim to make sure that the filter and pump work correctly, the water is the right temperature and is changed on schedule, and that everyone in the household knows when and how much to feed it.
#Quality Control is where a product is inspected or tested to ensure that it meets the requirements for the specific product. For instance, a car part may need to be made from aluminium, weight 54.5g and measure 3mm x 6mm. If out of 50 parts inspected, 49 match these requirements, but one weighs 55g and is 3mm x 6.5mm, that part would fail its quality control check. Quality Control does not ensure quality – it informs where it is missing.
#Quality Assurance seeks to look more closely at the process of making the product, seeks to find common areas where quality has the potential to slip and looks to address these so that manufactured parts fail less often. This can happen right through the design, development and manufacture stages.
#[http://www.iso9001consultant.com.au/QA.html Read more here]

==European and British standards==
#It comprises a set of questions and answers that summarizes the role of standards in the European Single Market. The information in this document has been prepared by BSI (British Standards Institution), which is appointed by the UK Government (HMG) to act as the UK National Standards Body (NSB).

[[Design_Engineering|Design Engineering homepage]]

Technical understanding part 1

2024-02-27T13:56:47Z

Stcd11:

Considerations made about the structural integrity of a design solution

==6.1a You should understand how and why some materials and/or system components need to be reinforced or stiffened to withstand forces and stresses to fulfil the structural integrity of products.==

==6.1b Show an understanding of the processes that can be used to ensure the structural integrity of a product, such as:==

* Triangulation

A triangle is one of the strongest shapes available for engineers to use. It is used to create a shape that is rigid and will not move. We find these shapes regularly used in the building industry to keep building upright and rigid.

[http://www.technologystudent.com/struct1/triag1.htm Click on this link for more information on triangulation.]

* Reinforcing

Reinforcing is used to strengthen materials and improve either their compressive or tensile strength.

<center><youtube>SwZ53txG1zs</youtube></center>

How mechanisms provide functionality to products and systems.

==6.2a Demonstrate an understanding of the functions that mechanical devices offer to products, providing different types of motion, including:==

* rotary
[[File:rotary.gif|500px|thumb|center]]
* linear
[[File:linear.gif|500px|thumb|center]]
* reciprocating
[[File:reciprocating.gif|500px|thumb|center]]
* oscillating.
Below is a Peg and Slot mechanism, this converts rotary to oscillating motion. However, the output is reciprocating motion.
[[File:oscillating.gif|500px|thumb|center]]
*To learn about converting from one type of motion to another, click [https://www.bbc.co.uk/bitesize/guides/zbt26yc/revision/3 here] for linkages and [https://www.bbc.co.uk/bitesize/guides/zbt26yc/revision/4 here] for rotary motion.
* You can learn more about gear trains [https://www.bbc.co.uk/bitesize/guides/zbt26yc/revision/5 here].
*You can learn about pulley systems [https://www.bbc.co.uk/bitesize/guides/zbt26yc/revision/6 here].

Sample Mechanisms from exam paper:
[[File:2019_P1_Q1b.png|500px|thumb|center]]

i. The lift moves at a speed of 0.08 m s–1.
Calculate the time taken in seconds (s) for the lift to rise between floors which are 2800 mm apart. Show your working.

Speed = distance/time Time = distance/speed (1).
Conversion of 2800 mm to 2.8 m (1).
Time = 2.8/0.08 Time = 35 s (1).

ii. Analysing the data in Fig. 1.2, calculate the motor rotational speed required in revolutions per minute (rpm) to cause the nut to climb up the thread at a speed of 0.08 m s–1.

Show your working.

In 1 second, number of nut revolutions = linear distance / thread pitch = 80/8 = 10 revolutions (1).
Sprocket gear ratio = driven / driver = 30/20 Motor revolutions in 1 second = 10* x 30/20 = 15 revolutions (1).

OR

Calculate that the nut rotation at 10 revolutions is 600rpm therefore at 15 revolutions multiply by 1.5 = 900rpm (1)
Conversion to rpm: Motor rotational speed = 15*x60 = 900 rpm (1).

iii. Give two reasons why a double chain drive is used in this application.

* Safety – if one chain fails there is a backup (1).
* The two chains share the load (1).
* Each chain can be thinner which could save cost, reduce weight, and allow a more compact drive system (1).
* If one chain fails, the lift will continue to work (1).
* They are more secure in instances where a belt drive might be used due to them being non slip drives (1).
* Any other valid suggestion.

iv. The maximum total mass of the lift and occupants is 350 kg.

- Calculate the power required in watts (W) to raise the 350 kg lift at a velocity of 0.08 m s–1.

- Show your working.

- gravitational potential energy = mgh

- power = E/t

- gravitational field strength, g = 9.81 N kg–1

Showing understanding that the lift rises 0.08m in 1s (1). i.e. 0.08 = h (1)
GPE = mgh = 350x9.81x0.08 = 274.68 J (1).
Showing understanding that the power required is equal to the increase in GPE in 1s (or for ‘calculating’ the power):
Power = E/t = 274.68*/1 = 274.68 W (1). I.e. time = 1s

==6.2b Demonstrate an understanding of devices and systems that are used to change the magnitude and direction of forces and torques, including:==
#For gears, cams, pulleys and belts, levers, linkages, screw threads, worm drives, chain drives and belt drives, click on this [https://www.bbc.co.uk/bitesize/guides/zbt26yc/revision/3 here] to see images and explanations of gears, cams, pulleys, levers, chain drives and belt drives.
#Screw threads and worm drives are often used to control linear motion in CNC machines, such as 3D printers.
[[File:worm_gear.gif|500px|thumb|center]]

===Epicyclic gear systems===
#An epicyclic gear train consists of two gears mounted so that the center of one gear revolves around the center of the other. A carrier connects the centers of the two gears and rotates to carry one gear, called the planet gear, around the other, called the sun gear. The planet and sun gears mesh so that their pitch circles roll without slip. A point on the pitch circle of the planet gear traces an epicycloid curve. In the simplified case in the image below, the sun gear is fixed and the planetary gear(s) roll around the sun gear.
[[File:epicyclic.gif|500px|thumb|center]]
#An epicyclic gearbox has a co-linear (in-line) input and output shaft which enables the design of a product to be more compact.
#Epicyclic gears can handle higher torque than a compound gear chain because of their design, which is required in products like food mixers and drills.
#Epicyclic gearbox is compact which leads to a smaller product.

===Bearings===
*See textbook, pg. 251 for more.
*A bearing is a component which supports a moving part and allows it to move only in the desired motion, with little friction. Bearings are most commonly used to support a drive shaft so it can rotate freely. A drive shaft needs to
be supported at a minimum of two points along its length (sometimes more in high-load applications) so that the shaft is held accurately in place, ensuring that gears and other components stay in precise mesh with each other. The forces acting on a shaft can be radial forces which try to push the shaft sideways, or axial forces which try to push the shaft along its axis.
*A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts. The design of the bearing may, for example, provide for free linear movement of the moving part or for free rotation around a fixed axis; or, it may prevent a motion by controlling the vectors of normal forces that bear on the moving parts. Most bearings facilitate the desired motion by minimizing friction. Bearings are classified broadly according to the type of operation, the motions allowed, or to the directions of the loads (forces) applied to the parts.
*Using bearings in the rotating parts of the mechanical systems (e.g. on a car park barrier gate) reduces the torque required to overcome frictional losses and increases the mechanical efficiency of the system.
*Reducing static friction in systems enables parts to start moving quicker meaning they can operate more rapidly, allowing increased productivity.
*Bearings reduce wear between mechanical parts, increasing the longevity / life of the mechanical system.
*Reducing friction will also reduce the noise created, which may be desirable in a commercial product.
[[File:ball_bearing.jpg|500px|thumb|center]]

===Lubrication===
*A lubricant is a substance, usually organic, introduced to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. The property of reducing friction is known as lubricity.
*Lubrication can also protect ferrous metal parts from corrosion, as the oil/grease will prevent air and moisture from being able to attack the metal.
*Where moving parts are under-lubricated or not lubricated, friction between these surfaces will lead to an increase in temperature at the joint / system. Over time, this can result in parts fusing/welding themselves together, leading to system failure. May also lead to...
**Increased wear and tear of joint / system resulting in quickened fatigue and failure of joint / system.
**Parts escaping intended joint / system causing issues and damaging others system, e.g. electronics.
**Slippage of joint / system leading to inefficient performance of joint / system.
**Difficulties for future maintenance causing increases to maintenance costs and maintenance time required.
*Types of lubricants:
**[https://en.wikipedia.org/wiki/Lubricant#Mineral_oil Mineral Oil]
**[https://en.wikipedia.org/wiki/Lubricant#Synthetic_oils Synthetic oils]
**[https://en.wikipedia.org/wiki/Lubricant#Solid_lubricants Solid Lubricants]
**[https://en.wikipedia.org/wiki/Lubricant#Aqueous_lubrication Aqueous Lubricants]
**[https://en.wikipedia.org/wiki/Lubricant#Biolubricants Bio Lubricants]

===Efficiency in mechanical systems===
1. Mechanical efficiency measures the effectiveness of a machine in transforming the energy and power that is input to the device into an output force and movement. Efficiency is measured as a ratio of the measured performance to the performance of an ideal machine:
Efficiency = Measured performance/Ideal performance
or
Efficiency = (Mechanical Advantage X 100)/Velocity Ratio

2. Because the power transmission system or mechanism does not generate power, its ideal performance occurs when the output power equals the input power, that is, when there are no losses. Real devices dissipate power through friction, part deformation and wear.

3. The ideal transmission or mechanism has an efficiency of 100%, because there is no power loss. Real devices will have efficiency less than 100% because rigid and friction-less systems do not exist. The power losses in a transmission or mechanism are eventually dissipated as heat.

The forces that need consideration to ensure structural and mechanical efficiency.

==6.3a Demonstrate an understanding of static and dynamic forces in structures and how to achieve rigidity, including:==

* Tension, compression, torsion and bending.

[[File:Tension.JPG|500px|thumb|center]]

1. Tension may describe the pulling force transmitted axially by means of a string, cable, chain, or similar one-dimensional continuous object, or by each end of a rod, truss member, or similar three-dimensional object; tension might also be described as the action-reaction pair of forces acting at each end of said elements. Tension could be the opposite of compression.

2. Compression is the application of balanced inward ("pushing") forces to different points on a material or structure, that is, forces with no net sum or torque directed so as to reduce its size in one or more directions.

3. Torsion is the twisting of an object due to an applied torque. Torsion is expressed in newton per squared meter (Pa) or pound per squared inch (psi) while torque is expressed in newton metres (N·m) or foot-pound force (ft·lbf).

4. Bending (also known as flexure) characterises the behaviour of a slender structural element subjected to an external load applied perpendicularly to a longitudinal axis of the element.

* Stress, strain and elasticity.

1. Stress is a physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other.

[[File:types_of_stress.png|500px|thumb|center]]

2. Strain is the measure of the deformation of the material. For example, when a solid vertical bar is supporting a weight, each particle in the bar pushes on the particles immediately below it. When a liquid is in a closed container under pressure, each particle gets pushed against by all the surrounding particles.

3. Elasticity is the ability of a body to resist a distorting influence or deforming force and to return to its original size and shape when that influence or force is removed.

* Mass and weight.

1. Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied.[1] It also determines the strength of its mutual gravitational attraction to other bodies. The basic SI unit of mass is the kilogram (kg).

2. Weight of an object is usually taken to be the force on the object due to gravity.[1][2] Weight is a vector whose magnitude (a scalar quantity), often denoted by an italic letter W, is the product of the mass m of the object and the magnitude of the local gravitational acceleration g;[3] thus: W = mg. The unit of measurement for weight is that of force, which in the International System of Units (SI) is the newton.

* Rigidity.

1. Rigidity is the property of a solid body to resist deformation. Structural rigidity, a mathematical theory of the stiffness of ensembles of rigid objects connected by hinges.

* Modes of failure.

1. Mechanical failure. Some types of mechanical failure mechanisms are: excessive deflection, buckling, ductile fracture, brittle fracture, impact, creep, relaxation, thermal shock, wear, corrosion, stress corrosion cracking, and various types of fatigue.

[[File:fractures.jpg|500px|thumb|center]]

[[Design_Engineering|Design Engineering homepage]]
.

Technical understanding part 1

2024-02-26T15:16:56Z

Stcd11:

Technical understanding part 1

2024-02-26T15:16:04Z

Stcd11:

Considerations made about the structural integrity of a design solution

==6.1a You ccccc should understand how and why some materials and/or system components need to be reinforced or stiffened to withstand forces and stresses to fulfil the structural integrity of products.==

==6.1b Show an understanding of the processes that can be used to ensure the structural integrity of a product, such as:==

* Triangulation

A triangle is one of the strongest shapes available for engineers to use. It is used to create a shape that is rigid and will not move. We find these shapes regularly used in the building industry to keep building upright and rigid.

[http://www.technologystudent.com/struct1/triag1.htm Click on this link for more information on triangulation.]

* Reinforcing

Reinforcing is used to strengthen materials and improve either their compressive or tensile strength.

<center><youtube>SwZ53txG1zs</youtube></center>

How mechanisms provide functionality to products and systems.

==6.2a Demonstrate an understanding of the functions that mechanical devices offer to products, providing different types of motion, including:==

* rotary
[[File:rotary.gif|500px|thumb|center]]
* linear
[[File:linear.gif|500px|thumb|center]]
* reciprocating
[[File:reciprocating.gif|500px|thumb|center]]
* oscillating.
Below is a Peg and Slot mechanism, this converts rotary to oscillating motion. However, the output is reciprocating motion.
[[File:oscillating.gif|500px|thumb|center]]
*To learn about converting from one type of motion to another, click [https://www.bbc.co.uk/bitesize/guides/zbt26yc/revision/3 here] for linkages and [https://www.bbc.co.uk/bitesize/guides/zbt26yc/revision/4 here] for rotary motion.
* You can learn more about gear trains [https://www.bbc.co.uk/bitesize/guides/zbt26yc/revision/5 here].
*You can learn about pulley systems [https://www.bbc.co.uk/bitesize/guides/zbt26yc/revision/6 here].

Sample Mechanisms from exam paper:
[[File:2019_P1_Q1b.png|500px|thumb|center]]

i. The lift moves at a speed of 0.08 m s–1.
Calculate the time taken in seconds (s) for the lift to rise between floors which are 2800 mm apart. Show your working.

Speed = distance/time Time = distance/speed (1).
Conversion of 2800 mm to 2.8 m (1).
Time = 2.8/0.08 Time = 35 s (1).

ii. Analysing the data in Fig. 1.2, calculate the motor rotational speed required in revolutions per minute (rpm) to cause the nut to climb up the thread at a speed of 0.08 m s–1.

Show your working.

In 1 second, number of nut revolutions = linear distance / thread pitch = 80/8 = 10 revolutions (1).
Sprocket gear ratio = driven / driver = 30/20 Motor revolutions in 1 second = 10* x 30/20 = 15 revolutions (1).

OR

Calculate that the nut rotation at 10 revolutions is 600rpm therefore at 15 revolutions multiply by 1.5 = 900rpm (1)
Conversion to rpm: Motor rotational speed = 15*x60 = 900 rpm (1).

iii. Give two reasons why a double chain drive is used in this application.

* Safety – if one chain fails there is a backup (1).
* The two chains share the load (1).
* Each chain can be thinner which could save cost, reduce weight, and allow a more compact drive system (1).
* If one chain fails, the lift will continue to work (1).
* They are more secure in instances where a belt drive might be used due to them being non slip drives (1).
* Any other valid suggestion.

iv. The maximum total mass of the lift and occupants is 350 kg.

- Calculate the power required in watts (W) to raise the 350 kg lift at a velocity of 0.08 m s–1.

- Show your working.

- gravitational potential energy = mgh

- power = E/t

- gravitational field strength, g = 9.81 N kg–1

Showing understanding that the lift rises 0.08m in 1s (1). i.e. 0.08 = h (1)
GPE = mgh = 350x9.81x0.08 = 274.68 J (1).
Showing understanding that the power required is equal to the increase in GPE in 1s (or for ‘calculating’ the power):
Power = E/t = 274.68*/1 = 274.68 W (1). I.e. time = 1s

==6.2b Demonstrate an understanding of devices and systems that are used to change the magnitude and direction of forces and torques, including:==
#For gears, cams, pulleys and belts, levers, linkages, screw threads, worm drives, chain drives and belt drives, click on this [https://www.bbc.co.uk/bitesize/guides/zbt26yc/revision/3 here] to see images and explanations of gears, cams, pulleys, levers, chain drives and belt drives.
#Screw threads and worm drives are often used to control linear motion in CNC machines, such as 3D printers.
[[File:worm_gear.gif|500px|thumb|center]]

===Epicyclic gear systems===
#An epicyclic gear train consists of two gears mounted so that the center of one gear revolves around the center of the other. A carrier connects the centers of the two gears and rotates to carry one gear, called the planet gear, around the other, called the sun gear. The planet and sun gears mesh so that their pitch circles roll without slip. A point on the pitch circle of the planet gear traces an epicycloid curve. In the simplified case in the image below, the sun gear is fixed and the planetary gear(s) roll around the sun gear.
[[File:epicyclic.gif|500px|thumb|center]]
#An epicyclic gearbox has a co-linear (in-line) input and output shaft which enables the design of a product to be more compact.
#Epicyclic gears can handle higher torque than a compound gear chain because of their design, which is required in products like food mixers and drills.
#Epicyclic gearbox is compact which leads to a smaller product.

===Bearings===
*See textbook, pg. 251 for more.
*A bearing is a component which supports a moving part and allows it to move only in the desired motion, with little friction. Bearings are most commonly used to support a drive shaft so it can rotate freely. A drive shaft needs to
be supported at a minimum of two points along its length (sometimes more in high-load applications) so that the shaft is held accurately in place, ensuring that gears and other components stay in precise mesh with each other. The forces acting on a shaft can be radial forces which try to push the shaft sideways, or axial forces which try to push the shaft along its axis.
*A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts. The design of the bearing may, for example, provide for free linear movement of the moving part or for free rotation around a fixed axis; or, it may prevent a motion by controlling the vectors of normal forces that bear on the moving parts. Most bearings facilitate the desired motion by minimizing friction. Bearings are classified broadly according to the type of operation, the motions allowed, or to the directions of the loads (forces) applied to the parts.
*Using bearings in the rotating parts of the mechanical systems (e.g. on a car park barrier gate) reduces the torque required to overcome frictional losses and increases the mechanical efficiency of the system.
*Reducing static friction in systems enables parts to start moving quicker meaning they can operate more rapidly, allowing increased productivity.
*Bearings reduce wear between mechanical parts, increasing the longevity / life of the mechanical system.
*Reducing friction will also reduce the noise created, which may be desirable in a commercial product.
[[File:ball_bearing.jpg|500px|thumb|center]]

===Lubrication===
*A lubricant is a substance, usually organic, introduced to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. The property of reducing friction is known as lubricity.
*Lubrication can also protect ferrous metal parts from corrosion, as the oil/grease will prevent air and moisture from being able to attack the metal.
*Where moving parts are under-lubricated or not lubricated, friction between these surfaces will lead to an increase in temperature at the joint / system. Over time, this can result in parts fusing/welding themselves together, leading to system failure. May also lead to...
**Increased wear and tear of joint / system resulting in quickened fatigue and failure of joint / system.
**Parts escaping intended joint / system causing issues and damaging others system, e.g. electronics.
**Slippage of joint / system leading to inefficient performance of joint / system.
**Difficulties for future maintenance causing increases to maintenance costs and maintenance time required.
*Types of lubricants:
**[https://en.wikipedia.org/wiki/Lubricant#Mineral_oil Mineral Oil]
**[https://en.wikipedia.org/wiki/Lubricant#Synthetic_oils Synthetic oils]
**[https://en.wikipedia.org/wiki/Lubricant#Solid_lubricants Solid Lubricants]
**[https://en.wikipedia.org/wiki/Lubricant#Aqueous_lubrication Aqueous Lubricants]
**[https://en.wikipedia.org/wiki/Lubricant#Biolubricants Bio Lubricants]

===Efficiency in mechanical systems===
1. Mechanical efficiency measures the effectiveness of a machine in transforming the energy and power that is input to the device into an output force and movement. Efficiency is measured as a ratio of the measured performance to the performance of an ideal machine:
Efficiency = Measured performance/Ideal performance
or
Efficiency = (Mechanical Advantage X 100)/Velocity Ratio

2. Because the power transmission system or mechanism does not generate power, its ideal performance occurs when the output power equals the input power, that is, when there are no losses. Real devices dissipate power through friction, part deformation and wear.

3. The ideal transmission or mechanism has an efficiency of 100%, because there is no power loss. Real devices will have efficiency less than 100% because rigid and friction-less systems do not exist. The power losses in a transmission or mechanism are eventually dissipated as heat.

The forces that need consideration to ensure structural and mechanical efficiency.

==6.3a Demonstrate an understanding of static and dynamic forces in structures and how to achieve rigidity, including:==

* Tension, compression, torsion and bending.

[[File:Tension.JPG|500px|thumb|center]]

1. Tension may describe the pulling force transmitted axially by means of a string, cable, chain, or similar one-dimensional continuous object, or by each end of a rod, truss member, or similar three-dimensional object; tension might also be described as the action-reaction pair of forces acting at each end of said elements. Tension could be the opposite of compression.

2. Compression is the application of balanced inward ("pushing") forces to different points on a material or structure, that is, forces with no net sum or torque directed so as to reduce its size in one or more directions.

3. Torsion is the twisting of an object due to an applied torque. Torsion is expressed in newton per squared meter (Pa) or pound per squared inch (psi) while torque is expressed in newton metres (N·m) or foot-pound force (ft·lbf).

4. Bending (also known as flexure) characterises the behaviour of a slender structural element subjected to an external load applied perpendicularly to a longitudinal axis of the element.

* Stress, strain and elasticity.

1. Stress is a physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other.

[[File:types_of_stress.png|500px|thumb|center]]

2. Strain is the measure of the deformation of the material. For example, when a solid vertical bar is supporting a weight, each particle in the bar pushes on the particles immediately below it. When a liquid is in a closed container under pressure, each particle gets pushed against by all the surrounding particles.

3. Elasticity is the ability of a body to resist a distorting influence or deforming force and to return to its original size and shape when that influence or force is removed.

* Mass and weight.

1. Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied.[1] It also determines the strength of its mutual gravitational attraction to other bodies. The basic SI unit of mass is the kilogram (kg).

2. Weight of an object is usually taken to be the force on the object due to gravity.[1][2] Weight is a vector whose magnitude (a scalar quantity), often denoted by an italic letter W, is the product of the mass m of the object and the magnitude of the local gravitational acceleration g;[3] thus: W = mg. The unit of measurement for weight is that of force, which in the International System of Units (SI) is the newton.

* Rigidity.

1. Rigidity is the property of a solid body to resist deformation. Structural rigidity, a mathematical theory of the stiffness of ensembles of rigid objects connected by hinges.

* Modes of failure.

1. Mechanical failure. Some types of mechanical failure mechanisms are: excessive deflection, buckling, ductile fracture, brittle fracture, impact, creep, relaxation, thermal shock, wear, corrosion, stress corrosion cracking, and various types of fatigue.

[[File:fractures.jpg|500px|thumb|center]]

[[Design_Engineering|Design Engineering homepage]]

2023-05-26T13:58:33Z

Stcd11:

Use of Mathematics in Design Engineering

==M1 - Confident use of numbers and percentages==

* Calculation of quantities of materials, components, costs and size with consideration of percentage profits and tolerances as appropriate.
* Substitute numerical values into and rearrange learnt formulae and expressions.
* Confident use of decimal and standard form.
* Calculate positive integer powers and exact roots.
* e.g. [[File:301b.png|500px|thumb|center]]
* Interpret and order numbers expressed in standard form. Convert numbers to and from standard form
* e.g. [[File:302b.png|500px|thumb|center]]
* Round answers to an appropriate level of accuracy.
* Use inequality notation to write down an error interval for a number or measurement rounded or truncated to a given degree of accuracy.
* Calculate the upper and lower bounds of a calculation using numbers rounded to a known degree of accuracy.
* e.g. [[File:401c.png|500px|thumb|center]]
* Formulate simple formulae and expressions from real-world contexts.
* e.g. [[File:602a.png|500px|thumb|center]]
* Substitute positive numbers into simple expressions and formulae to find the value of the subject and into more complex formulae, including powers, roots and algebraic fractions.
* e.g. [[File:602b.png|500px|thumb|center]]
* Rearrange formulae to change the subject, including cases where the subject appears twice, or where a power or reciprocal of the subject appears.
* e.g. [[File:602c.png|500px|thumb|center]]
* Understand and use the symbols <, ≤, > and ≥. Solve linear inequalities in one variable.
* e.g. [[File:604a.png|500px|thumb|center]]
* Use and convert standard units of measurement for length, area, volume/capacity, mass, time and money and in algebraic contexts.
* Use and convert standard units of measurement for length, area, volume/capacity, mass, time and money and in algebraic contexts. Use and convert simple compound units (e.g. for speed, rates of pay, unit pricing) and (e.g. density, pressure). Know and apply in simple cases: speed = distance ÷ time and density = mass ÷ volume. Use and convert compound units in algebraic contexts.
* e.g. [[File:1001a.png|500px|thumb|center]]
* Substitute positive numbers into simple expressions and formulae to find the value of the subject or negative numbers into more complex formulae, including powers, roots and algebraic fractions.
* Use and convert simple compound units (e.g. for speed, rates of pay, unit pricing) and (e.g. density, pressure). Know and apply in simple cases: speed = distance ÷ time and density = mass ÷ volume. Use and convert compound units in algebraic contexts.

[[File:youngs_modulus.png|500px|thumb|center]]

* Pressure = force / area
* Wave frequency = 1 / period
* Turning effects, torque = Fd , or moment = Fx

==M2 - Use of ratios==

* Understand and use ratios in the scaling of drawings and pattern grading.
* Understand and apply fractions and percentages when analysing data, survey responses and user questionnaires given in tables and charts.
* Calculate percentages e.g. with profit, waste saving calculations or comparing measurements.
* Recognise and use equivalence between simple fractions and mixed numbers.
* e.g. [[File:201a.png|500px|thumb|center]]
* Calculate a fraction of a quantity.
* e.g. [[File:201c.png|500px|thumb|center]]
* Convert between fractions, decimals and percentages.
* e.g. [[File:203a.png|500px|thumb|center]]
* Calculate a percentage of a quantity, and express one quantity as a percentage of another.
* Express percentage change as a decimal or fractional multiplier. Apply this to percentage change problems (including original value problems).
* e.g. [[File:203c.png|500px|thumb|center]]
* Find the ratio of quantities in the form a : b and simplify. Find the ratio of quantities in the form 1 : n.
* e.g. [[File:501a.png|500px|thumb|center]]
* Split a quantity into two parts given the ratio of the parts. Express the division of a quantity into two parts as a ratio. Calculate one quantity from another, given the ratio of the two quantities.
* e.g. [[File:501b.png|500px|thumb|center]]
* Interpret a ratio of two parts as a fraction of a whole.
* e.g. [[File:501c.png|500px|thumb|center]]
* Solve simple ratio and proportion problems. e.g. Adapt a recipe for 6 for 4 people.
* Compare lengths, areas and volumes using ratio notation and scale factors. Understand the relationship between lengths, areas and volumes of similar shapes.
* e.g. [[File:904c.png|500px|thumb|center]]

==M3 - Calculation of surface areas and/or volumes==

* Determining quantities of materials by surface area.
* Calculate the overall surface area of different shapes, such as, cuboids, cylinders and spheres to determine quantities of material and feasibility analysis.
* Calculate the volume of different shapes, such as, cuboids, cylinders and spheres to determine suitability of objects and products.
* Recognise and know the properties of the cube, cuboid, prism, cylinder, pyramid, cone and sphere.
* Calculate the surface area and volume of cuboids and other right prisms (including cylinders).
* Calculate the surface area and volume of spheres, cones and simple composite solids **(formulae will be given)**.
* Calculate the surface area and volume of a pyramid (the formula area of base × height will be given).

==M4 - Use of trigonometry==

* Calculate the sides and angles of objects to determine structural integrity, marking out and direction of movement.
* Determining projectile motion and direction of movement.
* Determining how to resolve force vectors using F(x) = F cosi and F(y) = F sinθ.
* Know the basic properties of the square, rectangle, parallelogram, trapezium, kite and rhombus. Use these facts to find lengths and angles in rectilinear figures and in simple proofs. Use these facts in more formal proofs of geometrical results.
* Know, derive and apply Pythagoras’ theorem to find lengths in right-angled triangles in 2D figures. Apply Pythagoras’ theorem in more complex figures, including 3D figures.
* e.g. [[File:1005a.png|500px|thumb|center]]
* Know and apply the trigonometric ratios, sinθ, cosθ and tanθ and apply them to find angles and lengths in right-angled triangles in 2D figures. Apply the trigonometry of right-angled triangles in more complex figures, including 3D figures.
* Know the exact values of sinθ and cosθ for θ = 0°, 30°, 45°, 60° and 90°. Know the exact value of tanθ for θ = 0°, 30°, 45° and 60°.
* Know and apply the sine rule to find lengths and angles.
* Know and apply the cosine rule to find lengths and angles.
* e.g. [[File:1005d.png|500px|thumb|center]]

==M5 - Constuction, use and/or analysis of graphs and charts==

* Representation of data used to inform design decisions and evaluation of outcomes.
* Presentation of market data, user preferences, outcomes of market research as part of product design, fashion and textiles.
* Interpret and extract appropriate data.
* Work with x- and y- coordinates in all four quadrants.
* e.g. [[File:701a.png|500px|thumb|center]]
* Construct and interpret graphs in real-world contexts. Recognise and interpret graphs that illustrate direct and inverse proportion.
* Interpret and construct charts appropriate to the data type, including frequency tables, bar charts, pie charts and pictograms for categorical data, vertical line charts for ungrouped discrete numerical data. Interpret multiple and composite bar charts. Design tables to classify data. Interpret and construct line graphs for time series data, and identify trends (e.g. seasonal variations).
* Interpret and construct diagrams for grouped data as appropriate, i.e. cumulative frequency graphs and histograms (with either equal or unequal class intervals).
* Calculate the mean, mode, median and range for ungrouped data.
* Find the modal class, and calculate estimates of the range, mean and median for grouped data, and understand why they are estimates.
* Describe a population using statistics.
* Make simple comparisons.
* Compare data sets using ‘like for like’ summary values.
* Understand the advantages and disadvantages of summary values.
* Calculate estimates of mean, median, mode, range, quartiles and interquartile range from graphical representation of grouped data.
* Draw and interpret box plots.
* Use the median and interquartile range to compare distributions.
* Plot and interpret scatter diagrams for bivariate data.
* Recognise correlation.
* Interpret correlation within the context of the variables and appreciate the distinction between correlation and causation.
* Draw a line of best fit by eye, and use it to make predictions.
* Interpolate and extrapolate from data, and be aware of the limitations of these techniques.
* Identify an outlier in simple cases.
* Appreciate there may be errors in data from values (outliers) that do not ‘fit’.
* Recognise outliers on a scatter graph.
* Calculate or estimate gradients of graphs, and interpret in contexts such as distance-time graphs, velocity-time graphs and financial graphs.
* Apply the concepts of average and instantaneous rate of change (gradients of chords or tangents) in numerical, algebraic and graphical contexts.
* Calculate or estimate areas under graphs, and interpret in contexts such as distance-time graphs, velocity-time graphs and financial graphs.
* Present and interpret velocity/time graphs, stress-strain and resistance-temperature graphs.
* Representation of frequency, period, amplitude and phase.

==M6 - Use of coordinates and geometry==

* Use of datum points and geometry when setting out design drawings, when setting out patterns and within engineering drawings.
* Present accurate 2D and 3D graphics to communicate design solutions.
* Use x- and y-coordinates in plane geometry problems, including transformations of simple shapes.
* Interpret plans and elevations of simple 3D solids.
* Construct plans and elevations of simple 3D solids and representations (e.g. using isometric paper) of solids from plans and elevations.
* Understand addition, subtraction and scalar multiplication of vectors.
* Use vectors in geometric arguments and proofs.
* Construct and interpret scale drawings.

==M7 - Use of statistics and probability as a measure of likelihood==

* Interpret statistical analyses to determine user needs and preferences.
* Use data related to human scale and proportion to determine product scale and dimensions and sizes and dimensions of fashion products.
* Understanding of dimensional variations in mass produced components.
* Defects in batches and reliability linked to probabilities.
* Use the 0–1 probability scale as a measure of likelihood of random events, for example, ‘impossible’ with 0, ‘evens’ with 0.5, ‘certain’ with 1.
* Record, describe and analyse the relative frequency of outcomes of repeated experiments using tables and frequency trees.
* Use relative frequency as an estimate of probability.
* Understand that relative frequencies approach the theoretical probability as the number of trials increases.
* Use the addition law for mutually exclusive events.
* Use p(A) + p(not A) = 1.
* Derive or informally understand and apply the formula.
* p(A or B) = p(A) + p(B) - p(A and B)
* Use tree diagrams and other representations to calculate the probability of independent and dependent combined events.
* Understand the concept of conditional probability, and calculate it from first principles in known contexts. Derive or informally understand and apply the formula p(A and B) = p(A given B)p(B).
* Know that events A and B are independent if and only if p(A given B) = p(A).

==Example questions==

*[https://sixthform.bourne-grammar.lincs.sch.uk/images/2/27/Maths_1_Trig_and_Triangles.pdf Trigonometry and Triangles]

[[Design_Engineering|Design Engineering homepage]]

2023-05-24T08:28:35Z

Stcd11:

Identifying Requirements

2023-03-21T16:09:46Z

Stcd11: Spelling error fixed

==Exploring Contexts==
#Before starting the course, you will come across many new words and technical terms.
#[https://www.electricalschool.org Electrical School] have created, and are continuing to develop, a glossary of electrical terms.
#What can be learnt by exploring contexts that design solutions are intended for?
##Understand that all design practice is context dependent and that investigations are required to identify what makes a context distinct in relation to:
###environment and surroundings
###user requirements
###economic and market considerations
###product opportunities

==Environment and surroundings==
#Environment and surroundings Products are designed for use in different environments
#A robot that welds car body panels together will be used exclusively in a factory.
#A photocopier might be designed for use in a School or office.
#A plug-in air freshener would be typically used in the home.
#When engineers and designers work to create new items, the context for where it is to be used will heavily influence the form of the finished product. A product that is to be used in an industrial environment (like a labelling machine) will be designed solely to perform the task it exists to do, in a safe way. If it has a human operator, any interface (e.g. display, buttons, etc) are large, clear and is intuitive to use as far as possible. Durability will heavily influence the design, as the product may be mission-critical and could cause production to slow or halt in the event of its failure. Industrial products will likely be engineered to make replacing defective parts as convenient as possible (e.g. through the addition of removable access panels).
#A product for an office must be designed to both serve its purpose, but to also give a look and feel in keeping with a professional environment. A common colour scheme is grey and silver, objects often have an ‘industrial’ look and ergonomics should be carefully considered to ensure that products are comfortable to use for extended periods. Microsoft produce an ergonomic keyboard, for example.
#Products designed for a home environment will commonly be more heavily influenced by the cosmetic finish of the product. For luxury goods, the materials used to finish the product will be of a higher quality, and may include varnished wood and premium plastics (like those seen in coffee machines). As young children are often present in home settings, safety considerations must include making sure that small fingers can’t make their way into areas that cause harm (e.g. think about how plug sockets are designed).
#For all products, safety must be the prime consideration, ensuring that there are no sharp edges, exposed wires or moving parts that could trap a body-part and cause injury.

==User Requirements==
#When a client approaches an engineering team to solve a problem, they will have a list of specific requirements which will need to be satisfied. This list is developed with the engineering team and is called a Design Specification. This may cover areas such as: Aesthetics, size, weight, materials, cost, durability, functionality (i.e. what it actually does), performance (how fast/accurately it does it) and power (e.g. batteries, solar, generator and mains AC).
#Once the product prototype has been built, the engineering team can test the product against the specification to demonstrate that they have designed a product or system which does exactly what the client asked for.

==Economic and Market Considerations==
#All clients have a budget. At the outset of a new project, they will advise on what their development budget (how much they want to spend on manpower + prototypes to develop a mass-producible product) is, and will indicate the budget for building the actual new product (e.g. Should cost no more than £3 to manufacture per unit).
#The market that the product is to be aimed at will influence this heavily; a water purification unit for refugees in a third-world country would need to be built as cheaply as possible (to maximise the number of people who can have one), while ensuring that the product works consistently and safely. Any unnecessary flourishes (e.g. branding, nice-to-have features like an LED indicator) would need to be stripped away to the bare minimum amount of hardware to produce the desired result.
#The market for a new top-spec iPhone would be very different, and to ensure that the client feels they’re receiving value for money, the quality of the product would need to be of the highest standard available in order to justify the price tag that such an item could be expected to command.

==Product Opportunities==
#Events happen around the World daily. These can often represent opportunities for entrepreneurs. Some are short-term (e.g. fidget spinners becoming cool) and others may be longer-term (e.g. combating global warming), necessitating new products to solve new problems. By looking for trends and following global events, designers and engineers can identify new, unsolved problems and create successful products to tackle them.

==1.2 Stakeholders Analysis==
#What can be learnt by undertaking stakeholder analysis?
#Demonstrate an understanding of methods used for investigating stakeholder requirements, such as:
##user-centred design and stakeholder analysis
##SWOT analysis
##focus groups
##qualitative observations
##market research to identify gaps for new products or opportunities to update existing products.

===User Centred Stakeholder Analysis===
#When a new product is to be designed and built, in order for it to be successful, the target audience must be carefully considered. The different people/groups involved in a product are called stakeholders. In a School, stakeholders include students, teachers, support staff and governors.
#For a piece of industrial manufacturing equipment like a robot that places toppings on frozen pizzas in a factory, stakeholders can include managers, machine operatives, maintenance engineers and system programmers. Each of these people will have particular wants in terms of what the machine might do.
#The manager will likely want the robot to keep track of how many pizzas it tops each day, how much product falls off the pizza onto the floor (waste), how often it breaks down (costing the company money).
#The maintenance engineers will want to ensure that all the main parts can be removed in as short a time as possible, that they’re easy to reach and that the reliability of the machine is such that it seldom breaks down.
#The operative (where one is required) will want a machine which requires minimal human input to work, is comfortable to use, reduces the amount of repeated body movement to operate and is safe to use.
#Practice task: Make a stakeholder list for a new vacuum cleaner and suggest some stakeholder priorities that they might raise.

[[File:SWOT_analysis.png|400px|thumb|center|SWOT Analysis]]

#A SWOT analysis (Strengths, Weaknesses, Opportunities and Threats) is a process developed in the 60’s by which as many considerations as possible are recorded under each of the SWOT headings. For a new smartphone, one might identify:
##Strength: The new design is ultra light-weight.
##Weakness: The software is the same as available on every other Android phone
##Opportunities: Has a unique new chip that can be marketed to unlock users doors at homes
##Threats: There are many other phone manufacturers who could release this feature first.
#You can read a little more about it here. LINK HERE

==Focus Groups==
#Focus groups are meetings in which the engineering team meet with different stakeholders to discuss the new product. They may produce a SWOT analysis collaboratively as part of this.
#Qualitative Observation. The process of design engineers watching a pre-existing system operating in a live environment (e.g. a factory in which frozen pizzas are manually topped). By watching the process, engineers can fully understand the steps in the existing system and consider different solutions to improve the current system.
#Market Research. The process of looking online (or through product catalogues) at other ways in which the problem can be solved using products designed by other companies. Unless it can be made more cheaply, there is little point in releasing a product which another supplier is already selling. Equally, if an existing product has reviews stating that it lacks a particular feature, the opportunity to release a rival product to compete with it might arise.
#Developing New Product Ideas.

==Enterprise==
#In the design context, the term 'enterprise' relates strongly to innovation. It captures brave and courageous decision-making, initiative, resourcefulness, making the most of opportunities to earn money, create or support new businesses to make a profit.

#Demonstrate an understanding of how enterprise can help drive the development of new product ideas through routes to innovation such as:
#In order to develop, release and market a new product, substantial initial financial capital will be required.

===Entrepreneur===
#Entrepreneurship has traditionally been defined as the process of designing, launching and running a new business, such as a start-up company, often offering a product or service. Entrepreneurs are the people behind such initiatives or start-ups.
#An entrepreneur who has a high level of self-belief in her product will need funding. They might elect to borrow their start-up capital from a bank in the form of a large loan. As the bank will be taking a considerable risk (i.e. if your product doesn’t take off, they’ll lose their money), they would typically expect that you would demonstrate your commitment by sharing the risk. This usually comes by you putting up your own money (if you have enough) or your home against the loan, so that if your business fails, your house can be sold to allow the bank to recover their money. The advantage of this approach is that if you are able to launch a new product, you’ll be able to enjoy all the profits after you’ve paid back your debt. The disadvantage of this is that should your idea not be a success, you risk losing your home and any other assets you may have.
#Entrepreneurs will take the risk in hope for profit with the sector. The entrepreneur may already have businesses in other areas similar to the area they are interested in breaking into.

===Commercial Partnerships===
#This could be a partnership with another person or company, to use their skills or expertise in the field. Doing so means sharing the risk with them and reducing the risk by using someone who has been in that field before.
#E.g. Apple teamed up with Nike to produce a version of the [https://www.apple.com/uk/apple-watch-nike/ Apple watch] targeted at runners.
#Read more: https://en.wikipedia.org/wiki/Business_incubator

===Venture Capitalists (VCs)===
#A [https://en.wikipedia.org/wiki/Venture_capital VC] is similar to a start-up incubator.
#Some engineers might seek funding this way (similar to the TV show, Dragons’ Den). By ‘pitching’ your idea and presenting your business plan to a panel of experienced investors, you may be able to negotiate to obtain the funding you need in exchange for a (often considerable) percentage of your profits if/when your product takes off. Incubators are often able to supply experienced business people to offer advice as well as providing office space for start-ups.
#Using a venture capitalist to secure funding will remove some of the risk to the person wanting to start this new venture.
#In exchange for providing funding, the VC will own a percentage of the company.

===Crowd Funding Websites===
#Made popular through sites such as [https://www.Kickstarter.com Kickstarter.com]. Crowd funding works by the engineer creating a web page outlining the details of the product they intend to design and create.
#Investors to pay for different ‘rewards’, typically at considerably lower prices than the retail price of the product once launched to the general public.
#If the designer is able to reach a certain level of funding, the website transfers them the money pledged by the individual investors and they are then able to create and launch their product. If they don’t reach the intended funding level, the investors’ money is returned. This has the advantage of not requiring any up-front investment by the engineer and doesn’t expose the investor to as much risk. The disadvantage is that one may not reach their funding target, and that the inventor may not actually be able to deliver the product they’ve promised with the funding they raise if their calculations are incorrect.
#A risk-free way of getting funding for a project.
#Funding is usually given by people with similar interests as that of the project, thus creating a market when the project comes up for sale

===Exam style questions===
#Explain what is meant by ‘enterprise’ in the context of designing.
#Possible responses may include:
##A bold venture capturing innovation/courageous or bold decision making/initiative and resourcefulness (1).
#Plus one of the following...
##Making the most of an opportunity to earn money (1).
##Creating a new business (1).
##New and energetic undertakings (1).
##Breaking new ground (1).

#Describe two ways in which enterprise can help drive the development of new product ideas.
#Possible responses may include:
##Entrepreneurship (1) – the process of launching a new business, taking a financial risk in the hope of a good return (1).
##Ability to recover from setbacks (1), learning lessons along the way (1).
##Commercial partnerships (1), recognising the benefits of forging partnerships with others (1).
##Sharing ideas amongst other experts (1) to gain access to global technology (1).
##Venture capitalists – stakeholders who invest money into entrepreneurial companies (1) who then have a strong interest in the company’s success (1).
##Crowd funding – asking a large amount of people for a small amount of money (1), who may or may not then own a share in the company (1).

==Designing Prototypes==
How can usability be considered when designing prototypes?
==1.3a Learners should be able to analyse and evaluate factors that may need consideration in relation to the user interaction of a design solution, including:==
#the impact of a solution on a user’s lifestyle
#the ease of use and inclusivity of products
#ergonomic considerations and anthropometric data to support ease of use
#aesthetic considerations.
#Usability is the extent to which something is fit for purpose. By producing a new version of a kitchen knife which has a more comfortable grip, users would be able to use it to prepare food for longer before their hands tire. This can be considered from a number of stand-points.

==1.3ai Users lifestyles==
An obvious objective of a product designed for a homeowner should be to provide a positive impact. This may be:

To reduce the time spent on a domestic task to increase leisure time. The invention of washing machines freed up time that would be spent hand-washing.
To provide a financial saving. An LED lightbulb will save money spent on electricity.
To reduce the effort required to achieve a desired outcome. Remote controls for applicances like TVs remove the need to walk over to the set in order to change channel.
To enable a disabled user to function more independently. Speaking clocks allow blind or partially sighted users to tell the time.
To improve the environment of the home. Scented candles look attractive, and when lit release a pleasing fragrance.
To improve security. High-spec burglar alarms call homeowners when they are triggered, notifying them of a problem.

==1.3aii Ease of use and inclusivity==

Ease of use refers to how straightforward a product is for a user to learn to operate. Industry professionals often cite that aside from its cosmetic appearance, the Apple iPhone has been a runaway success largely because of how intuitive it is to use. Some systems (e.g. specialised industrial equipment) may be more complex by necessity, but the use of labels on control buttons, information engraved into panels and good-quality documentation, the ease of use can be increased.

Inclusivity is about designing a product in such a way that people of all shapes, sizes and those with disabilities are able to use the product. Using the iPhone again as an example, Apple have invested extensively in providing a user interface that speaks to users as they run their fingers around the screen. As a result, blind users can make calls, send messages and take advantage of many features through these adaptations. In many new homes, light-switches are installed lower down, allowing a wheelchair user to reach them. High-rise buildings have lifts installed, so that people with reduced mobility can access the upper floors.

==1.3aiiiErgonomics and Anthropmetrics==
Ergonomics is the study of people’s efficiency in their working environment. Many products are marketed as being ‘ergonomically designed’. An ergonomic computer mouse will more naturally fit around a human hand; an ergonomic chair will have support for the lower back, and lots of options to adjust the height/tilt of different parts to make it more comfortable to sit in for extended periods.

To design a product with ergonomics in mind, anthropometric data is used. This comes in the form of tables that can show figures on ‘typical’ human characteristics, like the height of US men over 20 year old. Data can also be obtained on grip strength in people’s hands, the mean average length of different body parts, range of movement of a head, etc. This can be useful for all manner of things, such as establishing how tightly a Coke bottle’s screw-top lid can be done up to minimize the loss of CO2 while ensuring that most children can open them without assistance.

==1.3aiv Aesthetic Considerations==

This was touched on previously, but for a domestic or office product, if the item is physically attractive and stylistically in-keeping with current trends, a premium price can be charged. A good example of this is an electric kettle; these consist of a heating element, a temperature sensor and a switch. While incremental improvements have appeared such as better heating elements, the circuit inside is largely unchanged since the original 1891 design. Nonetheless, consumers have the ability to spend £6 on a kettle, or over £200. Both achieve the same outcome and share the same fundamental parts, but they look cosmetically different. It is worth remembering that while the profit margin is considerably greater for a ‘designer’ kettle, far fewer are sold. It is entirely possible that the manufacturer selling vastly greater number of their product for a lower profit would actually operate a more profitable overall business – this principal can be seen when comparing supermarkets like Aldi and Waitrose.

==1.3bi Anthropometric data to help define design parameters==

Anthropometric Data Explained. Of course not all people are the same size. There will be huge differences between the heights, weights, and other dimensions due to: gender, age, diet, growth rate, genetic make up and other factors. Therefore the Anthropometric data needs to be organised in a specific way.

Anthropometric data to help the design parameters associated with the human body.
[[File:anthropo_data.jpg|500px|thumb|center]]
The table above could be used when designing a grip for a power tool, or when designing a keyboard.
It is important to know the dimensions of a hand.

==1.3bii User comfort, control layout and software user-interface==
#The user experience is the core of the design process.
#Designers should put themselves in the shoe of the end consumer in order to achieve empathic design.
#In order to achieve success in the highly competitive market, the innovation should walk side by side with the deep understanding of the consumer interaction with both the physical and digital aspects of the products.
#This understanding should be achieved through the understanding of the user ergonomics and apply the principles of ergonomics in the design process.
#Ergonomics refer to designing products, services, systems and processes with social interaction in mind.
#The principles of ergonomics ensures that the design complement the consumer ability strengths for and strives to minimize the effort and limitations while using the product rather than forcing them to adapt.
#Ergonomics is widely implemented in different industries effecting the creative sector. Many designers believe ergonomics is only considered in product design. However, designers in different fields such as graphic and interactive design are required to consider ergonomics in their design projects. For example, the interactive designers should consider the user experience research as an essential stage in designing mobile applications, websites, and user interfaces.
#Principles of Ergonomics - In order to consider the ergonomics involved in different design projects, universal principles of ergonomics can be applied. While the principles below may not be applicable in some projects, the concepts can be adapted to both physical and digital projects.
##Neutral postures - The neutral posture refers to the human body aligned and balanced. The standard and balanced posture reduces the stress applied on muscles, tendons, nerves, and bones. The unbalanced posture for the human body is known as an “awkward posture”.
##Reduce Excessive force - The design for heavy products should consider reducing the excessive force needed or used to pull, push, or carry the product. Alternative solutions should be adapted to reduce the use of force such as using wheels to these products.
##Keep Things Easy to Reach - This principle is widely applied in both the physical and digital domains. The interaction with a specific product should be made easy. Consumers should reach the product easily and interact with it. For example, the control panel for dish washers should be reachable with the minimum amount of effort and time. In digital designs such as website and mobile application, users should be able to reach functions and navigation links easily through the usable implementation of the layout.
##Work in Power or Comfort Zone - The power zone refers to the zone where interacting with objects has the least amount of effort spent, it is also known as “hand shake zone”. It is the area between mi-thigh and mid-chest height. If the product is designed to be held, the designer should consider this position as the standard.
##Reduce Excessive motion - This principle aims to reduce the amount of motion spent while dealing with the design. The motion refers to any movement applied using the figures, wrist, or other parts of the body. One of the examples of applying this principle is the usage of screwdriver. The electric screwdriver is designed to reduce hand motion during usage.
##Reduce Static Load - Static load refers to the position where the person stays in the same position or holds something for a long time. This load create discomfort fatigue. If the product requires the consumer to stand still for a long time such as holding a specific tool, a fixture solution needs to be applied in order to eliminate the need to hold the object.
##Minimise Pressure Points - The pressure point refers to the point where the object is in contact with the consumer body during the usage of the product. For example, high chairs makes a pressure point between the user legs and table or desk. Therefore, designing the chair should allow users to modify the height and subsequently it can be used with any table height.
##Provide Clearance - The design for products and interior should provide a space for the user to move freely and avoid bumping into any of the objects. The same concept is applied in the digital domain. Placing the functions and elements in the website design or mobile application device should allow the user to move between the function smoothly and avoid any confusion such as clicking on wrong buttons.
##Enable Movement and Stretching - The product design should consider the user needs to move, exercise, and stretch. For example, seat design includes options to adjust the setting style. Tables that forces one to stand up or be in in one place may be modified in some places to avoid the a long setting time.
##Reduce Excessive Vibration - Vibration has a serious impact on consumer health. Contacting vibrating tools may cause hand-arm vibration syndrome (HAVS). Therefore, designing products that use motors or vibrate while holding should consider this principle. For example, the motor part can be separated from the tool itself and connected to it using a cord instead. This reduces the vibration on the tool.
##Provide Good Lighting Conditions - The overall work environment should be comfortable and allow users or designers to have good lighting, fresh air, and enough space. In offices where computer screens are installed, the design of the light systems should avoid reflections caused by the polished computer screens.

===Practice questions/Recap===
#Apart from the bridge crew (i.e. Captain and first officer), name two different stakeholder groups that might be identified when designing a new cruise ship.
#The design team are drafting specification points for different stakeholders. One point the bridge crew have identified is that it must be possible to reliably communicate with the different teams on the ship at all times. For each of the two stakeholder groups you identified above, describe one specification point they might suggest when designing the new ship.
#Describe the term, ‘focus group’.
#Mary has recently finished her A-levels and has designed a mobile phone charger with an integrated radio and torch. She wants to release it as a commercial product, but has never launched a product. Suggest a funding mechanism she could use, and justify your choice.
#A stationary company wants to create a pencil dispenser that can be put into school classrooms to allow students who have forgotten their pencil to take a replacement.
##The company want to set up a focus group.
##Identify a stakeholder group that might be invited.
##Suggest 3 user requirements that might be proposed in an initial meeting with the client, and justify your answers.

[[Design_Engineering|Design Engineering homepage]]

Materials and component considerations

2023-03-21T16:09:08Z

Stcd11: changed names on images

==5.1 Factors that influence the selection of materials that are used in engineered products==
===Specification===
#Understand that the selection of materials and components is influenced by a range of factors, including:
##functional performance
##aesthetics
##cost and availability
##properties and characteristics
##environmental considerations
##social, cultural and ethical factors

===Why should I know about material properties?===
#It is important to understand material properties and characteristics when designing a product or component for several reasons:
##A materials properties/characteristics make it suitable for a given application for example, using aluminium alloy in a car frame because it’s a tough and light material.
##If you chose the wrong material for a component you may increase the cost of the overall product. E.g. Using titanium for a car frame.
##If you chose the wrong material for a component you could also increase the probability of that component failing when the product is in use. Making a metal vice out of mild steel would be an example of this as mild steel is not a hard or strong enough material for this operation.
##A person’s safety could also be an issue for example, if the wrong material was used for a saucepan handle someone could burn themselves if the chosen material is a good thermal conductor.
##A products shelf life could also be affected if the wrong materials were used for example, using plastic for garden chairs instead of wood will increase the life of the garden chairs as plastic is waterproof whereas wood requires constant treatment to maintain it.

===Considerations===
#As an engineer or designer plans a new product or project, the question of what to make it from needs to be carefully considered.
#In terms of electronic components, functional performance might refer to how much current a resistor can handle or how quickly a transistor can turn on and off.
#With materials, functional performance might refer to how much compressive force a particular concrete can withstand before rupturing, the ductility of a metal or how hard-wearing a particular grade of steel is when designing gears.
#Aesthetics concerns how a product looks. Not all clients will value this; someone wanting a robot arm for moving car chassis about a factory would want all design effort to be put into making the arm work as quickly, reliably, safely and cost-effectively as possible.
#A company designing bottles for high-end perfumes would put *aesthetics* high on their list of considerations. Does the material allow the perfume to be clearly seen? Is the density of the glass sufficiently high to give a good tactile experience? Does it need a dye in the glass to further enhance it?
#Cost and availability (availability will dictate cost) will always heavily influence selection; a low-budget electronic mousetrap for first-time homebuyers would see the designers aim to economise in every area. Could a 555 timer be used in place of a PIC? How thin can the walls of the housing be? Could it be a little smaller?
#Properties and characteristics in the context of components can refer to what their specific capabilities are. The 4000 series logic ICs offer a range of chips, each of which performs a specific job (E.g. Decade counter, 7-segment display driver, AND gates). These components can also have quirks (e.g being especially sensitive to electrostatic discharge and needing special handling.
#Every material will have its own unique properties; you can research different woods, manufactured boards, plastics and metals, but a few examples are:
##Copper and its alloys (e.g. Brass) have anti-microbial effects and are able to kill bateria effectively within a few hours
##Stainless steel will rust less quickly than other grades of steel
##Nylon is often selected to make small gears with as it is self-lubricating
##Balsa is the least dense hardwood, and so is commonly selected for making light-weight models
##Because its made with sawdust and urea formaldehyde, MDF is usually very flat and consistent throughout the material (wood will have a grain and 'knots' in it, making it harder to cut)

==5.2 Materials and components that should be selected when designing and manufacturing products and prototypes==
#A systems engineer needs to know something about all aspects of Technology in order to produce the best work. One aspect of this is knowing what’s available when selecting materials to fabricate products with. For both the exam and your coursework, you will require a general understanding of the following groupings of materials. Links to external sites have been included throughout;

Below are materials selection charts which provide comparative data on materials and their properties in an easy to use format.
[[File:youngs_vs_density.jpg|600px|thumb|center|Young's modulus vs density comparison]]
[[File:strength_vs_cost.jpg|600px|thumb|center|strength vs cost comparison]]

it is strongly recommended that you read up on examples.

===Woods===
#Wood has been used since pre-historic times to provide fuel for heat, and as a building material to produce homes and tools. We divide woods into three categories.
#[http://en.wikipedia.org/wiki/Hardwood Hardwoods] come from broad-leaved, deciduous trees. The main hardwood timbers are ash, beech, birch, cherry, elm, mahogany, oak, balsa and teak.
##Ash is light, creamy-brown in colour and both tough and flexible. It is often used to make sports equipment, wooden ladders and tool handles.
##Beech is white to pinkish-brown in colour, close-grained, hard, tough, strong, but warps easily. Commonly found in furniture, toys and tool handles.
##Elm is light to medium brown in colour, tough, resists splitting, and is durable in water. Elm is commonly used for indoor and outdoor furniture.
##Mahogany is Pink to reddish-brown colour, fairly strong, durable and used for good quality furniture.
##Oak is light brown colour, strong, hard, and tough. It corrodes steel screws and fittings. It is used for interior woodwork and good quality furniture.
##Balsa is creamy/light brown in colour, which is extremely fast growing and very lightweight. While low in density, it is high in strength and is commonly used for light, stiff structures, such as model aircraft and model buildings.
#[http://en.wikipedia.org/wiki/Softwood Softwoods] are from fast-growing coniferous trees which are evergreen, needle-leaved, cone-bearing trees, such as cedar, fir and pine.
#Tip: Hardwood and Softwood do not refer to the properties of the wood: some softwoods can be hard and some hardwoods can be soft.

===Manmade Boards===
#[http://en.wikipedia.org/wiki/Engineered_wood Manmade boards] are created from other woods, to give specific properties (and are usually relatively cheap compared to hard and softwoods).
##Blockboard is built up with a core of softwood strips bonded together with adhesive and covered with a sheet of plywood on either side. Used as a building material and for furniture manufacture including fitted kitchens / bedrooms.
##[http://en.wikipedia.org/wiki/Particle_board Chipboard] is made up of small chips of wood bonded together with resin and formed into sheets by compression. It is not as strong as plywood and block board but it is not expensive. Chipboard is often covered with a plastic laminate or wood veneer and used in furniture. Chipboard could contain partials of metal, grit and any other rubbish that gets taken up into a tree whilst growing, is also the most unstable board because of air pockets, will swell up to twice its thickness when damp.
#Hardboard is made from wood fibres that have been pulped. The pulp is put under pressure until the fibres bond to produce a tough board that is smooth on one side and rough on the other. It is not as strong as the other boards. When supplied, it is smooth one side and rough the other, because of the drying process and is flexible, generally buckles at the first sign of dampness in the air, used mainly for backs of cupboards.
##[http://en.wikipedia.org/wiki/Medium-density_fibreboard MDF] (Medium Density Fibreboard) is quality board, which is relatively cheap. This board is composed of fine wood dust and resin pressed into a board. MDF is the most stable manmade board, and can have a ply or laminate finish added to it to make its finish more aesthetically pleasing. Low Density and High density re also available, as it water resistant MDF (which is usually green in colour). MDF can be worked, shaped and machined easily. Paint can be applied to it without the need for an undercoat or primer. Used in the building and furniture trades, as well as in schools.
##[http://en.wikipedia.org/wiki/Plywood Plywood] is made from veneers (thin plies) of timber with each grain layer being at right angles to each other and bonded together by resin and pressure. A number of grades are available, designed to suit a variety of situations, such as Marine plywood that is moisture resistant (although it will still warp) or weatherproof plywood. Ply is the only board that uses layers of pure wood. If the grains are laid parallel with each other it becomes flexible along the grain; if laid at right angles it becomes more rigid.
#All boards come in standard thicknesses of 3, 6, 9, 12, 15, 18 & 25mm.

===Metals===
#[https://en.wikipedia.org/wiki/Ferrous Ferrous metals] are those that contain [http://en.wikipedia.org/wiki/Iron iron]. Steel, for example. All ferrous metals will rust over time, due to their iron content. All metals change their properties, dependent on how they are heated and cooled.
#[http://en.wikipedia.org/wiki/Non-ferrous_metal Non-ferrous metals] are those which do not contain iron, such as brass.
##A good conductor of electricity and heat, [http://en.wikipedia.org/wiki/Aluminium aluminum] is a light-weight metal, used in aircraft construction, for power cables, drinks cans and in cookware.
##[http://en.wikipedia.org/wiki/Titanium Titanium] is a very strong metal, used in making the strongest and lightest parts of modern fighter jet planes, as well as in high-performance sports equipment, medical implants and jewelry. It does not corrode, and has good resistance to sea water and chlorine.

===Metals Alloys===
#[http://en.wikipedia.org/wiki/Brass Brass]. Made since biblical times from copper and zinc, brass is used in low-friction applications (e.g. gears and locks), and has a golden colour. It is also used in musical instruments as it has pleasant acoustic properties.
#[http://en.wikipedia.org/wiki/Bronze Bronze]. Made from copper and tin, this was the first alloy to be discovered. Bronze is used when it is desirable for parts to be able to last a long time, and not be corroded by air or water.
#[https://en.wikipedia.org/wiki/Tungsten Tungsten]. In its raw form, tungsten is a hard steel-grey metal that is often brittle and hard to work. If made very pure, tungsten retains its hardness (which exceeds that of many steels), and becomes malleable enough that it can be worked easily.
#[https://en.wikipedia.org/wiki/Steel Steel] is an alloy of iron and carbon and other elements. Because of its high tensile strength and low cost, it is a major component used in buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons.
#Different [http://en.wikipedia.org/wiki/Steel steels] are made by adding carbon to iron (0.02%-1.7% carbon). Steel is harder and stronger than iron alone; adding additional carbon results in harder and stronger steel, at the expense of it becoming increasingly brittle. It is used for car bodies, bridge construction, buildings and tools.
#Stainless steel is made with the addition of around 11% chromium, which adds an increased resistance to staining and rusting compared to regular steel. It is used for surgical instruments, sinks and cutlery.

===Plastics===
#Polymers (and the discovery of plastics) revolutionized the 20th century, giving rise to the mass production of strong, cheaply produced products for the masses. The environmental cost was only considered in the latter half of the 20th century, when the impact of oil-based products which took hundreds of years to break down in landfill sites started to be realized.
#A [http://en.wikipedia.org/wiki/Thermoplastic thermoplastic] is one that becomes soft when heated and hard when cooled.
#[http://en.wikipedia.org/wiki/Acrylonitrile_butadiene_styrene ABS] (Acrylonitrile butadiene styrene) is highly impact resistant and tough. Commonly used for musical instruments, golf clubs, car trim components, car bumpers, medical devices for blood access, protective headgear, whitewater canoes and Lego bricks.
#[http://en.wikipedia.org/wiki/Poly(methyl_methacrylate) Acrylic] (Polymethyl methacrylate) is stiff, hard (but scratches easily), durable, brittle in small sections, a good electrical insulator, which machines and polishes well. It is used for many applications, such as making signs, covers of storage boxes, aircraft canopies and windows, covers for car lights, wash basins and baths.
#[http://en.wikipedia.org/wiki/Nylon Nylon] (Polyamide) is creamy in colour, tough, fairly hard, resists wear, self-lubricating and has good resistance to chemicals. Commonly used to produce bearings, gear wheels, casings for power tools, hinges for small cupboards, curtain rail fittings and clothing.
#[http://en.wikipedia.org/wiki/Polystyrene#Copolymers HIPS] (High Impact Polystyrene) is economical and impact-resistant plastic that is easy to machine and fabricate. Used for low strength structural applications when impact resistance, machinability, and low cost are required. It is frequently used machining pre-production prototypes since it has excellent dimensional stability and is easy to fabricate, paint, and glue.
#A [http://en.wikipedia.org/wiki/Thermosetting_polymer thermosetting plastic] (also known in industry as thermoset) is a plastic which irreversibly cures. They typically start off in a liquid form (so they can be molded into shape), and are then cured by a process such as heat, chemical reaction or irradiation to set them.
#[http://en.wikipedia.org/wiki/Urea-formaldehyde Urea formaldehyde] provides high tensile strength, good surface hardness and heat resistance as well as being a good electrical insulator. It is used for electrical fittings, handles and control knobs and to make adhesives. Its is also used as the bonding agent in.
#[http://en.wikipedia.org/wiki/Melamine_resin Melamine formaldehyde] is stiff, hard, strong and resists some chemicals and stains. It is commonly used in laminates for work surfaces, electrical insulation and tableware.
#[http://en.wikipedia.org/wiki/Epoxy Epoxy resin] is a good electrical insulator, which is hard, brittle unless reinforced and resists chemicals well. It is used mainly for casting and encapsulation, adhesives and for the bonding of other materials.
#Polyester resin works as an adhesive (less strong than epoxy) and is commonly used for boat hull repairs (when combined with fibreglass cloth) and can be used for casting. It has a strong, unpleasant smell, which many find off-putting.
#[https://en.wikipedia.org/wiki/Polyimide Polyimides] are strong synthetic polymers that are also astoundingly heat and chemical resistant. Their properties are so great that these materials often replace glass and steel in many demanding industrial applications. They are used for the struts and chassis in some cars as well as some parts under-the-hood because they can withstand the intense heat and corrosive lubricants, fuels, and coolants cars require. Polyimides are also self-extinguishing; if they catch fire, they quickly char and then put themselves out. An example is kaptan tape, which we use on the bed o the 3D printer to encourage the first layer of the model to bond to the machine bed.

===Textiles===
#Textiles are used for reinforcement and visually attractive coverings in civil engineering and construction.
#[https://en.wikipedia.org/wiki/Geotextile Geotextiles] are materials designed to work with soil, such as membranes that allow water to pass through, but that resist weeds growing through them.
#Leather (made from cow hide) is hard-wearing, can have an attractive glossy or matte finish and can be wiped clean. This makes it a popular covering for furniture like sofas.

===Composites===
#[https://en.wikipedia.org/wiki/Composite_material Composite materials] are those which are made by bringing two or more different types of material together to produce a new material with unique properties.
#[https://en.wikipedia.org/wiki/Fibre-reinforced_plastic Fibre-reinforced plastics] including [[https://en.wikipedia.org/wiki/Fiberglass Glass-Reinforced Plastics (GRP)] and [https://en.wikipedia.org/wiki/Carbon_fiber_reinforced_polymer Carbon fibre (CFRP)] are composite materials made of a polymer matrix reinforced with fibres.
##Carbon fibre is an extremely strong and light fibre-reinforced plastic which contains carbon fibers. It can be expensive to produce but are commonly used wherever high strength-to-weight ratio and rigidity are required, such as aerospace, automotive, civil engineering, sports goods and an increasing number of other consumer and technical applications. [https://en.wikipedia.org/wiki/Carbon_fiber_reinforced_polymer#Applications This Wikipedia link] provides examples of specific real-world applications.
###CFRP is extremely lightweight and stiff which will improve user experience, ideal for F1 car bodies, crash helmets and sports equipment.
###CFRP can be made into complex shapes which gives more design options than simple geometric shapes like tubes.
###CFRP has a good aesthetic which can place a ‘premium’ label onto products, allowing sellers to command a higher price.
##Cheaper and more flexible than carbon fibre, GRP (fibreglass) is stronger than many metals by weight, and can be molded into complex shapes. Applications include aircraft, boats, automobiles, bath tubs and enclosures, swimming pools, hot tubs, septic tanks, water tanks, roofing, pipes, cladding and surfboards.

===Smart Materials===
#Advances in technology have yielded cutting edge, Smart materials, which have been created to provide specific properties.
#[http://en.wikipedia.org/wiki/Shape-memory_alloy Shape memory alloy] is sometimes called ‘Nitinol’, as it is a composed of nickel and titanium. It can be folded to form complex shapes quite easily and it conducts electricity, but is very expensive when compared to ordinary steel or even copper wire. However, it has properties that make it very special:
##The wire has a memory - for example, if it is folded to form a shape and then heated above 90°C it returns to its original shape.
##The material can also be ‘programmed’ to remember a shape. This can be achieved by folding the wire to a particular shape and clamping it in position. The wire is then heated for approximately five minutes at precisely 150° or pass an electric current through the wire. If the wire is now folded into another shape and then placed in hot water it returns to the original ‘programmed’ shape.
#Motion control gels (e.g. smart grease) can be used to slow output speeds of shafts, or to dampen the movement on systems like volume sliders in a mixing desk (See a [https://www.stem.org.uk/resources/elibrary/resource/31610/smart-grease demo here]).
#Inspired by nature, self-healing materials are those which have some ability to repair damage over time. This is seen in self-healing concrete which contains a bacteria and a food source. When water creeps into the concrete and activates the bacteria, it excretes limestone which heals the crack. You can watch a video about this [[here]].
#thermochromic, photochromic and electrochromic materials are those which change their colour in response to temperature, light and electric current respectively. The last of these is popular in making windows that can be toggled between frosted and clear at the push of a button.
#*Muscle wire* is also a nickel and titanium alloy. At room temperature it can be stretched by a small force. However, when a small current is passed through the wire it returns to a much harder form and to its original length with a reasonable force. When in use a muscle wire can be stretched up to 8 percent of its length and still recover. However, this can only be done a few times until it breaks or stops returning to its original length. Its life cycle can be extended dramatically if it is stretched to between 3 to 5 percent of its overall length. Within this range it will go through the stretching and return cycle millions of times.
#[http://en.wikipedia.org/wiki/Polycaprolactone Polymorph] is a thermoplastic material that can be shaped and reshaped any number of times. it is normally supplied as granules that look like small plastic beads. In the classroom it can be heated in hot water and when it reaches 62 degrees centigrade the granules form a mass of ‘clear’ material. When removed from the hot water it can be shaped into almost any form and on cooling it becomes as solid as a material such as nylon. Although expensive, polymorph is suitable for 3D modeling as it can be shaped by hand or pressed into a shape through the use of a mold.
#[http://en.wikipedia.org/wiki/Quantum_tunnelling_composite Quantum Tunneling Composite (QTC)] is available as small “pills”. This material provides increasing levels of conductivity as pressure is applied to it, making it useful for dimmer switches, pressure sensors and for integrating into clothing.
#Other materials have only recently been developed.
##[https://en.wikipedia.org/wiki/Sandwich_panel Sandwich panels] are any material which is made by sandwiching a (different) material between two slices of a material. This is used in aircraft, to create light-weight, well-insulated planes.
##[https://en.wikipedia.org/wiki/E-textiles e-textiles] are garments and products which have the ability to have electronics integrated into them. These can be either for aesthetic reasons (e.g. clothing that lights up), or functional (e.g. trainers containing a step-counter).
##[https://en.wikipedia.org/wiki/Rare-earth_magnet Rare earth] (e.g. neodymium) magnets are the strongest permenant magnets made. These allow for the creation of small (but powerful) headphones, greater distance when being used with a reed switch or for creating turbines for energy generation.
##[https://en.wikipedia.org/wiki/Superalloy High performance] / super-alloys have highly specialised properties, and are used extenstively in marine applications or for jet-propulsion.
##Graphene is a (form) of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice. While not widely used yet, it could have various material/device applications, including solar cells, LEDs, touch panels and smart windows or phones.
##Carbon nanotubes are carbon molecules organised in a cylindrical structure. They have unique Mechanical, electrical, optical and thermal properties. They are not used extensively at the moment, but a number of potential applications have been identified (click [https://en.wikipedia.org/wiki/Carbon_nanotube#Current][here]] for list)

==5.3 Considering the properties/characteristics of materials when designing and manufacturing products==
===5.3a Suitability of materials based on the following properties===
#When selecting materials for a particular task, it may be necessary to test different samples to ensure that they will need the product specification (e.g. for weight, cost, durability, etc). Many of the explanations here have been taken from the (linked) Wikipedia pages. These are worth a skim-read, as you will be able to then use these vocab words confidently in exam answers and coursework where appropriate.
#[http://en.wikipedia.org/wiki/Ultimate_tensile_strength Tensile strength] (how much something can be stretched before it breaks) can be tested in a workshop by clamping a sample, then hanging increasing amounts of weight from it until the sample breaks. Some materials will start to stretch first, whereas others hold their shape and break suddenly.
#[http://en.wikipedia.org/wiki/Compressive_strength Compressive strength] (resistance to deformation by a crushing load) can be measured by finding the amount of weight required to deform a material. Some materials rupture when the load exceeds their ultimate compressive strength (e.g. Concrete), whereas other materials (e.g. Wood and some plastics) deform. With non-rupturing materials, measurements can be taken of how much force is required to deform samples by 1%, 5%, 10%, etc.
#[http://en.wikipedia.org/wiki/Hardness Hardness] can be measured by taking samples of the different materials that are to be tested which have a sharp corner, and seeing which sample can scratch which material. By comparing all the materials, it will be possible to rank all the samples to establish which is the hardest.
#[http://en.wikipedia.org/wiki/Toughness Toughness] (impact resistance) can be tested by placing identical-sized samples of materials in a vice, then subjecting each one to an identical impact (e.g. a hammer blow set up by a jig, and dropped from the same angle each time), and measuring the angle the material is bent to. An [https://en.wikipedia.org/wiki/Izod_impact_strength_test Izod] test is a similar test (which destroys the sample) that is used in industry.
#[http://en.wikipedia.org/wiki/Fusibility Fusibility] can be measured by heating samples until they melt, and recording the temperature at which this occurs.
#[https://en.wikipedia.org/wiki/Density Density] is a material's mass per unit volume, calculated as ρ = m / V. Lead, gold and tungsten are increasingly dense metals. Balsa and cork are low-density woods.
#[https://en.wikipedia.org/wiki/Specific_strength Strength to weight ratio] is a material's strength (force per unit area at failure) divided by its density. Another way to describe specific strength is breaking length, also known as self support length: the maximum length of a vertical column of the material (assuming a fixed cross-section) that could suspend its own weight when supported only at the top. The Wikipedia link at the start of this definition contains an interesting table showing a range of breaking lengths for different materials.
#[https://en.wikipedia.org/wiki/Durability Durability] is the ability of a physical product to remain functional, without requiring excessive maintenance or repair, when faced with the challenges of normal operation over its lifetime.
#Thermal conductivity is the extent to which a material transmits heat or insulates from it. Asbestos is a superior (but deadly) thermal insulation material, and so used to be used to 'lag' (wrap around) heating pipes to minimise heat loss and increase efficiency. Copper, on the other hand, is a good conductor of heat and is often used to make the base of high-end saucepans.
#Electrical conductivity is the extent to which a material allows or restricts the flow of electrical current. Rubber is a well-known insulating material, whereas copper and gold are the best conductors. Given its high cost, gold is only used for high-end professional applications like audio connectors. Conductivity can be measured with a multimeter's resistance setting.
#[https://www.thebalance.com/what-is-corrosion-2339700 Corrosion resistance] is a measure of how quickly a material (usually metal) will break down in response to different types of corrosion. The most common type of corrosion is oxidation of iron alloys (e.g. rust forming on steel). Steps can be taken to reduce the rate of corrosion (e.g. painting or covering in grease).
#[https://en.wikipedia.org/wiki/Stiffness Stiffness] is the rigidity of an object — the extent to which it resists deformation in response to an applied force. This could be tested for a range of samples by placing a rod of the material on two objects a distance apart, and then incrementally applying a force in the middle. The amount each material moves after each additional weight will show which material is the stiffest.
#[https://en.wikipedia.org/wiki/Elasticity_(physics) Elasticity] is the ability of a body to resist a distorting influence and to return to its original size and shape when that influence or force is removed. A rubber band has high elasticity. Concrete will hold its shape until it fails.
#[https://en.wikipedia.org/wiki/Plasticity_(physics) Plasticity] is a little like elasticity, but (quoting Wikipedia), 'describes the deformation of a solid material undergoing non-reversible changes of shape in response to applied forces. For example, a solid piece of metal being bent or pounded into a new shape displays plasticity as permanent changes occur within the material itself.'
#[https://simple.wikipedia.org/wiki/Malleability Malleability] is substance's ability to deform under pressure (compressive stress). If malleable, a material may be flattened into thin sheets by hammering or rolling (e.g. gold, iron, aluminium).
#[https://simple.wikipedia.org/wiki/Ductility Ductility] is a material's ability to be drawn into a wire by being stretched.
#[https://en.wikipedia.org/wiki/Machinability Machinability] the ease with which a metal can be cut (machined) permitting the removal of the material with a satisfactory finish at low cost. Materials with good machinability require little power to cut, can be cut quickly, easily obtain a good finish, and do not wear the tooling much; such materials are said to be free machining.

===5.3b Costs and properties of materials===
#Stakeholder and user requirements - the designed product must satisfy stakeholders and users.
#Raw materials to be used - You need to consider the raw materials to be used, their availability and the forms and quantities in which they are supplied.
#Production facilities - you must ensure that you have the correct tools, equipment and all necessary facilities to produce your product.
#Cost and commercial availability - cost is one of the main factors which will influence the design of a product.

[[Design_Engineering|Design Engineering homepage]]

Materials and component considerations

2023-03-21T16:07:41Z

Stcd11: Added images

==5.1 Factors that influence the selection of materials that are used in engineered products==
===Specification===
#Understand that the selection of materials and components is influenced by a range of factors, including:
##functional performance
##aesthetics
##cost and availability
##properties and characteristics
##environmental considerations
##social, cultural and ethical factors

===Why should I know about material properties?===
#It is important to understand material properties and characteristics when designing a product or component for several reasons:
##A materials properties/characteristics make it suitable for a given application for example, using aluminium alloy in a car frame because it’s a tough and light material.
##If you chose the wrong material for a component you may increase the cost of the overall product. E.g. Using titanium for a car frame.
##If you chose the wrong material for a component you could also increase the probability of that component failing when the product is in use. Making a metal vice out of mild steel would be an example of this as mild steel is not a hard or strong enough material for this operation.
##A person’s safety could also be an issue for example, if the wrong material was used for a saucepan handle someone could burn themselves if the chosen material is a good thermal conductor.
##A products shelf life could also be affected if the wrong materials were used for example, using plastic for garden chairs instead of wood will increase the life of the garden chairs as plastic is waterproof whereas wood requires constant treatment to maintain it.

===Considerations===
#As an engineer or designer plans a new product or project, the question of what to make it from needs to be carefully considered.
#In terms of electronic components, functional performance might refer to how much current a resistor can handle or how quickly a transistor can turn on and off.
#With materials, functional performance might refer to how much compressive force a particular concrete can withstand before rupturing, the ductility of a metal or how hard-wearing a particular grade of steel is when designing gears.
#Aesthetics concerns how a product looks. Not all clients will value this; someone wanting a robot arm for moving car chassis about a factory would want all design effort to be put into making the arm work as quickly, reliably, safely and cost-effectively as possible.
#A company designing bottles for high-end perfumes would put *aesthetics* high on their list of considerations. Does the material allow the perfume to be clearly seen? Is the density of the glass sufficiently high to give a good tactile experience? Does it need a dye in the glass to further enhance it?
#Cost and availability (availability will dictate cost) will always heavily influence selection; a low-budget electronic mousetrap for first-time homebuyers would see the designers aim to economise in every area. Could a 555 timer be used in place of a PIC? How thin can the walls of the housing be? Could it be a little smaller?
#Properties and characteristics in the context of components can refer to what their specific capabilities are. The 4000 series logic ICs offer a range of chips, each of which performs a specific job (E.g. Decade counter, 7-segment display driver, AND gates). These components can also have quirks (e.g being especially sensitive to electrostatic discharge and needing special handling.
#Every material will have its own unique properties; you can research different woods, manufactured boards, plastics and metals, but a few examples are:
##Copper and its alloys (e.g. Brass) have anti-microbial effects and are able to kill bateria effectively within a few hours
##Stainless steel will rust less quickly than other grades of steel
##Nylon is often selected to make small gears with as it is self-lubricating
##Balsa is the least dense hardwood, and so is commonly selected for making light-weight models
##Because its made with sawdust and urea formaldehyde, MDF is usually very flat and consistent throughout the material (wood will have a grain and 'knots' in it, making it harder to cut)

==5.2 Materials and components that should be selected when designing and manufacturing products and prototypes==
#A systems engineer needs to know something about all aspects of Technology in order to produce the best work. One aspect of this is knowing what’s available when selecting materials to fabricate products with. For both the exam and your coursework, you will require a general understanding of the following groupings of materials. Links to external sites have been included throughout;

Below are materials selection charts which provide comparative data on materials and their properties in an easy to use format.
[[File:youngs_vs_density.jpg|600px|thumb|center|WOT Analysis]]
[[File:strength_vs_cost.jpg|600px|thumb|center|WOT Analysis]]

it is strongly recommended that you read up on examples.

===Woods===
#Wood has been used since pre-historic times to provide fuel for heat, and as a building material to produce homes and tools. We divide woods into three categories.
#[http://en.wikipedia.org/wiki/Hardwood Hardwoods] come from broad-leaved, deciduous trees. The main hardwood timbers are ash, beech, birch, cherry, elm, mahogany, oak, balsa and teak.
##Ash is light, creamy-brown in colour and both tough and flexible. It is often used to make sports equipment, wooden ladders and tool handles.
##Beech is white to pinkish-brown in colour, close-grained, hard, tough, strong, but warps easily. Commonly found in furniture, toys and tool handles.
##Elm is light to medium brown in colour, tough, resists splitting, and is durable in water. Elm is commonly used for indoor and outdoor furniture.
##Mahogany is Pink to reddish-brown colour, fairly strong, durable and used for good quality furniture.
##Oak is light brown colour, strong, hard, and tough. It corrodes steel screws and fittings. It is used for interior woodwork and good quality furniture.
##Balsa is creamy/light brown in colour, which is extremely fast growing and very lightweight. While low in density, it is high in strength and is commonly used for light, stiff structures, such as model aircraft and model buildings.
#[http://en.wikipedia.org/wiki/Softwood Softwoods] are from fast-growing coniferous trees which are evergreen, needle-leaved, cone-bearing trees, such as cedar, fir and pine.
#Tip: Hardwood and Softwood do not refer to the properties of the wood: some softwoods can be hard and some hardwoods can be soft.

===Manmade Boards===
#[http://en.wikipedia.org/wiki/Engineered_wood Manmade boards] are created from other woods, to give specific properties (and are usually relatively cheap compared to hard and softwoods).
##Blockboard is built up with a core of softwood strips bonded together with adhesive and covered with a sheet of plywood on either side. Used as a building material and for furniture manufacture including fitted kitchens / bedrooms.
##[http://en.wikipedia.org/wiki/Particle_board Chipboard] is made up of small chips of wood bonded together with resin and formed into sheets by compression. It is not as strong as plywood and block board but it is not expensive. Chipboard is often covered with a plastic laminate or wood veneer and used in furniture. Chipboard could contain partials of metal, grit and any other rubbish that gets taken up into a tree whilst growing, is also the most unstable board because of air pockets, will swell up to twice its thickness when damp.
#Hardboard is made from wood fibres that have been pulped. The pulp is put under pressure until the fibres bond to produce a tough board that is smooth on one side and rough on the other. It is not as strong as the other boards. When supplied, it is smooth one side and rough the other, because of the drying process and is flexible, generally buckles at the first sign of dampness in the air, used mainly for backs of cupboards.
##[http://en.wikipedia.org/wiki/Medium-density_fibreboard MDF] (Medium Density Fibreboard) is quality board, which is relatively cheap. This board is composed of fine wood dust and resin pressed into a board. MDF is the most stable manmade board, and can have a ply or laminate finish added to it to make its finish more aesthetically pleasing. Low Density and High density re also available, as it water resistant MDF (which is usually green in colour). MDF can be worked, shaped and machined easily. Paint can be applied to it without the need for an undercoat or primer. Used in the building and furniture trades, as well as in schools.
##[http://en.wikipedia.org/wiki/Plywood Plywood] is made from veneers (thin plies) of timber with each grain layer being at right angles to each other and bonded together by resin and pressure. A number of grades are available, designed to suit a variety of situations, such as Marine plywood that is moisture resistant (although it will still warp) or weatherproof plywood. Ply is the only board that uses layers of pure wood. If the grains are laid parallel with each other it becomes flexible along the grain; if laid at right angles it becomes more rigid.
#All boards come in standard thicknesses of 3, 6, 9, 12, 15, 18 & 25mm.

===Metals===
#[https://en.wikipedia.org/wiki/Ferrous Ferrous metals] are those that contain [http://en.wikipedia.org/wiki/Iron iron]. Steel, for example. All ferrous metals will rust over time, due to their iron content. All metals change their properties, dependent on how they are heated and cooled.
#[http://en.wikipedia.org/wiki/Non-ferrous_metal Non-ferrous metals] are those which do not contain iron, such as brass.
##A good conductor of electricity and heat, [http://en.wikipedia.org/wiki/Aluminium aluminum] is a light-weight metal, used in aircraft construction, for power cables, drinks cans and in cookware.
##[http://en.wikipedia.org/wiki/Titanium Titanium] is a very strong metal, used in making the strongest and lightest parts of modern fighter jet planes, as well as in high-performance sports equipment, medical implants and jewelry. It does not corrode, and has good resistance to sea water and chlorine.

===Metals Alloys===
#[http://en.wikipedia.org/wiki/Brass Brass]. Made since biblical times from copper and zinc, brass is used in low-friction applications (e.g. gears and locks), and has a golden colour. It is also used in musical instruments as it has pleasant acoustic properties.
#[http://en.wikipedia.org/wiki/Bronze Bronze]. Made from copper and tin, this was the first alloy to be discovered. Bronze is used when it is desirable for parts to be able to last a long time, and not be corroded by air or water.
#[https://en.wikipedia.org/wiki/Tungsten Tungsten]. In its raw form, tungsten is a hard steel-grey metal that is often brittle and hard to work. If made very pure, tungsten retains its hardness (which exceeds that of many steels), and becomes malleable enough that it can be worked easily.
#[https://en.wikipedia.org/wiki/Steel Steel] is an alloy of iron and carbon and other elements. Because of its high tensile strength and low cost, it is a major component used in buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons.
#Different [http://en.wikipedia.org/wiki/Steel steels] are made by adding carbon to iron (0.02%-1.7% carbon). Steel is harder and stronger than iron alone; adding additional carbon results in harder and stronger steel, at the expense of it becoming increasingly brittle. It is used for car bodies, bridge construction, buildings and tools.
#Stainless steel is made with the addition of around 11% chromium, which adds an increased resistance to staining and rusting compared to regular steel. It is used for surgical instruments, sinks and cutlery.

===Plastics===
#Polymers (and the discovery of plastics) revolutionized the 20th century, giving rise to the mass production of strong, cheaply produced products for the masses. The environmental cost was only considered in the latter half of the 20th century, when the impact of oil-based products which took hundreds of years to break down in landfill sites started to be realized.
#A [http://en.wikipedia.org/wiki/Thermoplastic thermoplastic] is one that becomes soft when heated and hard when cooled.
#[http://en.wikipedia.org/wiki/Acrylonitrile_butadiene_styrene ABS] (Acrylonitrile butadiene styrene) is highly impact resistant and tough. Commonly used for musical instruments, golf clubs, car trim components, car bumpers, medical devices for blood access, protective headgear, whitewater canoes and Lego bricks.
#[http://en.wikipedia.org/wiki/Poly(methyl_methacrylate) Acrylic] (Polymethyl methacrylate) is stiff, hard (but scratches easily), durable, brittle in small sections, a good electrical insulator, which machines and polishes well. It is used for many applications, such as making signs, covers of storage boxes, aircraft canopies and windows, covers for car lights, wash basins and baths.
#[http://en.wikipedia.org/wiki/Nylon Nylon] (Polyamide) is creamy in colour, tough, fairly hard, resists wear, self-lubricating and has good resistance to chemicals. Commonly used to produce bearings, gear wheels, casings for power tools, hinges for small cupboards, curtain rail fittings and clothing.
#[http://en.wikipedia.org/wiki/Polystyrene#Copolymers HIPS] (High Impact Polystyrene) is economical and impact-resistant plastic that is easy to machine and fabricate. Used for low strength structural applications when impact resistance, machinability, and low cost are required. It is frequently used machining pre-production prototypes since it has excellent dimensional stability and is easy to fabricate, paint, and glue.
#A [http://en.wikipedia.org/wiki/Thermosetting_polymer thermosetting plastic] (also known in industry as thermoset) is a plastic which irreversibly cures. They typically start off in a liquid form (so they can be molded into shape), and are then cured by a process such as heat, chemical reaction or irradiation to set them.
#[http://en.wikipedia.org/wiki/Urea-formaldehyde Urea formaldehyde] provides high tensile strength, good surface hardness and heat resistance as well as being a good electrical insulator. It is used for electrical fittings, handles and control knobs and to make adhesives. Its is also used as the bonding agent in.
#[http://en.wikipedia.org/wiki/Melamine_resin Melamine formaldehyde] is stiff, hard, strong and resists some chemicals and stains. It is commonly used in laminates for work surfaces, electrical insulation and tableware.
#[http://en.wikipedia.org/wiki/Epoxy Epoxy resin] is a good electrical insulator, which is hard, brittle unless reinforced and resists chemicals well. It is used mainly for casting and encapsulation, adhesives and for the bonding of other materials.
#Polyester resin works as an adhesive (less strong than epoxy) and is commonly used for boat hull repairs (when combined with fibreglass cloth) and can be used for casting. It has a strong, unpleasant smell, which many find off-putting.
#[https://en.wikipedia.org/wiki/Polyimide Polyimides] are strong synthetic polymers that are also astoundingly heat and chemical resistant. Their properties are so great that these materials often replace glass and steel in many demanding industrial applications. They are used for the struts and chassis in some cars as well as some parts under-the-hood because they can withstand the intense heat and corrosive lubricants, fuels, and coolants cars require. Polyimides are also self-extinguishing; if they catch fire, they quickly char and then put themselves out. An example is kaptan tape, which we use on the bed o the 3D printer to encourage the first layer of the model to bond to the machine bed.

===Textiles===
#Textiles are used for reinforcement and visually attractive coverings in civil engineering and construction.
#[https://en.wikipedia.org/wiki/Geotextile Geotextiles] are materials designed to work with soil, such as membranes that allow water to pass through, but that resist weeds growing through them.
#Leather (made from cow hide) is hard-wearing, can have an attractive glossy or matte finish and can be wiped clean. This makes it a popular covering for furniture like sofas.

===Composites===
#[https://en.wikipedia.org/wiki/Composite_material Composite materials] are those which are made by bringing two or more different types of material together to produce a new material with unique properties.
#[https://en.wikipedia.org/wiki/Fibre-reinforced_plastic Fibre-reinforced plastics] including [[https://en.wikipedia.org/wiki/Fiberglass Glass-Reinforced Plastics (GRP)] and [https://en.wikipedia.org/wiki/Carbon_fiber_reinforced_polymer Carbon fibre (CFRP)] are composite materials made of a polymer matrix reinforced with fibres.
##Carbon fibre is an extremely strong and light fibre-reinforced plastic which contains carbon fibers. It can be expensive to produce but are commonly used wherever high strength-to-weight ratio and rigidity are required, such as aerospace, automotive, civil engineering, sports goods and an increasing number of other consumer and technical applications. [https://en.wikipedia.org/wiki/Carbon_fiber_reinforced_polymer#Applications This Wikipedia link] provides examples of specific real-world applications.
###CFRP is extremely lightweight and stiff which will improve user experience, ideal for F1 car bodies, crash helmets and sports equipment.
###CFRP can be made into complex shapes which gives more design options than simple geometric shapes like tubes.
###CFRP has a good aesthetic which can place a ‘premium’ label onto products, allowing sellers to command a higher price.
##Cheaper and more flexible than carbon fibre, GRP (fibreglass) is stronger than many metals by weight, and can be molded into complex shapes. Applications include aircraft, boats, automobiles, bath tubs and enclosures, swimming pools, hot tubs, septic tanks, water tanks, roofing, pipes, cladding and surfboards.

===Smart Materials===
#Advances in technology have yielded cutting edge, Smart materials, which have been created to provide specific properties.
#[http://en.wikipedia.org/wiki/Shape-memory_alloy Shape memory alloy] is sometimes called ‘Nitinol’, as it is a composed of nickel and titanium. It can be folded to form complex shapes quite easily and it conducts electricity, but is very expensive when compared to ordinary steel or even copper wire. However, it has properties that make it very special:
##The wire has a memory - for example, if it is folded to form a shape and then heated above 90°C it returns to its original shape.
##The material can also be ‘programmed’ to remember a shape. This can be achieved by folding the wire to a particular shape and clamping it in position. The wire is then heated for approximately five minutes at precisely 150° or pass an electric current through the wire. If the wire is now folded into another shape and then placed in hot water it returns to the original ‘programmed’ shape.
#Motion control gels (e.g. smart grease) can be used to slow output speeds of shafts, or to dampen the movement on systems like volume sliders in a mixing desk (See a [https://www.stem.org.uk/resources/elibrary/resource/31610/smart-grease demo here]).
#Inspired by nature, self-healing materials are those which have some ability to repair damage over time. This is seen in self-healing concrete which contains a bacteria and a food source. When water creeps into the concrete and activates the bacteria, it excretes limestone which heals the crack. You can watch a video about this [[here]].
#thermochromic, photochromic and electrochromic materials are those which change their colour in response to temperature, light and electric current respectively. The last of these is popular in making windows that can be toggled between frosted and clear at the push of a button.
#*Muscle wire* is also a nickel and titanium alloy. At room temperature it can be stretched by a small force. However, when a small current is passed through the wire it returns to a much harder form and to its original length with a reasonable force. When in use a muscle wire can be stretched up to 8 percent of its length and still recover. However, this can only be done a few times until it breaks or stops returning to its original length. Its life cycle can be extended dramatically if it is stretched to between 3 to 5 percent of its overall length. Within this range it will go through the stretching and return cycle millions of times.
#[http://en.wikipedia.org/wiki/Polycaprolactone Polymorph] is a thermoplastic material that can be shaped and reshaped any number of times. it is normally supplied as granules that look like small plastic beads. In the classroom it can be heated in hot water and when it reaches 62 degrees centigrade the granules form a mass of ‘clear’ material. When removed from the hot water it can be shaped into almost any form and on cooling it becomes as solid as a material such as nylon. Although expensive, polymorph is suitable for 3D modeling as it can be shaped by hand or pressed into a shape through the use of a mold.
#[http://en.wikipedia.org/wiki/Quantum_tunnelling_composite Quantum Tunneling Composite (QTC)] is available as small “pills”. This material provides increasing levels of conductivity as pressure is applied to it, making it useful for dimmer switches, pressure sensors and for integrating into clothing.
#Other materials have only recently been developed.
##[https://en.wikipedia.org/wiki/Sandwich_panel Sandwich panels] are any material which is made by sandwiching a (different) material between two slices of a material. This is used in aircraft, to create light-weight, well-insulated planes.
##[https://en.wikipedia.org/wiki/E-textiles e-textiles] are garments and products which have the ability to have electronics integrated into them. These can be either for aesthetic reasons (e.g. clothing that lights up), or functional (e.g. trainers containing a step-counter).
##[https://en.wikipedia.org/wiki/Rare-earth_magnet Rare earth] (e.g. neodymium) magnets are the strongest permenant magnets made. These allow for the creation of small (but powerful) headphones, greater distance when being used with a reed switch or for creating turbines for energy generation.
##[https://en.wikipedia.org/wiki/Superalloy High performance] / super-alloys have highly specialised properties, and are used extenstively in marine applications or for jet-propulsion.
##Graphene is a (form) of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice. While not widely used yet, it could have various material/device applications, including solar cells, LEDs, touch panels and smart windows or phones.
##Carbon nanotubes are carbon molecules organised in a cylindrical structure. They have unique Mechanical, electrical, optical and thermal properties. They are not used extensively at the moment, but a number of potential applications have been identified (click [https://en.wikipedia.org/wiki/Carbon_nanotube#Current][here]] for list)

==5.3 Considering the properties/characteristics of materials when designing and manufacturing products==
===5.3a Suitability of materials based on the following properties===
#When selecting materials for a particular task, it may be necessary to test different samples to ensure that they will need the product specification (e.g. for weight, cost, durability, etc). Many of the explanations here have been taken from the (linked) Wikipedia pages. These are worth a skim-read, as you will be able to then use these vocab words confidently in exam answers and coursework where appropriate.
#[http://en.wikipedia.org/wiki/Ultimate_tensile_strength Tensile strength] (how much something can be stretched before it breaks) can be tested in a workshop by clamping a sample, then hanging increasing amounts of weight from it until the sample breaks. Some materials will start to stretch first, whereas others hold their shape and break suddenly.
#[http://en.wikipedia.org/wiki/Compressive_strength Compressive strength] (resistance to deformation by a crushing load) can be measured by finding the amount of weight required to deform a material. Some materials rupture when the load exceeds their ultimate compressive strength (e.g. Concrete), whereas other materials (e.g. Wood and some plastics) deform. With non-rupturing materials, measurements can be taken of how much force is required to deform samples by 1%, 5%, 10%, etc.
#[http://en.wikipedia.org/wiki/Hardness Hardness] can be measured by taking samples of the different materials that are to be tested which have a sharp corner, and seeing which sample can scratch which material. By comparing all the materials, it will be possible to rank all the samples to establish which is the hardest.
#[http://en.wikipedia.org/wiki/Toughness Toughness] (impact resistance) can be tested by placing identical-sized samples of materials in a vice, then subjecting each one to an identical impact (e.g. a hammer blow set up by a jig, and dropped from the same angle each time), and measuring the angle the material is bent to. An [https://en.wikipedia.org/wiki/Izod_impact_strength_test Izod] test is a similar test (which destroys the sample) that is used in industry.
#[http://en.wikipedia.org/wiki/Fusibility Fusibility] can be measured by heating samples until they melt, and recording the temperature at which this occurs.
#[https://en.wikipedia.org/wiki/Density Density] is a material's mass per unit volume, calculated as ρ = m / V. Lead, gold and tungsten are increasingly dense metals. Balsa and cork are low-density woods.
#[https://en.wikipedia.org/wiki/Specific_strength Strength to weight ratio] is a material's strength (force per unit area at failure) divided by its density. Another way to describe specific strength is breaking length, also known as self support length: the maximum length of a vertical column of the material (assuming a fixed cross-section) that could suspend its own weight when supported only at the top. The Wikipedia link at the start of this definition contains an interesting table showing a range of breaking lengths for different materials.
#[https://en.wikipedia.org/wiki/Durability Durability] is the ability of a physical product to remain functional, without requiring excessive maintenance or repair, when faced with the challenges of normal operation over its lifetime.
#Thermal conductivity is the extent to which a material transmits heat or insulates from it. Asbestos is a superior (but deadly) thermal insulation material, and so used to be used to 'lag' (wrap around) heating pipes to minimise heat loss and increase efficiency. Copper, on the other hand, is a good conductor of heat and is often used to make the base of high-end saucepans.
#Electrical conductivity is the extent to which a material allows or restricts the flow of electrical current. Rubber is a well-known insulating material, whereas copper and gold are the best conductors. Given its high cost, gold is only used for high-end professional applications like audio connectors. Conductivity can be measured with a multimeter's resistance setting.
#[https://www.thebalance.com/what-is-corrosion-2339700 Corrosion resistance] is a measure of how quickly a material (usually metal) will break down in response to different types of corrosion. The most common type of corrosion is oxidation of iron alloys (e.g. rust forming on steel). Steps can be taken to reduce the rate of corrosion (e.g. painting or covering in grease).
#[https://en.wikipedia.org/wiki/Stiffness Stiffness] is the rigidity of an object — the extent to which it resists deformation in response to an applied force. This could be tested for a range of samples by placing a rod of the material on two objects a distance apart, and then incrementally applying a force in the middle. The amount each material moves after each additional weight will show which material is the stiffest.
#[https://en.wikipedia.org/wiki/Elasticity_(physics) Elasticity] is the ability of a body to resist a distorting influence and to return to its original size and shape when that influence or force is removed. A rubber band has high elasticity. Concrete will hold its shape until it fails.
#[https://en.wikipedia.org/wiki/Plasticity_(physics) Plasticity] is a little like elasticity, but (quoting Wikipedia), 'describes the deformation of a solid material undergoing non-reversible changes of shape in response to applied forces. For example, a solid piece of metal being bent or pounded into a new shape displays plasticity as permanent changes occur within the material itself.'
#[https://simple.wikipedia.org/wiki/Malleability Malleability] is substance's ability to deform under pressure (compressive stress). If malleable, a material may be flattened into thin sheets by hammering or rolling (e.g. gold, iron, aluminium).
#[https://simple.wikipedia.org/wiki/Ductility Ductility] is a material's ability to be drawn into a wire by being stretched.
#[https://en.wikipedia.org/wiki/Machinability Machinability] the ease with which a metal can be cut (machined) permitting the removal of the material with a satisfactory finish at low cost. Materials with good machinability require little power to cut, can be cut quickly, easily obtain a good finish, and do not wear the tooling much; such materials are said to be free machining.

===5.3b Costs and properties of materials===
#Stakeholder and user requirements - the designed product must satisfy stakeholders and users.
#Raw materials to be used - You need to consider the raw materials to be used, their availability and the forms and quantities in which they are supplied.
#Production facilities - you must ensure that you have the correct tools, equipment and all necessary facilities to produce your product.
#Cost and commercial availability - cost is one of the main factors which will influence the design of a product.

[[Design_Engineering|Design Engineering homepage]]

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Technical understanding part 3

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==6.4c Interfacing electronic circuits with mechanical and pneumatic systems and components==
===Electronic Control for inputs===
#Electronic control can be used as an input to mechanical or pneumatic output. Watch the video below, which shows the basics of electro-pneumatics.
#Tip: A detailed guide to pneumatics which includes everything you need to know can be downloaded [https://sixthform.bourne-grammar.lincs.sch.uk/images/c/c8/Pneumatics.doc here].
<center><youtube>GhS1qpHoSX0</youtube></center>
[[File:52_DCV_valve.gif|500px|thumb|center]]

#In a pneumatic circuit, restrictor valves can be used to control cylinder speed by slowing the speed at which air can travel through an air-line. To read more about flow restrictors and the many different types and how they work, click [http://www.hydraulicspneumatics.com/200/TechZone/HydraulicValves/Article/False/6409/TechZone-HydraulicValves here].

Exam style question:

An engineer wishes to design a system to bend a aluminium bar 30 degrees using pneumatic cylinders and valves. They are concerned for the operator’s safety, so wish to ensure that they place both hands on push actuators before the cylinder is activated in order to ensure their hands are not accidentally crushed.

Sketch a system which will send a '''single-acting''' cylinder positive (extend) '''slowly''' when '''two''' push actuators are pushed at the same time. As soon as either actuator (or both actuators) is released, the cylinder should immediately go negative (retract) '''slowly'''. [6 marks]
# This solution requires an AND configuration, see image below:
[[File:ANDpneumatic.png|500px|thumb|center]]
# Here is an example of an OR configuration:
[[File:ORpneumatic.png|500px|thumb|center]]

===Sensors to measure rotational speed===
#There are a number of ways to measure rotational speed, the most common being an instrument called a tachometer. A tachometer (revolution-counter, tach, rev-counter, RPM gauge) is an instrument measuring the rotation speed of a shaft or disk, as in a motor or other machine. The device usually displays the revolutions per minute (RPM) on a calibrated analogue dial, but digital displays are increasingly common - you can see tachometers in the rev-counter in a car. In the diagram below, you can see that as the input rotates faster, the fly-weights are spun faster and the resulting force causes the coil-spring to be increasingly compressed. This leads to the output 'needle' moving further to the right.
[[File:tachometer.jpg|500px|thumb|center]]
<center><youtube>Ndq-IoF2o9Y</youtube></center>
#You can create your own instrument to measure rotational speed in a lab, such as:
##Electro-magnetic systems. A small magnet can be mounted on a disc connected to a rotating shaft. A reed switch can be placed in the path of the magnet so that once per revolution, the switch is closed momentarily as it passes. This can be connected to a microcontroller which can count the number of times the switch is closed per minute and display this to the end-user. As this approach uses a mechanical part (the reed switch) which takes a few milliseconds to open and close, the system won't be able to accurately record very high speed rotation.
[[File:electromag_tachometer.gif|500px|thumb|center]]
##The use of an LED near a photo-detector (e.g. LDR or phototransistor) with a slotted shaft between them. Every time the shaft rotates to allow light to shine onto the detector, this can be read by a microcontroller and used to accurately count rotational speed (right-hand side of picture below).
[[File:LED_tachometer.gif|500px|thumb|center]]

===Sensors to measure strain/force===
#The resistance of a strain gauge changes when force is applied and this change will give a different electrical output (read more [https://www.michsci.com/what-is-a-strain-gauge/ here]). Strain gauges use this method to measure pressure, force, weight and tension. They are commonly used to measure stress on railway lines and for testing structural components for bridges and buildings.
#These are sometimes integrated into load cells, which can be used to weigh heavy objects.

===Sensors to measure distance===
#An ultrasonic distance sensor can be used to measure objects up to around 3m away. These work by producing an ultrasonic 'click'. As we know the speed of sound, the time taken for the click to bounce off the surface being measured and for its echo to be detected can then be used to calculate the distance.
#IR distance sensors can be used over shorter ranges (up to about 80cm), and can also approximate distance. As sunlight can interfere with their operation, they can't be used in bright conditions.
#You can read more about distance sensors [https://www.maxbotix.com/articles/ultrasonic-or-infrared-sensors.htm here].

==6.4d Demonstrate an understanding of networking and of communication protocols, such as:==
#A network consists of two or more devices connected together so they can exchange data. E.g. A set of 30 PCs in a classroom can be networked so that everyone can access the same printer as well as files from a shared location. The Internet is a large international network, allowing devices all over the world to exchange information stored on web-pages.
#A protocol is an agreed method for communications between devices in a network.
##Serial communication is a protocol to transmit data one bit (a bit is a single 1 or 0) from one device to another. E.g. between two PIC chips.
##TCP/IP (Transfer control Protocol/Internet Protocol) is used to enable communications over the Internet.
##SMTP (Simple Mail Transfer Protocol) is used for the sending of email.
##FTP (File Transfer Protocol) is a protocol used for transferring files from one computer to another over the web.
#Radio-frequency identification (RFID) Works when a microchip inside the ticket receives power by electromagnetic induction from a radio frequency field generated by the reader unit, and it responds by sending a unique identifier code by radio back to the reader unit. Unlike a barcode, the tag need not be within the line of sight of the reader, so it may be embedded in the tracked object.
[[File:rfid_system.gif|500px|thumb|center]]
#Near-field communication (NFC) Similar to RFID in which data is transferred through a short range (4cm) radio field. NFC tickets can be passive (they receive energy from the radio field) or active such as a mobile phone running a payment app.
[[File:nfc_comms.jpg|500px|thumb|center]]
#Bluetooth is a wireless technology standard for exchanging data over short distances from fixed and mobile devices, and building personal area networks (PANs). In order to exchange data
#Wi-Fi most commonly uses the 2.4 gigahertz and 5GHz radio bands. Anyone within range with a wireless modem can attempt to access the network; because of this, Wi-Fi is more vulnerable to attack than wired networks. Wi-Fi Protected Access (WPA2) is a security technology created to protect information moving across Wi-Fi networks by encrypting data that is transmitted to prevent malicious 3rd parties from reading it.
#Embedded devices are computer systems integrated into a product. It is embedded as part of a complete device often including hardware and mechanical parts. Embedded systems control many devices in common use today, such as calculators and microwave ovens.
#Smart Objects are those which have sensors and microcontrollers installed, often with networking features to enable 2-way communications. E.g. a Smart fridge can have an integrated screen showing a family's calendar, using data taken from their smartphones. A smart printer could order more ink cartridges for itself when it detects that they need to be replaced. A smart home thermostat could communicate with your phone to know when you're on your way home and put the heating on for you automatically.
===Other ways to share data===
#Integrated Circuit Card or IC e-card Similar to RFID, but these cards are self-powered and rechargeable.
#Barcodes Every barcode contains a unique identifier code printed as a series of vertical lines. This is read by an optical laser scanner when the barcode is held over the scanner window.
#Quick Response (QR) Code Similar to a barcode but in 2D allowing much more data to be stored and then transferred during the scanning process.

==6.4e Demonstrate an understanding of the basic principles of electricity, including:==
#Voltage (also called potential difference) is the difference in electric potential between two points. The voltage between two points is equal to the work done per unit of charge against a static electric field to move a test charge between two points. This is measured in units of volts (a joule per coulomb); moving 1 coulomb of charge across 1 volt of electric potential requires 1 joule of work.

#Current is a flow of electric charge. In electric circuits this charge is often carried by moving electrons in a wire. It can also be carried by ions in an electrolyte, or by both ions and electrons such as in an ionised gas (plasma). The SI unit for measuring an electric current is the ampere (amp), which is the flow of electric charge across a surface at the rate of one coulomb per second. Electric current is measured using a device called an ammeter. Electric currents cause Joule heating, which creates light in incandescent light bulbs. They also create magnetic fields, which are used in motors, inductors and generators. The moving charged particles in an electric current are called charge carriers. In metals, one or more electrons from each atom are loosely bound to the atom, and can move freely about within the metal. These conduction electrons are the charge carriers in metal conductors.

#Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, one arrives at the usual mathematical equation that describes this relationship: V = I X R

#Power is the rate, per unit time, at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Electric power is usually produced by electric generators, but can also be supplied by sources such as electric batteries. It is usually supplied to businesses and homes by the electric power industry through an electric power grid. Electric power is usually sold by the kilowatt hour which is the product of power in kilowatts multiplied by running time in hours. Electric utilities measure power using an electricity meter, which keeps a running total of the electric energy delivered to a customer. Electrical power provides a low entropy form of energy and can be carried long distances and converted into other forms of energy such as motion, light or heat with high energy efficiency.

==6.5a Demonstrate an understanding of how smart materials change the functionality of engineered products, such as:==
#A smart material has a property which reacts in response to a stimulus. This may lead to colour changes, shape-shifting, motion control, self-cleaning or self-healing. For a more detailed list of smart materials, click on [https://en.wikipedia.org/wiki/Smart_material this] link.
#Possible materials may include:
##Thermochromic pigment is coloured at low temperature but loses its colour above a transition temperature. For instance, in a battery tester, a thin conductive strip heats up when current is passed through it and this heats the thermochromic material. The conductive strip is tapered, so for low currents it only heats the thermochromic pigment at one end, revealing red ink behind, whilst at higher currents it heats the entire length of strip, revealing red, yellow and green ink. Thermochromic pigment is also used in baby feeding products, such as bowls, cups and spoons. These products are made of polymers mixed with thermochromic pigments that change colour with heat, allowing the user to check the temperature, without contaminating the food by touching it.
##Photochromic pigment changes colour in response to light levels. Lenses in glasses can be coated in a photochromic pigment to make them 'reactive'. When the wearer goes outside in bright sunshine, the pigment reacts to the light by becoming coloured, effectively turning the glasses into sunglasses.
##Electroluminescent materials emit light when an electric current passes through them. This is used commonly with back-lit LCD panels, light-up wristwatches or sometimes on car dashboard instruments where a thin film is placed over the surface to be illuminated to help the user read displays in dark conditions.
##Piezoelectric materials are commonly seem in piezo transducers. Compressing certain crystals such as quartz causes electricity to flow through them. The reverse is also true: if you pass electricity through the same crystals, they "squeeze themselves" by vibrating back and forth. One application is for switches (e.g. in an electric drum kit or charity boxes where coins dropped in strike a piezo transducer after a short fall), where striking the transducer triggers an input than can be detected by a microcontroller to trigger an action. The other piezoelectric effect can be used to make very small speakers such as in a musical birthday card, energising a transducer at high frequencies in order to produce sound.
##Shape memory alloy (sometimes known as Nitinol) are metals which are able to 'remember' their original shape and return to it when deformed. This has been used for making [https://youtu.be/XPrg8EZlD1E glasses frames] which can be deformed and will automatically return to their original shape. There are also bioengineering applications such as dental wires such as those used in dental braces and mending broken bones using metal plates.
##Shape memory polymer materials can be deformed. By applying a stimulus, such as [https://youtu.be/50zu5HSdlLc heat] or light, will return to its previous shape. This could be used to create wrinkle-free, anti-shrinkable and crease retention fabrics. In robotics, shape memory foams are used to provide a soft grip when gripping objects. Foams can be cooled to harden and make a shape adaptive grip.
##Motion control grease regulates the movement of components in contact to provide the right 'feel' or desirable characteristics. Soft-close toilet seats/cupboard doors, sliding microscope barrels and slow spring-return Blu-Ray drawers all incorporate motion control gels.
##Electrochromic material (privacy glass). Electrochromic windows are used in airliners, by the use of suspended particle device (SPD) glass films which provide active shading, applied between the double glazing. When off (no voltage) the particles are scattered creating opacity, as voltage is increased by the user pressing a button, the particles align and light can pass through the window. Similarly, electrochromic glass, known as privacy glass is used in shower and bathrooms; these switch from transparent to opaque when a voltage is applied to them. When the voltage is applied, the liquid crystals inside the glass align and allow light to pass through. When the voltage is nor present the liquid crystal molecules are positioned randomly and block out any light, becoming opaque (private).

==6.5b Demonstrate an understanding of how programmable devices are used to add functionality to products, relating to coding of and specific applications of programmable components, such as:==
#We use Circuit Wizard to complete all of the tasks below. You will have used the program to develop you own project, from storing data in a variable, to running the program, in the Circuit Wizard virtual environment.

===Incorporating enhanced features that can improve the user experience and solve problems===
#When using programmable devices, it is possible to create functionality that could not be achieved simply by using discreet components. Loops, IF statements and variables can be used to produce systems such as robotic parts that can make decisions based on different inputs. E.g. A robot arm could be made to sort different parts based on their colour, or a robot vaccuum system could be created to run around a room in a random pattern, hitting walls and changing direction until all of the room is clean.
[[File:user_needs_programming.jpg|500px|thumb|center]]

===Basic techniques for measuring, controlling, storing data and displaying information===
#Data can be measured by connecting sensors to a PIC input pin - these can be either digital (i.e. capable of being in a finite number of states, like a switch) or analogue (able to hold an infinite number of values in a given range). Common input components are:
##Push-to-Make (PTM) switches. A digital component which allows current to flow into an input pin when the switch is pressed.
##Push-to-Break (PTB) switches. A digital component which stops current from flowing into an input pin when the switch is pressed.
##Light Dependent Resistor (LDR). An analogue component whose resistance increases from about 400 Ohms to 2 million Ohms as it gets darker.
##Potentiometer. An analogue component that is rotated through about 270 degrees, with increasing resistance. Used commonly for volume knobs on amplifiers.
#Output devices can be controlled by connecting them to a microcontroller output pin. Most microcontrollers can only deliver about 25mA from their output pins, so cannot 'drive' components that require more current. Where larger components (e.g. motors) are to be used, either transistors or dedicated driver chips can be used. Common components are:
##LEDs, which can light up when the output pin is energised
##Buzzers, which produce a sound when turned on. As these need about 100mA to operate, they need to be connected via a transistor to ensure they can work correctly.
##DC motors, which rotate continuously when energised. As these need about 1000mA (1A) to operate, they need to be connected via a transistor to ensure they can work correctly. These are used for driving small buggies or powering fans. The down-side of using a DC motor is that it is not possible to know how many times the motor has rotated, making these less ideal for applications where precise motion is required (e.g. robot arms).
#To store information, microcontrollers can store data in variables. The Genie microcontrollers that we use in school store these values in locations labelled as letters A,B,C...J. This could be used to build a drawer alarm, when the project is placed in a drawer, it could store the value of the analogue input (the light level) and then compare it until more light is present, thus setting off the alarm. A variable could be created to store a random number as part of an electronic dice project.
#To display information, there are a number of options available to engineers. Some of the most common are:
##LEDs. These can be installed into panels, with labels near them (e.g. 'power'). When the LED is illuminated, the user knows what is happening in the system.
##7-segment displays are sets of 7 LEDs (8 if you include the decimal point) inside a [https://uk.rs-online.com/web/p/led-displays/2358755/?cm_mmc=UK-PLA-DS3A-_-google-_-CSS_UK_EN_Displays_%26_Optoelectronics_Whoop-_-LED+Displays_Whoop-_-2358755&matchtype=&pla-300344153893&gclid=CjwKCAjwoP6LBhBlEiwAvCcthDrWB6kUwPKt6CON9lHaQNqAOFA_xK0TTzkvcet6-zs9soPFsKvZnhoCvQwQAvD_BwE&gclsrc=aw.ds plastic shape], which shows individual segments of a number. By turning on the different LEDs, numbers can be shown to the user.
##LCD displays. These need a microcontroller to operate. LCDs are able to show several characters of text/numbers on multiple rows, but not graphics. Common sizes are 16x2 and 20x4 characters. The 16x2 units work with Circuit Wizard.
##OLED displays. More complex than an LCD, these need to be used with a more powerful PIC such as an Arduino. These provide high-resolution graphics such as graphs or shapes in addition to text, but require additional programming to make them work. While smartphone and TV displays are full-colour, hobbyist displays such as the ones we get in school tend to be single-colour.
##TFT displays. Similar to OLED displays, but these are able to render graphics in full colour.

===Prototyping platforms===
#Prior to designing a PCB and etching it, engineers will make prototypes first to ensure that their ideas will work.
#One approach is to build a [https://learn.sparkfun.com/tutorials/how-to-use-a-breadboard/all breadboard] using actual components. This will be certainty that your idea will work, but it has a number of draw-backs:
##You may not already have all the components you wish to use
##You are likely to destroy some components if you mis-wire them while you develop your circuit, necessitating the purchase of additional gear
##It is slow and fiddly to create a breadboard. More complex circuits always have the risk of wires not quite making good connections, leading to delays in development
#Electronic prototyping platforms and IDEs for simulation in virtual environments help with this.
#An IDE (integrated development environment) is a set of software that performs multiple functions.
##E.g. Circuit Wizard allows for circuit design, programming, simulation of the circuit/code, PCB design and uploading of code to microcontrollers.
##E.g. Arduino allows for coding and debugging of code, as well as uploading of code and debugging through it's serial monitor.
#We can prototype most circuits needed in school using Circuit Wizard, these prototypes can then be tested in the virtual environment. You need to be careful, as this is a virtual environment, the components will not always act exactly as they would in the 'real' world.
[[File:cct_wizard_simulation.png|500px|thumb|center]]
#The use of programmable components and microcontrollers found in products and systems such as robotic arms or cars. This would be the same as above, you will need to start using motors to control robotic arms. Different types of motors are discussed earlier in principle 7. As a recap, these would usually be servo motors or stepper motors which offer accurate rotary movement.
#Creating flowcharts to describe processes and decisions within a process to control input and output components. You have created many flowchart in Circuit Wizard, but you can create flowcharts to explain nearly any situation. Flowcharts are ways to graphically display a process. Flowcharts display steps using the following blocks (there are many more):
##Terminators
##Inputs/outputs
##Decision
##Process
##Directional arrows
[[File:flowchart.jpg|500px|thumb|center]]

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2022-06-17T12:26:37Z

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