Convert Your Old 3D Printer Into a CNC Plasma Cutter

If you want to cut flat patterns from large sheets of metal, a CNC plasma cutter is one of the best tools for the job. It will be dramatically more convenient to run than a waterjet and will be able to easily cut steel, unlike a large CNC router that should really only be used for wood — or maybe aluminum in pinch. On top of that, you can build a CNC plasma cutter on a modest budget by salvaging parts from an old 3D printer.

This works because pretty much all machines that run g-code, including CNC mills, routers, 3D printers, and plasma cutters, have similar motion systems. A 3D printer’s components aren’t suitable for CNC mills or routers, because they don’t have the torque to push an end mill through material. But like a 3D printer, a CNC plasma cutter doesn’t make physical contact with the material and doesn’t need much torque. All it really needs is enough frame rigidity to support the weight of the torch and enough motor torque to move that around smoothly.

In this case, Mechanceism salved the motors, belts, pulleys, and RAMPS 1.6 control board from an old Anet A8 3D printer. A GRBL 1.1 firmware update made that suitable for the new setup. He then added a frame made from aluminum extrusion and 3D-printed brackets on to a small off-the-shelf plasma table from JEGS that costs about $150.

The last piece of the puzzle was selecting a plasma cutter and that requires careful consideration. Not all plasma cutters with handheld torches are suitable for CNC use. Mechanceism chose a Yeswelder CT2050, which is a combination TIG welder and plasma cutter designed for CNC use — it even has a CNC control port to make that easy. The CT2050 costs $1,499, which is affordable for its capability, but still pretty pricey for a DIY hobbyist CNC plasma cutter build. However, there are more affordable options (even below $300), you’ll just need to make sure they work for CNC and they may require some minor modifications.

Mechanceism still has some parameter tuning to do in order to get high-quality cuts, but this converted 3D printer is already able to cut through thick steel plate with easy. He even used the machine to fabricate caster mounts for the machine, because wheels made everything better.