How To Solve Sintering Shrinkage & Distortion Of MIM Precision Parts

MIM metal injection molding precision parts are characterized by complex irregular shapes, small size and high precision requirements. Sintering shrinkage inconsistency and local deformation are the most common and difficult-to-solve quality problems in MIM production, directly restricting product qualification rate and batch stability.

Most shrinkage and deformation defects are not caused by raw material problems, but by unstable furnace temperature field and unreasonable heating and cooling curves. Optimizing furnace equipment performance and process parameters can fundamentally control MIM part sintering deformation.

Root Causes of Sintering Deformation

Uneven furnace temperature field leads to inconsistent heating speed of different parts of complex-shaped workpieces, resulting in asynchronous shrinkage and local distortion. Excessively fast heating rate causes unbalanced internal and external stress of parts, which cannot be released in time and remains as deformation residual stress.

Unreasonable furnace atmosphere flow leads to uneven surface sintering speed of workpieces. Irregular workpiece placement and stacking cause local stress accumulation, further aggravating dimensional deviation and deformation defects.

Targeted Solutions to Reduce Distortion

Adopt multi-zone independent PID temperature control technology to realize overall uniform furnace temperature field and eliminate local temperature difference. Set slow gradient heating curves to release internal metal stress step by step and avoid stress concentration.

Optimize the internal furnace circulation wind field to ensure uniform contact between protective atmosphere and all surfaces of workpieces. Standardize workpiece placement specifications and support with professional fixture trays to fix workpiece shapes and reduce free deformation.

Effect After Process Optimization

After equipment and process optimization, the sintering shrinkage rate of each batch of MIM parts tends to be consistent, with stable dimensional tolerance and greatly reduced local distortion rate. The qualification rate of precision parts is significantly improved, effectively reducing rework and scrap losses and improving factory profit margin.

Conclusion

MIM precision part sintering deformation is a controllable quality problem. Stable furnace temperature uniformity and scientific gradient heating curves are the core solutions to shrinkage and distortion. Professional furnace equipment optimization and process parameter debugging can help MIM factories achieve stable high-precision part production.