Polyoxymethylene (POM), commonly known by the brand name Delrin®, is a high-performance, engineering thermoplastic renowned for its exceptional dimensional stability, low friction, and high stiffness. Unlike metals, it operates smoothly with minimal lubrication, resists moisture absorption, and is immune to corrosion. CNC machining transforms POM into precise, durable components that excel in demanding mechanical and wear applications, offering a superior alternative to metals like aluminum and brass in many scenarios. When your design calls for smooth, reliable, and long-lasting movement, POM is the material of choice.
KEY BENEFITS
POM stands out in the world of engineered plastics due to its unique combination of properties. It delivers metal-like strength and rigidity with the added advantages of a polymer.
| Benefit | Description | Why It Matters |
|---|---|---|
| Low Friction & High Wear Resistance | Has an inherently low coefficient of friction and excellent abrasion resistance. | Ideal for gears, bearings, and sliding parts, reducing the need for external lubrication and ensuring long service life. |
| Excellent Dimensional Stability | Maintains its shape and size across a wide range of temperatures and humidity levels. | Critical for producing high-tolerance parts that must perform reliably without warping or swelling. |
| High Stiffness & Strength | Offers excellent rigidity and strength-to-weight ratio, comparable to some metals. | Provides structural integrity for load-bearing components while being lightweight. |
| Good Chemical Resistance | Resists most solvents, hydrocarbons, and neutral chemicals. | Suitable for parts exposed to oils, greases, and fuels in automotive or industrial environments. |
| Superb Machinability | Machines to a superb surface finish with tight tolerances; it does not produce brittle, powdery chips. | Allows for the production of complex, high-precision parts with excellent aesthetic and functional surfaces. |
APPLICATIONS
From consumer electronics to heavy machinery, CNC-machined POM parts are the workhorses inside countless devices, enabling smooth and quiet operation.
| Industry | Example Parts |
|---|---|
| Automotive | Fuel system components (gears, valves), window regulators, seat belt mechanisms, interior latches. |
| Consumer Electronics | Gears in printers and scanners, conveyor belt components, camera mechanisms, audio equipment parts. |
| Industrial Machinery | Insulating parts, guide rollers, conveyor chain links, custom bushings, bearings, and jigs & fixtures. |
| Medical Devices | Drug delivery device components, inhaler mechanisms, surgical instrument housings (non-implantable). |
| Food & Beverage | Food conveyor components, milk pump impellers, bottle filling machine parts (meets FDA compliance grades). |
| Consumer Goods | Zipper sliders, lightweight gear sets for RC models, kitchen appliance gears, sprayer triggers. |
TECHNICAL SPECIFICATIONS
This table provides key technical data for standard, unfilled POM (Homopolymer Acetal). Specific grades (e.g., Copolymer, PTFE-lubricated) may have varying properties.
| Property | Value / Description | Test Standard |
|---|---|---|
| Material Type | Engineering Thermoplastic (Acetal Homopolymer) | – |
| Density | 1.41 – 1.42 g/cm³ | ASTM D792 |
| Tensile Strength (Yield) | 70 MPa (10,000 psi) | ASTM D638 |
| Flexural Modulus | 3,100 MPa (450,000 psi) | ASTM D790 |
| Impact Strength (Izod Notched) | 80 J/m | ASTM D256 |
| Melting Point | 175 °C (347 °F) | – |
| Continuous Service Temperature | -40 °C to 85 °C (-40 °F to 185 °F) | – |
| Coefficient of Friction | 0.1 – 0.3 (Dynamic, vs Steel) | ASTM D1894 |
| Water Absorption (24hr) | 0.2% | ASTM D570 |
| Machinability | Excellent – Produces continuous chips, achieving tight tolerances and fine surface finishes. | – |
| UV Resistance | Poor (unless modified with carbon black or other UV stabilizers) | – |
| Color Availability | Natural (White/Opaque), Black, and other colors available. | – |