MIM mold temperature is typically set to 40-80°C for standard binder systems, controlled to ±2°C across the mold surface. POM-based binders run at the higher end (60-80°C), wax-polymer binders at the lower end (40-60°C). Water temperature controllers provide adequate control for most MIM molds.
Mold temperature guidelines by binder system:
| Binder System | Recommended Mold Temperature | Temperature Uniformity | Cooling Medium |
|---|---|---|---|
| POM (catalytic) | 60-80°C | ±2°C across cavity | Hot water or oil |
| Wax-polymer | 40-60°C | ±3°C | Water |
| Water-soluble (PEG) | 35-50°C | ±3°C | Water |
A temperature difference of just 5°C across the mold cavity can cause:
- Non-uniform shrinkage — parts warp toward the colder side
- Gate freeze timing differences — inconsistent packing
- Surface finish variation — zones of different gloss levels
| Symptom | Cause | Fix |
|---|---|---|
| Part sticking on cavity side | Mold too cold at core; too hot at cavity | Balance temperatures between A and B sides |
| Sink marks near thick sections | Mold too hot — material solidifies too slowly | Reduce mold temperature 5-10°C |
| Short shots in thin sections | Mold too cold — material freezes before fill | Increase mold temperature 5-10°C |
| Inconsistent shot weight | Mold temperature oscillation | Check temperature controller calibration |
| Flash at one corner only | Local hot spot on mold | Check cooling channel function in that quadrant |