Injection moulding is by far the most common process employed by designers for plastic products. This is because the dimensions and shapes can be accurately controlled and the process is very reliable in production. A diagram of the equipment required is shown below and should be familiar from your notes on extrusion.
is fed from the hopper and forced through the heating units by an Archimedian
screw. The molten plastic is then forced into mould, which, after sufficient
cooling time, is opened and the product removed.