CNC Milling for PEEK (Polyether Ether Ketone)
CNC milling PEEK requires understanding its unique properties as a semi-crystalline thermoplastic. Proper thermal management is critical — too much heat changes crystallinity and dimensions.
Recommended Machining Parameters
| Parameter | Value |
|---|---|
| Achievable Tolerances | ±0.02 mm (±0.001") |
| Surface Finish | Ra 0.8-3.2 μm |
| Cutting Speed | 100-250 m/min (SFM 330-820) |
| Feed Rate | 0.05-0.15 mm/tooth |
| Tooling Recommendations | Sharp uncoated carbide, 2-3 flutes with polished flutes. O-flute single-flute for finishing. |
Expert Machining Tips
1
Use sharp, uncoated carbide tools
2
Moderate speeds to avoid melting
3
Compressed air cooling preferred (no oil contamination)
4
Support thin walls to prevent deflection
5
Anneal stock before machining for stability
Common Parts Made
Semiconductor fixtures
Medical device housings
Bearing retainers
Valve seats
Electrical insulators
Machining Challenges
- Material cost ($100+/kg) — minimize scrap
- Thermal expansion during machining
- Crystallinity changes affect properties
- Dust can irritate lungs (use extraction)