MIM vs Investment Casting: Which Process Delivers Better Value?

MIM and investment casting are both near-net-shape metal processes, but MIM suits small, intricate parts under 100g with tighter tolerances and better surface finish, while investment casting wins for large parts over 250g, low volumes, and hollow features. MIM becomes 30-50% cheaper at 50,000+ pieces.

MIM vs Investment Casting: Two Precision Methods Compared

Both MIM and investment casting (lost wax) are near-net-shape processes for complex metal parts. But their cost structures and capabilities differ significantly.

Key Comparison

Factor	MIM	Investment Casting
Part Size	0.1g - 250g (ideal)	10g - 50kg+
Wall Thickness	0.3mm - 6mm	1.5mm minimum
Tolerances	±0.3% to ±0.5%	±0.5% to ±1%
Surface Finish	Ra 0.8-1.6μm	Ra 3.2-6.3μm
Density	>97%	95-99%
Tooling Life	100,000+ shots	1 use per mold
Small Features	Excellent (0.1mm)	Limited (1mm+)

When MIM Wins

• Small, intricate parts under 100g
• Superior surface finish as-sintered
• Tighter tolerances consistently
• High-volume production (10,000+ parts)
• Thin walls down to 0.3mm
• Less post-processing needed

When Casting Wins

• Large parts over 250g
• Very low volumes (under 1,000)
• Internal cavities and hollow features
• Extremely thick sections over 6mm

Cost Analysis

For a typical 20g stainless steel part:

• 1,000 pcs: Casting cheaper
• 10,000 pcs: MIM becomes competitive
• 50,000+ pcs: MIM 30-50% cheaper

Contact us for a free MIM vs casting analysis for your part.

Frequently asked questions

What part sizes suit MIM versus investment casting?

MIM is ideal for parts from 0.1g to 250g, while investment casting handles 10g to 50kg+. MIM wins for small, intricate parts under 100g; casting wins for large parts over 250g.

At what production volume does MIM become more cost-effective than investment casting?

For a typical 20g stainless steel part, casting is cheaper at 1,000 pieces, MIM becomes competitive at 10,000 pieces, and at 50,000+ pieces MIM is 30-50% cheaper.

How do MIM and investment casting compare on tolerances and surface finish?

MIM achieves tolerances of ±0.3% to ±0.5% and surface finish of Ra 0.8-1.6μm, while investment casting offers ±0.5% to ±1% and Ra 3.2-6.3μm. MIM also supports thinner walls down to 0.3mm versus casting's 1.5mm minimum.

See how MIM compares with all major metal processes in our MIM vs alternatives comparison guide.