At PuKong Prototype, we specialize in
providing high-quality rapid prototyping solutions to meet diverse
industrial needs. One of the key materials we utilize is Polyoxymethylene (POM),
also known as acetal or Delrin® (a well-known brand). POM is an
engineering thermoplastic widely used in rapid prototyping due to its
excellent mechanical properties, dimensional stability, and wear
resistance. This document provides a comprehensive overview of POM’s
applications, material properties, processing capabilities, and
limitations in the rapid prototyping industry.
1. Applications of POM in Rapid Prototyping
POM is widely used in functional prototyping and end-use parts across various industries, including:
Automotive: Gears, bushings, clips, and fuel system components.
Consumer Electronics: Snap-fit enclosures, hinges, and sliding mechanisms.
Medical Devices: Surgical instrument handles, drug delivery components.
Industrial Machinery: Bearings, rollers, conveyor components.
Aerospace: Low-friction components and structural parts.
POM is particularly favored for applications requiring high stiffness, low friction, and resistance to wear and chemicals.
2. Material Properties: Advantages & Disadvantages
Key Advantages of POM:
| Property | Value/Description | Benefit |
|---|
| Tensile Strength | 60-70 MPa | High mechanical strength for load-bearing parts |
| Flexural Modulus | 2.5-3.0 GPa | Excellent rigidity and stiffness |
| Impact Resistance | Good (but notch-sensitive) | Suitable for dynamic applications |
| Friction Coefficient | 0.1-0.3 (low) | Ideal for sliding/rotating parts |
| Chemical Resistance | Resistant to hydrocarbons, solvents | Suitable for harsh environments |
| Moisture Absorption | Very low (~0.2%) | Minimal dimensional change in humid conditions |
Disadvantages of POM:
Poor adhesion (difficult to bond or paint).
Notch sensitivity (prone to cracking under sharp stress points).
Limited high-temperature performance (softens above 90°C).
Difficult to print with FDM (mostly machined or CNC-milled).
3. Processing Methods & Tolerances
POM is primarily processed in rapid prototyping via:
A. CNC Machining (Most Common)
Standard Tolerances: ±0.1 mm (can reach ±0.05 mm with precision machining).
Max Part Size: Up to 500 × 500 × 300 mm (depends on machine capacity).
Surface Finish: Smooth (Ra 0.8-3.2 µm), can be polished further.
B. Injection Molding (For Mass Production)
C. 3D Printing (Limited Use)
4. Dimensional Stability & Warping Issues
POM has low moisture absorption, meaning it resists swelling in humid environments. However, it is prone to internal stresses and warping during machining due to:
Mitigation Strategies:
Stress-relieving annealing (post-machining heat treatment).
Controlled machining speeds to reduce heat buildup.
Proper fixturing to minimize distortion during cutting.
5. Comparison with Alternative Materials
| Material | POM | Nylon (PA6) | ABS | PEEK |
|---|
| Strength | High | Moderate | Moderate | Very High |
| Wear Resistance | Excellent | Good | Fair | Excellent |
| Max Temp. | 90°C | 120°C | 80°C | 250°C |
| Cost | $$ | $ | $ | $$$$ |
POM is the best choice for precision mechanical parts where low friction and stiffness are critical, but not ideal for high-temperature or high-impact applications.
6. Conclusion
POM is a high-performance engineering plastic widely used in rapid prototyping services for functional parts requiring dimensional stability, low friction, and wear resistance.
While it has some limitations (warping, notch sensitivity), proper
machining techniques can produce highly accurate and durable prototypes.
At PuKong Prototype, we offer CNC-machined POM parts
with tight tolerances and expert post-processing to ensure optimal
performance. Contact us today to discuss your project requirements!
