POM-C (Polyoxymethylene Acetal Copolymer)
POM (Polyoxymethylene) is a semi-crystalline thermoplastic that belongs to the group of engineering plastics. The material is characterized by high mechanical strength, stiffness, and excellent dimensional stability.
Due to its favorable combination of strength, dimensional stability, and good sliding properties, POM is frequently used for precision mechanical components that must function reliably under moderate thermal and mechanical stress.
Features at a Glance
Typical properties of POM include:
- high mechanical strength and stiffness
- Excellent dimensional stability
- low water absorption
- good wear and sliding properties
- high surface hardness
- Good chemical resistance to many substances
- good machinability
- good electrical insulation properties
Due to its semi-crystalline structure, POM remains largely stable in terms of its mechanical properties even under changing environmental conditions.
Typical Applications
Due to its mechanical properties and good sliding properties, POM is used for technically sophisticated precision components.
Typical applications include:
- Food Processing and Packaging
- Water and Process Technology
- Warehouse and Material Handling Technology
- Machinery and Plant Engineering
Typical Components
POM is often used for components that require precise motion and low friction.
Typical components include, for example:
- Plain Bearings and Bearing Bushings
- Guides and Sliding Elements
- Snap-fit connections
- Housing Parts
- Precision components with tight tolerances
Technical Specifications
The following values are typical guidelines and may vary depending on the type of material and the manufacturer.
| Property | Value |
|---|---|
| Max. operating temperature | ca. 100-120 °C |
| Melting temperature | ca. 165-175 °C |
| Tensile strength | ca. 60-75 MPa |
| Elastic modulus | ca. 2.500–3.000 MPa |
| Density | ca. 1,40–1,43 g/cm³ |
| Wasseraufnahme | very low |
Chemical Resistance
Particularly resistant to
- Oils and greases
- Fuels
- Many organic solvents
- Weak acids and alkalis
Limited resistance to
- Strong acids
- Oxidizing media
Machining and Manufacturing
POM is very easy to machine and is ideal for precise CNC manufacturing processes.
Typical characteristics during machining:
- Very well suited for CNC milling and CNC turning
- high dimensional accuracy of the components
- Tight tolerances can be achieved
- High-quality finishes can be achieved
- Suitable for prototypes, individual parts, and small-batch and mass production
The selection of the appropriate material should be made on a project-by-project basis, taking into account the load, temperature range, and contact with media.
Comparison with Other Materials
| Property | POM-C | PA | PET |
|---|---|---|---|
| Operating temperature | medium | medium | medium |
| Mechanical strength | high | high | high |
| Wear resistance | very high | good | good |
| Moisture absorption | very low | high | low |
| Dimensional stability | very good | limited | good |
POM-C is often used when both high mechanical strength and chemical resistance are required.
Possible alternative materials
Depending on the application, other engineering plastics may also be considered:
- PA 6 – good mechanical properties, but higher moisture absorption
- PET – good dimensional stability and strength
- POM-H – high wear resistance with low moisture absorption
Frequently asked questions about Polyoxymethylene Acetal Copolymer
What kind of plastic is POM-C?
POM-C is a semi-crystalline engineering plastic with high strength, good dimensional stability, and excellent sliding properties.
What is the maximum temperature that POM-C can withstand?
POM-C can typically be used continuously at temperatures ranging from about 100 to 120 °C.
What is the melting temperature of POM-C?
The melting point is approximately 165 to 175 °C.
Is POM-C chemical-resistant?
POM-C is resistant to many substances, such as oils, fats, and organic solvents. There are limitations when it comes to strong acids and oxidizing substances.
Is POM-C resistant to hydrolysis?
POM-C absorbs very little water and therefore retains its dimensional stability. When it comes to hydrolytic resistance, a distinction should be made between POM-C and POM-H: POM-C is more resistant to hot water and steam, while POM-H may be more sensitive in these areas.
What are the mechanical properties of POM-C?
POM-C has high strength, stiffness, and surface hardness, as well as good wear resistance.
What components are typically made from POM-C?
Typical components made of POM-C include plain bearings, gears, guides, snap-fit connections, and precision parts.
Can POM-C be machined?
Yes, POM-C is very easy to machine and is suitable for CNC milling and CNC turning.
When is POM-C used?
POM is often used when precise components with good sliding properties and high dimensional stability are required.