What is CNC?

CNC is short for “Computer Numeric Control” which is how a computer talks to a milling machine to control its movements to cut the part you design. The language it uses is called “g-code”, which is a series of instructions that, combined with X, Y and Z coordinates denotes direction, speeds and key points of the shape to be cut. In the past, for example, even the most skilled machinist would have a problem cutting a circle because both the X and Y handwheels would have to be cranked at the same time at constantly varying rates at the same time. The computer, however, has no trouble doing this, and a complicated shape can be cut just as easily as a straight line. The advantage of CNC beyond cutting difficult 3D shapes is that once the program is written and the holding fixtures made, multiple identical parts can be made rapidly.

Free software utilities and CAD programs included

Loaded on your Linux computer and also on the backup CD are a number of free utilities to make your job of getting from idea to finished part a little easier. For those who already work with Windows® CAD programs, there are several free Windows utilities that will translate .dxf and .stl format CAD drawings into the text language of g-code that EMC understands. These text files are simply saved to a floppy or CD, transferred to your Linux computer, opened in EMC and run. There is even a free Windows program that will translate the outline of any TrueType font into g-code to make it easy to engrave lettering. There are also a couple of useful programs that can be opened right in Linux if you want to do all your work on one computer. QCad is a free drawing program that is easy to learn. It can be a big help in both drawing your part and can also be used to accurately locate points to help you write your own g-code. There is a CAM portion that is available for purchase from the supplier that will write your g-code for you. (You can try it for free to learn how it works, but you cannot save the files until you buy it.) A 2D, 3D wireform and full 3D solid modeling program called Synergy is also included for you to try. It is more complicated and more full-featured, but the 2D CAD portion can be opened and used for free. You can also use the instructions that come with these programs as a way to learn to use CAD/CAM programs if you do not already own or know how to use one.