Which materials can be CNC-machined?

Most metals can be CNC-machined, and the same applies to many plastics. However, not all materials behave in the same way in the machine.

The material affects how quickly the part can be machined, which tools are used and what the surface finish will be like. It is therefore a good idea to be aware of these differences right from the stage of selecting the material.

Steel – the most common material used in machining

Steel is one of the most widely used materials in sheet metal working and CNC machining. It is stable, predictable and delivers good results in both CNC milling and CNC turning.

Standard structural steel is relatively easy to machine. Hardened steels are tougher and place greater demands on both tools and machinery.

Stainless steel – more durable but more demanding

Stainless steel is used where components need to withstand moisture, chemicals or high hygiene standards. These same properties make the material more difficult to machine.

Stainless steel is tough and does not dissipate heat as effectively as ordinary steel. The heat builds up at the tool, causing it to wear out more quickly. Machining is therefore often carried out at a lower speed.

Aluminium – quick to machine

Aluminium is soft and light, and can be machined at high speeds. This makes the material time-efficient, particularly for parts that require a great deal of milling.

As it is soft, aluminium can stick to the tool. However, with sharp tools and the right cooling, the surfaces will still turn out well.

Brass – one of the easiest materials to work with

Brass is considered one of the easiest metals to machine. The chips are short, there is little wear on the tools, and the surfaces often turn out smooth straight away.

For this reason, brass is often used for components with many machined surfaces or where a high standard of finish is required.

Copper – soft but tough

Copper is an excellent conductor of heat and electricity, and is often used in electrical components. However, it is a more difficult material to work with.

Copper is soft and ductile, which produces long chips and makes it more difficult to achieve clean edges. This requires sharp tools and the correct settings.

Plastic – can be processed but requires other considerations

Many plastics can also be CNC-machined. They are soft and easy to cut, but sensitive to heat.

If it gets too hot, the plastic may melt or become deformed. Plastic also expands and contracts more than metal in response to temperature changes, which makes it more difficult to maintain tight tolerances.

The material affects the time and cost of processing

The time it takes to machine a part is largely determined by the material. Stainless steel and copper require a lower speed and a gentler machining process, whilst aluminium and brass can be machined considerably faster.

It’s not just about the cutting process itself. A tough material can also produce more burrs that need to be removed, and require more tool changes during a production run. When CNC machining Therefore, the same component may take different lengths of time to produce, depending on the material it is made from.

Choose materials based on their function – but bear in mind the machining process

It is the function of the component that primarily determines the choice of material – for example, whether it needs to be corrosion-resistant, lightweight or able to conduct electricity. The manufacturing process is of secondary importance.

However, if several materials would be suitable, it may be worth choosing the one that is easiest to machine. This can shorten the lead time without compromising the quality of the part.

Do you need help with CNC machining?

At Linde Maskiner, we use CNC machining for the final machining of sheet metal structures. With both CNC milling and CNC turning we tailor the machining process to the drawings and requirements. Contact us today, and we will help you further.