The machinery to facilitate the process comprises a self-contained injection moulding machine (IMM) and a mould. The mould is designed and manufactured to produce a specific part and is mounted between the fixed and moving platens of the clamping unit of the IMM. The clamping unit (or press) opens and moves the two halves of the mould apart from each other - to enable ejection of the cooled moulding. The whole machine is commonly driven by hydraulic actuators and motors although the usage of entirely electrical actuators has been increasing since the early 1980's.
The history of the first injection moulding machine can be traced back to1872 when an American engineer James Hyatt patented a machine to injection mould cellulose nitrate (Celluloid) billiard balls, but most modern machinery owes its heritage to James Hendry. In 1946 he made the most significant development of the injection unit by replacing the simple plunger inside a heated cylinder that Hyatt configured, with an auger.