Technical Article

Machining Special Alloys: PEEK, Invar, Kovar & More

Special alloys reward preparation and punish guesswork. Here is how we hold tolerances on the materials that defeat standard setups.

Know the material behaviour

Invar is dimensionally stable but gummy; Kovar work-hardens; PEEK springs back. Each needs its own speeds, feeds and tool geometry.

Rigidity and heat

Use rigid clamping and sharp tools. For plastics, manage heat so the part does not distort; for alloys, control work hardening with consistent depth of cut.

Finish and inspection

Special alloys often serve measurement or sealing roles — hold Ra and flatness, and verify with CMM rather than relying on visual checks.

Frequently asked questions

Why does PEEK need special care?

It has low thermal conductivity and elastic memory; poor heat management causes size drift and poor finish.

Can Invar hold micron tolerances?

Yes with stable fixturing and controlled temperature during machining and measurement.