Skip to content 
POM CNC machining is very important process for making highly precise components with outstanding performance attributes. By knowing about this procedure, you can enhance your production methods, improve product quality, and decrease price.
This all-inclusive guide will cover POM CNC machining, its use cases and advantages in multiple fields.
What is POM CNC Machining?
POM CNC machining combines the creativity of Polyoxymethylene (POM) with the precision of Computer Numerical Control technology. This latest process uses computer controlled cutting tools to eliminate material automatically from a POM workpiece.
Properties of POM
The following extraordinary characteristics of POM make it appropriate material for CNC machining.
Tensile Strength
It can handle large tension forces without breaking or warping due to its tensile strength of 62-79 MPa.
Hardness
POM’s shore D hardness of 80-90 and Rockwell hardness of M85-M100 provide outstanding resistance to wear and scratches. These qualities make it particularly perfect for precision-machined components such as bearings and gears.
Dimensional stability
This material has low moisture absorption rate (0.2-0.3% in 24 hours) which guarantees minimal dimensional changes. POM can also keep tolerance within ±0.002 inch/inch under different weather conditions.
Low friction coefficient
It allows for self-lubrication due to its dynamic friction coefficient which ranges from 0.2 to 0.3. This DFC also improves proficiency in precision mechanical operations and minimizes wear in moving parts.
Moisture resistance
POM has a water absorption rate less than 0.2% in 24 hours due to its hydrophobic nature. So it can maintain dimensional stability and mechanical features in humid environments.
Thermal and electrical insulation
It is a good insulator for high voltage applications and electronic components because of its low thermal conductivity (0.31 W/(K·m)) and high dielectric strength (20 kV/mm).
Comparison with Other Materials
Now we will see POM’s characteristics more clearly when we compare it with other common engineering plastics like nylon, ABS and polycarbonate.
POM vs Nylon
In moisture resistance and dimensional stability, POM is better than Nylon. It has a 0.2% water absorption rate which is much lower than Nylon’s 1.5%. POM can keep strict tolerances in damp conditions but nylon has better adaptability and impact resistance.
POM vs ABS
POM has higher tensile strength (62-79 MPa) than ABS (40-50 MPa). It has also better wear properties and chemical resistance. But for less demanding applications, ABS is more cost effective with better impact resistance.
POM vs Polycarbonate
For moving parts, POM is the best material due to its better wear resistance and low friction coefficient. Whereas polycarbonate provides higher impact strength and transparency. So it is good for applications which need extreme durability and need optical clarity.
CNC Machining Methods for POM
POM is used in many CNC machining methods as it shows outstanding machinability. These methods are following.
Turning
Turning procedure of POM is similar to brass machining as both produce best results at medium feed rates and fast turning speeds. Chip breakers are used to guarantee accuracy and avoid chip build up. POM turning uses cutting speed of 250 ft/min to attain accurate and smooth products.
Milling
In this process, single-fluted mills are used to obtain better surface finish and avoid chip build up. It combines high cutting speeds with medium feed rates. Sharp tools are needed to acquire precise angles and complex shapes. During high speed milling, coolants are recommended to control heat and preserve dimensional stability of POM parts.
Grinding
For strict tolerances and better surface finish, grinding is best choice for POM. It uses fine grit abrasive wheels to remove material without producing too much heat. As POM has low thermal conductivity, operators must control grinding settings carefully to avoid local melting. Coolants are important to preserve surface quality and dimensional stability throughout the grinding procedure.
Drilling
A thoughtful approach is needed for drilling POM to assure accuracy and avoid deformation. Standard twist drills operating at 1500 rpm with a 118° twist angle and ground flat leading edges are good for this process. For better chip removal and less heat accumulation, retract the drill every 5–6 mm. This process combined with moderate feed rate will give clean and accurate holes in POM parts.
Surface Finishing Techniques
Two surface finishing options for POM CNC machined parts are as-machined and bead blasting. As-machined finish preserves tool marks with surface roughness from 0.8 to 6.3 microns. Whereas bead blasting gives uniform matte finish improving both lifespan and appearance. For even smoother surfaces, polishing and buffing can be used. Moreover, anodizing (for POM composites) gives color customization options and corrosion resistance.
POM CNC Machining Benefits
For making top quality parts, POM CNC machining has following advantages.
Precision and Accuracy
POM CNC machining can reach very tight tolerances up to ±0.05 mm. It is better than injection molding as it can produce complicated geometries of fine details. This level of accuracy is important in industries like medical device and aerospace production.
Material Efficiency
The process uses accurate cutting and streamlined toolpaths to decrease material waste. POM generates minimum heat during machining due to low friction. So it facilitates chip removal and prevents material deformation. As a result, manufacturers can get the most out of raw materials with less price and environmental footprint.
Design Flexibility and Rapid Prototyping
Manufacturers can use POM CNC machining for quick design iterations with some turnaround time as fast as 24 hours. Its high machinability permits the creation of complicated geometries and complex details. This capability supports rapid prototype development and functional testing in sectors like automotive.
Consistency and Quality
POM CNC machining assures part to part consistency with dimensional fluctuations as small as ±0.025 mm. This extraordinary accuracy combined with POM’s inherent stability makes best quality parts which preserve their properties in production runs of particular industries like medical and aerospace.
Cost Effective
Automation in POM CNC machining decreases labor costs. Optimized toolpaths and better material usage reduce waste, while fast speed machining minimizes cycle times. All of these factors together make POM CNC machining a cost effective solution for large volume production.
Applications of POM Parts
POM’s peculiar properties make it a great fit for many industries. Let’s see uses of POM CNC machining in different sectors.
Automotive
POM CNC machining is used to produce high precision parts like bushings, fuel system parts and gear. Its wear resistance and low friction features improve vehicle longevity and performance.
Medical
For implants and surgical instruments, POM machining is used because of biocompatibility and sterilization resistance. POM’s low friction coefficient is useful to improve performance in orthopedic devices and joint replacements.
Electronics
POM is broadly used in electronics industry for switches, connectors and housings in electronic devices as it has outstanding electrical insulation properties with dielectric strength of 20 kV/mm.
Aerospace
Its low density of 1.42 g/cm2 and high strength make it a great material for non-load bearing parts like bushings, interior fittings and fasteners to reduce weight.
Robotics
Critical parts such as bearings, structural parts and robotic gears are made from POM to improve lifespan and accuracy.
POM Machining Challenges
POM has high elasticity and low thermal stability with a melting point of 175°C which causes cracking and deformation. Pressure from clamping mechanisms, heat generated during cutting and internal stress can cause dimensional inaccuracies.
To overcome these issues, sharp cutting tools, cutting settings and proper cooling techniques are used to produce precise, best-quality POM parts constantly.
Conclusion
POM CNC machining is a proficient and adaptable way to produce intricate parts in many industries. Their distinct characteristics combined with new CNC technology can create best quality parts with outstanding performance characteristics and strict tolerances.
If you need POM CNC machining services, contact RICHCONN today for precise parts according to your particular project needs.
FAQs
1. How does CNC machining POM compare to other plastic machining methods like injection molding or 3D printing?
As compared to injection molding, CNC machining POM has better precision with tolerances as tight as ±0.005mm and more design flexibility. This makes it expensive for large volumes. While 3D printing is good for rapid prototyping, CNC machined POM parts usually have better mechanical properties and surface finishes for functional parts.
2. What are best post-processing approaches for finishing CNC machined POM parts?
For parts that need a non-reflective surface, bead blasting is used as it gives a matte finish. Polishing is also very effective for smooth surfaces, while anodizing (for POM composites) improves appearance and lifespan.
3. How does POM compare to PTFE and Nylon in CNC machining?
POM is better than Nylon in machinability and dimensional stability with lower moisture absorption and friction. POM shows great toughness and strength but it has bit more friction than PTFE. These characteristics make POM particularly appropriate for precision parts which need structural integrity.
4. How does CNC machining POM improve the precision and dimensional stability of manufactured parts?
CNC machining POM process can achieve very narrow tolerance of ±0.005 mm. POM’s properties contribute to this precision and dimensional stability with less than 0.1% moisture absorption in 24 hours and minimal thermal expansion. These characteristics assure that POM parts maintain their dimensions and shape across a broad range of environmental conditions.
