Manufacturing services · Chapter E · Method 31

Metal injection moulding (MIM)

Fine metal powder mixed with binder is injection moulded, then debound and sintered into dense, small, complex metal parts.

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Metal injection-moulded components. Representative process photo · INDO-MIM PVT. LTD. · CC BY-SA 4.0 · Wikimedia Commons

How it works

Metal injection moulding (MIM), step by step.

A labelled schematic of the process (not to scale), and the four steps every job goes through.

Labelled diagram showing how metal injection moulding (mim) works — Schematic · not to scale. Drawn by TCI Group.

STEP 01

Feedstock

Mix metal powder with a polymer binder.

STEP 02

Mould

Injection mould an oversized 'green' part.

STEP 03

Debind

Remove most of the binder chemically or thermally.

STEP 04

Sinter

Sinter to near-full density; the part shrinks.

Reference figures

What to expect.

Typical industry values to help you plan. We agree the figures for your part on the drawing.

ShrinkLarge, predictableCompensated in the tool

SizeSmall partsTypically under 100 g

DensityNear fullAfter sintering

VolumeHighTool cost amortised

Materials	Stainless 316L and 17-4PH, low-alloy steels, titanium and tungsten alloys.
Finishes	As sintered; machined, polished, heat treated or plated.
Design guidance	Keep walls uniform and small parts small. Avoid large flat areas that can sag in sintering. Treat as injection moulding for draft and gating.
Best suited to	Small complex parts for medical, firearms, watches and consumer devices.
Watch-outs	Only economical at volume; size is limited.

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Reference figures are typical published industry values for planning, not a guarantee; final tolerances, materials and finishes are agreed in writing for each project.