Materials · Polymer

POM / Acetal

A dimensionally useful, low-friction engineering plastic widely used for gears, bushings, clips and precision mechanisms.

BM
Prepared by Bertrand Mezatio

Mechanical engineering perspective focused on CAD, DFM and manufacturing. Values are educational starting points, not procurement specifications.

Why engineers choose POM / Acetal

POM is attractive where low friction, wear behavior, spring action and dimensional repeatability are important. It machines well and is common in small functional components.

Manufacturing routes

POM / Acetal is commonly encountered in Injection molding · machining. The process route matters because material condition, anisotropy, tolerances, surface finish and residual stress can differ substantially between molding, machining and additive manufacturing.

Design considerations

Avoid large thick masses, provide radii at stressed snap features, and account for molding shrinkage. Bonding can be difficult because of its low surface energy, so mechanical retention is often preferable.

Environment and durability

Moisture uptake is low compared with many nylons. UV resistance is limited without stabilization, and strong acids/oxidizers require compatibility review.

Relative engineering profile

These 1–5 ratings are deliberately qualitative. They help shortlist materials but must not replace grade-specific datasheets, testing or supplier guidance.

Relative stiffness
4/5
Toughness
4/5
Heat capability
3/5
UV/weather
2/5
Moisture resistance
5/5

What to compare before specifying it

Compare POM with PA for tougher/moisture-sensitive mechanisms, PP for lower-cost living hinges, and metals when wear load or temperature exceeds polymer capability.

Specification note: Material names such as ABS, PA6, 316L or Ti-6Al-4V describe families or alloy designations, not a complete purchasing specification. Grade, temper/condition, reinforcement, colorant, certification, processing route and supplier data can materially change performance.