The mould is the tool that shapes the part in injection moulding. It consists of two precision-machined halves: a fixed half on the injection side and a moving half on the ejection side. Each cycle, the halves close, molten plastic is injected under high pressure, the part cools and the ejection system pushes it out. The process repeats thousands, sometimes millions of times.
The main components of a mould
The cavity and the core together form the impression where the part is created. The feed channel brings molten material from the press to the impression. Cooling channels, drilled at constant distance from the part, remove heat and largely determine cycle time. Ejector pins push the solidified part out. Complex parts require extra mechanisms: sliders for undercuts, unscrewing cores for threads.
What is a mould made of?
For validation and limited volumes, aluminium wins: faster to machine and to deliver. For series production, hardened steel is the norm, usually P20 or H13. Glass-filled plastics are abrasive and always require hardened steel. The mould material follows from two questions: how many parts will you produce, and in which plastic?
How long does a mould last?
An aluminium pilot mould produces thousands to tens of thousands of parts. A steel series mould reaches hundreds of thousands to millions of cycles, provided it is maintained: cleaning, lubrication of moving elements and periodic inspection of the parting faces. An idle mould is stored dry and greased to prevent corrosion.
Why mould design decides everything
The quality of your part is not decided at the injection press but on the mould drawing board. Draft angles, wall thicknesses, gate position and thermal regulation determine whether the part comes out without warpage or visual defects. That is why every project starts with a DfM analysis by our design office, before any steel is ordered. Moulds are then adjusted and fine-tuned in our Belgian workshop.
Need a mould for your project?
Send us your 3D file or even a sketch: our design office analyses feasibility within 48 hours and advises on material, cavity count and mould type. For start-ups and SMEs, our co-investment model finances part of the mould.
