POM-H
Grade
ASTM D4181 · also Delrin
POM-H = acetal homopolymer
Pick when maximum stiffness, strength, creep and wear resistance are needed and hot alkali/hot water exposure is limited.
Values for the POM-H condition
Other POM grades and fills
POM is listed in 10 conditions; see the grade overview at POM.
Compare all 10 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Impact modified | Select for snap-fits, clips and cold-climate parts needing high notched impact and ductility, at the cost of stiffness and heat resistance. | 43 | 45 | 120 | 70 Shore D |
PTFE-lubricated bearing grade | Use for unlubricated bearings, slides and gears where the lowest friction and wear rate against steel is required. | 45 | 45 | 15 | 78 Shore D |
Carbon-black conductive / antistatic | Pick for fuel-system parts, conveyor and electronics-handling components that must dissipate static charge. | 47 | 48 | 6 | 82 Shore D |
internally silicone-oil lubricated | Cost-effective friction and noise reduction for gears and clips where mechanicals must stay close to unfilled acetal. | 58 | 28 | 79 Shore D | |
Molybdenum disulfide filled | Dark, wear-resistant bearing grade for moderate loads where PTFE cost or FDA compliance is not required. | 58 | 60 | 15 | 82 Shore D |
High-flow / thin-wall injection grade | Use for thin-wall, multi-cavity or long-flow-path parts; higher MFR trades some toughness for fill and cycle time. | 60 | 61 | 20 | 81 Shore D |
POM-HThis page Acetal homopolymer | Pick when maximum stiffness, strength, creep and wear resistance are needed and hot alkali/hot water exposure is limited. | 70 | 70 | 30 | 92 HRM |
10% glass fiber reinforced | Modest stiffness and dimensional-stability boost with much lower shrinkage than unfilled, while retaining some ductility. | 85 | 7 | ||
25% glass fiber reinforced | Choose for load-bearing housings, brackets and gears needing high stiffness, low creep and tight dimensional tolerance at elevated temperature. | 130 | 3 | 90 HRM | |
30% glass fiber reinforced | Maximum-stiffness acetal for structural parts; accept brittleness, abrasive wear on tools and strong shrinkage anisotropy. | 135 | 2.5 |
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 79% 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 83% of polymer grades. Its glass-transition temperature is -60°C (-76 °F).
Advantages
- Tough — resists crack growth — 4 MPa·√m (3.64 ksi·√in), better than 92% of polymer grades
- Easy to machine — 88/100, better than 92% of polymer grades
- Conducts heat well — 0.31 W/m·K (0.179 BTU/hr·ft·°F), better than 87% of polymer grades
- High strength — 70 MPa (10.2 ksi), better than 79% of polymer grades
- Polishes to a fine finish — 70/100, 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 83% of polymer grades
- Needs corrosion protection — 70/100, worse than 78% of polymer grades
POM-H properties
Typical room-temperature values for POM-H; 14 are specific to this condition. Other listed values are POM reference data and may not represent this condition. Bars are the position among polymer grades.
Physical5
POM-H has a density of 1.42 g/cm³ (0.0513 lb/in³), heavier than 83% 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 79% 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 87% 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 78% 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. Confirm any required mill or lot documentation when quoting.
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 79% of polymer grades. Strength varies by condition: see the 10 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.
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.