Product design - Lunchboxes!

In choosing materials. there is lots to consider:

• Functional requirments - demands on material? E.g. Hold heavy things. Outdoors/ indoors? Need to fit in with an environment look? May need certain look.
• Availability - Get the fabric in suitable form? Mainly only in standard sizes, can be very expensive. Direct effect on cost, and method of manufacture.
• Production method - Some are easier to join than others, e.g. wood can be glues, screwed, nailed, bolted, knock-down fitting. It must be suitable for intened production method. E.g. use injection moulding with plastics but not wood.
• Economics - think about size, some are expensive, but may be a good choice. Is it a one-off, batch or mass produced? Will make difference. One-off; more expensive. Mass; cheap.

Thermoplastics - Recyclable and bendy!

They are easily formed into shapes, but don't resits heat! They are easy to recycle - they're ground down, melted and re-used.

Thermoplactics and their uses

• Acetate - hard, transparent and flexible. Used for overhead projector transparencies and packaging.
• Acrylic - hard, shiny. Resists weather well. For making motorcyle helmet visors, baths, signs, etc.
• Low-density Polyethylene (LDPE) - soft,strong but lightweight. For packaging, carrier bags, washing up liquid bottels, and to laminate paper.
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