Converting a casting (investment, die, or sand casting) to MIM can significantly reduce per-part cost — but only if the part fits MIM's capabilities.
Feasibility screening checklist:| Screening Question | Pass | Fail | If Fail — Options |
|---|---|---|---|
| Part weight under 50 g? | Proceed | Not suitable for MIM | Keep as casting |
| Max dimension under 50 mm? | Proceed | Not suitable for MIM | Keep as casting |
| Annual volume over 5,000? | Proceed | MIM tooling may not pay back | Use casting or CNC |
| Material available in MIM? | Proceed | Check if switching to MIM-compatible alloy is possible | Consider 316L or 17-4PH substitute |
| Wall thickness below 6 mm? | Proceed | May need cavity design change | Core out thick sections |
| Tolerances achievable in MIM? | Proceed | Relax to ±0.3% of dimension | Identify which tolerances are truly critical |
| Original Process | Typical Savings | When MIM Wins |
|---|---|---|
| Investment casting (small parts) | 20-40% | Volumes >10,000/yr, complex geometry |
| Die casting (zinc) | 10-30% (if switching to SS) | When stainless properties are needed |
| Sand casting (small parts) | 30-50% | When machining reduction offsets tooling cost |
If the part weighs under 50 g, maximum dimension under 50 mm, annual volume over 5,000, and the material is MIM-compatible (stainless steel, low-alloy steel, titanium), conversion is feasible. The main changes needed are: adding draft angles (0.5-1.0°), increasing internal radii (R ≥ 0.2 mm), and adjusting tolerances to MIM's ±0.3% capability. Expect 20-40% cost savings vs investment casting at comparable volumes.