POM (Delrin)
High-stiffness acetal with low friction, excellent dimensional stability, and fatigue resistance. Ideal for precision mechanical components, gears, and sliding mechanisms.
About POM (Delrin)
POM (Polyoxymethylene), commonly known by the trade name Delrin, is the precision engineer's thermoplastic. Its combination of high stiffness, low friction, excellent dimensional stability, and outstanding fatigue resistance makes it the first choice for precision mechanical components.
FabRapid CNC machines POM for gears, cam followers, bearings, conveyor components, and precision mechanisms. POM machines beautifully — producing smooth surfaces with tight tolerances and minimal burring. Its low moisture absorption (0.2%) ensures that machined dimensions remain stable in service.
Two main types exist: POM-H (homopolymer, "Delrin") offers slightly higher strength and stiffness, while POM-C (copolymer) provides better chemical resistance and easier processing for injection molding.
Material Properties
Compatible Manufacturing Processes
POM (Delrin) can be processed using these manufacturing methods.
Available Surface Finishes
Surface treatments compatible with POM (Delrin).
Common Applications
Design Guidelines for POM (Delrin)
POM is ideal for snap-fit designs — its high yield strain allows significant elastic deformation
Minimum wall thickness: 0.5 mm for CNC machining — POM supports very thin walls
For gear applications, pair POM with nylon for optimal noise reduction and wear performance
Avoid sharp corners — POM is notch-sensitive; use minimum R0.5 mm fillets
POM (Delrin) FAQ
Delrin is DuPont's trade name for POM-H (homopolymer). Generic POM is typically POM-C (copolymer). Homopolymer has slightly higher strength (69 vs 65 MPa) and stiffness but lower chemical resistance. Copolymer has better resistance to hot water and alkaline solutions. For most mechanical applications, the difference is minimal.
POM has residual stresses from the extrusion or molding process. Aggressive machining can release these stresses, causing warping. To minimize this: machine from stress-relieved stock, take light passes, allow the part to stabilize between roughing and finishing, and avoid removing material asymmetrically.
POM has very low surface energy, making adhesive bonding difficult. Surface preparation (plasma treatment, flame treatment, or chemical etching) is required before bonding. Mechanical fastening or press-fitting is generally more reliable for POM assemblies.
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