What Is POM? Properties and Precision Machining of POM Plastic
What Is POM
POM (polyoxymethylene, also known as acetal), a highly crystalline thermoplastic engineering plastic, is used to replace non-ferrous metals such as copper, zinc, and aluminum in gears, bearings, fasteners, and other parts that must withstand mechanical stress, thanks to its excellent mechanical properties and wear resistance.
Core Properties of POM
- High wear and fatigue resistance: Stable under repeated friction and cyclic loading; well suited to gears, slide rails, and snap-fits.
- Good dimensional stability: Low water absorption and low molding shrinkage, making it suitable for precision structural parts.
- Creep and chemical resistance: Good resistance to organic solvents, fuels, and weak acids and bases.
- Self-lubricating: A low coefficient of friction reduces lubrication and maintenance.
- Good mechanical strength and stiffness: Retains toughness as well, so it is not prone to brittle fracture.
Typical Applications of POM in Automation Equipment
In automation and semiconductor equipment, POM is commonly used for:
- Insulating structural parts and connectors for servo motors
- Drive gears, racks, and cams
- Linear guide sliders and wear-resistant bushings
- Seals and valve cores for pneumatic and hydraulic systems
- Insulating brackets in anti-static (ESD-safe) environments
Key Points for Machining POM
POM can be machined to high-precision parts by CNC. When machining it, note the following:
- Tooling and cutting parameters: POM has poor thermal conductivity. Use sharp tooling, relatively high spindle speeds, and appropriate feed rates to avoid localized overheating and distortion.
- Tolerance control: With proper process sequencing and temperature management, critical dimensions can be held to a tolerance of ±0.01mm.
- Stress relief: For parts with very high dimensional stability requirements, relieve stress after roughing, then finish machine.
- Workholding: POM is relatively soft, so clamping must not be so tight that it distorts the part or leaves surface marks.
POM vs. Other Engineering Plastics
| Material | Advantages | Typical Uses |
|---|---|---|
| POM | Wear-resistant, fatigue-resistant, self-lubricating | Gears, sliders, servo components |
| PC | High impact resistance, high transparency | Guards, viewing windows |
| Acrylic (PMMA) | High light transmission, easy to machine | Displays, guards, signage |
| PTFE | High-temperature and chemical resistance, very low friction | Seals, corrosion-resistant parts |
| ABS | Good all-round performance, easy to injection mold | Housings, structural parts |
Material Selection Guidance
- Wear-resistant drive elements: POM is the first choice.
- Transparent guarding: choose acrylic or PC.
- High-temperature or chemical resistance: choose PTFE.
- High-volume housings: choose injection-molded ABS.
Cremage provides precision machining for engineering plastics including POM, acrylic, PC, PTFE, ABS, PP, PVC, PET, and PS, with an accuracy of ±0.01mm, serving high-precision fields such as automation and semiconductors. For material selection advice or prototyping, please contact us.