CNC machining

How To Choose The Right Materials for CNC Machining

Metals, plastics, and a number of other materials are commonly used in CNC machining. Each material has unique properties that can have an impact on product performance and machining.

In this article, we will focus on introducing you to materials commonly used for CNC machining to help you choose the right material for your project.

Related reading: 11 types of CNC machines and what they do.

Common Metal Materials for CNC Machining

Metals are the most commonly used materials. They have many advantages, including high hardness, strong heat resistance, good conductivity, etc. Therefore, they are usually the preferred materials for CNC machining. The following are some of the most commonly used CNC machining materials:

Stainless Steel

There are many stainless steel alloys on the market today, which generally have excellent toughness, wear resistance, corrosion resistance, and have a shiny aluminum-like appearance, suitable for use in harsh environments. However, due to its high hardness, it is generally a more difficult CNC material to process. In addition, it is a moderately priced metal.

Stainless steel is machinable, and some grades of stainless steel are easier to process than others. For example, 430 stainless steel has a lower hardness, is not prone to work hardening, and is easier to CNC process. It is widely used in industries such as home appliances, kitchen equipment, and automobile manufacturing.

CNC Machining


Titanium has revolutionized many industries and solved many manufacturing problems. Because titanium is tough, strong, relatively light and corrosion-resistant. Titanium is also considered the most expensive metal. It can resist various corrosive environments well and has an advantage over other metal materials in terms of corrosion resistance. 

However, it also has some disadvantages, such as poor conductivity and difficulty in processing. General high-speed steel and low-strength carbide tools are not suitable for processing titanium alloys. Even so, titanium is still a popular material and has been widely used in industries such as biomedicine and aerospace.


Aluminum is the most versatile and widely used material in CNC machining. It has excellent strength-to-weight ratio, strong corrosion resistance, and light weight. In addition, aluminum has relatively good thermal and electrical conductivity, which makes it suitable for thermal management and electronic applications. Therefore, aluminum has a wide range of uses.

Compared to other CNC metals like titanium, aluminum is relatively easy to machine. Aluminum is commonly used in industries such as aerospace, automotive, medical, and consumer goods. Aluminum is a commonly used material for casting or brazing. However, aluminum is not the cheapest alternative as it is generally priced higher than other materials such as stainless steel.


Copper has good thermal and electrical conductivity and is widely recognized. It is often used in the electrical and electronic industries. At the same time, its excellent ductility and beauty make it widely used in the jewelry industry, such as bracelets, rings and necklaces.

In addition, brass and bronze are also alloys composed of copper and other elements. Brass has good corrosion resistance, excellent electrical conductivity and machinability. It is usually used to process low-strength fasteners, consumer products and electrical equipment. Bronze can be used to process gears, bearings and some precision parts.


Compared to other metals, magnesium is a lightweight, high-strength, and lowest-density metal. It also has good thermal properties, so it is often used in automotive engine processing. So it is more common in the automotive industry.

However, magnesium does not have excellent corrosion resistance like other metals, such as aluminum. And its processing cost is higher.

Carbon Steel and Alloy Steels

Carbon steel and related alloys have excellent strength and machinability. Carbon steel mainly contains iron and carbon, with carbon content up to 2.1% by weight. Alloy steel is made by adding various alloying elements to carbon steel. These elements include chromium, nickel, manganese and molybdenum, which can increase properties such as strength, hardness, wear resistance and toughness. In addition, carbon steel is relatively cheap compared to other CNC metal processing materials.

Therefore, carbon steel and alloy steel are widely used in many industries, such as manufacturing knives, springs, high-strength wire, rebar, etc.

Common Plastic Materials for CNC Machining

In CNC machining, plastics can also be used if good elasticity, special chemical properties or good transparency are required. The following are some commonly used plastics in CNC machining:


ABS is a very economical plastic material, and it is also a tough, impact-resistant plastic. In addition, ABS is relatively easy to color, so it has a good visual effect in appearance. It is also often used for rapid prototyping. For example: automotive parts, power tools, toys and sporting goods.

However, the disadvantage of ABS is that it is difficult to biodegrade and is not suitable for use in high temperature environments. It also emits foul-smelling smoke during combustion, which brings certain troubles to CNC workshop processing.

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Polypropylene (PP)

Polypropylene is a widely used polymer material with good chemical corrosion resistance and fatigue resistance. At the same time, it can also be used for medical-grade materials and has a good polishing effect. However, since it is easy to soften and wear during cutting, its limitation is that it is not resistant to high temperatures, which brings certain difficulties to processing.

At present, polypropylene is still popular in different uses. Because it has excellent properties, it is suitable for processing various parts, such as medical products.


Acetal is also known as POM (polyoxymethylene). It has good toughness, moisture resistance and impact resistance. Therefore, it has a wide range of applications. In addition, it also has high rigidity, which gives it good processing performance and high dimensional accuracy. Therefore, it is widely used in the manufacture of some precision parts, such as gears, valves, bearings, etc.

At the same time, Acetal also has good mechanical properties and strong corrosion resistance, and is widely used in industries such as automobiles, consumer electronics, and aerospace.


Acrylic is a widely used material with many excellent properties, such as high hardness and good optical transmittance. Therefore, it can also be used as a substitute for glass.

Although acrylic has some disadvantages, such as easy cracking and thermal softening, it is still popular in CNC processing due to its good adaptability and versatility. Acrylic can produce high-precision and high-quality products and is widely used in manufacturing in different industries, such as lenses, transparent housings, decorations, etc.

Polycarbonate (PC)

Polycarbonate (PC) has also become one of the most popular materials due to its good performance. It has a high degree of transparency and is suitable for the manufacture of some products that require transparency, such as goggles, electronic displays, medical equipment, etc.

However, its disadvantage is that it is easy to scratch and does not have UV protection. Therefore, its application in some industries is subject to certain restrictions. If it is exposed to sunlight for a long time, it will turn yellow and become brittle. Polycarbonate is also commonly used in the production of automotive parts, electronic components and medical equipment.


Nylon is an impact-resistant, durable material for machining that can be used in a variety of applications. It has excellent surface lubricity and can be used in a variety of composite materials, such as glass-reinforced nylon. However, it is not recommended for use in wet environments.

Nylon is the best choice if you need to machine parts that are not affected by friction. For example, parts such as bearings, sliding surfaces, and gears.


UHMWPE is widely used in CNC machining due to its excellent toughness, wear resistance and durability.

Although UHMWPE is difficult to process, it is still an ideal material for manufacturing sliding surfaces such as bearings, gears, and rollers. Because of its excellent performance, it is very suitable for the manufacture of parts that require high wear resistance and durability. Compared with other materials, UHMWPE has a significantly longer service life after proper treatment.

Polyvinyl chloride (PVC)

It is a low-cost, highly processable plastic material. It has high resistance to impact, corrosion, and chemical corrosion. Therefore, polyvinyl chloride plastic is an ideal material for manufacturing valves, pump housings, cabinets, and other components.

Other Materials

Common materials used in CNC machining are metals and plastics, but other materials can also be used. Some of these other materials are listed below.


Wood is relatively easy to process, has high strength and hardness, and comes in many varieties. In addition, wood is an organic compound that does not have adverse effects on the environment. At the same time, wood is also a popular material for furniture and home decoration.

However, wood produces a lot of dust during processing, which poses a health hazard to workers. Therefore, wood processing requires a safe and healthy management system.


Foam is also a material that can be used for CNC processing. There are some high-density Foam materials that are strong, light, and easy to process. For example: polyurethane and polystyrene Foam materials.

In addition, due to its light weight, Foam also makes it a good choice for protective packaging. It can be processed into different shapes and sizes, and it can also be used to make decorations.

Composite Materials

In CNC machining, commonly used composite materials include carbon fiber, glass fiber, etc. These materials are widely used in various industries, such as aerospace, automobile, sports and other industries.

In addition, composite materials with different components have different mechanical properties and forms, such as fiber, plate, etc. In addition, the bonding material itself will also have some special properties, which is a problem we need to pay attention to during production.

How to Choose the Best CNC Machining Material

There are many factors that must be considered when choosing the right material for your project. Here are a few of them.


First, make sure that the CNC material you are using is suitable for a specific environment. For example, let’s compare carbon steel and stainless steel in marine applications.

Although both are highly machinable, stainless steel is more suitable for marine use due to its greater corrosion resistance. However, in a generally dry environment, carbon steel would be a better choice because it is stronger and more durable.


Choosing the right weight for a component can improve the usability of the component because it affects the entire process and the overall performance of the part. For heavier components, stronger and denser materials are usually required to ensure that they can withstand the load. For parts that need to be lighter, lower density materials such as aluminum and titanium can be used.

Precision and Tolerances

Some materials are difficult to achieve precise tolerances. For example, some materials that are easy to bend, such as some plastics (PVC). In order to achieve the required tolerance, a larger machining allowance may be required.

For applications that require high precision and high tolerances, it is recommended to use materials such as steel or titanium.


CNC machining can process a variety of materials, which is one of the reasons why CNC machining always maintains the best process. Because it can make parts with metal, plastic, and some other materials.

If you are looking for a service provider with many years of CNC machining experience, you can contact us immediately to get a quote for your project.