Traditional milling and CNC milling: differences

Milling refers to the process by which it is possible to remove parts of material from a blank through the use of machines that move the workpiece itself or a tool. 

This type of processing has evolved over the years to become automated thanks to the use of a computer that controls the machine and controls the processing.

Let's understand together the difference between traditional milling and CNC milling.

Traditional milling

The milling machine is a machine capable of working raw pieces and obtaining complex shapes. These are machines that can have different sizes depending on their power and processing capacity. 

In general, the milling machine for industrial production has a rather powerful motor that is connected to the milling cutter by means of a spindle. The tool (milling cutter) operates by rotary movement and thanks to the sharp edges is able to process different types of materials.

Although the movement of the cutter is very similar to that of a drill, it is important to know that the cutter can work in two ways:

• the workbench moves with respect to the milling cutter which instead remains stationary, moving on the X and Y axes and sometimes also Z (depends on the number of axes with which the machine is equipped).
• leaving the workbench fixed and moving the motorized head on the 3 axes X, Y, Z.

In the case of traditional milling, these movements are managed manually, which requires a lot of experience on the part of the operator.

CNC milling

CNC milling differs from the traditional technique because the machine is managed by an integrated system ("brain") that automates the movement processes.

In fact, the acronym CNC (Computer Numerical Control) refers to the integration into the machine of a computer that numerically controls the operations necessary to carry out the project. The blank is then modified according to parameters and methods managed and monitored by the computer, which is also able to replace the tools, start or suspend processing if necessary and report inconsistencies. 

In this case, the use of the control unit (the central computer) is very advantageous since the machine is able to process large volumes, guaranteeing quality and precision.

In addition, CNC machining involves the creation of a file (CAD or CAM), which once sent to the computer is read by the machine, which is able to faithfully reproduce the project thanks to the information contained in the file. 

This allows you to make changes or improvements to the file in a timely manner, reducing processing times.

In general, CNC machines differ in the number of axes that allow the machine to move the workpiece or the work table. The greater the number of axes, the more machining it will be possible to perform. 

Conclusions 

The main difference between CNC milling machine and traditional milling machine is that CNC machining is an automated computer processing which governs the axes during machining. On the contrary, in traditional machining, the change of tools and the movement of the machine according to the axes (minimum 3 – maximum 7), are managed manually, requiring extreme precision on the part of the operator. 

In addition, another aspect that can change the choice of milling machine is the type of material on which you intend to work. Hardness, strength, thickness are just some of the parameters to consider when deciding which type of milling machine to use.