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POM CNC Machining
High-Precision POM CNC Machining Services
Learn about POM CNC machining- a process that makes use of polyoxymethylene (otherwise known as acetal), an engineering plastic known for being strong, stable, and friction-minimal; the comparison between it and Delrin; and its usage in creating precision-oriented, high-performance items for industries.
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±0.025mm Precision
POM CNC Machining
What is POM Material? Understanding Polyoxymethylene
Polyoxymethylene, or POM for short, better known as acetal, Polyacetal, and by the trade name Delrin®, is a high-performance engineering thermoplastic that should be chosen over alternatives for its exceptional mechanical strength, low friction, and excellent dimensional stability. Hence, this is one of the most common material choices for precise CNC machining applications.
Since the 1960s, when marketed by DuPont, POM has become a material used across industries for its metal-like strength and plastic benefits, such as lower weight, self-lubrication, and corrosion resistance.
Key Terminology
POM
Polyoxymethylene (chemical name)
Acetal
Industry common name
Delrin®
DuPont brand (homopolymer)
Celcon®
Celanese brand (copolymer)
Gallery of Custom POM Parts
Explore our gallery of custom POM parts. See examples of high-quality, precision-machined Polyoxymethylene components for various industrial applications.
Key Properties of POM for CNC Machining
POM’s wide range of properties makes it a good candidate for CNC machining. What makes this engineering plastic stand out?
High Mechanical Strength
POM has high tensile strength of 60-70 MPa and great fatigue resistance, so it exhibits a capacity to satisfy mechanical requirements repeatedly.
Low Friction Coefficient
It has an ultra-low friction coefficient of 0.04 (dry); it is one of the least frictional engineering plastics, with natural self-lubrication.
Dimensional Stability
It maintains the tightest tolerances for the longest period; insignificant moisture absorption (0.2-0.5%) lends to stable performance.
Machinability
One of the easiest engineering plastics to machine on CNC; it forms clean chips and has a superb surface finish.
Wear Resistance
This material has an outstanding resistance, resisting abrasion and wear; therefore, this plastic material is frequently used for slides, gears, and bearings.
Chemical Resistance
They are resistant to many solvents, fuels, and lubricants, which makes them a perfect material for automotive and industrial applications.
Complete Technical Specifications
| Property | Value | Test Standard |
|---|---|---|
| Density | 1.41-1.42 g/cm³ | ISO 1183 |
| Tensile Strength | 60-70 MPa | ISO 527 |
| Flexural Modulus | 2.8-3.5 GPa | ISO 178 |
| Hardness | Shore D 85-95 | ISO 868 |
| Melting Point | 165-175°C | ISO 11357 |
| Continuous Use Temperature | -40°C to +80°C | – |
| Coefficient of Friction | 0.04 (dry) | ASTM D1894 |
| Water Absorption (24hr) | 0.2-0.5% | ISO 62 |
Pro TIp
For applications requiring the lowest possible friction, choose Delrin AF, which has PTFE-containing POM, actually, 13% PTFE for enhanced lubricity in dry-running systems.
Optimal CNC Machining Parameters for POM
For POM machining, it is necessary to take into consideration with what parameters the best results can be achieved. With respect to where it is sensitive to heat like metals, plastics have a high tendency to break apart: heat build-up, causing melting, warping, and poor finish.
Recommended Cutting Speeds
| Operation | Cutting Speed (m/min) | Cutting Speed (SFM) | Notes |
|---|---|---|---|
| Turning | 150-300 | 500-1000 | Use sharp carbide tools |
| Milling | 200-500 | 650-1650 | End mills with 2-3 flutes preferred |
| Drilling | 50-100 | 165-330 | Peck drilling for deep holes |
| Tapping | 10-30 | 35-100 | Use spiral flute taps |
Tool Selection Guidelines
Carbide tools are recommended over HSS for prolonged tool life and better surface finish
Cutting edges of tools need to be sharp; dull cutting tools produce more heat
Positive rake angles of 10-15° decrease cutting forces and heat generation
Consider TiN (Titanium Nitride) and DLC (Diamond-Like Carbon) coated force tools for long production runs
For precision turning, Polycrystalline Diamond (PCD) tools are the answer; they deliver excellent results
Cooling and Chip Control
To ensure machining POM can be achieved at the best level, temperature control is a must:
Compressed Air Cooling
The most effective in POM machining. Provided cooling without polluting the piece. Though do not point the 0.6 MPa air current straight at the working region. Could be selectable technically speaking depending on setups.
Flood Coolant (Optional)
Water-soluble coolants are possible in heavy cuttings. Always ensure dryness for measurement or storage.
Chip Evacuation
Clear chips from the material at 30-second intervals to prevent heat. Vacuum extraction should be used whenever possible.
Temperature Monitoring
The temperature of POM should be maintained below 150°C to prevent softening. Any infrared thermometer can be used for checking purposes.
⚠️ Important Warning
Laser cutting is strictly prohibited for POM! The laser cutting releases formaldehyde gas – a hazardous substance for the human body. For POM processing, you can only use the mechanical CNC machining process.
POM Machining Capabilities Showcase
Explore our precision Delrin® and Acetal components engineered for high-performance applications.
High Precision
Precision Machined POM Gears
Burr-free teeth machining for high wear resistance systems.
Industrial
Self-Lubricating Bushings
Low friction components designed for high-load environments.
Electronics
Complex CNC Milled Insulators
Intricate black POM housings with micro-drilled holes.
Fluid Control
Custom Acetal Manifolds
Leak-proof designs with precision internal threading.
Medical
Medical Grade Components
FDA compliant, biocompatible parts for surgical use.
Automotive
Automotive Valve Parts
Chemical resistant black Delrin with ±0.02mm tolerances.
Consumer
High Cosmetic Quality
Aesthetic parts with Ra 0.4μm finish for consumer goods.
Prototyping
Rapid Prototyping Kits
Low volume production runs for design verification.
Achievable Tolerances and Surface Finish in POM Machining
POM’s outstanding dimensional stability and machinability enable tight-tolerance machining capabilities rivaling those of metals. Here is what one can expect:
| Standard | Linear Tolerance | Hole Diameter | Surface Finish | Cost Impact |
|---|---|---|---|---|
| Baseline | ±0.1 mm | ±0.05 mm | Ra 1.6-3.2 μm | Baseline |
| Precision | ±0.05 mm | ±0.025 mm | Ra 0.8-1.6 μm | +20-40% |
| Ultra-Precision | ±0.025 mm | ±0.01 mm | Ra 0.4 μm | +50-100% |
Surface Finish Options
As-Machined
Ra 1.6-3.2μm
Standard finish with visible tool marks, suitable for functional parts
Fine Machined
Ra 0.8μm
Reduced tool marks, ideal for consumer-facing components
Polished
Ra <0.4 μm
Mirror-like finish for precision optical or medical applications
Bead Blasted
Uniform matte texture
Note: may look duller on black POM
Engineering Tools
POM CNC Machining Calculator
Professional-grade tools for POM/Delrin material selection, CNC parameter optimization, and cost estimation
POM Material Comparison
Technical specifications based on ISO/ASTM standards
POM-C
Copolymer
Acetal Copolymer (Celcon®, Hostaform®)
- Density 1.41 g/cm³
- Tensile Strength 67 MPa
- Tensile Modulus 2,800 MPa
- Elongation at Break 30%
- Melting Point 160-175°C
- Service Temp -40 to 100°C
- Min. Tolerance ± 0.10 mm
- Friction Coeff. 0.21
POM-H / Delrin®
Homopolymer
Acetal Homopolymer (DuPont Delrin®)
- Density 1.42 g/cm³
- Tensile Strength 70 MPa
- Tensile Modulus 3,100 MPa
- Elongation at Break 25%
- Melting Point 172-184°C
- Service Temp -40 to 120°C
- Min. Tolerance ± 0.05 mm
- Friction Coeff. 0.20
POM-GF
Glass Filled
25% Glass Fiber Reinforced POM
- Density 1.58 g/cm³
- Tensile Strength 80-105 MPa
- Tensile Modulus 4,500 MPa
- Elongation at Break 3-10%
- Melting Point 165-180°C
- Service Temp -40 to 140°C
- Min. Tolerance ± 0.15 mm
- Friction Coeff. 0.30
Design Guidelines: Minimum wall thickness of 1mm (0.039 in) recommended. For robust strength, use 2mm (0.079 in). Internal radii preferred over 90° angles. Thread depth should not exceed 3× hole diameter.
CNC Machining Parameters
Calculate optimal spindle speed, feed rate, and material removal rate
Formulas Used:
RPM = (Cutting Speed × 1000) / (π × Tool Diameter)
Feed Rate = RPM × Chip Load × Number of Flutes
MRR = Feed Rate × Depth of Cut × Width of Cut
RPM = (Cutting Speed × 1000) / (π × Tool Diameter)
Feed Rate = RPM × Chip Load × Number of Flutes
MRR = Feed Rate × Depth of Cut × Width of Cut
m/min
mm
2 Flutes
mm
mm
mm
Calculated Results
7,958RPM
Spindle Speed
796mm/min
Feed Rate
4,776mm³/min
Material Removal Rate
31.3in/min
Feed Rate (Imperial)
POM Machining Tip: For POM, recommended cutting speeds are 100-300 m/min with carbide tools. Use chip loads of 0.03-0.08 mm per tooth. Avoid excessive heat buildup – use coolant or air blast for deep cuts.
Material Weight & Cost Estimator
Calculate material requirements and estimated costs for POM parts
mm
mm
mm
POM-C (Copolymer) – 1.41 g/cm³
$/kg
pcs
Estimation Results
100cm³
Volume per Part
141g
Weight per Part
1.41kg
Total Weight
$11.28
Material Cost
Note: This estimates raw material cost only. Actual part cost includes machining time, setup, tooling, finishing, and overhead. Typical material waste factor is 20-40% for CNC machining. Contact us for a complete quote.
Material Data Sheets (PDF) of POM CNC Machining
POM-H (Homopolymer)
High stiffness & fatigue resistance. Ideal for precision gears. (Delrin® Equivalent)
PDF
POM-C (Copolymer)
Standard engineering grade. Excellent chemical resistance & thermal stability.
PDF
POM-C FDA Compliant
Food-contact safe grade. Perfect for food processing & medical components.
PDF
POM-C ESD (Antistatic)
Electrostatic dissipative grade for sensitive electronic fixtures & jigs.
PDF
Common POM CNC Machining Applications
POM’s versatile advantages ensure that it finds suitable applications in the field of machining precision in multiple industries.
Bearing Gears & Sprockets
Spur gears, helical gears, worm gears are among others. It says low noise and self-lubrication make them ideal for transmission systems POM.
Bearings & Bushings
Plain bearings, thrust washers, a guide bush. In many cases, external lubrication is not even necessary.
Automotive Applications
Fuel system parts, window regulators, seatbelt mech, door handles, switches, and clips.
Electrical Insulations
Connectors, switch housings, terminal blocks. Excellent electrical insulating materials.
Medical Devices
Surgical instrument handles, drug delivery mechanisms, pump components. FDA-compliant grades available.
Industrial Equipment
Conveyor components, rollers, cams, valve bodies, pump impellers, chain guides.
CNC Machining vs Injection Molding for POM
When should you choose CNC machining over injection molding for POM parts? Here’s a comprehensive comparison:
| Factor | CNC Machining | Injection Molding |
|---|---|---|
| Ideal Quantity | 1 – 1,000 parts | 1,000+ parts |
| Tooling Cost | None ($0) | $5,000 – $50,000+ |
| Lead Time | 3-10 days | 4-8 weeks (including tooling) |
| Design Changes | Easy & low cost | Expensive mold modifications |
| Part Complexity | Limited undercuts | Complex geometries possible |
| Tolerances | ±0.025mm achievable | ±0.1mm typical |
| Surface Finish | Ra 0.4μm possible | Depends on mold quality |
Decision Guide
Select CNC for prototypes, low-volume production (<1000 parts), stringent-tolerance features, or when production is time-sensitive, and no tooling investment is available. Pick Injection Molding when producing 1000+ of the exact pieces, where the unit cost is a vital concern.
Precision POM CNC Machining Case Studies
Real-world examples of how we solve warping, tolerance, and surface finish challenges for Delrin® and Acetal components.
Automotive Industry
High-Wear POM Gears & Fuel System Components
The Challenge
Client required POM-H (Delrin) gears with high fatigue resistance. Previous suppliers failed due to heat deformation and poor surface finish leading to noise >65dB.
Our Technical Solution
We utilized Carbide tooling to reduce friction and implemented a double-cooling system to manage POM’s low melting point. Optimized feed rates minimized burrs.
Tolerance Achieved
±0.025mm
Noise Reduction
< 55dB
Material
Delrin® 150
Medical Devices
Surgical Instrument Handles & Pump Housings
The Challenge
Needed Medical Grade POM-C parts capable of withstanding repeated autoclave sterilization. Critical requirement: absolute zero stress cracking and burr-free finish.
Our Technical Solution
Performed annealing treatment post-roughing to release internal stress. Applied cryogenic deburring to ensure clean edges without altering dimensions.
Surface Finish
Ra 0.4μm
Rejection Rate
0% (5k units)
Compliance
ISO 13485
Electronics & Insulators
Thin-Wall Connectors & Insulating Fixtures
The Challenge
Project involved thin-wall POM machining. The primary pain point was warping due to clamping force and material removal, affecting the assembly fit.
Our Technical Solution
We designed custom vacuum fixtures to hold parts without mechanical stress. Programmed symmetric material removal paths to balance internal forces during milling.
Flatness
Within 0.05mm
Production Time
Reduced 20%
Material
POM-C ESD
POM CNC Machining FAQs
POM machining refers to CNC machining of POM (polyoxymethylene), also known as acetal or polyacetal. POM is an engineering thermoplastic having excellent dimensional stability, low friction, and excellent mechanical strength, suitable for various equipment and products requiring precise accuracy. As it is engineered to resist wear, POM is also used in a range of industries, from automotive to medical devices, where precision parts with tight tolerances are required for operation.
Computerized numerical control milling and injection molding are standard techniques used to manufacture POM articles. CNC-machined POM components can be manufactured for POM prototypes, custom small-run production of POM applications, or low- to medium-volume applications that require high-quality POM materials and precision CNC machining. Injection molding is intended for very high manufacturing volumes, which will initially lower the cost per part, but only for a limited period. Depending on the case, both CNC machining and injection molding may be used for complex POM parts, where precision is required and tight tolerances must be maintained to account for volume and lead time.
Working with POM is a good way to machine the material, given its ease of machining and excellent characteristics such as low cutting force, good chip formation, and reduced burring. The best results in machining POM are achieved with sharp tools, controlled speeds, and proper cooling to prevent melting. POM material removal, as done in modern CNC operations, is highly effective for standard practices and precise CNC methods, turning crude parts into finished products with the tightest tolerance.
Yes, that is a fact. POM parts with very intricate shapes can be made by plastic machining methods, including the technique of precision cnc and milling, in order to custom-make POM-made components according to the customer’s exact specifications. Some POM machining parts are capable of realizing great precision and good repeatability over time, owing to the way the plastic is machined on an advanced CNC machine. For these reasons, pump parts, gears, and other parts with demanding performance requirements, such as those crucial for aerospace applications and even some within the food and beverages sectors, favor the processing of POM.
POM is used in numerous industrial sectors where its low friction, dimensional stability, and chemical resistance are required. It provides superior wear properties in parts and, as such, is typically used in pump components, bearings, sliding components, fasteners, and gears. The material may be medicated to enhance its properties, for example, to improve heat conduction. Naturally resistant to moisture and retaining good mechanical properties over time, POM is governing markets across the automotive, consumer products, and industrial machinery industries.
While making a design for prototyping or custom machining using CNC, always follow the material removal process and operational norms: avoid overly thin walls that carry high loads, keep the radiating easy and friendly to allow the milling cutter, and do everything in relation to precise CNC technology, that is, bracketing the tolerancing. Design-for-manufacturability minimizes manufacturing costs and helps ensure that the final parts satisfy the target specifications. Keep in constant communication with the shop in matters that pertain to the surface finish, tolerances, and the need or absence of the second operations like drilling and placing.
High-quality POM components can be manufactured to tight tolerances, with finishes that are mostly smooth or polishable; in some cases, a bit of deburring and light polishing may be needed to smooth the edges. Such desirable finishes can be executed via precision CNC machining, which ensures consistent dimensions and repeatable quality. Finally, these components may undergo ultrasonic cleaning or assembly to become ready-to-use plastic products; in some cases, machining can be performed without further finishing, unlike processes for other thermoplastics.
A lot of issues come into play with POM cutting, specifically heat and pressure combining to cause melting and tool wear due to the fiber-reinforced plastics, improper processing would cause dimension changes. Thus, the prevention of several defects is accelerated by using sharp tools with appropriate feed and speed, and by employing good chip-control strategies. Proper clamping and cooling processes in CNC machining help maintain tolerances. The consistent behavior of engineering plastics such as POM ensures the production of parts with near-tolerance and high performance. Best-practice guidelines in POM processing aim to minimize defects and maintain tolerance.
There are several mechanical properties that make POM attractive for CNC machining: tensile strength, flexural modulus, and impact resistance are among the key properties. On the one hand, high tensile strength enables the material to resist significant tensile forces without failure, while high flexural modulus provides resistance to shear forces. Impact resistance indicates that it can absorb sudden shocks without fracturing. Wear resistance is another significant benefit of POM, making it suitable for friction- and abrasion-resistant applications. These mechanical properties, taken together with the polymer’s combinations, include low coefficients of friction and good dimensional stability, rendering it the best material for machining outstanding performance CNC applications that need durability, precision, and long-term operability. This is why POM is ideal for high-performance parts, given its unique combination of properties.
