Tool Paths — Introduction

Computer-aided manufacturing (CAM) programs analyze your models or drawings, creating toolpaths from them that represent the motion of a cutting tool as it cuts the part. This is then processed into a set of instructions specific to your CNC machine, telling it exactly how and where to move in order to cut out your part. Typically written in a language called “G-code”, they are the bridge between a part created in a modeling program (or an unaltered 3D scan) and your mill or lathe.

The CAM programs in this section import your model or scan and using information you supply—such as the cutting tool you plan to use, the speed you wish to cut at, and the desired fineness of cut—write a G-code program, which is essentially a text file, although it may have a different extension like .nc or .tap. This file is opened by the control software in the computer running your machine, or by the machine itself if it has a proprietary controller. Since the format in which each machine expects its programs to be written varies slightly from controller to controller, it is important to use the correct “post-processor”, which massages your toolpath program into the form appropriate for the machine you will be using. Most CAM programs have a list of post-processors (or “posts” for short) to choose from that encompasses a wide range of controllers, but if yours is an odd one, then a customized post may be necessary.