PEI Machining CNC Services

What is PEI CNC Machining?

Polyetherimide (PEI), often known by the trade name ULTEM®, is a high-temperature engineering plastic with excellent rigidity, creep resistance, and dimensional stability. It machines crisply with sharp carbide and controlled heat, making it ideal for aerospace, semiconductor, and medical components.

• Tooling: Sharp micro-polished carbide (TiAlN/TiCN when needed); high positive rake.
• Heat control: Air blast or light mist; avoid local overheating and stress whitening.
• Feeds/Speeds: Moderate SFM with steady chip load; finish pass for critical faces.
• Workholding: Rigid fixturing/soft jaws; minimize vibration on thin walls.

Key Considerations

PEI is notch-sensitive—avoid sharp internal corners and heavy deburr pressure. For tight stability on large or thin parts, use a rough → condition/anneal → finish approach.

Keep moisture low (dry stock before machining if required). Use climb milling for cleaner edges and a light skim on show surfaces to unify color/texture.