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Reference · IM Machine

Press components.
Hopper. Barrel.
Machine basics.

Injection molding machine components reference. Hopper, barrel, screw, mold clamp, ejector. Understanding machine helps design.

01 · Key principles

Key principles.

Hopper

Material feed

Holds plastic pellets. Drying for hygroscopic materials.

Barrel + screw

Melt + inject

Heated barrel melts plastic. Reciprocating screw injects.

Nozzle

Gate to mold

Connects barrel to mold. Hot or cold runner.

Mold clamp

Mold halves

Closes mold during injection. Clamp force = projected area × pressure.

Ejector

Part removal

Pushes part out of mold after cooling.

Cooling

Mold temperature

Cooling channels in mold. Critical for cycle time.

FAQ

Clamp tonnage selection?

Tonnage = projected area × cavity pressure. Typical 30-100 tons for small parts. 1000+ tons for large.

Screw vs barrel?

Screw rotates and slides forward. Barrel heats material. Both maintain melt temperature.

Hot vs cold runner?

Hot runner: faster cycle, less waste, $5-20K tool premium. Cold runner: cheaper, slower, runner waste.

Cooling cycle time?

Cooling 50-80% of cycle time. Conformal cooling channels reduce significantly.

Mold release agent?

Spray-on release for difficult parts. Periodically as needed. Permanent coatings premium.

Machine sizing?

Match machine to part. Too small: not enough force. Too big: wastes capacity.

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