POM / Delrin CNC Machining — Low Friction, High Precision
POM (Polyoxymethylene / Acetal / Delrin) is the engineer’s plastic — exceptional dimensional stability, low friction, and moisture resistance. The first choice for gears, bushings, and mechanical components requiring consistent performance.
Why Machine POM / Delrin?
No other engineering plastic matches POM’s combination of machinability, dimensional stability, and friction performance — at a price point a fraction of PEEK’s.
Excellent Machinability
POM machines cleanly with minimal burring, producing tight tolerances with standard HSS or carbide tooling. Low tool wear and excellent chip breakage.
Low Friction Without Lubrication
POM's low coefficient of friction (0.2 vs steel) and good wear resistance allow self-lubricating operation — eliminating oil or grease maintenance in gear and bushing applications.
Dimensional Stability
Only 0.2% water absorption — ten times less than nylon. POM parts hold their dimensions in humid environments and maintain gear mesh tolerances where nylon would swell and bind.
FDA-Compliant Grades Available
Natural (white) POM and specific copolymer grades are FDA-compliant for food contact. Used in food processing machinery, beverage dispensing, and packaging equipment.
POM vs Alternatives
Head-to-head against the materials engineers most often cross-shop for precision machined parts.
POM Grades We Machine
Five POM/acetal grades covering mechanical, chemical, food-safe, and high-load applications.
| Grade | Tensile (MPa) | Machinability | Best For | Common Uses |
|---|---|---|---|---|
| POM-H (Homopolymer / Delrin) | 70 MPa | Excellent | Mechanical precision parts | Gears, cams, bearings |
| POM-C (Copolymer / Acetal) | 62 MPa | Excellent | Chemical environments | Valves, fluid handling parts |
| POM FDA Grade | 62 MPa | Excellent | Food & medical contact | Food processing, medical |
| POM+PTFE (15%) | 55 MPa | Excellent | Ultra-low friction | Self-lubricating bearings |
| POM+Glass Fiber (20%) | 105 MPa | Good | Higher strength/stiffness | Structural gears, housings |
POM Machining Specifications
Design Tips for POM Machining
POM machines well but has a relatively high CTE (12×10⁻⁵/°C). For precision gear applications, account for thermal expansion between assembly and operating temperatures.
Use POM-C (copolymer) in chemical environments — better resistance to strong acids and bases than POM-H (homopolymer/Delrin).
Avoid anodizing or plating on POM — it is a plastic. If corrosion resistance is needed for mating metal parts, choose anodized aluminum or stainless steel.
POM welds poorly — bonded or snap-fit joints are preferred. Mechanical fasteners work well; self-tapping screws provide good hold with proper pilot hole sizing.
For FDA/food-contact applications, specify 'natural/white POM' or 'POM-C FDA grade' on drawings — black POM may contain carbon black which is not food-safe.
Common Applications
Surface Finishes for POM
POM’s as-machined surface is glossy and crisp out of the machine. These four finishes cover everything else customers request.
As-Machined
Ra 1.6 μm typical. POM’s glossy native surface is fine for most mechanical applications — no post-process needed.
Bead Blasted
Uniform matte texture removes tool marks. Common for cosmetic enclosures and grip surfaces; doesn’t affect dimensions.
Polished
Buffed to Ra 0.4 μm for sealing surfaces, optical components, or where parts mate against soft elastomers.
Laser Engraving
Permanent markings for part numbers, logos, or compliance data. Works on black, white, and natural POM without surface prep.
Industries Using Machined POM
POM ships into every industry that needs precise, self-lubricating, dimensionally stable plastic parts at scale.
Automotive
Fuel-system components, interior clips, door latches, EV charge-port flaps. POM survives oils, fuels, and -40 °C to +90 °C cycling.
Consumer Goods
Zipper sliders, buckles, lock cams, snap-fit cases. POM’s self-lubricating friction makes click-stop mechanisms feel premium.
Medical
Instrument housings, surgical staplers (non-implant), drug-delivery components. FDA-grade POM-C is standard for cleaning protocols.
Industrial
Conveyor wheels, gear racks, valve bodies, pump impellers. POM replaces brass and bronze in many gear/bushing applications at 1/10 the weight.
Electronics
Connector bodies, switch housings, slide rails. Excellent insulator with predictable dimensions for press-fit and tolerance stack-ups.
Food & Beverage
Bottle-filling nozzles, conveyor pucks, dispensing valves. White POM with FDA 21 CFR 177.2470 compliance certificates available.
Compare with Other Materials
Cross-shop POM against the materials it most often loses or wins against.
PEEK
Step up from POM when service temp exceeds 100 °C, you need biocompatibility, or the part sees aggressive chemicals.
View detailsAluminum 6061-T6
Step sideways when you need 4× the tensile strength, electrical conductivity, or full thread strength for fasteners.
View detailsBrass
The traditional bushing material POM often replaces. Pick brass when you need higher load capacity or a metallic mating surface.
View detailsReady to Machine POM / Delrin Parts?
Upload your drawings and get a detailed POM machining quote within 24 hours. No minimum order quantity. All grades in stock.
