How to select materials suitable for CNC machining

There are hundreds of alloys available for CNC milling and turning. The best choice for your next project depends on many factors, including price, workability, corrosion resistance, strength, weight, and appearance. To help you choose, we detailed the products we use every day and the benefits they can bring to your next project.

Aluminum 6061

This is the most common and common aluminum grade. The main alloying elements are magnesium, silicon and iron. Like all other aluminum alloys, it has excellent strength to weight ratio and is inherently resistant to atmospheric corrosion. Another advantage is that it has good workability, can be welded and anodized, and its wide availability means it is economical.

When heat-treated to the T6 state, the yield strength of aluminum 6061 is much higher than that of annealed 6061, although the price is slightly higher. One of the disadvantages of 6061 is its poor corrosion resistance when exposed to salt water or other chemicals. For more demanding applications, it is not as strong as other aluminum alloys.

6061 is commonly used in auto parts, bicycle frames, sporting goods, some aircraft parts and remote control car frames.

Aluminum 7075

7075 is a high-grade aluminum, mainly alloyed with zinc. It is one of the strongest aluminum alloys and has excellent strength-weight characteristics.

Due to its strength, it has average workability, which means that it tends to spring back to its original shape during the cold forming process. 7075 is also machinable and can be anodized.

7075 often freezes on T6. However, this is an unsuitable option for welding and should be avoided in most cases. We often use aluminum 7075 T6 to make injection molds. It is also used in high-strength leisure equipment for mountaineering, automotive and aerospace frames, and other pressurized parts.


Copper pipe joint thread lead pipe fitting 4 points

Brass is an alloy of copper and zinc. It is a very soft metal and can usually be processed without lubrication. It is also very suitable for use at room temperature, so it is often used in occasions where the strength is not high. There are many types of brass, mainly depending on the ratio of zinc. As the ratio increases, the corrosion resistance decreases.

Brass looks like gold. This is why it often occurs in cosmetic applications. Brass is conductive but non-magnetic and easy to recycle.

Brass can be welded, but low-temperature processes such as brazing and welding are the most common. Another characteristic of brass is that it does not produce sparks when it collides with other metals. Therefore, it can be used as a tool in an explosive environment. Interestingly, brass machining has natural antibacterial and antibacterial properties, and its use in this field is still being studied.

Brass is common in plumbing fittings, household furniture fittings, zippers, navy hardware, and musical instruments.

Magnesium AZ31 is an alloy of aluminum and zinc. It is 35% lighter than aluminum, has the same strength, but is also more expensive.

Magnesium is easy to process, but it is very flammable, especially in powder form, so it must be processed with a liquid lubricant. Magnesium can be anodized to improve its corrosion resistance. It is also very stable as a structural material and is the best choice for die casting.

Magnesium AZ31 is commonly used for the lightest and most robust aircraft components, as well as power tools, laptop housings and camera housings.

Stainless steel 303

There are many types of stainless steel, because the addition of chromium helps prevent oxidation (rust). All stainless steels look similar, so use the latest weighing equipment (such as OES detectors) very carefully to test raw materials to characterize the steel you are using…
In the case of 303, sulfur was also added. This sulfur helps make 303 the easiest stainless steel to work, but it also helps reduce its corrosion protection.

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

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

This is the most common form of stainless steel in various consumer and industrial products. Usually called 18/8, this is the addition of 18% chromium and 8% nickel to the alloy. These two elements also make the material particularly tough and non-magnetic.

304 is easy to process, but unlike stainless steel 303, it can be welded. It is also more resistant to corrosion in most normal (non-chemical) environments. For mechanics, they must be processed with very sharp cutting tools and must not be contaminated with other metals.
304 stainless steel is an ideal material for kitchen appliances, tableware, water tanks and pipes used in industry, construction and car decoration.

Stainless steel 316

316 stainless steel quick coupling type

The addition of molybdenum makes 316 more resistant to corrosion, so it is generally considered to be marine grade stainless steel 316. It is also very strong and easy to solder. 316 is used for construction and ship fittings, industrial pipelines and storage tanks, automotive decoration parts and kitchen utensils.

This is not ordinary low-carbon steel, that is, stainless steel. It is usually cheaper than stainless steel, but it is strong and durable. It is easy to process and weld, and can be cured and heat treated to achieve different hardnesses.

1045 steel (European standard, C45) is used in many industrial applications for nuts, bolts, gears, shafts, connecting rods and other mechanical parts that require higher toughness and strength than stainless steel. It is also used in construction, but if exposed to the environment, it is usually surface treated to prevent rust.


3D printed composite titanium skeleton

As we all know, titanium has high strength, light weight, toughness and corrosion resistance. It can be welded, passivated and anodized to enhance protection and improve its appearance. Titanium is not particularly well polished. It is a poor-quality electrical conductor, but it is an excellent thermal conductor. It is a rigid material and can only be used with professional punching machines.

Titanium is generally biocompatible and has a very high melting point. Although it is more expensive than other metals in commercial form, it is actually very abundant in the earth’s crust, but it is more difficult to extract.

Titanium is suitable for powder bed 3D printing metal. It is suitable for the most demanding aerospace, military, biomedical and industrial fields, and also has heat resistance and corrosion resistance to acids.

Have you found what you want?

These are the most commonly used metal alloys in most CNC milling and turning operations, but there are other metal alloys that can be used in almost all applications. When you upload a CAD file to get a quote, we are happy to work with you to recommend the best solution.

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