DT Theory - Year 12

• How does CAD benefit designers?

  Allows testing of ideas, analysis, developments so ideas can be improved.

  efficent, no physical components are required.

  easily modified

  can be communicated to users to other specalists
• -What is anthropometrics?

  -importance to the designer

  -importance to the manufacturer

  -importance to the user


  -measurements of human beings, human body dimensions, sizes. How physical features and traits can vary.

  • allows designers to ensure the product fits the target market.
  • product made accuractley and efficently, ensuring product is correct size for target market.
  • product- well recieved, not rejected. Postive user opinion is extremely valuable to the popularity of emerging products
• What are ergonomics?

  Importance to manufacturer

  importance to end user

  uses anthropometric data to ensure product fits the user, is comfortable to use.

  sucess of the product relies on effective design

  if final product fits perfectly, operates effectively and meets user needs, it will be sucessful.
• Benefits of CAD


  Higher quality designs can be achieved.

  designs can be edited

  cad files- easily shared

  no physical space required

  saves time, improves accuracy
• Benefits of CAM


  faster and more accurate than manual workers.

  produces identical outcomes

  creates complex outcomes

  cost effective
• Disadvantages of CAD/CAM


  can be expensive.

  faults can delay design and production

  upgrades may be required
• Natural timbers: softwoods 


  Grow faster than hardwoods, usually have needles and pines instead of leaves. e.g pine,cedar and spruce.

  Softwoods tend to be paler in colour, darker grain, generally lightweight.

  Popular for household construction and fencing
• Natural timbers : hardwoods

  Grow slower than softwoods, more expensive. e.g oak beech ash

  hardwoods are tough, durable, close grain

  traditonally used for higher end furniture
• polymers: thermosetting plastics


  heated, formed, cooled once, Cannot be reshaped.

  e.g epoxy resin, polyester resin
• ploymers: thermofroming plastics


  Heated, shaped, cooled more than once.

  e.g PVC, acrylic
• metals and alloys : ferrous metals


  Ferrous metals contain iron,are magnetic and corrode.

  e.g mild steel, carbon steel, cast iron.

  all require a protective finish
• Metal and alloys : non-ferous metal 


  Do not contain iron, not magnetic, corrosion resistant.

  e.g aluminium, copper,lead

  Tend to polish well but can oxidise
• Metals and alloys : alloys

  mixtures of metals with an element to improve its properties or aesthetics.

  e.g bronze, brass, stainless steel

  Can be ferrous and non-ferrous, may require protective finishing
• Smart materials


  are reactive, change to fit its environment

  e.g shape memory alloys, photochromic ink
• Combining


  'mixing' them to form a composite material. e.g epoxy resin
• Laminating 


  layers of materials are added together. e.g kitchen worktop. Laminating can be used to create curved shapes using layers of materials
• Properties of metals


  Good conductors of heat and electricity. Most metals- high density, malleable and ductile
• properties of alloys


  hardness, toughness and ductility
• Production process : moulding


  Shaping a liquid or raw material using a frame or mould
• Production process: extrusion


  hot or cold material can be pushed through a die to create complex shapes that are consistent in length
• Production process: laminating


  materials in multiple layers. Can improve strength, stability, apperance
• production process: milling


  Process using rotary cutters to remove materials from a workpiece
• production process: turning


  involves rotating a workpiece, using a cutting tool to remove material
• Production process: casting


  liquid is poured into a mould of the desired shape then cools to solidify. Then ejected
• Production process: stamping


  placing a flat sheet metal into a press and using a tool or die to remove the shape
• Production process: forming


  Mechanical deformation changes the shape of a material