Selection Of Materials And Components

There is a moment in every project when a material stops being a word in a folder and becomes something that has to be ordered, in a size that exists, from somebody who has it, before Thursday. That moment is when most design specifications quietly fall apart, because oak is not an order and 3 millimetre acrylic is not an order either until you know what size sheet it comes in, how many parts you can get out of one, and whether the price is per sheet or per square metre.

This topic is the practical half of material selection. The Section B topic gave you eight factors for judging a material; here the specification names only three, and they are the three that decide whether a prototype gets made: functional need, cost and availability. Alongside them it asks you to use SI units correctly and to identify appropriate commercially available stock and select appropriately. You will build a cutting list, cost it, convert between units without losing a factor of a thousand, and decide what to do when the material you wanted cannot be had. This is designing and making principles content, examined in Section C of Paper 1.