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DT > Material And Components 2 > Flashcards

Material And Components 2 Flashcards

1
Q

Natural mineral textiles - glass fibre

A
  • glass manufactured into filament yarns and staple fibres to produce long-lasting, durable, woven-mesh glass fabric
  • used by the aerospace and military industries to produce flame and heat barriers, light and ultraviolet filters e.g. roof of 02
  • characteristics: heat/cold resistant, non-toxic/stick, resistant to chemicals, mildew and fungus and have reflective properties
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2
Q

Natural mineral textiles - synthetic textiles

A
  • formed entirely by chemical synthesis from oil/coal (polymers)
  • non-renewable and not biodegradable
  • used for a soldiers protective headwear/prom dress
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3
Q

Manufactured fibres - polyamide (nylon)

A
  • produced by chemical chips by melting and extruding into fibres
  • characteristics:
    • thermoplastics
    • insulating
    • don’t absorb water which means that they are susceptible to electrostatic charge
    • easy to wash/dry
    • strong, resilient and durable
    • good elasticity and dye well
    • resistant to moulds and fungi, but yellow and fade in sunlight
  • uses: parachute, canopies, tents, sleeping bags
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4
Q

Manufactured fibres - aramids

A
  • highly flammable retardant, withstands high temperatures
  • e.g. Nomex: uses - firefighters/ racing drivers clothing
  • e.g. Kevlar: high strength-to-weight ratio, uses - bullet-proof vests
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5
Q

What is a composite material

A

Mixture of 2 or more materials used to strengthen each other

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6
Q

carbon fibre (CFRP)

A
  • made with resin - a thermosetting polymer
  • stronger than metals but takes longer to form
  • lightweight
  • very expensive so only used where high performance is essential e.g. bikes, helmets
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7
Q

Glass reinforced plastic (GPR)

A
  • lower in cost but has a long production time
  • e.g. canoes and boats
  • first lay on pre-gelled coat, then put fibre layer down and cover with a resin and wait for it to harden (sped up by heating)
  • also use a rubber bag/matched-die moulding method e.g. car bodies
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8
Q

what are modern materials

A

developed to perform particular functions and have specific properties

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9
Q

E-textiles

A
  • innovative textile materials that have conductive fibres/ elements in the textile itself (eliminate wires/electronics)
  • e.g. sensors, thermochromic displays, antennas and heating elements
  • found in interior design and wearable products
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10
Q

super alloys

A
  • developed for use in extreme applications
  • characteristics: mechanical strength, performance at high temperatures, resistance to creep (deformation under continuous stress), resistance to corrosion/oxidisation/wear
  • e.g. turbine engines, nuclear reactors, oil and gas industries
  • nickel is primary metal
  • manufactured by investment costing and sintering
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11
Q

high-performance alloys

A
  • uses: pharmaceutical mixing tanks on a production line
  • high- performance nickel and molybdenum alloys increase the resistance to corrosion and pitting of the stainless steels
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12
Q

graphene

A
  • consists of carbon atoms arranged in a perfect hexagonal lattice, 1 atom thin layer of graphite
  • world’s strongest material, thinnest material which is harder than diamond
  • 300x stronger than steel and lightweight
  • 97% transparent, flexible to 120% of original length
  • conducts electricity and heat better than almost any other metal
  • uses: tennis rackets, skis, helmets, li-Ion batteries
  • uses under development: membranes to purify water, smaller batteries, flexible/foldable phones and tablets
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13
Q

Bioplastics

A
  • form of plastic derived from organic and renewable biomass sources e.g. veg oil/corn starch (plant based sources)
  • means they have a lower carbon footprint and their manufacture emits less CO2 and requires less energy
  • uses: packaging, crockery, cutlery, straws (disposable items)
    phone casings, insulation (non-disposable)
  • ingredients: agar, veg glycerine, purified water, food colouring/flavour
  • glycerine is a plasticiser that makes polymer chain molecules bend and slide past each other = flexibility
  • biodegradable, creates problems like large- scale mono-cropping
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14
Q

Nano materials

A
  • involves altering the material’s properties by changing the individual atoms that form the material
  • e.g. Aerogel - solid but has an extremely low density and thermal conductivity (‘frozen smoke’)
  • 98.2% air, lightest solid on earth but can support up to 4000x its own weight
  • good insulator (a blow torch on one side cannot light a match on the other
  • uses: insulation, ski jackets, tennis rackets, flexible batteries, clear nanoscale films on glass prevent damage
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15
Q

smart materials

A

respond/ react to changes in temperature, light, electric currents, pressure etc.
- some have memory and can revert back to their original shape

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16
Q

thermochromic materials

A
  • colour changes with temperature
  • in the form of semi-conductor compounds, liquid crystals or metal compounds
  • uses: side of batteries, kettles, food packaging, thermometers
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17
Q

phosphorescent materials

A
  • glow in the dark after being ‘charged up’ in the day
  • the pigments absorb natural/artificial light and store it in their molecules, this energy is slowly released, either in a few seconds or over a period of time
  • uses: emergency signs, novelty decoration, lighting for the garden/toys/glow-in-the-dark stuff
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18
Q

photochromic materials

A
  • colour changes with light intensity
  • colourless in a subdued light but with sunlight, the molecular structure changes and produces a different colour - the colour disappear when removed
  • uses: light sensitive sunglasses, security markers that can only be seen in ultraviolet light
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19
Q

electrochromic materials

A
  • materials which change their colour or opacity when a voltage is applied
  • also called electroluminescent - produces brilliant colours if stimulated by an AC current
  • uses: smart goggles and motorcycle helmets, in the illumination of buildings and displays on public transport
20
Q

piezochromic materials

A
  • colour changes with pressure (either reversible or irreversible) or other mechanical effects such as bending or scratching
  • powders or paints can be made from this pigment
  • uses: security coatings on buildings/ structures where attempts to damage need to be evident
21
Q

solvatochromic materials

A
  • they are dyes that change colour when are dissolved with a liquid
  • the colour is dependent on the solvent so they could be used detect the presence of fluids for chem/bio
22
Q

shape memory alloys

A
  • most common are made up of nickel and titanium (nitinol)
  • when heated they retain their original shape
  • uses: robotics and wing flaps on aeroplanes, thermostats and dental braces (body heat shortens the wire and pulls teeth back)
  • used to make stents, they are inserted into blood and they expand to allow flow
23
Q

shape memory polymers (SMP)

A
  • are polymer materials in which deformation can be created and removed by a change in temperature or stress
  • can store up to 3 different temperature
  • tolerates 200% elongation
  • uses: reusable moulds, toys, containers, packaging
24
Q

Polymorph (polycapralactone)

A
  • thermoplastic polymer in the form of plastic pellets
  • heated in hot water/by a hairdryer to 62 degrees C and then it can be moulded
  • it can be cut, drilled, machined, dyed, etc
  • 100% biodegradable
  • ## uses: modelling materialalso there is coolmorph which is the same but heated to 42 degrees C which is easier and safer
25
Q

conductive paints

A
  • paints that conduct electricity
  • can paint “wires” onto any material - dries in 30 mins
  • water based containing pure silver - flexible/tough
  • uses: repair broken track on circuit boards, heated rear windscreens
  • also conductive ink delivers printed items that conduct electricity e.g. membrane switches in computer keyboards
26
Q

smart and performance textiles

A
  • include being waterproof, windproof and breathable
  • simplex -> allows persiration to pass through but doesn’t allow any water to penetrate
  • uses: plasters/dressings
  • fastskin -> swimwear that replicates the skin of a shark enabling movement through the water with less resistance
  • stomax -> keeps wearer dry/comfortable during exercise
27
Q

factors to consider for the available forms, costs and properties of materials

A
  • stakeholder and user requirements
  • raw materials to be used
  • production facilities
  • cost and commercial viability
28
Q

The available forms, costs and properties of materials: stakeholder and user requirements

A

they must be satisfied. quality, performance, reliability and durability are essential when selecting materials and components

29
Q

The available forms, costs and properties of materials: raw materials to be used

A

consider sizes, profiles, liquids or resins

30
Q

The available forms, costs and properties of materials: production facilities

A

ensure you have the correct tools, equipment and all necessary facilities to produce your product

31
Q

The available forms, costs and properties of materials: cost and commercial viability

A

using standard sizes of materials/components reduces cost. This is one of the main factors which will influence the design of the product

32
Q

material forms: Metal

A
  • sheet - SWG (standard wire gauge)
  • Bar - cross section: circular, square, rectangular, L/I shape
  • ingot
  • wire
  • tube
  • powder - sintering
33
Q

material forms: wood

A
  • planks/ sheets - standardised forms e.g. 4’ x 6’
  • cross section- mouldings; beadings; architrave
  • rough sawn - SE (square edge), PAR (planed all round)
34
Q

material forms: plastic

A
  • sheet - standardised mm form
  • pellets - thermoplastics
  • powder - dip coating
  • liquid - 3D printing
  • cross-section - extrusions
  • ‘wire’ - FDM (fuse deposition modeling): 3D printing
35
Q

Sandwich panels

A

Composite made of 3 layers:

  • lightweight core (honeycomb shape)
  • 2 thin skin layers

Achieves good rigidity with minimum weight

Uses: cladding, roofing, advertisement boards, aeroplanes

36
Q

Explain why it is important to undertake product analysis/ evaluation.

A
  • Explore materials and components, as this allows the designer to understand material performance requirements, potentially changing material choices in relation to the components used in the product.
  • Explore construction/manufacturing methods, as this allows the designer to identify how the product has been made, and make informed changes to how future products could be made.
  • Testing functionality/ease of use/fitness for purpose, as this allows the designer to appreciate what the product does well, and propose changes to these where it could do better.
  • Testing the product in use, so that the user can test the product and assess its merits.
  • Comparing the product against the list of requirements will allow the product to be compared to the intended list generated from research to see where the product meets requirements.
  • Analysis with users, giving potential customers the opportunity to critique the finished product prior to project completion.
37
Q

What is planned obsolescence

A

it is a policy of planning or designing a product with a limited life span, so that it becomes obsolete after a certain period of time

38
Q

Explain why a design engineer would consider planned obsolescence when designing a new engineered product.

A
  • Ensuring the life expectancy of a product in the customer’s eyes is achieved, as this will ensure customer satisfaction from the product in use.
  • Ensuring that the product can be updated/upgraded (e.g. firmware or part replacement) to extend the life expectancy of a product will provide an ongoing improvement of the product over time.
  • Design for repair allows the product to be updated as required with new technologies.
  • Installing components with predictable life expectancy through appropriate use creates the opportunity for service provision to be offered by the manufacturer post sales.
39
Q

Discuss how environmental incentives or directives have impacted on the way in which engineered products and systems are produced.

A
  • Considering the need to accept returned
    products at the end of their lifecycle, for recycling, repair, reuse or landfill (e.g. the WEEE directive).
  • Considering which products or systems are currently receiving end of life incentives for customers to update their product or system (end of life diesel vehicle directive).
  • Considering products that benefit from existing systems that avoid the product ending up in landfill at the end of its lifecycle (existing recycling directives/incentives).
  • Considering the impact of different choices in power supply, by choosing carefully whether to allow batteries to be replaced or not, use USB or standard power connectors, using a sustainable power supply.
  • Considering the need to package products through their lifecycle and ensuring materials used can be reclaimed or recycled using existing packaging systems.
  • Considering the inclusion of hazardous materials or substances, their function in the product/system, and how these can be removed to meet directives relating to their
    disposal (RoHS).
  • Helping a manufacturer in meeting recycling targets through the products they manufacture.
  • Ensuring communication of
    products meeting incentives is well communicated through packaging/marketing
  • Being proactive in meeting new or existing incentive or directive programmes so that the manufacturer is well perceived in the market.
40
Q

explain why a non-ferrous metal is a suitable material for manufacturing an automatic sensor sink tap.

A
  • The material will not need an addition finish applied after the components have been made, because
    the material will not rust/corrode in use.
  • Non-ferrous metals are suitable for a range of casting, drilling and machining processes required to make the taps body, because of their working properties.
  • Non-ferrous metals can be polished to improve their appearance which would then remove the need for applying a finish.
  • Non-ferrous metals do not rust/corrode and will not be affected by water/air during testing and use
41
Q

Describe how a reflective infra-red sensor works

A
  • An infra red sensor sends out an infra red signal which hits an object in front of it
  • if the object is close, it will bounce back where the signal is received and causes the micro controller to turn the water on
  • at the end of the 2 second timer, another signal will be sent out. If the object is still there it will do nothing but if it isn’t, it will wait 2 seconds and then tell the micro controller to turn off the water.
42
Q

How are speed and direction controlled in a motor

A
  • The speed can be controlled by increasing or decreasing the current through the motor
  • The direction can be controlled by reversing the current flow, which can be done with a dpdt relay:
43
Q

The difference between analogue and digital sensors

A
  • analogue: for sensing something that has a range of outcomes e.g. distance
  • infra-red distance signal, battery voltage level sensor
  • digital: for things with 2 outcomes e.g. on and off, push buttons, bin correctly in place ( yes or no )
44
Q

Discuss, using examples, how considerations regarding the design, purchase and supply of
products can extend their usable lives.

A
  • Products can be designed so that parts which commonly fail can be easily replaced. Such parts might
    include batteries or touchscreens. The use of standard parts helps achieve this, as does making the
    spare parts readily available on the
    open market. (sacrificial parts)
  • Providing a service/maintenance schedule so that the product is regularly maintained and kept
    working to a high standard. Servicing can spot problems early on and correct these cheaply before the problem develops into a full product failure.
  • Providing freely available service manuals so that independent repairers can tackle the problem and not just franchised dealers.
  • Designing the product so that standard tools and diagnostic equipment can be used to trace faults and fix them.
  • Using higher quality components which are less likely to failure prematurely, and designing the product so that the components are working well within their rating and not being stressed.
  • Providing facility for regular software updates to fix known issues and to keep the product in line with the
    features available on the latest models. The same applies to hardware updates, e.g. new cases, better cameras etc.
45
Q

Explain the implications of the improper use of lubrication on mechanical systems

A
  • can result in fusion / welding of components.
  • Escapes intended joint / system causing issues and
    damaging others system, e.g. electronics.
  • Causes slippage of joint / system leading to inefficient
    performance of joint / system.
  • Difficult for future maintenance causing increases to
    maintenance costs and maintenance time required

DT (9 decks)

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