POM-C · grade · default condition
POM-C Unfilled
Properties of the Unfilled condition, compared with the other POM-C grades.
Default choice for gears, bushings, snap-fits and precision machined parts needing stiffness, low friction and dimensional stability.
What is POM-C Unfilled?
POM-C Unfilled is POM-C in the Unfilled grade — default choice for gears, bushings, snap-fits and precision machined parts needing stiffness, low friction and dimensional stability. POM-C Unfilled has a yield strength of 63 MPa (9.14 ksi) and a tensile strength of 65 MPa (9.43 ksi) — stronger than 72% of polymer grades. Elongation at break is 32% and the elastic modulus is 2.8 GPa (0.406 Msi). POM-C Unfilled has a density of 1.41 g/cm³ (0.0509 lb/in³), heavier than 80% of polymer grades. Its glass-transition temperature is -60°C (-76 °F).
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
Limitations
- High mold shrinkage — 2%, worse than 81% of polymer grades
- Heavy — 1.41 g/cm³ (0.0509 lb/in³), worse than 80% of polymer grades
POM-C Unfilled properties
Typical room-temperature values for POM-C Unfilled — 7 properties are specific to this condition; the rest are grade-level values shared by every POM-C grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical6
POM-C Unfilled has a density of 1.41 g/cm³ (0.0509 lb/in³), heavier than 80% of polymer grades. Its glass-transition temperature is -60°C (-76 °F).
Mechanical17
POM-C Unfilled has a yield strength of 63 MPa (9.14 ksi) and a tensile strength of 65 MPa (9.43 ksi) — stronger than 72% of polymer grades. Elongation at break is 32% and the elastic modulus is 2.8 GPa (0.406 Msi).
Thermal11
POM-C Unfilled is rated for continuous service to 100°C (212 °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-C Unfilled 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 (72/100), worse than 72% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of POM-C Unfilled takes about 100 MJ of energy and emits 3.9 kg of CO₂ — less than 61% of polymer grades. Typical recycled content is 0%.
Manufacturability8
POM-C Unfilled's machinability is excellent (88/100, better than 92% of polymer grades); weldability fair (35/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other POM-C grades and fills
POM-C is also supplied in 13 other conditions. The full side-by-side table is on the POM-C overview.
- UnfilledDefaultDefault choice for gears, bushings, snap-fits and precision machined parts needing stiffness, low friction and dimensional stability.65 MPa tensile
- StandardDefaultChoose the standard unmodified grade when the drawing calls out no filler, lubricant or specific approval; it is the baseline supply condition for machined and molded parts.summary only
- GF30Highest-stiffness standard POM-C grade for structural brackets, pump housings and load-bearing gears at 80–110 °C.130 MPa tensile
- GF25Use where stiffness, creep resistance and elevated-temperature load bearing matter more than toughness or wear on mating parts.120 MPa tensile
- Extruded StockPick for machined parts from bar or plate; slightly higher crystallinity and stiffness than molded parts but with residual extrusion stress (annealing recommended for tight tolerances).66 MPa yield · 82 Shore D
- MoS2Low-cost wear grade with slightly higher stiffness and better wear against steel than natural POM-C; MoS2 also nucleates a finer crystalline structure.60 MPa tensile
- ESDUse for handling tooling, wafer/electronics fixtures and fuel-contact parts where charge build-up must be bled off (10⁴–10⁹ Ω surface).52 MPa tensile
- Metal DetectableSpecify for food, pharma and packaging machinery parts that must be found by inline metal detectors or X-ray if a fragment breaks off.50 MPa tensile
- PTFE FilledChoose for dry-running bearings, slides and wear parts needing the lowest friction and stick-slip-free motion.47 MPa yield · 78 Shore D
- Impact ModPick for snap-fits, clips and parts seeing shock or low-temperature impact, at the cost of stiffness and heat resistance.45 MPa yield · 60 HRM
Working with POM-C Unfilled
Is POM-C easy to machine?
Excellent — sharp positive-rake tools, high speed and light feed give chip-free, mirror-like surfaces; anneal (140–150 °C, slow cool) before finish cuts on thick or tight-tolerance parts.
Can POM-C be welded?
Poor to fair — hot-plate, ultrasonic, vibration and spin welding work with a joint design; solvent bonding is impossible and adhesives need flame/plasma or chromic-acid surface activation.
Can POM-C be formed, bent or molded?
Injection mould at 190–210 °C melt (never above ~230 °C or 20 min residence — decomposes to formaldehyde), mould 80–100 °C, generous gates and 2 % shrink allowance; extrusion of rod/plate needs slow, controlled cooling to avoid centre voids.
What surface finishes work on POM-C?
Machined or moulded surfaces are naturally low-friction and can be buffed; paint, print and plating require pre-treatment (etch/primer) because POM is chemically inert and non-polar.
POM-C 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 |
|---|---|---|
| comonomer (ethylene oxide / 1,3-dioxolanC–C linkages that block unzipping and give alkali/hot-water resistance | 1 – 4 | 2 |
| stabilizers (antioxidant, formaldehyde shindered phenol + amine/nitrogen scavenger package | 0.2 – 1 | 0.5 |
| pigment / carbon blackblack and UV grades only | 0 – 2 | 0.3 |
| oxymethylene (–CH2O–) unitsfrom trioxane polymerization | ≥ 96 (balance) | — |
POM-C Unfilled — frequently asked
What is POM-C Unfilled used for?
POM-C Unfilled is typically used for chemical-resistant gears, bearings and bushings, slide plates and wear guides, valve bodies and seats, pump housings and impellers and conveyor chain components. In short: strong precise copolymer.
What is the yield strength of POM-C Unfilled?
POM-C Unfilled has a typical yield strength of 63 MPa (9.14 ksi) and a tensile strength of 65 MPa (9.43 ksi) — stronger than 72% of polymer grades. Strength varies by condition: see the 14 listed tempers.
Is POM-C Unfilled easy to machine?
Yes — machinability is rated excellent (88/100, better than 92% of polymer grades). Excellent — sharp positive-rake tools, high speed and light feed give chip-free, mirror-like surfaces; anneal (140–150 °C, slow cool) before finish cuts on thick or tight-tolerance parts.
Can POM-C Unfilled be welded?
With care — weldability is rated fair (35/100). Poor to fair — hot-plate, ultrasonic, vibration and spin welding work with a joint design; solvent bonding is impossible and adhesives need flame/plasma or chromic-acid surface activation.
What surface finishes work on POM-C Unfilled?
Machined or moulded surfaces are naturally low-friction and can be buffed; paint, print and plating require pre-treatment (etch/primer) because POM is chemically inert and non-polar.
Can POM-C Unfilled be formed, bent or molded?
Injection mould at 190–210 °C melt (never above ~230 °C or 20 min residence — decomposes to formaldehyde), mould 80–100 °C, generous gates and 2 % shrink allowance; extrusion of rod/plate needs slow, controlled cooling to avoid centre voids.
What is the maximum service temperature of POM-C Unfilled?
POM-C Unfilled is rated for continuous use to about 100°C (212 °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-C Unfilled?
Yes — POM-C Unfilled 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
- ISO 9988-1/-2 Plastics — Polyoxymethylene (POM) moulding and extrusion materials — ISO (2020)
- ASTM D6100 Standard Classification for Polyoxymethylene (POM) Molding and Extrusion Materials — ASTM (2020)
- Hostaform C 9021 / GV1-30 / TF product data sheets — Celanese (2023)
- Ultraform (POM) product range brochure — BASF (2022)
- TECAFORM AH natural / LA / ELS / MDblue datasheets — Ensinger (2023)
- Ertacetal C stock shapes data — Mitsubishi Chemical Advanced Materials (2022)
- CAMPUS plastics database — POM-C single-point data (ISO 10350) — CWFG (2024)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
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.