Application of POM in Rapid Prototyping Services

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:

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)

• Mold Shrinkage: 1.8-2.5% (must be accounted for in design).

• Cycle Time: Fast (30-60 sec depending on part geometry).

C. 3D Printing (Limited Use)

• FDM POM Filament: Rare due to warping and adhesion issues.

• SLA/DLP: Not applicable (POM is not UV-curable).

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:

• High crystallinity (leads to uneven cooling).

• Thermal expansion (coefficient: 8-15 × 10⁻⁵/°C).

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

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!