POM / Delrin (Acetal Homopolymer) (UNS POM-H) is a excellent-to-machine material that we run regularly for export customers. It has a density of 1.42 g/cm3, a tensile strength of 72 MPa and a typical hardness of M 84 (Rockwell). Those numbers make it the right choice for gears and bushings, and a poor choice when cost or corrosion resistance matters more than mechanical performance.
On our machines we hold +/-0.01 mm on turned and milled features and reach Ra 0.4 um where the drawing calls for it. Standard lead time for POM / Delrin (Acetal Homopolymer) parts is 3-7 working days, including material procurement, machining and any finishing operation you specify.
POM / Delrin (Acetal Homopolymer): key properties
| Property | Value |
|---|---|
| UNS / designation | POM-H |
| Density | 1.42 g/cm3 |
| Tensile strength | 72 MPa |
| Hardness | M 84 (Rockwell) |
| Machinability | Excellent |
| Suggested cutting speed (carbide) | 300-600 m/min |
| Relative material cost | 1 of 5 |
Machining POM / Delrin (Acetal Homopolymer): what to plan for
- Thermal expansion 10x steel
- No glue bonds
- Stress cracking in tight fits
Cutting speed for POM / Delrin (Acetal Homopolymer) with carbide tooling sits around 300-600 m/min. Going faster burns the edge; going much slower causes rubbing and a poor surface. Air blast or flood coolant both work, but chip evacuation must be positive. If your part has thin walls or a lot of stock to remove, say so in the RFQ — we plan roughing, stress relief and finishing as separate operations when the geometry demands it.
Parts we machine in POM / Delrin (Acetal Homopolymer)
- Gears
- Bushings
- Slides
- Pump impellers
- Insulators
Most POM / Delrin (Acetal Homopolymer) work arrives as 2D drawings with a mix of critical and non-critical features. Loosening tolerance on the non-critical ones is the fastest way to cut cost, and we will tell you which features those are before we quote.
Tolerances, finish and lead time
| Item | Capability |
|---|---|
| General tolerance | +/-0.01 mm |
| Achievable surface finish | Ra 0.4 um |
| Minimum wall thickness | 0.8 mm (aluminium) / 1.0 mm (steel and stainless) |
| Typical lead time | 3-7 working days |
| Prototype quantity | 1 piece |
| Production quantity | 10 to 50,000 pieces |
Frequently asked questions
What is the lead time for POM / Delrin (Acetal Homopolymer) parts?
Standard is 3-7 working days from drawing release, assuming the material is in stock. Exotic grades and cast forms can add 5 to 10 days. Finishing such as anodizing or plating adds 3 to 5 days.
What tolerance can you hold in POM / Delrin (Acetal Homopolymer)?
+/-0.01 mm is routine on turned and milled features. Tighter than that is possible on specific features by grinding or lapping, but it is quoted separately because it changes the process.
Do you keep POM / Delrin (Acetal Homopolymer) in stock?
We hold common sizes of POM / Delrin (Acetal Homopolymer) and buy mill-certified stock for everything else. Material certificates are supplied with the parts on request.
Can you supply POM / Delrin (Acetal Homopolymer) parts with a certificate of conformity?
Yes. We issue a dimensional report, a material certificate and a certificate of conformity as standard for production orders, and full PPAP or AS9102 paperwork when the programme requires it.
Related pages
- Materials — the full index for this section.
- PEEK CNC Machining for Semiconductor and Medical Parts
- Nylon (PA6 / PA66) CNC Machining Guide
- Beryllium Copper CNC Machining: Safety and Tolerances
- PTFE CNC Machining: Chemical-Resistant Components
- Instant CNC quote
- Tolerance quick reference
- Frequently asked questions
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