Materials → Acetal (POM)
Material profile · 05/06
ACETAL (POM)
A rigid, low-friction engineering plastic for guide and wear ring duty.
- -40°C to 90°C
- Temp. range
- High rigidity
- Hardness
- Low
- Friction
- Excellent
- Dimensional stability
Overview
Where Acetal (POM) earns its place.
Acetal (POM) is not a sealing material in the elastomeric sense — it is a rigid engineering thermoplastic used where the job is guiding, not sealing. Wear rings carry side-load from the rod or piston and keep metal away from metal, and POM's stiffness, low moisture absorption, and dimensional stability under load make it a reliable choice for that structural role, particularly in cleaner, moderate-duty applications.
Trade-offs
Advantages and limitations.
Advantages
- High stiffness and load-bearing capacity for guide-ring duty.
- Low moisture absorption keeps dimensions stable across humidity swings.
- Naturally low friction against metal running surfaces.
- Machines cleanly to tight tolerances for custom groove fits.
Limitations
- Lower load and heat capacity than phenolic composite in heavy-duty service.
- Can degrade under prolonged UV or certain acid/oxidiser exposure.
- Not a sealing material — always paired with a dedicated seal element.
Operating envelope
Typical technical reference.
Figures are typical for the compound family and vary by specific grade and cure. Confirm exact limits against your fluid, pressure, and duty cycle before finalising a specification.
| Operating temperature | -40°C to 90°C continuous |
| Typical hardness | Rigid engineering plastic |
| Friction coefficient | Low |
| Fluid compatibility | Mineral oils; limited acid/oxidiser resistance |
| Duty type | Structural guide/wear ring, non-sealing |
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Engineering support
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