POM (Polyoxymethylene) CNC Machining

POM (Polyoxymethylene), known by brand names such as Delrin® (DuPont) or Hostaform® (Celanese), is one of the most important engineering plastics for CNC machining. With its excellent dimensional stability, low friction coefficient, and good wear resistance, POM replaces metallic bearings and guide elements in many applications.

POM exists in two variants: POM-H (homopolymer, e.g., Delrin) with higher stiffness, and POM-C (copolymer, e.g., Hostaform) with better chemical resistance.

Pro tip: When in doubt, choose POM-C — it is more versatile, less expensive, and sufficient for 90% of applications. POM-H only when highest stiffness or spring properties are required.

POM machines excellently — it behaves almost like free-machining brass:

• Cutting speed: 200–500 m/min — very high speeds possible
• Tools: Sharp solid carbide end mills, polished edges. No coating needed
• Coolant: Compressed air or dry. Emulsion can cause swelling!
• Chip form: Short-breaking chips, similar to brass
• Tolerances: ±0.05 mm reproducible. For tighter tolerances: temperature-condition the workpiece

Caution: POM has a thermal expansion coefficient of ~110 × 10⁻⁶/K (10× higher than steel). Room temperature fluctuations can cause dimensional changes — for tight tolerances, machine in a climate-controlled environment.

• Mechanical Engineering — Gears, sliding elements, guide bushings, rollers
• Automotive — Fuel components, lock mechanisms, door handle parts
• Food Industry — Conveyor chains, dosing, valve seats (FDA compliant)
• Electrical Engineering — Insulators, coil bobbins, connector housings