How to choose the plastic material used for your CNC Machining Parts?

CNC parts

In the field of CNC machining processing industry, plastics are often used as raw materials for further processing. Meanwhile plastics materials are integral to the modern manufacturing industry — they’re widely available, most are affordable, and they’re compatible with popular manufacturing processes like injection molding, 3D printing, and CNC machining. Now there are many types of plastic material on the market, so what kind of plastic materials should be selected when processing cnc machining.


In this article, we will introduce all the CNC Machining plastic material, including their chemical resistance, excellent dimensional stability, high temperature resistance, abrasion resistance, CT.

1. POM(Delrin/Acetal)

Plastic materials -Pom is a white or black plastic granule with high hardness, high steel and high wear resistance. Mainly used for gears, bearings, auto parts, machine tools, instrument internals and other products that play a skeleton role.This material is widely used for cnc machining.

(1) POM is a crystalline plastic, density of 1.42g/cm3, its steel is very good, commonly known as "race steel".

(2) POM has fatigue resistance, creep resistance, wear resistance, heat resistance, impact resistance and other excellent performance, and the coefficient of friction is small, self-lubricating good.

(3) POM is not easy to absorb moisture, water absorption rate of 0.22 ~ 0.25%, good dimensional stability in a humid environment, its shrinkage rate of 2.1% (larger), injection molding size is difficult to control, the heat deflection temperature of 172 , paraformaldehyde has two kinds of homopolymer formaldehyde, different performance (homopolymer formaldehyde temperature resistance is better).


Plastic materials -Nylon is a good material for cnc plastic machining instead of mild steels, iron, copper and other metals, is an important engineering plastic; cast nylon is widely used to replace the wear-resistant parts of machinery and equipment, instead of copper and alloy for the wear-resistant parts of equipment. Suitable for making wear-resistant parts, transmission structure parts, household appliance parts, automobile manufacturing parts, filament preventing mechanical parts, chemical machinery parts, chemical equipment. Such as turbines, gears, bearings, impellers, cranks, instrument panels, drive shafts, valves, vanes, filaments, high-pressure washers, screws, nuts, seals, bobbins, sleeve Jane, bushing connectors, etc. This material has good machinability so is widely used for cnc machining.

(1)High mechanical strength, high precision chemical resistance, with high tensile and compressive strength.

(2)fatigue resistance is outstanding, the parts can still maintain the original mechanical strength after repeated bending.

(3)High softening point, heat resistant

(4)Smooth surface, small coefficient of friction, wear-resistant, low friction.

(5)Corrosion resistance, high stiffness, as a packaging material for lubricants, fuel, industrial applications.


ABS plastic is a kind of "tough, hard and rigid" material with easy access to raw materials, good overall performance, low price and wide range of uses, ABS plastic has been widely used in mechanical, electrical, textile, automobile, aircraft, automotive parts and other manufacturing industries for many industries. This material is widely used for cnc machining.

(1) ABS is a very good overall resin with high impact strength and surface hardness over a relatively wide temperature range, higher heat deflection temperature than PA and PVC, and good dimensional stability.

(2) ABS has excellent mechanical properties, and its moisture absorption is good and can be used at very low temperatures.

(3) ABS is an amorphous polymer with no apparent melting point; it has high melt viscosity and chemical resistance, low friction, poor fluidity and poor weatherability.

(4) ABS has good plastic machining material properties and is virtually unaffected by temperature, humidity and frequency, and can be used in most environments.

(5) ABS is not affected by water, inorganic salts, alkali alcohols and hydrocarbon solvents and many acids, but is soluble in ketones, aldehydes and chlorinated hydrocarbons, and is subject to stress cracking from erosion by ice acetic acid and vegetable oils.


Peek is a special engineering machining plastics with excellent performance of high temperature resistance, self-lubrication, tight tolerances, low cost, easy processing and high mechanical strength, which can be manufactured and processed into various mechanical parts, such as automobile gears, oil sieves, electronics enclosures; aircraft engine parts, automatic washing machine rotors, medical devices, etc. This material is widely used for cnc machining.

(1) Corrosion resistance, anti-aging;

(2) resistance to solubility.

(3) High temperature, high frequency and high voltage electrical performance conditions ;

(4) both toughness and rigidity.

(5)Dimensional requirements for precision conditions;

(6) irradiation resistance wear resistance, corrosion resistance conditions;

(7) resistance to hydrolysis, high temperature and high pressure can still maintain excellent characteristics

(8) Lightweight instead of metal for fiber optic components;

(9) wear-resistant, anti-static electrical insulation properties;

(10) High mechanical strength requirements components

(11)Excellent chemical resistance of manufacturing process for cnc machined parts


PTFE is used in the electrical industry, in aerospace, aviation, electronics, instrumentation, computers and other industries as the insulation layer of power and signal lines, corrosion-resistant, wear-resistant cnc materials can be made of film, pipe plate bar, bearings, gaskets, valves and chemical pipes, pipe fittings, equipment container lining .This material is widely used for cnc machining.

(1) stable at room temperature and pressure, avoiding humidity, heat and high temperature  

(2) white, odorless, tasteless, non-toxic powder, commonly known as "plastic king". It has excellent high heat resistance, sealing, scratch resistance and non-stick, electrical insulation and good anti-aging resistance. High temperature resistance, good weather resistance, the best aging life of plastics. High lubrication, the lowest coefficient of friction among solid materials. Non-adhesive, the lowest slippery surface tension among solid materials, does not adhere to any substance. Non-toxic, physiologically inert, no adverse reactions to long-term implantation as artificial blood vessels and organs.


(1) mechanical properties: high strength and elastic coefficient, high impact strength, good fatigue resistance, good dimensional stability, small creep (very little change under high temperature conditions), high transparency and free coloring. This material is widely used for cnc machining.

(2) Heat resistance to aging: wide range of use temperature, enhanced UL temperature index of 120 ~ 140 (outdoor long-term aging is also very good).

(3) solvent resistance: no stress cracking.

(4) stability to water: easy to decompose under high temperature in contact with water (caution is needed when using in high temperature and high humidity environment)

(5) insulation performance: excellent (moisture, high temperature can also maintain the electrical properties of stable, is the ideal material for the manufacture of electronic and electrical parts).

(6) dielectric coefficient: 3.0-3.2.

(7) arc resistance: 120s.

(8) molding processability: common equipment injection or extrusion.


Polyethylene is odorless, non-toxic, feels like wax, has excellent low temperature resistance, good chemical stability, and can resist the erosion of most acids and bases. Insoluble in general solvents at room temperature, small water absorption, excellent electrical insulation. This material is widely used for cnc machining.

(1) The mechanical properties of polyethylene are general, the tensile strength is low, creep resistance is not good, impact resistance is good.

(2) High density Polyethylene has low heat resistance, good low temperature resistance.

(3) Because polyethylene is non-polar, it has excellent electrical properties of low dielectric loss and high dielectric strength, that is, it can be used as FM insulating material, corona resistant plastic, and high voltage insulating material.

(4) Polyethylene has good chemical stability. It is resistant to corrosion by aqueous solutions of acids, alkalis, and salts at room temperature.


PVC used to be the world's most produced general-purpose plastic and has a wide range of applications. It is widely used in construction materials, industrial products, daily necessities, floor leather, floor tiles, artificial leather, pipes, wires and cables, packaging films, bottles, foaming materials, sealing materials, fibers, etc. This material is widely used for cnc machining.

  Mechanical properties


Young's modulus of elasticity (E)

Tensile strength (σt)

Elongation at break

Glass transition temperature

Melting point

Softening temperature

Thermal conductivity (λ)

Thermal expansion coefficient (α)

Heat capacity (c)

Water absorption (ASTM)

Refractive index

1380 kg/m3

2900-3400 MPa

50-80 MPa





0.16 W/(m-K)

8×10-5 /K

0.9 kJ/(kg-K)



 Mechanical properties


Polypropylene has small density, rigid strength, hardness and heat resistance are better than low-pressure polyethylene, and can be used at about 100 degrees. It is widely used in the production of clothing, blankets and other fiber products, medical equipment, automobiles, bicycles, parts, transport pipes, chemical containers, etc. It is also used in food and pharmaceutical packaging.

10.Plexiglass (PPMA/Acrylic)

Plexiglass (Polymethyl methacrylate) is a common name, abbreviated as PMMA, and the chemical name of this polymeric transparent material is polymethyl methacrylate, a polymer compound made by polymerizing methyl methacrylate. It is an important thermoplastic that was developed earlier. Plexiglass is divided into four kinds of colorless transparent, tinted transparent, pearlescent, embossed plexiglass. Plexiglass is commonly known as acrylic, C.X. acrylic, Agglomeration, plexiglass has the advantages of better transparency, chemical stability, mechanical properties and weather resistance, easy to dye, easy processing, beautiful appearance. Plexiglass is also called gelatin glass, acrylic, etc.

11. G-10(Glass Fiber)

"G" stands for glass fiber (glass fiber) "10" should refer to the glass fiber in which contains 10%.

G10 material has insulation, corrosion resistance and wear resistance. It can be used to make tool handles.

G10 is a composite material made of glass fiber cloth and epoxy resin, which was originally developed as a material for aircraft and can withstand great force without deformation. G-10 is available in black, red, blue, green and other colors, and some G-10 has two levels of colors at the same time, and the texture and performance of G-10 are better than ZYTEL.

12.Carbon Fiber

High strength and high modulus fiber with carbon content of over 90%. It has the highest temperature resistance of all chemical fibers. It is made of acrylic and viscose fibers, which are carbonized by high temperature oxidation. It is an excellent material for the manufacture of aerospace and other high technology equipment.

13. Bakelite

Bakelite is the first type of plastic to be put into industrial production. It has high mechanical strength, good insulation, heat and corrosion resistance, so it is often used in the manufacture of electrical materials, such as switches, lamp holders, earphones, telephone cases, instrument cases, etc. .

14. PPS

PPS (polyphenylene sulfide) is a thermoplastic special engineering plastic with excellent comprehensive properties. Its outstanding features are high temperature resistance, corrosion resistance and superior mechanical properties.

Excellent electrical insulation (especially high-frequency insulation), white hard and brittle, metallic noise when dropped on the ground, light transmittance second only to plexiglass, coloring and water resistance, and good chemical stability.

It has excellent flame retardancy and is a non-combustible plastic. The strength is general, the rigidity is good, but it is brittle and easy to produce stress brittleness; it is not resistant to organic solvents such as benzene and gasoline; the long-term use temperature can reach 260 degrees, and it is stable in air or nitrogen at 400 degrees.

After modification by adding glass fiber or other reinforcing materials, the impact strength can be greatly improved, heat resistance and other mechanical properties are also improved, the density is increased to 1.6-1.9, and the molding shrinkage rate is as small as 0.15-0.25%. Used in the production of heat-resistant parts, insulating parts, chemical instruments, optical instruments and other parts.


Soft polyurethane mainly has a thermoplastic linear structure. It has better stability, chemical resistance, resilience and mechanical properties than PVC foam materials, and has less compression deformation. Good heat insulation, sound insulation, anti-vibration and anti-virus performance. Therefore, it is used as packaging, sound insulation, and filter material.

Rigid polyurethane plastic is light in weight, excellent in sound insulation, heat insulation, chemical resistance, good electrical properties, easy to process, and low water absorption. It is mainly used as a structural material for construction, automobile, aviation industry, and thermal insulation.

The performance of polyurethane elastomer is between plastic and rubber, oil resistance, abrasion resistance, low temperature resistance, aging resistance, high hardness and elasticity. Mainly used in the shoe industry and medical industry. Polyurethane can also be used to make adhesives, coatings, synthetic leather, etc.

16. Rubber

Rubber refers to a highly elastic polymer material with reversible deformation. It is elastic at room temperature and can produce greater deformation under a small external force. It can be restored to its original state after the external force is removed.

Rubber is divided into two types: natural rubber and synthetic rubber. Natural rubber is processed by extracting gum from rubber trees, rubber grass and other plants; synthetic rubber is obtained by polymerization of various monomers. Rubber products are widely used in all aspects of industry or life

Now that you’ve been introduced to the different plastic materials that are used with CNC machining, you can finally plan out which will be best suited for your application. If you want to learn more about the CNC machining services offered by Worthy Hardware, visit our website or contact us. Our contact information is [email protected] or +86-13143254839WeChat and Whatsapp)


Worthy Hardware is a CNC manufacturing and sheet metal fabrication company,including CNC machining services,CNC milling services, CNC turning services, laser cutting services and stamping services.Call us +86-76989919645 or email us [email protected] for more discounts for your projects.