Fighting with computers

After some changes I have been able to get it working reliably with two motors. But one of the changes I have made is to use a new type of motor that I reckon is better suited to the task. Instead of using brushed motors that are cheaper, I have found other brushless motors that have several advantages:  Being brushless, there is no other wear than the bearings They have built-in driving electronics, so they can be controlled with the Arduino digital outputs, which simplifies things and reduces interface costs.  Motors have built-in encoder disks, too, but the one they carry is just 100 lines per revolution (a bit poor, in my opinion) that can turn into 400 "steps" per revolution with the 4x decoding of the program. The lower number of lines per revolution puts less stress on the Arduino interrupt code, which may be one of the reasons it works ok now. I have moved all the encoder signals to pins that are monitored with the interrupt on pin change, and I have reserved

I have been using a [cheap] laser cutter machine. You can see which one on the following video.   Till now it kind of works but what is really annoying is the software you have to use to be able to cut and engrave. It is called Moshidraw and for reasons I cannot really understand it comes with a USB dongle for protection (it will not run without it).  Not in a million years I would like to copy such a program. This is what I have learned so far that causes trouble: If you DXF file contains curves, the operation will fail randomly (suddenly the cut will take an unexpected route and it will ruin your stock material). If you import a DXF and fail to select the part, the cut will did not work properly. If you have several parts in DXF, it may fail at any point (mostly when it is almost finished and all your stock material will be ruined). Best results and lower risk if you do multiple parts one at a time. There not seem to be a way to force inside cuts first, so some operation