POM stock — view 01
POM
POM, or acetal, is a stiff, low-friction engineering plastic for precision moving parts.
Review the moving fit and the material together
For a POM slider, sleeve or locating part, explain how it mates with the surrounding components. Aria reviews the selected material with the critical fits and surface requirements, so those details are part of the manufacturing brief. Specify the intended POM grade; copolymer, homopolymer and modified materials should not be treated as one interchangeable set of properties.
Aria offers both CNC machining and injection molding. Discuss the prototype quantity and expected repeat demand together so the material, tooling and production choices can be reviewed as the project develops.
Material photos
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POM texture detail
Material options
| Property | Details |
|---|---|
| Available variants | POM Black, POM Blue, POM White, Dark brown (coffee) POM 100AF |
| Colors | Black, Blue, White, Dark brown (coffee), Natural milky white / pale yellow, Custom colors |
| Special properties | Low-friction PTFE- or silicone-modified, antistatic, glass-filled, UV-stabilized and antimicrobial grades are available as separate specifications. |
Detailed values describe Celanese Hostaform C 9021, POM copolymer (2018-01-17). Family ranges are broader selection references and may include different grades or reinforcement levels. Confirm the selected grade, condition and test method for your part.
Material properties
| Property | Metric | Imperial | Test method / conditions |
|---|---|---|---|
| Density | 1.41 g/cm³ | 0.0510 lb/in³ | ISO 1183 · 23°C · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| MVR | 8 cm³/10min | 8 cm³/10min | ISO 1133 · 190°C, 2.16 kg · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| Molding Shrinkage | 1.9~2.0 % | 1.9~2.0 % | ISO 294-4 · Parallel / perpendicular · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| Tensile Modulus | 2,850 MPa | 413,000 psi | ISO 527 · 23°C · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| Yield Stress | 64 MPa | 9,280 psi | ISO 527 · 50 mm/min · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| Nominal Strain at Break | 30 % | 30 % | ISO 527 · 50 mm/min · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| Flexural Modulus | 2,700 MPa | 392,000 psi | ISO 178 · 23°C · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| Charpy notched impact (23°C) | 6.5 kJ/m² | 3.1 ft·lb/in² | ISO 179/1eA · 23°C · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| Ball Indentation Hardness | 144 N/mm² | 144 N/mm² | ISO 2039-1 · 30s · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| Melting Temperature | 166 °C | 331 °F | ISO 11357 · 10°C/min · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| HDT (1.80 MPa) | 104 °C | 219 °F | ISO 75-1/-2 · 1.80 MPa · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| HDT (0.45 MPa) | 160 °C | 320 °F | ISO 75-1/-2 · 0.45 MPa · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| Vicat softening temperature | 150 °C | 302 °F | ISO 306 · 50N, 50°C/h · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| Water Absorption (saturated) | 0.65 % | 0.65 % | ISO 62 · Saturated, 23°C · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
| Flammability | HB (UL94) | HB (UL94) | UL 94 · 1.5 mm · Reference: Celanese Hostaform C 9021, POM copolymer (2018-01-17) |
Material family ranges — selection reference
| Property | Family reference |
|---|---|
| Material class | Engineering plastic |
| Density (g/cm³) | 1.40–1.42 |
| Tensile strength (MPa) | 60–70 |
| Elongation at break (%) | 15–40 |
| Elastic modulus (GPa) | 2.6–3.2 |
| Hardness | R110–M80 |
| Temperature reference (°C) | HDT 90–110 |
Compatible manufacturing processes
Selection requirements
- CNC Milling Services
CNC Milling Services: Conventional injection molding and CNC milling or turning. Typical molding shrinkage in the supplied guidance is 1.9–2.1%. Control processing temperature and follow the grade datasheet; excessive heat can decompose POM and release formaldehyde. Homopolymer and copolymer values are not interchangeable. 3-axis milling, 4-axis milling, 5-axis milling: Use a machinable stock grade; geometry, workholding and material condition determine feasibility.
- Injection molding
Injection molding: Conventional injection molding and CNC milling or turning. Typical molding shrinkage in the supplied guidance is 1.9–2.1%. Control processing temperature and follow the grade datasheet; excessive heat can decompose POM and release formaldehyde. Homopolymer and copolymer values are not interchangeable. Single-material injection molding, Insert location and retention, Multi-shot / two-shot (2K) molding: Use an injection-molding grade. Fillers, shrinkage and processing temperatures affect tool and part design.
- Insert molding · Overmolding
Use an injection-molding grade. Fillers, shrinkage and processing temperatures affect tool and part design.
- Precision CNC machining
CNC Milling Services, CNC turning: Conventional injection molding and CNC milling or turning. Typical molding shrinkage in the supplied guidance is 1.9–2.1%. Control processing temperature and follow the grade datasheet; excessive heat can decompose POM and release formaldehyde. Homopolymer and copolymer values are not interchangeable. 3-axis milling, 4-axis milling, 5-axis milling, Cylindrical Turning, Boring, Threading, Grooving: Use a machinable stock grade; geometry, workholding and material condition determine feasibility.
- CNC turning
CNC turning: Conventional injection molding and CNC milling or turning. Typical molding shrinkage in the supplied guidance is 1.9–2.1%. Control processing temperature and follow the grade datasheet; excessive heat can decompose POM and release formaldehyde. Homopolymer and copolymer values are not interchangeable. Cylindrical Turning, Boring, Threading, Grooving: Use a machinable stock grade; geometry, workholding and material condition determine feasibility.
Advantages and considerations
Advantages
Good hardness, dimensional stability, wear and fatigue resistance, with low water absorption and excellent machinability. It resists oils and many solvents.
Material limitations
Avoid strong acids, oxidizers, prolonged high heat and unprotected outdoor exposure. POM is notch-sensitive, difficult to bond or paint and has substantial molding shrinkage.
How Aria supports your project
Help choosing a material
Compare materials for the loads, temperature and environment your part will face.
Design feedback before production
We review tool access, geometry and material choice before manufacturing.
Inspection to your drawing
Dimensional checks and inspection reports for the critical features on your drawing.
Compatible surface finishes
Selection requirements
- Laser engraving
Typical molding shrinkage in the supplied guidance is 1.9–2.1%. Control processing temperature and follow the grade datasheet; excessive heat can decompose POM and release formaldehyde. Homopolymer and copolymer values are not interchangeable. Laser marking; printing, painting or bonding need a suitable primer or flame/plasma pretreatment. Electroplating is generally unsuitable.
- Glossy · Semi-glossy · Matt · Textured
Mold-transferred appearance depends on the resin and tool surface; gloss and texture do not specify a material-independent roughness.
Applications
Typical applications
Precision gears, cams, bearings, slides, fasteners, zippers, automotive and electronics parts, pumps and valves.
Design considerations
Processing options
Conventional injection molding and CNC milling or turning.
Finishing options
Laser marking; printing, painting or bonding need a suitable primer or flame/plasma pretreatment. Electroplating is generally unsuitable.
Grade and finish combinations
Typical molding shrinkage in the supplied guidance is 1.9–2.1%. Control processing temperature and follow the grade datasheet; excessive heat can decompose POM and release formaldehyde. Homopolymer and copolymer values are not interchangeable.
Color and grade options
Natural milky white to pale yellow; copolymer grades tend toward white. Black and custom colors.
Melt temperature and residence time
POM processing limits depend on the exact grade and how long the melt remains in the machine. Celanese’s Hostaform processing guidance links thermal stability to both temperature and residence time; a single 220°C limit is not applicable to all POM grades. Use the selected grade’s current processing sheet, control hold-up time and provide appropriate extraction. Overheating or contamination can cause decomposition and formaldehyde release.
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