DT

• reasons why blended and mixed fibres are used in clothing.

  • produce different fibres with more desirable properties, eg polyester can mitigate against shrinkage
  • improve durability in the fibre, eg poly-cotton
  • produce clothing more cheaply, eg poly-cotton
  • cotton + synthetic material = more breathable -> comfortable to wear
• Disadvantages of fossil fuels as a source of energy:

  • Pollution from extraction of fossil fuels deep in the ground atmospheric pollution -> global warming

  • Shale gas extracted by pumping pressurised water and chemicals

  deep into the ground believed to cause earthquakes + damage to water courses.

  • Drilling for oil -> pollution of marine ecosystems + pollution

  • Mining of coal produces lots of waste (slag heaps) and pollution

  (of water courses).

  • Visual pollution by with open cast mining, location of power plants near rivers (water needed for cooling).
• Mail packaging 


  Corrugated cardboard ( lightweight, impact resistant ) does not add to package weight a lot and protects against penetration
• Baseball bat


  Ash ( tough, durable, springy ) Prevents excessive marking from ball impact
• Screwdriver blade


  High carbon steel ( hard, durable ) ability to screw without removing screwdriver tip
• Food container


  Melamine-formaldehyde ( strong, scratch resistant, soft touch polymer) Non-reactive, dishwasher safe
• Active wear


  Polyester ( Breathable, Lightweight, Wear resistant, Durability)

  • Comfortable to wear – hugs the body.

  • Stretchy, dries quickly crease resist
• Bending


  Bending materials in a curve can stiffen and strengthen a structure. Middle fluted layer of corrugated cardboard adds strength and rigidity which helps package heavy loads
• Folding


  Can add strength, impact resistance, eg corrugated cardboard as well as flexibility. A crease is created between two sides of bend
• Interfacing


  Sewing or ironing additional layers of fabric where they are usually unseen to strengthen and add stiffness, eg shirt cuffs and collars, hats.

  Improve aesthetics, functionality also.
• Lamination


  Building up a material in layers forming a composite constriction, eg plywood

  Increases:

  • strength
  • resistance to shock and impact
  • rigidity
  • moisture resistance in some cases
• Webbing


  Fabric eg nylon, cotton , polyester woven to give high tensile strength by adding additional material- resists force added!
• Nut and bolt


  • Fasten two or more components or more pieces of sheet material together.

  • Used where a non-permanent joint is required.
• Benefits of standard components in manufacturing

  • No need to design and manufacture own components as standard

  components can be bought in.

  • Standard components are mass produced so they are low cost to

  the manufacturer.

  • Speeds up the manufacture of products.

  • Components are quality assured before they arrive at the

  manufacturer for them to use.

  • Defective standard components can be easily replaced as part of

  a manufacturer guarantee if needed.
• Injection moulding

  • Complex polymer shapes made rapidly in one piece eg buckets, watering cans, bottle lids
  • Components are self-coloured and can have surface features like grips added in one go
  • Polymer granules fed from a hopper into a heating chamber to melt
  • Molten polymer fed under pressure into closed mould of tool steel (hard but expensive)
  • Water used to cool so faster manufacturing process
  • Leftover material easily recycled + reused adding to efficiency, sustainability + reduces cost
• Offset lithography

  • Mass production eg book
  • Prints in a combination of cyan, magenta, yellow and black
  • Oil-based ink + water used -> oil + water don't mix
  • UV light transfers an image onto smooth aluminium printing plates
  • The image area holds ink + non-image area holds water
  • Ink + water applied to rollers from plate roller + water stops plates sticking
  • Image from plate cylinder -> rubber offset cylinder (mirror image of final print). Water squeezed out and ink is transferred.
• Turning

  • Wastage process used for wood and metal
  • Material is held and rotated by the lathe, and a stationary tool/ bit is pressed onto the material to cut it.
  • Speed of rotation depends on diameter and material
  • Hold the material tight and straight, secure at both ends to prevent wobbling
  • produces spindles
• Casting

  • For shaping a material eg. wax casting
  • Heated molten material poured in a hollow mould and left to cool and solidify before separation
  • To make a mould- a pattern is used to create a cavity in a box filled with moulding sand and this cavity will be filled with material when casting (must be slightly bigger to allow for shrinkage when cooling)
  • Moulds are made in two halves- split open and release cast material
  • Complex + one-piece products made- reducing assembly operation
  • Leftover material is recyled
• 3 processes ensuring quality control

  • Dimensional accuracy (tolerance, jigs, templates)
  • Process time (developing time for PCB manufacture to avoid UV exposure)
  • Registration accuracy (check printing quality)
• Reduce

  • save materials and energy in production
  • efficient manufacturing
  • sustainable materials (FSC)
  • reducing product parts and number of products
• Refuse

  • Reflect if a product is wasteful, inefficient, from far away so high carbon footprints
  • use of chemicals harm the environment
  • do you need it?
• Reuse

  • Extend a product's lifespan e.g bag for life
  • Visit charity shops
  • Up-cycle furniture for different purposes
• Repair

  • Fix don't throw away
  • Less waste
  • Manufacturers profit off selling replacement parts and can be suitable for lower-income consumers
• Recycle

  • Uses less energy than raw materials
  • Easy to separate ( buy products with limited materials)
  • Manufacturers include clear labelling as to how to recycle a product at end of life
• Rethink

  • Consider more sustainable ways to make a product.
  • Are materials locally sourced/ use sustainable energy/ production methods
  • Wind up radio is better that a battery run radio
• What is iterative design?

  • Prototype -> testing -> evaluating
  • Each iterative cycle -> small refinements in the product
  • Evaluate by seeking out user / client / potential customers views and opinions
  • Taking small steps with a design + responding to feedback
• What can iterative design do?

  • improve quality and function of a product
  • Identify and remove problems and quality issues before commercial production
  • Limit unnecessary expense of having to stop production in commercial stage because flaws have already been removed in design + prototyping
• Fair trade

  • Ensures workers in developing countries get a fair price for their labour and product eg. fair trade cotton
  • Improves working conditions and pay for workers and families
  • Improve education and access to social care. eg setting up local amenities like schools and wells
  • Empower workers to have power and influence over their lives by giving small scale farmers access to global trade markets
  • Supports sustainability
• How do focus groups help to design products?

  • Gathered group of people discuss opinions on a product
  • Very specific primary information with interested parties to help designing process
  • Allows people to interact together unlike a survey which is alone
  • A designer / manufacturer can directly talk to consumers
• How does market research help to design products?

  • Consider what is already on the market and analyse products
  • A critical evaluation of competition in the market
  • You can identify gaps in the market for particular products
  • This may involve interviews and surveys
  • Can understand if product development is viable
• Advantages of annotated sketches:

  • Material - designers share thoughts on choices + consider pros + cons. May include details about cost, availability, stock forms + sizes.
  • Construction - designers can share with third party construction details about a prototype, a scaled model, or a commercial product
  • Finishes - detail on appropriate finishes
  • Customer - analysis + evaluation of customer needs can clarify future design intentions
  • Specification - can revisit and review how well the design meets design requirements
• Why do designers make models?

  • identify issues before full production saving time + cost
  • Faster speed of manufacture
  • Allowing customers / potential target market to look at a model + give feedback
  • hold a product so test aspects like functionality, feel, fit
• Why is a design specification IMPORTANT?

  • Allows designers to summarise research
  • Provides clear criteria to work from
  • Provides point of agreement between designer and client
  • Clear focus for designers to achieve
  • HELPS TO ENSURE A SUCCESSFUL OUTCOME BY:
  • allowing modifications as an iterative design process
  • there is a criteria to test iterations
  • allows designers to evaluate success of final outcome
• Anthropometrics

  • Study of human measurements
  • ensure that wearable items fit
  • ensure that products are comfortable, easy to use and are suitable for their intended user
  • allows products to be adjusted within a range
• Why has renewable energy use increased?

  • Government targets to reduce CO2 emissions
  • Increased awareness of environmental issues
  • Home installation of solar panels – inducements for these which is minimising reliance on fossil fuels
  • Improved efficiency + technology over time
• Why are some people against renewable energy?

  • Cost - High initial investment + long payback period
  • Visual intrusion - Wind + solar farms spoil the landscape / views
  • Noise pollution - Sound of wind turbines impact upon local residents
  • Denial - People don't believe we need to avoid traditional sources of energy
  • Efficiency -Although the technology is improving not sufficient energy generated compared to the cost of installation etc
  • Danger to wildlife - Risk to bird + marine life as disturbs habitats
• How are polymer stock forms made?

  • Crude oil is extracted from the ground

  • Oil is transported by a tanker to an oil refinery

  • Oil is fractionally distilled as heavy crude oil is separated into fractions

  • Polymerisation takes place

  • Plastic is then extruded /injection moulded/ blow moulded/ vacuum formed/ cast.
• corrugated card formation

  • Trees cut down + debarked
  • Timber chipped -> water + chemicals added to create pulp
  • Pulp is washed, refined cleaned + bleached
  • Water drained out + paper is heated + dried
  • Wound onto large rolls.
  • Fluted inner layer is stuck to outer layers for strength and rigidity by lamination
• How to make sheets of aluminium

  • Bauxite is mined from the ground +washed to remove clay
  • Aluminium oxide extracted from bauxite by refining.
  • Aluminium created -> electrolysis
  • liquid aluminium is cast into different shapes depending on the intended use.
  • Outline of product is market out + cut from flat metal sheet
  • feed metal in sheet metal folder, mark folds, join corners with soldering
• How is wool yarn made

  • Sheep sheared -> remove wool fleece

  • fleece is cleaned, sometimes scoured using an acid bath to remove oils + dirt

  • wool dried + teased/picked

  • wool combed with wire rollers (carding)

  • wool spun + often twisted to make usable yarn