Differences between CNC milling and CNC turning

CNC machining indicates the technology capable of operating through Computerized Numerical Control, through the use of integrated software that automates the movements of the machine avoiding the need to operate manually and guaranteeing maximum quality and precision of the machining. 

Milling and turning by CNC technique are among the most widely used in mechanical workshops. Despite exploiting the same technological principle, these are two very different processes. 

Let's look at the differences together.

What is CNC milling and its advantages

CNC milling is used to cut, drill or customize materials such as metal, wood, glass and plastic.

In most CNC milling machines, the blank is clamped while the mill changes the surface, by rotary motion. Moreover, unlike other CNC machines, milling can operate on different inclinations through the use of different axes.

The advantages of using CNC milling are different:

• low labour costs;
• each process is easily reproducible in the case of series production;
• wide range of materials suitable for processing;
• great versatility regardless of the thickness of the material or different characteristics;
• ability to perform complex geometries.

What is CNC turning and its advantages

In the case of CNC turning, the tool is stopped and the blank is rotated. The trolley where the material is placed can be moved in different directions depending on the information sent to the computer, which manages the processing and supervises the process. 

The turning service is often requested in the case of prototypes, offering several advantages: 

• the machine is able to perform precise measurements limiting human errors;
• can be used on a wide range of different materials and sizes;
• high mechanical efficiency
• suitable for mass production of products while maintaining a high level of quality and limited costs.

Similarities and differences

The main difference between CNC milling and turning lies in the machining difference of the workpiece. In fact, in the first case, the cylindrical cutter moves on a vertical and horizontal axis, operating with a rotary movement. On the contrary, in the case of turning, the workpiece is moved by means of a support carriage, while the tool remains fixed. 

Another difference lies in the different movement capacity of the components.

CNC milling machines can have a minimum of 3 to a maximum of 7 axes, which allow the workpiece to be moved in different directions to be able to work on all surfaces. On the contrary, the workpiece is positioned horizontally or vertically on the lathe.

In addition, being two different techniques, turning and milling find different applications:

In the case of milling, it can be carried out on almost all materials and can be carried out on a flat, front, angular or shaped surface. 

Mainly used for limited quantities and commonly used for prototyping, and component parts. Especially aerospace, electronics and packaging companies use CNC milling, thanks also to the machine's ability to reproduce grooves and details precisely. 

As for turning, this technique allows you to perform turning, boring and threading operations. Turning can also be applied to different materials.

As for the metal elements: steel, aluminium, titanium and copper are among the most common materials. Among plastic materials, nylon, PE and POM are commonly used in this type of processing.

Industries turn to this processing in the case of prototyping, for the production of large quantities and to obtain high quality objects.

Conclusions

Both milling and CNC turning allow the processing of a wide variety of products. 

Although the two techniques are different in both the process and the result, they can both be used in the machining of the same piece. 

Therefore, a piece that has just finished milling could be subjected to turning and vice versa.