How Does CNC Machining Work?
CNC Machining is a ‘subtractive fabrication method’, meaning that it removes material as it does its work. This type of engineering is used for cutting and shaping materials such as metal, plastic, and even fabric. The automation process requires a digital file containing the code that instructs the machine about what tools and trajectories are needed. This file should be designed by an Engineer or Machinist who has experience with CAD (Computer-Aided Design) software.
CAD software is used by Machinists to define a number of considerations about the cutting process, and it often takes a fair bit of skill and experience to get to grips with. The CAD software is used to create a 3D model that defines the dimensions and needs of the part being made. Within the software, Machinists can build a digital tool library for different projects and if the CNC machine is advanced enough, it should be able to automatically change the tool mid-program. What this means is that if the code is good enough, the digital file should allow the part to be made from start to finish without human interaction.
This coding or programming process doesn’t come without its own challenges. One of those challenges is for the different coding languages to correlate. There are CAD programmes and CAM (Computer-Aided Manufacturing) programmes, and the CNC machining process requires both, but if they use different coding languages, the translation of files can cause minor issues.
In some cases, it’s possible to use a CAD-CAM package that combines both processes into one software. Where CAD is used to design the part, CAM is used to create the fabrication code that can be understood by the CNC Machine. This code contains the speed, RPMs, voltage, cutting heads, orientation, nesting and more.
The resulting code from all of this work is called a G Code or an M Code.