What is injection moulding: How does an injection moulding machine work

Injection Molding Overview

Injection moulding is one of the most widely used manufacturing processes in the plastic industry due to its quick cycle of production, material and colour flexibility, low labour costs, design flexibility and low waste. Injection moulding is the preferred process for manufacturing thermoplastic and thermosetting plastics parts of diverse industrial sectors such as packaging, electrical and electronics and automotive, etc.

This process converts solid plastic pellets to viscous masses by thermal conduction and pressure which are then injected into a mould where the melt acquires its final shape by cooling down. The process cycle can vary, typically from a few seconds to minutes, depending on the size of the moulds and materials used.

How does an injection moulding machine work?

Injection Moulding Machine

Material granules for the part is fed via a hopper into a heated barrel, melted using heater bands and the frictional action of a reciprocating screw barrel. The plastic is then injection through a nozzle into a mould cavity where it cools and hardens to the configuration of the cavity. The mould tool is mounted on a moveable platen – when the part has solidified, the platen opens and the part is ejected out using ejector pins.

After a product is designed, usually by an industrial designer or an engineer, moulds are made by a mouldmaker (or toolmaker) from metal, usually either steel or aluminum, and precision-machined to form the features of the desired part.