BRIGHTSTAR
PROTOTYPE CNC CO., LTD
+86 137 5010 5351
EN
June. 15, 2026
When it comes to CNC machining, many people first think of metal parts - aluminum alloys, stainless steel, titanium alloys. But in fact, CNC machining of plastic parts is equally important and is becoming more widely used. From medical implants to food machinery, from electr
onic housings to wear-resistant gears, plastic parts are everywhere.
But when facing common engineering plastics such as PEEK, POM, nylon, and ABS, many engineers and procurement professionals often find it difficult to choose. Why is PEEK so expensive? What is the difference between POM and nylon? What is ABS suitable for? Choosing the wrong material can lead to premature part failure or unnecessary higher costs.
This article will compare these four most commonly used engineering plastics in detail from multiple dimensions including strength, temperature resistance, wear resistance, chemical resistance, moisture absorption, machinability, and cost, helping you make the most suitable choice for your project.
Before diving into the comparison, let us understand the basic positioning of these four plastics.
PEEK (Polyether Ether Ketone) is the "aristocrat" of high-performance engineering plastics. It has very high strength, excellent chemical resistance, outstanding high-temperature resistance (long-term use up to 250°C), and good wear resistance. PEEK is a popular material for metal replacement and is commonly used in medical implants, aerospace parts, semiconductor equipment, and other high-end applications. The disadvantage is its extremely high price, about 10 to 20 times that of POM.
POM (Polyoxymethylene, often called Delrin) is one of the easiest engineering plastics to machine. It has high strength, high rigidity, excellent wear resistance, a low coefficient of friction, and excellent dimensional stability. POM is widely used for gears, bearings, bushings, fixtures, and other precision parts. Its moisture absorption is very low, and it maintains dimensional stability in humid environments. The price of POM is moderate, making it a cost-effective choice.
Nylon (typically Nylon 6 or Nylon 66) is known for its excellent wear resistance and toughness. It has good self-lubricating properties and is commonly used for wear parts such as gears, slides, cams, and washers. Nylon has strong moisture absorption. In humid environments, it absorbs water and swells, causing dimensional changes. Its strength and toughness are better than POM, but its dimensional stability is not as good as POM. The price is similar to POM.
ABS (Acrylonitrile Butadiene Styrene) is one of the most common general-purpose engineering plastics. It has good toughness, impact strength, and surface finish, with relatively low cost. ABS is widely used for electronic housings, automotive interior parts, prototypes, and more. Its chemical resistance and temperature resistance are average and it is not suitable for high-temperature or strongly corrosive environments. The price is the lowest among these four.
PEEK has a tensile strength of approximately 90 to 100 MPa, the highest among these four. This allows it to replace some metal parts.
POM has a tensile strength of approximately 60 to 70 MPa, with good strength suitable for most load-bearing structural parts.
Nylon has a tensile strength of approximately 50 to 85 MPa (depending on humidity and formulation), with higher strength in the dry state and a slight decrease in the wet state.
ABS has a tensile strength of approximately 40 to 50 MPa, the lowest among these four, but it is sufficient for non-load-bearing parts such as housings and brackets.
Flexural modulus measures the rigidity of a material. The higher the value, the less the material bends.
POM has a flexural modulus of approximately 2500 to 3000 MPa, with the best rigidity and excellent dimensional stability.
PEEK has a flexural modulus of approximately 3500 to 4000 MPa, actually higher than POM.
Nylon has a flexural modulus of approximately 1500 to 2500 MPa, lower than POM, making it more prone to deformation under load.
ABS has a flexural modulus of approximately 2000 to 2400 MPa, with acceptable rigidity.
Impact strength measures a material's ability to resist impact. The higher the value, the less likely the material is to break.
Nylon has very high impact strength, especially in the wet state, with excellent toughness.
ABS also has good impact strength, which is why it is widely used for housings that need to resist impact.
POM has moderate impact strength, lower than nylon and ABS.
PEEK has good impact strength, but not as good as nylon.
POM has relatively high hardness and good surface wear resistance.
PEEK also has high hardness and excellent wear resistance.
Nylon has lower hardness than POM, and its surface is more easily scratched.
ABS has the lowest hardness among these four.
PEEK has excellent fatigue strength, suitable for parts that withstand cyclic loading.
POM also has good fatigue strength and is commonly used for gears and other reciprocating motion parts.
Nylon has moderate fatigue strength.
ABS has poor fatigue strength and is not suitable for withstanding dynamic loads over long periods.
This is a very critical parameter when selecting plastics.
PEEK has a long-term use temperature of up to 250°C and can withstand over 300°C for short periods. This is one of PEEK's core advantages.
POM has a continuous use temperature of approximately 80 to 100°C. Above this temperature, POM begins to decompose, releasing formaldehyde gas.
Nylon has a continuous use temperature of approximately 80 to 120°C (depending on type and reinforcement).
ABS has a continuous use temperature of approximately 70 to 90°C. Above 90°C, ABS begins to soften and deform.
The coefficient of thermal expansion of plastics is much higher than that of metals. If a part needs to maintain dimensional stability at different temperatures, thermal expansion needs to be considered.
PEEK has a relatively low coefficient of thermal expansion, close to that of aluminum alloys.
POM has a moderate coefficient of thermal expansion.
Nylon has a relatively high coefficient of thermal expansion.
ABS also has a relatively high coefficient of thermal expansion.
POM has a very low coefficient of friction and excellent self-lubricating properties, making it very suitable for sliding parts.
Nylon also has a relatively low coefficient of friction and good self-lubricating properties.
PEEK has a low coefficient of friction and excellent wear resistance.
ABS has a relatively high coefficient of friction and is not suitable for sliding applications.
PEEK has excellent wear resistance, especially under high temperature and high load conditions.
POM has very good wear resistance and is an ideal material for gears and bearings.
Nylon has good wear resistance, but not as good as POM under dry friction conditions.
ABS has average wear resistance and is not suitable for wear environments.
The limiting PV value (pressure × velocity) is an indicator of a material's performance in sliding applications.
PEEK has the highest limiting PV value, suitable for high-load, high-speed sliding applications.
POM has a moderate limiting PV value, suitable for general sliding applications.
Nylon has a moderately low limiting PV value.
ABS is not suitable for sliding applications.
PEEK has excellent chemical resistance and is almost unaffected by common solvents, acids, and alkalis. Only concentrated sulfuric acid can dissolve PEEK.
POM has good chemical resistance but is not resistant to strong acids and strong alkalis.
Nylon has average chemical resistance and is affected by acids, alkalis, and certain solvents.
ABS has poor chemical resistance and is easily attacked by solvents such as acetone and esters.
This is the biggest disadvantage of nylon.
Nylon has very strong moisture absorption. In humid environments, it absorbs water, causing dimensional swelling and reduced strength. The water absorption rate can reach 1% to 3%. Nylon parts typically require conditioning treatment before use.
PEEK has very low moisture absorption, approximately 0.1% to 0.2%, with excellent dimensional stability.
POM also has very low moisture absorption, approximately 0.2% to 0.3%, with good dimensional stability.
ABS has moderate moisture absorption, approximately 0.3% to 0.5%.
POM is one of the easiest plastics to machine with CNC. It cuts smoothly, produces small powder-like chips, has good surface finish, and long tool life. POM is very suitable for high-volume production.
ABS also has good machinability, producing continuous chips and good surface finish. However, ABS tends to produce an odor during machining and requires good ventilation.
Nylon has average machinability. Nylon tends to produce stringy chips during machining that wrap around the tool. If the temperature gets too high during machining, nylon may melt or deform. Sharp tools and adequate cooling are required.
PEEK has average machinability. PEEK is hard and wear-resistant, causing relatively fast tool wear. PEEK is sensitive to heat; if the temperature gets too high during machining, the surface may degrade. Sharp tools, appropriate cooling, and optimized cutting parameters are required.
POM has the best dimensional stability and can consistently achieve tolerances of ±0.02 millimeters.
PEEK also has good dimensional stability and can achieve ±0.02 millimeters.
ABS has moderate dimensional stability, with tolerances around ±0.05 millimeters.
Nylon has the poorest dimensional stability. Due to moisture absorption, dimensions may change over time after machining. Tolerances are recommended to be loosened to ±0.1 millimeters.
POM has low internal stress after CNC machining and low risk of deformation.
PEEK has moderate internal stress after machining; thin-walled parts may deform.
ABS has low internal stress after machining.
Nylon has moderate internal stress after machining. Combined with moisture absorption swelling, the risk of deformation is relatively high.
ABS is the cheapest, approximately $2 to $4 per kilogram.
POM is moderately priced, approximately $4 to $8 per kilogram.
Nylon is similarly priced to POM, approximately $4 to $9 per kilogram.
PEEK is extremely expensive, approximately $80 to $150 per kilogram, 10 to 20 times the price of other materials.
POM has the lowest machining cost, with fast speed and long tool life.
ABS also has relatively low machining cost.
Nylon has moderate machining cost, requiring sharper tools and better chip evacuation.
PEEK has the highest machining cost, with slow machining speed and fast tool wear.
When selecting a material, you cannot look only at the material unit price. If PEEK can meet extreme requirements, although the material is expensive, it may be the only choice. If POM already meets the requirements, choosing PEEK is a waste.
Recommend POM or Nylon.
POM's wear resistance and low coefficient of friction make it very suitable for gears and bearings. Nylon has better toughness and is suitable for applications with larger impact loads.
Recommend PEEK.
If a part needs to operate in an environment above 200°C, PEEK is the only choice. POM and nylon will fail at this temperature.
Recommend PEEK.
PEEK has good biocompatibility and is widely used for spinal fusion cages, dental abutments, and other implants. POM and nylon are not suitable for implantation in the human body.
Recommend ABS.
ABS has low cost, is easy to machine, and has good surface finish, making it an ideal material for housings and prototypes.
Recommend POM or PEEK.
POM meets food contact requirements and is commonly used for food machinery parts. PEEK is more advanced and suitable for applications requiring high-temperature cleaning.
Recommend POM.
POM has the best dimensional stability and low moisture absorption, making it suitable for parts requiring tight tolerances.
Recommend PEEK.
PEEK has excellent chemical resistance and is almost unaffected by solvents. The other three materials will fail in strongly corrosive environments.
Q: Why is PEEK so expensive?
PEEK has a complex production process and high raw material costs. Its excellent performance can replace metals, making it worth the price in high-end applications.
Q: Which is better, POM or nylon?
There is no absolute "better"; it depends on the application. POM has better dimensional stability and wear resistance, making it suitable for precision gears. Nylon has better toughness and impact resistance, making it suitable for parts that endure impact.
Q: Is ABS suitable for load-bearing parts?
No. ABS has relatively low strength and is not suitable for bearing significant loads. ABS is mainly used for non-load-bearing parts such as housings and brackets.
Q: Why do nylon parts deform?
Nylon absorbs moisture from the air, causing dimensional swelling. If a part is machined in a dry environment and used in a humid environment, its dimensions will increase. The solution is to condition the nylon material before machining.
Q: Do you machine these four materials?
Yes. Brightstar can machine all common engineering plastics including PEEK, POM, nylon, and ABS. We can recommend the most suitable material based on your application requirements.
10. Summary
PEEK, POM, nylon, and ABS are the four most commonly used engineering plastics in CNC machining, each with its own advantages and disadvantages.
PEEK is the king of high performance, with high temperature resistance, chemical resistance, and high strength, but extremely expensive, suitable for high-end applications.
POM is the king of easy machinability, with dimensional stability, wear resistance, and moderate price, suitable for precision parts.
Nylon balances toughness and wear resistance, with good toughness, wear resistance, and moderate price, but has strong moisture absorption.
ABS is the economical general-purpose option, with low price and easy machinability, suitable for housings and prototypes.
When selecting a material, there is no "best" material, only the material that is "most suitable" for your application. Make a reasonable choice based on your application requirements, service environment, and budget constraints.
Brightstar has extensive experience in CNC machining of engineering plastics. If you are unsure which material to choose, please contact us. We can provide professional material recommendations based on your part drawings and usage requirements.
Whether you need the high performance of PEEK, the precision of POM, the toughness of nylon, or the cost-effectiveness of ABS, Brightstar can provide professional CNC machining services.
Email Amy: amy@brightstarprototype.com
Call or WhatsApp: +86 13750105351
Send us your CAD files and drawings for material recommendations and a quote.
Brightstar – Precision CNC Machining. Engineering Plastic Selection, Professional Guidance.
