What are the Solutions to address Sink Marks and Voids in MIM?

Date：2025-07-28   Views：1002

Formation Mechanisms

During MIM molding, precise control of temperature and pressure is critical. Low molding or hold pressure causes:

• Regions of low green density

• Incomplete cavity filling

Poor vent design combined with long runners leads to:

• Premature gate solidification

• Internal voids at thick sections

These low-density zones/voids form pits (sink marks) after sintering.

Root Cause Summary

Possible Solutions

• Increase hold pressure & molding pressure

• Enlarge gates

• Add venting channels

• Reduce speed through thick sections OR Relocate gates to thick sections

Critical Trade-offs

*Optimization requires balancing conflicting measures to find the optimal ratio.