Wednesday, June 4, 2014

Converting a "Cheap" China 40w Laser Cutter to run with the TinyG

A few months ago the. place I work at school bought a cheap Chinese laser cutter on eBay to use for various projects. The laser arrived in good shape, but the original controller board only works with the MoshiDraw software, which leaves much to be desired. We probably would have kept using it if not for the fact that the cutter would behave erratically while trying to cut something. The video below shows one of the more spectacular failures when trying to cut a basic circle:

After doing a bit of research I decided to try converting the laser cutter to run with the TinyG CNC controller that's sold on Adafruit. The TinyG isn't being used to it's full capabilities here since there are only two stepper motors, but I thought that if this controller worked well that we could buy another one to control the small CNC engraver that has been sitting unfinished for a while.

After adding in two limit switches to use instead of the powered opto-isolating switches and running some beefier phase wires to the stepper motor I was able to get some of the basic configuration done and performed a basic homing operation.

The next step is to get a workflow set up that will let us start cutting from DXF files. There are a few options available, I am starting with the JCNC control software since it is supposed to have support specifically for the TinyG. There are many options for generating gcode from a DXF file available on the internet and there is also a very handy tool for automatically modifying gcode to work for laser cutters by removing the data for the Z axis that most DXF to gcode generators include for CNC mills and by adding data to turn the laser on and off at the appropriate times.