gcse.textiles.product.design

• Thermoforming Polymers


  Materials that can be heated and shaped repeatedly, and are able to be recycled
• Acrylic


  • Hard with good plasticity when heated, so it can be bent and folded easily
  • Resists weather well, but it is easy to scratch and can be brittle
  • Popular for car headlights, protective visors and baths
  • Frequently used for D&T school projects
• Polypropylene (PP)

  • Lightweight, strong and tough, with good heat and chemical resistance
  • Used to make computer game cases, patio chairs, children's toys and food wrapping film
• Polyvinyl chloride (PVC)


  • Low-cost, can be flexible or rigid, glossy or matt, has good strength, chemical and weather resistance
  • Used to make window and door frames, guttering and building cladding
• High density polythene (HDPE)


  • Stiff and lightweight, provides excellent chemical resistance, has good plasticity when heated
  • Used for buckets, bottles, pipes and washing up bowls
• Polystyrene (PS)


  • Inexpensive sheet or foamed polymer, available in a range of opaque colours as well as transparent
  • Used in schools for vacuum forming
• Thermosetting Polymers


  Materials that are formed once and cannot be recycled
• Melamine formaldehyde


  • Excellent resistance to heat, moisture, scratching and staining, used for kitchen worktops and tableware
• Epoxy resin


  • Supplied in two parts, the resin and the hardener, creates a very strong adhesive with good chemical and heat resistance and excellent thermal insulation
• Urea formaldehyde


  • Hard, stiff polymer with excellent electrical insulation properties, used for switches, plugs and electrical fittings
• Polyester resin


  • Forms with a reaction of acids and alcohol, commonly used in sheet moulding compound, and in toner of laser printers
• Sources of polymers


  • Synthetic polymers made from crude oil by scientists and engineers
  • Natural polymers made using a variety of materials like silk, wool, cellulose and proteins
• Difference between thermoforming and thermosetting polymers

  • Thermosetting polymer will strengthen when heated, and cannot be remoulded or heated after the initial forming
  • Thermoplastic can be reheated, remoulded and cooled as needed without causing a chemical change
• Availability of polymers


  • Sheet
  • Film
  • Bar
  • Rod
  • Tube
• Ferrous metals


  Metals that contain iron and are magnetic
• Ferrous metals


  • Prone to rust and require a protective finish to prevent corrosion
• Cast iron


  Brittle if thin, can be cast in a mould, has strong compressive strength, good electrical and thermal conductivity, but poor resistance to corrosion
• Uses of cast iron


  • Gates, manhole covers, drains and vices
• High carbon steel (tool steel)

  Hard and brittle, less malleable than mild steel, good electrical and thermal conductor
• Uses of high carbon steel


  • Tools, screwdrivers, and chisels
• Low carbon steel (mild steel)


  Ductile and tough, easy to shape, braze and weld, good conductor of heat and electricity, but corrodes easily
• Uses of low carbon steel


  • Nuts and bolts, screws, bicycle frames and car parts
• Alloy


  A mixture of metals with an element to improve its working properties or aesthetics
• Alloys


  • Brass (copper and zinc)
  • Bronze (copper, aluminium and/or nickel)
  • Stainless steel (iron, chromium, nickel and magnesium)
• Non-ferrous metals


  Metals that do not contain iron and are not magnetic, do not rust
• Hardwoods


  • Come from trees that lose their leaves during autumn and are known as deciduous trees
  • Slow-growing and therefore less amounts are available, which makes it more expensive
• Aluminium


  Lightweight, malleable and strong, good conductor of heat and electricity
• Hardwoods


  • Oak
  • Beech
  • Mahogany
• Oak


  • Moderate brown colour with close, straight grain
  • Tough and durable hardwood, polishes well and is used for high quality furniture, doors, skirting and staircases
• Uses of aluminium


  • Drinks cans, cycle frames and saucepans
• Beech


  • Pink-tinted, closely grained hardwood
  • Very tough and durable material, smooth to finish, popular with products that require a hard-wearing and robust material
• Copper


  Very malleable and an excellent conductor of electricity and heat
• Mahogany


  • Dark red/brown hardwood with very close grain
  • Cuts and polishes easily, gives a deep finish, popular for furniture and cabinet making
• Uses of copper


  • Plumbing and central heating applications
• Natural timber availability


  • Plank
  • Board
  • Strip
  • Square
  • Dowel
• Silver


  Soft and malleable when hot, highly corrosion-resistant and a good conductor
• Uses of silver


  • Jewellery
• Natural timbers need to be cut at the sawmill and seasoned before use. Many are planed and cut to standard sizes ready for sale.
• Brass


  Strong, ductile and a good conductor of heat, works well when cast, golden in colour but darkens with age
• Softwoods


  • Come from trees that are evergreen, possibly bearing pinecones and needles, not leaves and are known as coniferous trees
  • Grow quicker and in more locations, readily available and less expensive