CNC milling machine: operation and technical components

The term CNC comes from English and stands for Computerized Numerical Control.

The first milling machines with this technology date back to the 1950s, when processing became automated and no longer operated by hand, however it was only in the 1970s that the CNC milling machine found its popularity and became part of the industrial production machinery fleet.

In this article we will try to better understand the technical characteristics of the CNC milling machine and how it works.

Technical specifications

CNC milling is a subtractive process, that is, it removes the material from the blank and is able to give details and dimensions in a personalized way. 

The machine is composed of several elements that allow quality processing in a short time. Let's see what these are:

Spindle

This is the motorized part of the machine, on which the various tools are connected, which can be changed both manually and automatically.

Axes

Depending on the type of milling machine, you can have a minimum of 3, up to a maximum of 7 axes, depending on the complexity of the processing. The most used are 3-axis and 5-axis milling machines.

In the first case, it is a simple process that requires the machine to work on dimensions X, Y, Z.

In the case of the 5-axis milling machine, on the other hand, there are mainly 2 variants on the market: simultaneous 5-axis machines and 3+2 machines.

Simultaneous machining with 5 axes operates following the X, Y, Z directions and simultaneously works on two rotary axes. In this way, milling takes place at the same time on 5 different dimensions, reducing processing times even in the case of complex milling.

The 3+2 technology, on the other hand, is a cheaper configuration since it does not offer the same processing speed and versatility. In this case, the machine works on the 3 linear axes while the rotary axes block the workpiece by tilting it or moving it in the direction necessary for processing.

Governing unit

As the name suggests, this is the brain of the machine. Here you control the information and operations to be performed. The software then executes the instructions that are set and takes into account the tools to be used.

Panelling

This element may vary depending on the machine. This is the possible presence of a work area dedicated to the supervision of the operator during the machining of the machine, allowing the person to work safely.

How the machine works

The CNC milling machine works through integrated software and the movements of the machine are therefore preset. Thanks to the integrated computer, the machining can be stored and replicated in a short time in case of series production.

The part-program, i.e. the program containing the instructions for processing executed by the control unit, is managed in real time by the control unit, which sends precise instructions to the machine. This program must be designed in advance using CAM tools that allow you to simulate the machining of the blank on a PC.

Usually, this type of processing takes place for production in large quantities since it guarantees homogeneity and precision, thanks also to numerical control that allows complex processing even on complex surfaces. However, it is not said that one machining is sufficient, in fact, more than one subsequent machining is often required, during the realization of complex projects.

Through the milling process it is possible to remove the material to build flat, perforated, grooved surfaces, etc.

In addition, the milling process is suitable for many metal, plastic, rubber and wood materials.

Therefore, CNC milling is a rather versatile process, but it requires different tricks and skills.

• The tasks of the operators include:
• monitor the machine during operation;
• monitor the control panel;
• monitor the configurations of the different components;
• check the correct status of the electronic components;
• remove or replace the tools depending on the processing;
• adjust the speed and movements of the machine if necessary;
• the insertion of instructions to the machine;
• control of the parameters to be sent to the machine for processing.

Conclusions

The CNC milling machine is a very popular tool within industrial production lines. Although there are relatively cheap models suitable for DIY machining, the use of the CNC milling machine requires skill and attention. 

In fact, from the creation of the part-program to the machining, the machine needs to be monitored to avoid any unforeseen events. 

In addition to this, it is necessary to know the characteristics of the different materials so as to be able to set the correct parameters when machining the blank. 

Therefore, CNC milling allows versatility of machining and materials, as long as the operator knows the rules to set, control and manage it.