POM-H
ASTM D4181-POM0210 · ISO POM · also POM H, Ramtal
POM-H is a highly crystalline acetal homopolymer of formaldehyde with acetylated end caps (Delrin, Kematal), stiffer and stronger in tension, creep, fatigue and wear than the POM-C copolymer.
POM-H grades and fills
POM-H is supplied in 10 conditions, soft to hard.
Compare all 10 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Impact modified / super-tough | Choose when notch sensitivity or cold impact governs — clips, latches and safety parts — at the cost of half the stiffness and strength. | 45 | 47 | 180 | 75 Shore D |
PTFE fiber filled | Use for unlubricated bearings, slides and gears where the lowest coefficient of friction and stick-slip-free motion are required. | 50 | 15 | 80 Shore D | |
Oil/silicone lubricated | For quiet, low-wear plastic-on-metal gear and slide contacts where oil bleed onto the mating face is acceptable. | 58 | 60 | 20 | 83 Shore D |
ESD / static-dissipative | For electronics handling fixtures, fuel-system parts and conveyor components requiring charge dissipation. | 58 | 58 | 8 | 87 Shore D |
MoS₂ filled | Economical low-wear bearing/gear grade where PTFE is not required; keeps most of the base stiffness. | 62 | 62 | 12 | 85 Shore D |
High viscosity | Pick when maximum toughness, fatigue life and creep resistance matter (gears, snap-fits) and the part is not thin-walled. | 68 | 72 | 45 | 85 Shore D |
Heat stabilized / low-emission | Use for continuous 100–120 °C service, hot-water contact or where formaldehyde emission and mold deposit must be minimized. | 69 | 70 | 30 | 86 Shore D |
High flow | For thin-wall, multi-cavity and long-flow parts where fill pressure dominates over toughness. | 70 | 70 | 18 | 86 Shore D |
20 % glass-fiber reinforced | Choose for higher stiffness, creep resistance and load-bearing temperature; accept brittleness, anisotropic shrinkage and abrasive wear on tools. | 105 | 3.5 | 90 HRM | |
25 % glass-fiber reinforced | Highest-stiffness standard acetal homopolymer grade for structural brackets and housings under sustained load. | 125 | 3 |
Supply forms, finishes and certifications
Ways POM-H is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
EXT | Extruded stock shape | Supply form |
FDA | FDA / food-contact and medical-compliant grade | Certification |
UV | UV stabilized / weather resistant | Grade option |
StandardDefault | General-purpose injection-molding viscosity | Standard supply |
UnfilledDefault | Natural/black homopolymer, general purpose | Standard supply |
What is POM-H?
POM-H is a highly crystalline acetal homopolymer of formaldehyde with acetylated end caps (Delrin, Kematal), stiffer and stronger in tension, creep, fatigue and wear than the POM-C copolymer. Typical values are 70 MPa tensile, 25 % elongation, Shore D 86 and 1.42 g/cm³; it is self-lubricating and used as rod, plate and mouldings for precision gears, bearings, cams and valve parts. Limits are a narrow processing window, depolymerisation to formaldehyde at high temperature or in acid or alkali, poor UV resistance, centre voids in thick sections and 90–100 °C continuous service; POM-C suits thick stock and hot water. 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). 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).
What is POM-H used for?
- Gears
- Sliding wear pads
- Bushings
Advantages
- Easy to machine — 90/100, better than 95% of polymer grades
- Tough — resists crack growth — 4 MPa·√m (3.64 ksi·√in), 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
- Degrades in UV without stabilisers — 25/100, worse than 76% of polymer grades
POM-H properties
Typical room-temperature values in the Unfilled 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 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (72/100), worse than 70% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of POM-H takes about 103 MJ of energy and emits 4.2 kg of CO₂ — less than 54% of polymer grades. Typical recycled content is 0%.
Manufacturability8
POM-H's machinability is excellent (90/100, better than 95% of polymer grades); weldability fair (40/100); formability fair (45/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. POM-H is highlighted; hover a dot for its name, or open the interactive family chart.
Working with POM-H
Is POM-H easy to machine?
Outstanding to machine — sharp positive-rake tools, high speed, light feed, air or mist cooling; anneal 160 °C (slow cool) before finish cuts on tight-tolerance parts to relieve stress.
Can POM-H be welded?
No solvent cement bonds acetal; join by hot-plate, ultrasonic, spin or laser welding, or use mechanical fasteners; adhesive bonding needs plasma/flame or chromic-acid surface activation.
Can POM-H be formed, bent or molded?
Dry lightly (80 °C, 2–3 h) if wet, hold melt 205–225 °C and never exceed ~230 °C or dwell long (depolymerization/formaldehyde gas); mold at 80–120 °C, use generous gates and thick runners to feed the 2 % shrinkage and avoid voids in thick sections.
Manufacturability
The process limits FabDigit's quote engine applies to POM-H. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Excellent90 / 100 |
|---|---|
| ISO material group | N.8 |
| Cutting speed (rough / finish) | 400 / 500 m/min |
| Minimum wall | 0.5 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 10× diameter |
| Best surface (machined / polished) | Ra 0.8 / 0.4 µm |
| Hardenable after machining | No |
Sheet metal
| Formability | Fair45 / 100 |
|---|---|
| Weldability | Better40 / 100 |
Injection molding
| Mold shrinkage | — |
|---|---|
| Wall thickness | — – — |
| Recommended draft | — |
| Pre-drying | — |
POM-H 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 |
|---|---|---|
| heat/antioxidant stabilizer packagehindered phenol + formaldehyde scavenger (nitrogen compound), typical | 0.3 – 2 | 0.8 |
| acid scavenger / lubricantprocessing aid; grade dependent | 0.1 – 1 | 0.3 |
| carbon black / pigmentblack and UV grades only | 0 – 2 | 0.5 |
| glass fiberGF20/GF25 reinforcement variants | 0 – 25 | 0 |
| PTFEDelrin AF bearing variants | 0 – 20 | 0 |
| polyoxymethylene homopolymer (-CH2O-)acetate end-capped formaldehyde homopolymer | ≥ 97 (balance) |
What surface finishes work on POM-H?
Machined or molded surfaces polish and burnish well; paints and adhesives require pre-treatment; can be laser-marked, hot-stamped or electroless-plated after specialized etch, but not anodized.
Surface treatments FabDigit runs on polymer parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Injection Molding Coating
Organic Coating
Metallization / Functional
Equivalent designations
Standards and trade names that resolve to POM-H in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- D4181-POM0210
- ISO
- POM
- Trade names
- POM HRamtalTenac HDelrinKematal
- Also called
- PolyacetalPolyformaldehydePolyoxymethylene HomopolymerPolypencoDelrin AcetalAcetal Homopolymer
How much does POM-H cost?
POM-H is a standard-cost polymer ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
POM-H — frequently asked
What is POM-H used for?
POM-H is typically used for gears, sliding wear pads and bushings. In short: maximum hardness homopolymer.
What is the yield strength of POM-H?
POM-H has a typical yield strength of 70 MPa (10.2 ksi) and a tensile strength of 70 MPa (10.2 ksi) — stronger than 79% of polymer grades. Strength varies by condition: see the 10 listed tempers.
Is POM-H easy to machine?
Yes — machinability is rated excellent (90/100, better than 95% of polymer grades). Outstanding to machine — sharp positive-rake tools, high speed, light feed, air or mist cooling; anneal 160 °C (slow cool) before finish cuts on tight-tolerance parts to relieve stress.
Can POM-H be welded?
With care — weldability is rated fair (40/100). No solvent cement bonds acetal; join by hot-plate, ultrasonic, spin or laser welding, or use mechanical fasteners; adhesive bonding needs plasma/flame or chromic-acid surface activation.
What surface finishes work on POM-H?
Machined or molded surfaces polish and burnish well; paints and adhesives require pre-treatment; can be laser-marked, hot-stamped or electroless-plated after specialized etch, but not anodized.
Can POM-H be formed, bent or molded?
Dry lightly (80 °C, 2–3 h) if wet, hold melt 205–225 °C and never exceed ~230 °C or dwell long (depolymerization/formaldehyde gas); mold at 80–120 °C, use generous gates and thick runners to feed the 2 % shrinkage and avoid voids in thick sections.
What is the maximum service temperature of POM-H?
POM-H is rated for continuous use to about 95°C (203 °F), and briefly to 140°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does POM-H cost?
POM-H is a standard-cost polymer ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in POM-H?
Yes — POM-H is available for CNC machining, sheet metal and injection molding with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Delrin acetal homopolymer product and processing guides — DuPont / Celanese (Delrin brand) (2023)
- Tenac / Tenac-C polyacetal technical data — Asahi Kasei (2022)
- Ertacetal H / TECAFORM AH stock shape datasheets — Mitsubishi Chemical Advanced Materials / Ensinger (2023)
- CAMPUS plastics database — POM homopolymer ISO 10350 datasets — CAMPUS/CWFG (2024)
- ISO 9988 Plastics — Polyoxymethylene (POM) moulding and extrusion materials — ISO (2020)
- ASTM D6100 Standard Classification for Polyoxymethylene (POM) Molding and Extrusion Materials — ASTM (2020)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.