If you have designed a precision mechanical part that has to move, there is a good chance you specified POM. Also called acetal or polyoxymethylene, POM is the engineering plastic that replaced a lot of metal — not because it is the strongest, but because it is the most useful when you need accuracy, low friction and repeatability.
The properties that matter
| Stiffness & strength | High — close to some metals |
| Dimensional stability | Excellent — low moisture absorption |
| Friction | Low, self-lubricating |
| Wear resistance | Very good in sliding contact |
| Machinability | Outstanding — takes fine finishes |
| Max service temp | Approx. 90 °C (short-term to ~140 °C) |
Homopolymer vs copolymer
POM comes in two main families. Homopolymer (like Delrin) is slightly stronger and stiffer. Copolymer is a little more forgiving, resists hot water and weak alkalis better, and is easier to mould. Both machine superbly; pick based on temperature, chemicals and long-term load.
Where POM shines
- Gears and racks — quiet, self-lubricating, dimensionally accurate.
- Bushings and bearings — low friction without external lubricant.
- Rollers and conveyor parts — wear-resistant under continuous motion.
- Precision machined components — where tight tolerances matter.
- Mechanical assemblies — cams, slides, and snap-fit parts.
Where it falls short
POM is not the material for strong acids or bases, and its temperature ceiling is modest compared with PTFE or PEEK. It is also relatively dense. But for dry, precise, sliding mechanical duties, it is very hard to beat — and it is usually the most cost-effective answer.
Get POM in the form you need
We stock POM-C and POM-H in sheets, rods and machined parts, including food-contact and wear-modified grades. See the full POM specification or ask for a quote.