POM compounds
General-purpose POM: wear resistant, self-lubricating, dimensionally stable.
Example grade / typical values — to be corrected by GREENPOLYMER
Selection criteria
- Wear resistance
- Self-lubrication
- Dimensional stability
- GRN-POM-G110Gears
POM (polyoxymethylene, acetal) is a highly crystalline engineering plastic. It is wear resistant, has a low coefficient of friction, resists fatigue, is dimensionally stable and absorbs very little moisture. POM is often used for gears, bushings, sliders, snap fits, spring elements and precision mechanism parts.
GREENPOLYMER POM grades
Full list · 1 grade
| Grade | Key features | Suitable parts |
|---|---|---|
| GRN-POM-G110 | General-purpose copolymer POM | Gears, snap fits, sliders, bushings; mechanism parts in tools, home appliances and robots |
Recycled-content versions (-R) can be customized.
Key properties
Typical values. Refer to the actual TDS.
| Item | Test standard | GRN-POM-G110 |
|---|---|---|
| Density | ISO 1183 | 1.39–1.42 g/cm³ |
| MFR | ISO 1133 | 7–12 g/10 min (190 °C / 2.16 kg) |
| Tensile strength | ISO 527 | 60–68 MPa |
| Flexural modulus | ISO 178 | 2.4–2.9 GPa |
| Notched impact (23 °C) | ISO 179/1eA | 5–8 kJ/m² |
| HDT (1.80 MPa) | ISO 75 | 90–105 °C |
| Flammability | UL 94 | HB @ 1.5 mm |
Strengths and limits of POM
| Strengths | Limits |
|---|---|
| Wear resistant and self-lubricating, suits moving parts | Not flame retardant; unsuitable for parts needing a V rating |
| Fatigue resistant, suits spring snap fits | Not resistant to strong acids; long-term contact with chlorine-based disinfectants is not recommended |
| Low moisture absorption, dimensionally stable | High shrinkage (about 1.8–2.2 %, typical value) |
| Resistant to oils and most solvents | Hard to bond and hard to paint |
| Good low-temperature toughness | Moderate weather resistance; outdoor use needs a UV-resistant version |
POM or PA
| Situation | Recommended |
|---|---|
| Precision gears needing dimensional stability | POM, little affected by moisture |
| Higher heat resistance and stiffness needed | Glass-fiber-reinforced PA (see PA6, PA66) |
| Flame retardancy needed | PA or another flame-retardant material; POM is unsuitable |
| POM running against POM | Not recommended, high wear; pair POM with PA or metal instead |
Processing advice
Typical values. Refer to the actual TDS.
- DryingUsually not needed; if damp, 80 °C, 2–3 h
- Melt temperature190–210 °C; do not exceed 230 °C
- Mold temperature60–90 °C; upper end for precision parts, for more stable dimensions
- Holding pressure
- Hold fully to compensate for crystallization shrinkage
- Residence time
- As short as possible. Overheating decomposes the material and releases formaldehyde; good ventilation is needed
- Material changeover
- Do not mix with PVC or flame-retardant materials in the same barrel; purge thoroughly before changeover
Full table
| Item | Recommended |
|---|---|
| Drying | Usually not needed; if damp, 80 °C, 2–3 h |
| Melt temperature | 190–210 °C; do not exceed 230 °C |
| Mold temperature | 60–90 °C; upper end for precision parts, for more stable dimensions |
| Holding pressure | Hold fully to compensate for crystallization shrinkage |
| Residence time | As short as possible. Overheating decomposes the material and releases formaldehyde; good ventilation is needed |
| Material changeover | Do not mix with PVC or flame-retardant materials in the same barrel; purge thoroughly before changeover |
Design points
Keep walls even
Crystallization shrinkage is high; uneven walls cause voids and distortion.
Gate into thick sections
This helps packing during holding.
Allow for post-shrinkage in gears
Dimensions keep changing slightly after molding; for precision gears, anneal or correct the mold for post-shrinkage.
Use the elasticity of POM in snap fits
Still control strain to avoid creep under long-term overload.
FAQ
Can POM be made flame retardant?
POM itself is very hard to make V-rated. For parts that need flame retardancy, switch to flame-retardant PA, PBT or PC/ABS.
What is the difference between homopolymer and copolymer POM?
Homopolymer POM has slightly higher stiffness and strength; copolymer POM has better thermal stability and chemical resistance, and a wider processing window. GRN-POM-G110 is a copolymer POM.
Related content
- Applications: Tools and hardware | Home appliances and cleaning | Robotics
Contact us
Tell us the part name, type of motion (sliding, rotating, elastic deformation), mating material, operating temperature, chemicals in contact and the expected volume. Phone +86 18822892298 | Email hello@greenpolymer.com