Engineering Plastic
Acetal (POM / Delrin)
The default machining plastic: stiff, strong, dimensionally stable, and easy to cut to tight tolerances with low friction and low moisture pickup.
Last verified: 2026-07-10
| PolymerChemistry / common trade name. | Polyoxymethylene |
|---|---|
| Density(g/cm³)Typical specific gravity. | 1.42 |
| Tensile(MPa)Typical tensile strength (unfilled grade). | 70 |
| Max service(°C)Typical continuous service temperature. | 90 |
| Water abs.(%)Typical 24 h water absorption. | 0.2 |
| Machinability | Excellent |
| Known forThe property it's usually chosen for. | Stiffness + dimensional stability |
- Typical uses: precision machined parts, gears, bushings, wear pads, manifolds, fittings.
- Excellent machinability and tight tolerances; low moisture absorption keeps parts stable.
- Homopolymer (Delrin) is stiffest; copolymer resists hot water and centreline porosity better.
Other engineering plastics
Sources
- Manufacturer datasheets (typical properties for common unfilled grades)
- ASM International — Engineering Plastics (Engineered Materials Handbook)