POM · grade
POM-H
Properties of the POM-H condition, compared with the other POM grades.
Pick when maximum stiffness, strength, creep and wear resistance are needed and hot alkali/hot water exposure is limited.
What is POM-H?
POM-H is POM in the POM-H grade — pick when maximum stiffness, strength, creep and wear resistance are needed and hot alkali/hot water exposure is limited. POM-H has a yield strength of 70 MPa (10.2 ksi) and a tensile strength of 70 MPa (10.2 ksi) — stronger than 77% of polymer grades. Elongation at break is 30% and the elastic modulus is 3.1 GPa (0.45 Msi). POM-H has a density of 1.42 g/cm³ (0.0513 lb/in³), heavier than 82% of polymer grades. Its glass-transition temperature is -60°C (-76 °F). Unfilled is the default condition FabDigit quotes; POM-H is available on request or by drawing note.
Advantages
- Easy to machine — 88/100, better than 92% of polymer grades
- Tough — resists crack growth — 4 MPa·√m (3.64 ksi·√in), better than 91% of polymer grades
- Conducts heat well — 0.31 W/m·K (0.179 BTU/hr·ft·°F), better than 86% of polymer grades
- Polishes to a fine finish — 70/100, better than 78% of polymer grades
- High strength — 70 MPa (10.2 ksi), better than 77% of polymer grades
Limitations
- High mold shrinkage — 2.1%, worse than 86% of polymer grades
- Heavy — 1.42 g/cm³ (0.0513 lb/in³), worse than 82% of polymer grades
- Needs corrosion protection — 70/100, worse than 80% of polymer grades
POM-H properties
Typical room-temperature values for POM-H — 14 properties are specific to this condition; the rest are grade-level values shared by every POM grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical5
POM-H has a density of 1.42 g/cm³ (0.0513 lb/in³), heavier than 82% of polymer grades. Its glass-transition temperature is -60°C (-76 °F).
Mechanical17
POM-H has a yield strength of 70 MPa (10.2 ksi) and a tensile strength of 70 MPa (10.2 ksi) — stronger than 77% of polymer grades. Elongation at break is 30% and the elastic modulus is 3.1 GPa (0.45 Msi).
Thermal11
POM-H is rated for continuous service to 95°C (203 °F). It conducts heat at 0.31 W/m·K (0.179 BTU/hr·ft·°F), better than 86% of polymer grades. Thermal expansion is 110 µm/m·K (61.1 µin/in·°F).
Electrical7
POM-H is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (70/100), worse than 80% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of POM-H takes about 100 MJ of energy and emits 4.5 kg of CO₂ — less than 61% of polymer grades. Typical recycled content is 0%.
Manufacturability8
POM-H's machinability is excellent (88/100, better than 92% of polymer grades); weldability good (55/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other POM grades and fills
POM is also supplied in 12 other conditions. The full side-by-side table is on the POM overview.
- UnfilledDefaultDefault choice for gears, snap-fits, bushings and precision mechanical parts needing toughness plus low friction.63 MPa tensile
- GF30Maximum-stiffness acetal for structural parts; accept brittleness, abrasive wear on tools and strong shrinkage anisotropy.135 MPa tensile
- GF25Choose for load-bearing housings, brackets and gears needing high stiffness, low creep and tight dimensional tolerance at elevated temperature.130 MPa tensile
- GF10Modest stiffness and dimensional-stability boost with much lower shrinkage than unfilled, while retaining some ductility.85 MPa tensile
- POM-HPick when maximum stiffness, strength, creep and wear resistance are needed and hot alkali/hot water exposure is limited.70 MPa yield · 92 HRM
- MoS2Dark, wear-resistant bearing grade for moderate loads where PTFE cost or FDA compliance is not required.60 MPa tensile
- Silicone LubricatedCost-effective friction and noise reduction for gears and clips where mechanicals must stay close to unfilled acetal.58 MPa tensile
- ESDPick for fuel-system parts, conveyor and electronics-handling components that must dissipate static charge.48 MPa tensile
- PTFE 20%Use for unlubricated bearings, slides and gears where the lowest friction and wear rate against steel is required.45 MPa yield · 78 Shore D
- IMSelect for snap-fits, clips and cold-climate parts needing high notched impact and ductility, at the cost of stiffness and heat resistance.43 MPa yield · 70 Shore D
Working with POM-H
Is POM easy to machine?
One of the best plastics to machine: sharp positive-rake tools, high speed, light feeds, air or mist cooling; relieve molded-in stress before tight-tolerance finishing and expect springback-free chips.
Can POM be welded?
Hot-plate, ultrasonic, spin and vibration welding all work well; no solvent bonding — adhesive joints require plasma, flame or chromic-acid surface activation.
Can POM be formed, bent or molded?
Dry only if resin is wet (≤0.1%), melt 190–215 °C, mold 80–100 °C, generous gates and full packing; watch ~2% shrinkage, sink and voids in thick sections and never overheat/stagnate melt (formaldehyde release).
What surface finishes work on POM?
Paints and inks need surface pretreatment or special primers; parts polish to a waxy sheen, can be laser-marked, and plating requires a dedicated acetal etch process.
POM chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| ethylene oxide comonomercopolymer (POM-C) only; absent in homopolymer POM-H, which is end-capped instead | 1 – 5 | 2.5 |
| heat/acid stabilizer package (antioxidanessential to prevent depolymerization | 0.2 – 1.5 | 0.6 |
| lubricant / mold release | 0 – 1 | 0.3 |
| pigment (carbon black, TiO2 etc.)carbon black also gives UV protection | 0 – 2 | 0.5 |
| oxymethylene (-CH2O-) repeat unitpolyacetal backbone from formaldehyde/trioxane | ≥ 94 (balance) | — |
POM-H — frequently asked
What is POM-H used for?
POM-H is typically used for gears, clips and fuel systems. In short: stiff dimensional acetal.
What is the yield strength of POM-H?
POM-H has a typical yield strength of 70 MPa (10.2 ksi) and a tensile strength of 70 MPa (10.2 ksi) — stronger than 77% of polymer grades. Strength varies by condition: see the 13 listed tempers.
Is POM-H easy to machine?
Yes — machinability is rated excellent (88/100, better than 92% of polymer grades). One of the best plastics to machine: sharp positive-rake tools, high speed, light feeds, air or mist cooling; relieve molded-in stress before tight-tolerance finishing and expect springback-free chips.
Can POM-H be welded?
Yes — weldability is rated good (55/100). Hot-plate, ultrasonic, spin and vibration welding all work well; no solvent bonding — adhesive joints require plasma, flame or chromic-acid surface activation.
What surface finishes work on POM-H?
Paints and inks need surface pretreatment or special primers; parts polish to a waxy sheen, can be laser-marked, and plating requires a dedicated acetal etch process.
Can POM-H be formed, bent or molded?
Dry only if resin is wet (≤0.1%), melt 190–215 °C, mold 80–100 °C, generous gates and full packing; watch ~2% shrinkage, sink and voids in thick sections and never overheat/stagnate melt (formaldehyde release).
What is the maximum service temperature of POM-H?
POM-H is rated for continuous use to about 95°C (203 °F), and briefly to 140°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between POM Unfilled and POM-IM?
Unfilled is the default condition — default choice for gears, snap-fits, bushings and precision mechanical parts needing toughness plus low friction. IM: select for snap-fits, clips and cold-climate parts needing high notched impact and ductility, at the cost of stiffness and heat resistance. Yield strength is 70 MPa in Unfilled versus 43 MPa in IM.
Can FabDigit make parts in POM-H?
Yes — POM-H is available for injection molding with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Hostaform / Celcon POM copolymer product and processing brochures — Celanese (2023)
- Delrin acetal homopolymer design and molding guides — DuPont / Delrin USA (2022)
- CAMPUS plastics ISO datasets for POM-C and POM-H injection grades — CWFG / CAMPUS consortium (2024)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- ISO 9988 Plastics — Polyoxymethylene (POM) moulding and extrusion materials — ISO (2020)
- ASTM D6100 Standard Classification for Polyoxymethylene (POM) Molding and Extrusion Materials — ASTM (2020)
- Ensinger TECAFORM AH / AD stock shape datasheets — Ensinger (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.