Long-associated with plastics, injection moulding can also be used to produce complex parts from metal. It uses a powder mixture of metal and polymer, which is then melted and poured into a mould tool where it settles into the cavities and solidifies in the required shape. When the metal/polymer powder mixture (also known as 'feed stock') is heated, the metal does not actually melt - only the polymer. This makes it suitable for a whole range of metals, with some of the most popular being stainless steel, iron, copper alloys, titanium alloys and low-alloy steel.
After the injection moulding process is complete, the components then need to undergo a process called de-binding, where either a solvent or the application of heat is used to remove the polymer binding from the parts. Finally, the components must be sintered to ensure high density - this process involves placing the parts in a high-temperature furnace, where any empty space inside the parts is reduced as the components shrink under the heat.