How to use a Microkinetics controller on a plasma table

[panozeng]

Ok, early this year I posted about acquiring both a Microkinetics Driverack USB motion controller system and a small 2 axis robotic arm. I was able to make it work, but the Microkinetics motion controller had some serious drawbacks making it impossible to use for plasma:

I had two configuration options - 1 was to use something called "continuous contouring" that resulted in nice, smooth motor control. However, it also resulted in a caching problem - it would stop in the middle of a cut and plan out the next moves, while the plasma torch burned a huge hole in the part. It also did this delay after turning the torch on every time. Completely unacceptable...

If I turned the continuous contouring off I had no problem with the caching. However, it made the motors run so rough that the whole table got into horrible harmonic vibrations. It was completely unusable that way as well... So, I went several months without using it.

The final issue I had with Microkinetics was the proprietary software. It would accept DXF files and make it's own Gcode with no options for leadins, cut order, etc. I tried using several dXF to Gcode converters and found that almost every one resulted in an error about halfway through the cut due to the control software claiming errors in the stops/starts of line segments many decimal places out. Must be a rounding issue? But, there was no way to get past those points.

About a week ago I finally got around to ordering a breakout board and looking at the plasma table again. I pulled the plug inside the driverack case on the motion controller card, and simply fed the outputs of the BB to the motor drives and control relays. I was able to re-use everything in the box and it only took minutes to do. Installed Mach3 on the computer, plugged it all in, and was cutting great parts in minutes! Here is the first part off the machine with very little time figuring it all out:


So, thanks to Microkinetics I do have nice drivers (80v, 10amps) wrapped in a nice enclosure with really nice power supplies. I'm surprised they haven't offered the driverack in a configuration like this to take advantage of the much more powerful Mach platform over thier outdated software... Seems like it'd open them up to more sales... The president did see my posts on here and came to the conclusion that I needed to buy an upgrade to servos to fix the problem! Humm - expensive complete hardware upgrade or $20 breakout board?

Here is the machine cutting 1/8" steel at 150ipm. I still have a ton to learn about getting it dialed in, but I'm already making good parts for my fabrication business.