Injection Moulding

Also called: Injection molding, IM

Injection moulding forms plastic parts by injecting molten plastic into a closed mould under pressure, then cooling and ejecting the part.

Injection moulding is a process in which plastic granules are melted in a heated barrel and injected under pressure into a closed steel mould. The plastic cools and solidifies in the shape of the cavity, and the part is ejected. It is used for a huge range of parts, from caps and crates to appliance housings and automotive components.

Why it matters when buying recycled plastic

• Injection moulding generally needs higher MFI than extrusion or blow moulding; thin-wall parts need the highest flow.
• Consistent MFI between lots helps keep cycle times, fill and part weight stable.
• Moisture-sensitive plastics such as ABS, PC and nylon must be dried before moulding.
• Fine metal or hard contaminants can block nozzles and damage moulds, so clean material is essential.

Recycled materials commonly used

Recycled PP, HDPE, ABS, HIPS, PC, nylon and POM are widely used, either alone or blended with virgin resin. Moulders also reuse their own runners and rejects as regrind.

Run a trial with each new recycled lot, checking fill, shrinkage, surface finish and part weight against your normal production.