What Makes Polyoxymethylene (POM) an Essential Engineering Plastic

Polyoxymethylene (POM), also known as acetal or polyacetal, is a high-performance engineering thermoplastic valued for its exceptional stiffness, low friction, and dimensional stability. It is widely used in precision mechanical components, automotive parts, and industrial machinery where durability and wear resistance are critical.

Composition and Properties

• Base Material: Polyoxymethylene homopolymers (POM-H) or copolymers (POM-C)

• Additives: Stabilizers, lubricants, fillers, and impact modifiers

• Processing Methods: Injection molding, extrusion, and machining

POM offers high mechanical strength, chemical resistance, and low moisture absorption, making it ideal for structural and moving parts.

Key Features

• High Strength & Stiffness: Excellent load-bearing capacity

• Low Friction & Wear Resistance: Suitable for gears, bearings, and slides

• Dimensional Stability: Maintains shape under mechanical and thermal stress

• Chemical Resistance: Resistant to fuels, oils, solvents, and many chemicals

• Good Processability: Compatible with injection molding and extrusion

• Low Moisture Absorption: Minimizes dimensional changes in humid environments

Applications

• Automotive: Gears, bushings, clips, fuel system components

• Mechanical & Industrial Equipment: Bearings, conveyor parts, fasteners

• Consumer Products: Zippers, sporting goods, precision tools

• Electronics: Connectors, switch components, insulating parts

• Medical Devices: Durable and chemically resistant parts for instruments

Advantages

• High mechanical strength and stiffness

• Excellent wear and friction properties for moving components

• Resistant to many chemicals and fuels

• Dimensional stability under varying temperature and humidity

• Versatile processing: molding, extrusion, or machining

Limitations

• Sensitive to UV; outdoor applications require stabilization

• Can be brittle under impact without modification

• Limited thermal resistance compared to some high-performance polymers

Technical Parameters (Typical)

• Density: 1.41–1.42 g/cm³

• Tensile Strength: 60–75 MPa

• Flexural Strength: 90–100 MPa

• Impact Strength (Notched Izod): 3–6 kJ/m²

• Melting Temperature: 165–175°C

• Water Absorption: 0.2–0.3% after 24h

• Processing Methods: Injection molding, extrusion, machining

FAQs

Q1: Why is POM widely used in mechanical components?
Because it has high strength, low friction, wear resistance, and dimensional stability, ideal for gears, bearings, and precision parts.

Q2: How does POM compare with Polyamide (PA)?
POM has lower moisture absorption and better dimensional stability, while PA offers higher impact toughness in some applications.

Q3: Can POM be used outdoors?
Yes, but UV stabilization is recommended to prevent degradation.

Q4: What are the main processing methods for POM?
Injection molding, extrusion, and precision machining for structural components.