POM vs PEEK for CNC Machining: Which Plastic Should You Choose?

POM and PEEK are two widely used engineering plastics for CNC machining, but they are designed for very different applications.

POM, also known as acetal or polyoxymethylene, is a cost-effective engineering plastic with excellent machinability, low friction, good wear resistance, and high dimensional stability. It is commonly used for gears, bushings, rollers, sliding components, fixtures, and general mechanical parts.

PEEK is a high-performance engineering plastic designed for more demanding operating conditions. It offers significantly higher temperature resistance, chemical resistance, mechanical strength, and long-term performance than POM. PEEK is commonly used in aerospace, medical, semiconductor, chemical processing, and other high-performance industrial applications.

So, how do you choose between POM and PEEK for CNC machined parts?

The answer depends on the part’s operating temperature, mechanical load, chemical exposure, wear conditions, dimensional requirements, application environment, and project budget.

This guide compares POM vs PEEK for CNC machining and explains how to select the right material for your application.

POM vs PEEK: Quick Comparison

The main difference between POM and PEEK is the balance between performance and cost.

For general mechanical components operating under moderate temperatures and loads, POM is often the more economical choice.

For components exposed to high temperatures, aggressive chemicals, high mechanical loads, or demanding operating environments, PEEK may provide better long-term performance.

What Is POM Plastic?

POM (polyoxymethylene), also known as acetal, is a widely used engineering thermoplastic for precision CNC machined plastic parts.

It offers a useful combination of stiffness, low friction, wear resistance, dimensional stability, and machinability.

Because POM absorbs relatively little moisture and maintains good dimensional accuracy, it is commonly selected for precision mechanical components.

Typical CNC machined POM parts include:

• Bushings

• Rollers

• Gears

• Sliding blocks

• Spacers

• Guide rails

• Bearing blocks

• Fixture components

• Automation equipment parts

• Insulating mechanical components

• Precision mechanical components

POM is particularly suitable for applications requiring smooth movement, low friction, good dimensional stability, and reasonable material cost.

What Is PEEK Plastic?

PEEK (polyether ether ketone) is a high-performance engineering thermoplastic used in demanding industrial applications.

Compared with POM, PEEK provides significantly better performance at elevated temperatures and in aggressive chemical environments.

It also offers high mechanical strength, excellent wear resistance, low moisture absorption, and good long-term dimensional stability.

Typical CNC machined PEEK parts include:

• High-temperature mechanical components

• Semiconductor equipment parts

• Medical device components

• Aerospace components

• Chemical-resistant parts

• High-performance bushings

• Electrical insulating components

• Wear-resistant sliding parts

• Valve and pump components

• Precision components for demanding environments

PEEK is generally selected when standard engineering plastics such as POM, nylon, or PTFE cannot meet the operating requirements.

POM vs PEEK: What Are the Main Differences?

Although both materials can be CNC machined into precision components, their performance levels and costs are very different.

The most important differences include:

• Operating temperature

• Mechanical strength

• Wear resistance

• Chemical resistance

• CNC machining requirements

• Material cost

• Application environment

Understanding these differences can help avoid unnecessary material costs or premature component failure.

1. CNC Machinability

Both POM and PEEK can be CNC milled, turned, drilled, bored, and tapped.

However, their machining characteristics are different.

POM Machining

POM is one of the easier engineering plastics to CNC machine.

It offers:

• Good chip formation

• Low cutting resistance

• Good dimensional stability

• Excellent surface finish

• Relatively easy milling and turning

• Cost-effective production of prototypes and small batches

POM is therefore widely used for CNC machined plastic parts requiring tight tolerances and good surface quality.

However, like other thermoplastics, excessive machining heat or improper clamping can still cause deformation.

PEEK Machining

PEEK also has good machinability, but the machining process generally requires more careful control.

Important considerations include:

• Cutting tool selection

• Cutting speed and feed rate

• Heat generation

• Workholding and clamping

• Burr control

• Internal stress

• Dimensional inspection

Because PEEK material is significantly more expensive than POM, machining errors and excessive material waste can substantially increase production costs.

For thin-wall, tight-tolerance, or complex PEEK components, machining strategy and process control become especially important.

2. Temperature Resistance

Temperature resistance is one of the most important differences when comparing POM vs PEEK.

POM performs well in normal industrial environments and moderate operating temperatures.

However, it is not generally selected for continuous exposure to very high temperatures.

PEEK offers significantly higher temperature resistance and can maintain useful mechanical properties at temperatures where POM would no longer be suitable.

PEEK may be the better choice for parts used near:

• Motors

• Heating systems

• High-temperature fluids

• Semiconductor processing equipment

• Industrial ovens

• Aerospace systems

• High-temperature machinery

If the component operates at room temperature or moderate temperatures, POM may provide sufficient performance at a much lower cost.

3. Mechanical Strength and Stiffness

POM provides good mechanical strength and stiffness for general mechanical applications.

It is commonly used for gears, rollers, bushings, guides, fixtures, and automation components.

PEEK offers higher mechanical performance and maintains its properties more effectively under demanding operating conditions.

PEEK should be considered when the component is exposed to:

• Higher mechanical loads

• Elevated temperatures

• Long-term stress

• Demanding wear conditions

• Critical industrial applications

However, selecting PEEK solely because it has higher performance is not always economical.

The material should be selected according to the actual operating requirements of the component.

4. Wear Resistance and Friction

Both POM and PEEK are suitable for applications involving sliding movement and friction.

POM has a low coefficient of friction and good wear resistance, making it suitable for:

• Gears

• Rollers

• Bushings

• Sliding blocks

• Guide components

• Conveyor components

For normal industrial applications, POM often provides an excellent balance between performance and cost.

PEEK offers superior performance in more demanding wear applications, particularly when high temperature, mechanical load, chemical exposure, or long service life are important.

For high-load or high-temperature wear applications, PEEK may provide better long-term reliability.

5. Chemical Resistance

Chemical exposure is another important factor when choosing between POM and PEEK.

POM has good resistance to many common oils, fuels, and solvents.

However, its chemical resistance is limited in certain aggressive environments.

PEEK offers excellent resistance to a much wider range of chemicals and is commonly used in:

• Chemical processing equipment

• Semiconductor manufacturing equipment

• Medical devices

• Oil and gas equipment

• Pumps and valves

• Laboratory equipment

Before selecting either material, it is important to identify the specific chemical, concentration, operating temperature, and exposure duration.

A material that performs well at room temperature may behave differently when exposed to the same chemical at elevated temperatures.

6. Dimensional Stability

Dimensional stability is critical for precision CNC machined plastic parts.

POM has excellent dimensional stability and low moisture absorption compared with many other engineering plastics.

This makes it suitable for:

• Precision fixtures

• Mechanical guides

• Automation components

• Gears

• Rollers

• Inspection equipment components

PEEK also provides excellent dimensional stability, particularly in demanding environments involving higher temperatures or chemical exposure.

For extremely tight tolerances, material selection alone is not enough.

The final dimensional accuracy can also be affected by:

• Raw material quality

• Internal material stress

• Part geometry

• Wall thickness

• Clamping method

• Machining sequence

• Heat generation

• Inspection temperature

These factors should be reviewed before CNC machining high-precision plastic components.

7. POM vs PEEK Cost

Cost is one of the biggest differences between POM and PEEK.

POM is significantly more economical and is widely available for general industrial applications.

PEEK is a premium engineering plastic with a much higher raw material cost.

In addition, the final cost of CNC machined PEEK parts can be affected by:

• Raw material size

• Material certification requirements

• Part geometry

• Material waste

• Machining time

• Tolerance requirements

• Inspection requirements

• Production quantity

For this reason, PEEK should not be selected simply because it offers higher performance.

If the application does not require high temperature resistance, exceptional chemical resistance, or demanding mechanical performance, POM may be the more cost-effective material.

When Should You Choose POM?

Choose POM for CNC machined parts when:

• The component operates in a normal industrial environment

• Cost control is important

• Low friction is required

• Good dimensional stability is needed

• The working temperature is moderate

• The chemical environment is not aggressive

• Good machinability is important

• The part is used in automation equipment or general machinery

Typical POM applications include gears, rollers, bushings, spacers, sliding blocks, guides, fixtures, and general mechanical components.

When Should You Choose PEEK?

Choose PEEK when:

• The component operates at elevated temperatures

• Higher mechanical performance is required

• Excellent chemical resistance is necessary

• The component operates under demanding wear conditions

• Long-term dimensional stability is important

• The application involves semiconductor equipment

• The application involves medical equipment

• The component is used in aerospace systems

• Standard engineering plastics cannot meet the requirements

• The project can accept higher material and machining costs

PEEK is particularly valuable when component failure, frequent replacement, or insufficient material performance would create significant operational costs.

POM or PEEK: Which Material Is Better for Your CNC Parts?

Neither material is universally better.

The correct choice depends on the application.

For general CNC machined plastic components operating at moderate temperatures and loads, POM is often sufficient and more cost-effective.

For high-temperature, chemically aggressive, high-load, or demanding precision applications, PEEK may provide better long-term performance.

Before selecting a material, consider the following factors:

• Maximum and continuous operating temperature

• Mechanical load

• Sliding and wear conditions

• Chemical exposure

• Required tolerances

• Dimensional stability

• Electrical insulation requirements

• Service life

• Regulatory or certification requirements

• Project budget

If these requirements are unclear, material selection should be reviewed before production begins.

Frequently Asked Questions About POM vs PEEK

Is PEEK stronger than POM?

PEEK generally offers higher mechanical performance than POM, particularly at elevated temperatures and under demanding operating conditions.

However, POM provides sufficient strength for many general mechanical and automation applications at a significantly lower cost.

Is POM easier to CNC machine than PEEK?

POM is generally easier and more economical to machine.

PEEK can also be CNC machined to tight tolerances, but careful control of cutting conditions, heat, workholding, and machining strategy is more important.

Is PEEK always better than POM?

No.

PEEK offers higher overall performance, but it is also significantly more expensive.

If the component operates under normal temperatures, moderate loads, and non-aggressive chemical conditions, POM may be the better engineering choice.

Can POM and PEEK be used for precision CNC machined parts?

Yes.

Both materials can be used for precision CNC components.

However, achievable tolerances depend on part geometry, dimensions, wall thickness, material condition, machining strategy, temperature control, and inspection requirements.

Which material is better for gears and bushings?

For general industrial gears and bushings, POM is often a cost-effective choice because of its low friction, wear resistance, and good machinability.

For high-temperature, high-load, chemically aggressive, or demanding long-life applications, PEEK may be more suitable.

Which material is more suitable for semiconductor equipment?

PEEK is commonly considered for semiconductor equipment because of its high temperature resistance, chemical resistance, dimensional stability, and high-performance characteristics.

However, the final material selection should depend on the specific operating environment, purity requirements, chemical exposure, temperature, and component function.

Conclusion

POM and PEEK are both excellent engineering plastics for CNC machining, but they serve different application requirements.

POM is a cost-effective, dimensionally stable, low-friction, and easy-to-machine engineering plastic. It is widely used for gears, bushings, rollers, sliding components, fixtures, and automation equipment parts.

PEEK is a high-performance engineering plastic designed for more demanding applications requiring elevated temperature resistance, excellent chemical resistance, higher mechanical performance, wear resistance, and long-term reliability.

The best material is not necessarily the one with the highest performance.

The correct choice is the material that meets the component’s technical requirements without creating unnecessary cost.

If you are unsure whether POM, PEEK, or another engineering plastic is suitable for your CNC machined parts, send us your 2D drawings, 3D models, material requirements, operating temperature, load conditions, chemical environment, tolerance requirements, and application details.

Our engineering team can review your project and recommend a suitable material and CNC machining solution before production.