machining parts

Materials Round-up: Common CNC Machining Metal and Plastic Materials

Metal CNC Machining Parts

One of the most common types of materials used in CNC machining is metal, and there are a variety of options. Let’s take a look at the best known options and an overview of the best applications for each metal. Depending on the size and shape of the part, the cost of materials can be a large part of the total price of the part.


Aluminum 6061

Aluminum 6061 is the most commonly used general purpose aluminum alloy with good strength to weight ratio and excellent workability. It is the most common general purpose aluminum brand and is commonly used in auto parts, bicycle frames, sports equipment, RC frames, etc.

The main alloying elements are magnesium, silicon and iron. Like other aluminum alloys, its strength and weight ratio is high, and can naturally resist atmospheric corrosion. One of the disadvantages of the 6061 is its low corrosion resistance when exposed to saltwater and other chemicals. In more demanding applications, it is not as powerful as other aluminum alloys.

Aluminum 6082 

Aluminum 6082 has the same composition and material characteristics as 6061. In Europe, it is more commonly used because it meets British standards.

Aluminum 7075


The 7075 is the luxury of aluminum. It is mainly alloyed with zinc. It’s one of the strongest aluminum alloys. Ideal for high-intensity entertainment equipment, automotive, and aerospace frames. Compared with steel, aluminum 7075 has excellent fatigue properties, and weight reduction is critical due to the high strength and hardness achieved by heat treatment. However, if welding is required, avoid welding at most.

Aluminum 5083


Aluminum 5083 is stronger than most other aluminum alloys and has excellent resistance to seawater, so it is commonly used in construction and Marine applications. It is also ideal for welding.

Steel machining parts ---stainless steel

Stainless steel alloys have properties such as high strength, high ductility, good wear resistance and strong corrosion resistance, and are easy to weld, process and polish. Depending on their composition, they can be non-magnetic or magnetic.


There are many types of stainless steel. It is called stainless steel because it contains chromium, which prevents oxidation (rust). Since all stainless steels look the same, the raw materials of the feed must be carefully tested using the latest measuring equipment, such as OES detectors, to confirm the properties of the steel used.

Stainless steel 303


In stainless steel 303, sulfur is also added. This sulfur helps make 303 the easiest stainless steel to work with, but also reduce corrosion resistance somewhat.


303 is not suitable for cold forming (bending) and cannot be heat treated. The presence of sulfur also means it is not suitable for welding. It has excellent machining performance, but attention must be paid to cutting tool speed/feed and sharpness.


303 is commonly used for stainless steel nuts and bolts, fittings, shafts and gears. However, do not use in shipboard grade accessories.

Stainless steel 304


It is the most common stainless steel alloy with excellent mechanical properties and excellent machinability. It can withstand most environmental conditions and corrosive media.


It is the most common form of stainless steel in a variety of consumer and industrial products. Commonly referred to as 18/8, it refers to the incorporation of 18% chromium and 8% nickel into the most common form of stainless steel alloy.


The 304 is very hard, non-magnetic, easy to process, and generally corrosion resistant, ideal for kitchen fittings, storage tanks and pipes used in the industrial, construction and automotive industries.


The 304 is easy to work but, unlike the 303, can be welded. It is also more resistant to corrosion in most normal (non-chemical) environments. For mechanics, use very sharp cutting tools to make sure there is no contamination from other metals.

Stainless steel 316


This is another common stainless steel alloy that has the same mechanical properties as 304. It is generally considered Marine grade stainless steel, strong and easy to weld. The material is very resistant to corrosion and the salt solution (such as seawater) is ideal for construction, Marine accessories, industrial pipelines and automotive applications.

Stainless steel 2205


Stainless steel 2205 two-phase stainless steel is the strongest stainless steel alloy (twice as strong as other common stainless steel alloys), with excellent corrosion resistance. It is used in harsh environments and has many applications in the oil and gas industry.

17-4 stainless steel


The mechanical properties of 17-4 stainless steel (SAE class 630) are comparable to those of 304. It is suitable for high performance applications such as turbine blade manufacturing due to its higher precipitation hardening and excellent chemical resistance compared to tool steels.

Tool steel


Tool steel is a metal alloy with very high hardness, stiffness, wear resistance and heat resistance. They are used to create manufacturing tools such as moulds, stamps, and dies (whence the name comes). In order to achieve good mechanical properties, they must undergo heat treatment.


Tungsten steel alloy milling tool steel D2 is a wear resistant alloy that maintains its hardness at a temperature of 425°C. D2 steel is an air hardened, high carbon, high chromium tool steel with excellent wear resistance. Heat treatment is possible and there is a wide range of hardness. D2 steel is ideal for making parts or products that bend easily but require bending.


Tool steel A2 is an air cured general purpose tool steel with excellent toughness and dimensional stability at high temperatures. It is commonly used to make injection moulds.


Tool steel O1 is a high hardness oil cured alloy with a hardness of 65HRC. Commonly used with knives and cutting tools.

Low carbon steel


Also known as low carbon steel, it has excellent mechanical properties, excellent machinability and excellent weldability. Because of the low cost, generic applications can be found, such as manufacturing mechanical parts, jigs and fixtures. Mild steel is vulnerable to corrosion and chemical attack. The commonly used

Low carbon steel 1018


Mild steel 1018 is a general purpose alloy with excellent toughness, strength and hardness, as well as excellent machinability and weldability. The most commonly used mild steel alloy.

Carbon steel 1045


This strong material is mild steel, not stainless steel, and is usually cheaper than stainless steel, but stronger. The material can be hardened and heat treated to facilitate machining and welding. It is most commonly used in industrial and mechanical parts that require high toughness and strength, such as nuts and bolts, gears, shafts and connecting rods. It is also used in construction, but when exposed to the environment, it is usually surface treated to prevent rust.

Low carbon steel A36


Mild steel A36 is a general purpose structural steel with excellent weldability. Suitable for a variety of industrial and architectural applications

Magnesium AZ31

Magnesium AZ31 machining parts

Magnesium AZ31 is an alloy of aluminum and zinc that is 35 percent lighter in weight than aluminum but stronger. However, the material is often expensive and is often used in aircraft parts. Easy to work with, but flammable.

Magnesium is easy to handle, but must be treated with liquid lubricants because it burns very easily, especially in powder form. Magnesium can be anodized to improve corrosion resistance. It is also a highly stable structural material, ideal for die casting.

Because of its light weight and high strength, it is often used around the house, including laptop cases, power tools and camera bodies.


Titanium is known for its high strength, light weight, toughness and corrosion resistance. Welding, passivation and anodizing can enhance protection and improve appearance. Titanium has low polishing effect and low electrical conductivity, but good thermal conductivity. It is a difficult material to work with and only professional tools can be used.

This material is usually more expensive than other metals. The crust is abundant but difficult to refine. It is most commonly used in military, aerospace, industrial and biomedical applications.


Brass machined parts Brass is recognized as one of the simplest and most cost-effective materials for CNC milling and is an alloy of copper and zinc, stable but lacking in strength. Typical applications include medical devices, consumer products, electrical hardware, and contacts. Because of its low coefficient of friction and high corrosion resistance, brass is also used in engineering, piping, steam engineering and even instrumentation. It is used in plumbing fittings, upholstery and Musical Instruments due to its soft material and ease of processing.

Excellent workability and excellent electrical conductivity are ideal for applications requiring low friction. It is also often used in architecture to produce a golden appearance with an aesthetic look.

Brass C36000 is a material with high tensile strength and natural corrosion resistance. It is often used for a large number of applications because it is one of the simplest materials.


For CNC milling materials, few metals offer the electrical conductivity of copper. High corrosion resistance helps the material to prevent rust, and thermal conductivity helps the molding process in the NC machining process. Common applications in the automotive industry include cooling systems and heat exchangers, as well as various engineering applications such as valves and radiators. However, it is important to know that copper is weak to certain chemicals such as acids, sulfide halogens, and ammonia solutions.


In addition to metals, SANS ‘high-precision CNC machining services are compatible with some plastics. The following are the most widely used plastics in CNC milling technology. Plastic processed parts


ABS is one of the most common thermoplastic materials, with excellent mechanical properties, excellent impact strength, high heat resistance and excellent workability.

ABS has a low density and is ideal for lightweight applications. ABS parts in CNC machining are usually used as prototypes before being injected for mass production.


Nylon, also known as polyamide (PA), is a thermoplastic. It is commonly used because of its excellent mechanical properties, excellent impact resistance, high chemical resistance, wear resistance and moderate flame retardancy. Includes short term products for insulators, bearings and injection molding. The disadvantage is that it easily absorbs water and moisture.


POM is also known as Dellin. It is an engineering thermoplastic with the highest plastic machinability.

POM (Delrin) is generally well suited for NC machining of plastic parts requiring extremely low water absorption and achieving excellent dimensional stability at high precision, high stiffness, low friction, high temperature.


PTFE, commonly known as polytetrafluoroethylene (PTFE), is an engineered thermoplastic with excellent chemical and heat resistance and the lowest friction coefficient of any known solid. Excellent electrical insulator. However, it has purely mechanical properties and is commonly used as a lining or insert for components.


High density polyethylene (HDPE) is a thermoplastic with a high strength-to-weight ratio, high impact strength and excellent weather resistance.

HDPE is a lightweight thermoplastic suitable for outdoor use and piping. Like ABS, it is commonly used to create prototypes prior to injection molding.


PEEK is a high performance engineering thermoplastic with excellent mechanical properties, thermal stability over a wide temperature range, and excellent tolerance to most chemicals.

PEEK is commonly used to replace metal parts because of its high weight to weight ratio. PEEK also offers medical grades for biomedical applications.

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