CNC milling, in it’s most basic terms, is a machining process which involves the use of computerised controls to operate cutting tools to remove material from a solid block, to form a required size and shape.
CNC milling offers high precision, accuracy, and production rates in comparison to more manual methods of production.
The CNC milling process begins with the creation of a CAD (Computer Aided Design) part design and exporting this into a file which the machine recognises in order to dictate the movements of the machine and the workpiece/raw material.
Before the operator runs the CNC program, they prepare the CNC milling machine by fixing the workpiece to the machine’s work surface, either directly to the base or worktable, or using a vice.
The required milling tools are then attached to the machine spindle. Some machines can hold multiple tools in the spindle and will automatically switch to the correct tool required, based on the program.
The CNC milling process employs horizontal or vertical CNC-enabled milling machines—depending on the specifications and requirements of the milling application—and rotating multi-point (i.e., multi-toothed) cutting tools, such as mills and drills.
Once the CNC milling process is initiated, the machine begins rotating the cutting tool at defined speeds. These speeds are often decided by the material type, as different density materials will require different cutting speeds
Dependant on the type of machine, and the complexity of the final component required, the machine will move the tools or material in different ways:
This milling process gradually removes material to form the desired shape and form of the part. On the first operation, the tools cut small pieces off the workpiece to form the approximate shape required. Then, the workpiece undergoes the milling process at much higher accuracy and with greater precision to finish the part with its exact features and specifications.
