One of the main reasons I built the 2.5W laser cutter was to prepare for building the CNC plasma cutter.
The idea to upgrade my handheld Lotos LTP5000D with CNC control has been percolating for the better part of 2 years. Now that I finally have the space and resources to pursue this idea, the project has started to take off.
The heart of the machine is the stepper motor drive board. I selected the MX4660 from Leadshine as it gave a lot of flexibility in terms of the amount of current the board could deliver to the steppers. This way, if I ever decided to re-purpose the driver board for another CNC, I could do so without issues. Also, the I/O for the board was well documented and it was ready-made to be driven by Mach3 (my control software of choice). In order to interface my Windows 10 PC with the MX4660 driver board, it was necessary to purchase a UC100 controller which allows the parallel port on the MX4660 to be driven smoothly by a USB port on the control PC.
The X and Y axes of the machine are driven by 420 oz-in NEMA 23 stepper motors which interface with 6mm belts that propel the axes. The Z axis is driven by an 8mm leadscrew and a 380 oz-in stepper. The X and Y axes each have about 4 feet of linear travel while the Z axis has about 6 inches (more than adequate for plasma cutting).
I designed the frame in SolidWorks using the OpenBuilds V-Slot platform. OpenBuilds is an open source hardware platform for all things CNC. They sell pre-packaged kits, but also sell linear motion components individually so that makers can customize their builds to suit their needs. I decided to build my own BOM using OpenBuilds hardware so that I could attain the cutting volume that I wanted for the CNC.
After much tinkering, I finally got the electronics and hardware operating in unison. As a final cherry on top, I decided to install a Mach3 macro that allows for an XBox controller to be used as a pendant controller for the CNC.
I have yet to install the plasma cutter on the machine due to some EMI concerns. The LTP5000D that I was planning to use has a high frequency pilot arc start. This high frequency start has been known to cause issues with driver boards which can cause the control PC to reset or the steppers to lock up if the plasma cutter leads are improperly shielded. This is my next challenge to overcome, and I will provide updates once it is fully addressed.