Metal forming is a wide ranging family of processes and techniques. Many developed over centuries. The important principle is that raw materials are shaped and reformed. This is about plastic deformation that changes the shape, form and character of materials. While many plastics and related processes are also available to designers, steel is the number one material worldwide due to availability, sustainability and low cost.
Materials are supplied as ingots, powder, bars, strip, wire, tubes and in sheet form. Often ready to process the metals are heat treated to anneal or normalise them prior to forming. Metals can be either cold worked or hot worked depending on the process. Both ferrous and non-ferrous materials need handling differently and many sheet metals are also pre-coated with a plastic or anodised finish.
Other jobs require finishing with a plate or galvanised finish after forming. The range of metal forming includes: Pressing, Rolling, Forging, extrusion, Drawing, Sheet metal folding, punching, piercing, blanking, shearing, spinning, powder metallurgy and even explosive forming.
Continuous forming of parts keeps unit costs down. Strip and sheet metal cost to volume ratio is high, so adding value into cold worked components and products. An innovative prospect is Metal matrix materials (MMC) where gas and heat are used to force liquid metal matrix (or powders) of combined materials and alloys into preformed shapes and networks with reinforced webs and fibres. Multi-layer sheet metal mouldings sandwiched together also creates high strength low weight structures like honeycombs.
Additionally a whole new family of rapid prototyping (RP) processes is available to designers and engineers: Fused deposition modelling (FDM), Stereolithography (SLA) where liquid polymer is cured under UV light and 3D printing (3DP) where particles are fused together. These are additive processes and are high cost-low volume processes working with plastics to produce prototypes and test pieces. Laminated object manufacture (LOM) is an exciting method of ‘growing’ prototypes from sheet materials in successive glued up layers. Additionally, Selective Laser Sintering (SLS) utilises a laser to create heat and fuse metallic and non-metallic powders to create working solid products.