I have been a bad buildlogger on this project.
I have made a lot of progress, but am not documenting it well. I have been so busy, that I just try to sneak and hour here and there to work on it, but don't have time to take pictures.
My goal has been to debut it at the Mini Maker Faire in the local suburb of Evanston, which is this weekend. I have done a big push to get it cleaned up and ready to go over the past few days.
I have had full three axis motion for a while, but not in a clean well wired way. That is done. The cable leading to the plasma is quite thick and heavy because it also carries the air hose. I did not want a huge cable carrier on a machine this size so used an overhead arm similar to what Torchmate uses. Mine rotates which works well to limit the slack required.
I have two slaved motors for the Y to drive the gantry. I did that because it is an easy way to insure squareness on such a light machine. I placed two hard stops at the back to square it. If it needs to be squared you just manually push it against those stops then engage the steppers. The 2.4:1 gear down on the rack drives has a lot of detent torque, even when off so it stays pretty square. Mach3 has a feature where you can use two limit switches to automatically square it when zeroing the axis. I may try that, but the plasma controls really eat up the inputs, so I may need a second parallel port.
The speeds are quite fast. I run 1500 ipm on the X, 800 on the Y and about 200 on the Z. It will run faster, but the acceleration is the limiting factor. The whole thing is on wheels right now. Fast accelerations tend to make try to roll around. Once I find the final home for it, I will loose the wheels.
I'll try to take some pictures tonight.