Metals Year 10 & 11 Product Design Materials 1 Plastics - Polymers Most metals are extracted from their ores using a chemical reaction. Metals are rarely used in their pure form, and are usually mixed with other metals to improve their properties. This is called an alloy. Most metals are good conductors and can be recycled. Ferrous metals Ferrous metals contain iron. Examples are cast iron, mild steel, medium carbon steel, high carbon steel, stainless steel and high speed steel. The ferrous metals listed below are all alloys. Plastics - Polymers Natural sources of polymers include: Plants - from which cellulose can be extracted Trees - from which latex, amber and resin can be extracted Animals - from which horn and milk (used to make glues) are obtained insects - from which shellac (used to make polish) is obtained Synthetic- Synthetic plastics are chemically manufactured from: crude oil, coal, natural gas Thermoplastics and thermoset plastics Plastics are divided into thermoplastics and thermoset plastics. Ferrous Metals Product Life Cycle Life cycle is the time from a product’s manufacture, to its recycling or disposal, at the end of its useful life. Customers often expect products to be designed and manufactured, so that they do as little damage to the environment as possible, throughout their entire lifetime. Products should: Be manufactured, from sustainable / recyclable materials, produce as little pollution as possible, during manufacture and use. Use as little energy / fuel as possible Non Ferrous Metals CNC router

Product Life Cycle Year 10 & 11 – Product Design Timber There are two types of timber, called hardwood and softwood. These names do not refer to the properties of the wood: some softwoods can be hard and some hardwoods can be soft. Softwood Softwoods come from coniferous trees which are evergreen, needle-leaved, cone-bearing trees, such as cedar, fir and pine. Hardwood Hardwoods come from broad-leaved, deciduous trees. The main hardwood timbers are ash, beech, birch, cherry, elm, iroko, mahogany, meranti, oak, obeche, sapele and teak. Working properties Different materials exhibit different working properties. Listed below are the key properties which determine how materials behave. conductivity is the ability of a material to conduct heat or electrical energy strength is the ability of a material to withstand a force without breaking or bending elasticity is the ability of a material to bend and then to return to its original shape and size plasticity is the ability of a material to permanently change in shape malleability is the ability of a material to permanently deform in all directions without cracking ductility is the ability of a material to deform, usually by stretching along its length hardness is the ability of a material to resist wear, scratching and indentation toughness is the ability of a material to withstand blows or sudden shocks without breaking durability is the ability of a material to withstand wear, especially as a result of weathering fusibility is the ability of a material to change into a liquid or molten state when heated to its melting point Product Life Cycle Life cycle is the time from a product’s manufacture, to its recycling or disposal, at the end of its useful life. Customers often expect products to be designed and manufactured, so that they do as little damage to the environment as possible, throughout their entire lifetime. Products should: Be manufactured, from sustainable / recyclable materials, produce as little pollution as possible, during manufacture and use. Use as little energy / fuel as possible Polymorph Polymorph is available in small pellets which fuse together when heated to 62˚C. It can be moulded into shape resulting in a very tough polymer. Unused pellets can be re-heated and re-used. Polymorph is used for: manufacturing awkward shapes such as ergonomic handles joining components together making moulds for vacuum forming. Smart Colours Smart colours are pigments which can be incorporated into paints, dyes, inks and plastics. thermochromic pigments react to changes in temperature photochromic pigments react to changes in light levels Photochromatic materials are used in the manufacture of sunglasses. Exposure to sunlight causes the lens of the glasses to darken to protect the eye. Graphene Graphene is made of a sheet of carbon atoms in a hexagonal lattice. Of the above, it is closest in form to graphite, but whereas that material is made from two-dimensional sheets of carbon held layer-upon-layer by weak intermolecular bonds, graphene is only one-sheet thick. Year 10 & 11 – Product Design CNC router