MIM Design Guide

Basic MIM Design Guide

Components made with metal injection molding (MIM) are similar to those made by plastic injection molding in complexity and artifacts. Gate, ejector pin, and parting line artifacts are mostly unavoidable and need to be strategically located for both application and process. MIM is best suited for components that will fit on the palm of your hand and components that have thin wall sections. A flat feature to provide uniform support for sintering is one feature that is strongly recommended to avoid sintering fixturing costs.

Design Dos

bullet-yellow Maintain uniform wall thickness

bullet-yellow Core out thick areas

bullet-yellow Deign with a flat surface, lettering, and threads

bullet-yellow Consider location of gates, ejector pins, and parting lines

Design Don’ts

bullet-yellow Don’t design walls thinner than 0.1 mm (0.0039 in)

bullet-yellow Don’t design holes smaller than 0.1 mm (0.0039 in) in diameter

bullet-yellow Don’t design components over 12.5 mm (0.5 in) thick and over 100 grams in mass

bullet-yellow Don’t design sharp corners

Typical Attributes Produced by the MIM Process

AttributeMinimumTypicalMaximum
Component Mass (g)0.03010-15300
Max Dimension (mm)2 (0.08 in)25 (1 in)150 (6 in)
Min Wall Thickness (mm)0.12 (0.005 in)*5 (0.2 in)15 (0.6 in)
Tolerance (%)0.02%0.5%1%
Density93%98%100%
Production Quantity1,000100,000100,000,000
*Features this small could have distortion.
Further Information: Handbook of metal injection molding, ed. D. Heaney, ISBN: 978 0 85709 066 9.