POM (Acetal)
POM (polyoxymethylene, acetal, often called Delrin) is a stiff, strong, low-friction plastic with excellent dimensional stability and machinability. It is the go-to material for precision gears, bushes, rollers, cams and small mechanical parts.
What it is
Acetal absorbs very little moisture, so it holds tight tolerances better than nylon. It machines cleanly with a good finish and has good fatigue and creep resistance. Homopolymer (such as Delrin) is slightly stronger; copolymer has better chemical and hot-water resistance.
Acetal is widely used in food machinery (FDA grades), automotive and consumer mechanisms.
Typical applications
- Precision gears and cams
- Bushes and bearings
- Rollers and guide wheels
- Valve and pump parts
- Food machinery components
Materials & grades
- POM homopolymer (e.g. Delrin)
- POM copolymer (POM-C)
- PTFE-filled acetal
- FDA/food-grade acetal
Points to consider
- Poor resistance to strong acids and chlorine; check chemicals.
- Not recommended for continuous use above ~100 °C.
- Difficult to bond; design for mechanical fixing.
- Excellent for tight-tolerance parts thanks to low moisture uptake.
Frequently asked questions
Is acetal the same as Delrin?
Delrin is a brand of acetal homopolymer. Acetal (POM) is the generic material, available as homopolymer or copolymer.
Acetal or nylon, which is better?
Acetal holds dimensions better (low moisture uptake) and machines more precisely; nylon is tougher and more wear resistant in abrasive conditions.
Is acetal food safe?
FDA-compliant acetal grades are widely used in food processing equipment.