CNC machines are incredibly useful, and it is fun to build your own. At my workplace they agreed to support with equipment needed if we invested the time. We did a complete rebuild of a Manual Milling Machine and added stepper motors and software to control it as a CNC
The CNC in action. It’s possible to mill a lot of pieces.
Our strategy was to a milling machine, and then rebuild it into a CNC using stepper motors. Because the milling machine probably was a little too cheap, my colleagues made a redesign on the spindle, and use much higher quality spindles than it was originally equipped with.
Generating CAM code
Finally we tested the CNC on a part. We used Autodesk Fusion as CAM software and one of their standard components.
From the software the G-Code is generated which can be transferred to the CNC mill.
After milling the piece of aluminium, we got this final showpiece
Because we were also on a budget, we tried to keep motors, and motor controls as cheap as possible. Also the software could not be too expensive. To achieve this, we used stepper motors that are open-looped which limits precision of the mill as compared to closed-loop servo-motors for example.
We managed to achieve precision within 0,1 mm most of the time, but sometimes it was within 0,3 mm for unexplainable reasons. It was a really cool, and even useful project and there are plenty of room for optimizations.