Controller and servos for other devices

[Norman Brewer]

I have a LoboCNC and am very happy with it.  I use it mostly for plastic and wood.  I am thinking about building a 2'x2' plasma cutter table and since I have the Lobo and am familiar with both the controller and code needed to drive it, I am thinking I might like to use a second controller and set of servo's to build the CNC plasma cutter.  I have a pretty complete machine shop so building it should not be too big a problem, and the forces needed on the plasma gun are pretty small.  The 30" per minute speed might be a little slow for thin cuts, but I can turn down the current if needed.  It would be nice to have a relay output to turn on and off the gun, and I probably would have to build a height sensing circuit based on the current or voltage of the gun to drive the z axis. Anyone have any thoughts about the feasibility of this?

[Jeff]

On a 2' x 2' machine, the little Lobo motors might be a little small.  They could work, but I'm guessing the low slew rate would get a little annoying.  Currently, I'm working on a new version of the closed-loop stepper controller which will use a larger driver chip and could be used with up to medium sized NEMA 23 motors.  This controller would use the same software, or it could be used wiht Step & Direction inputs.  I'll hopefully get going on this again soon.  Stay tuned.

Regarding a relay output to turn on & off a plasma gun (or a spindle), the S3x3 board actually has that capability, but I am reluctant to hook that up for liability reasons.  E-mail me directly about this if you want more info.

-Jeff

[Norman Brewer]

I really like the closed loop servo design of the S3x3 controller and the USB interface.  I have a cheap CO2 laser cutter, and the open loop servos sometimes hit a limit and lose track of where they are.  The whole project is ruined if this happens, and there is no possibility of restarting.  The laser cutter controller board is USB connected like the S3x3 which I like but the laser cutter software could be improved.

 

I would anticipate using larger diameter, possibly multi-start threaded rods for the plasma cutter, and you are right, the slew rate would be an issue.  I can wait for a while for a better controller board if you have one in the works.  I'm going to the Cabin Fever show in York, PA this weekend and will see what I can find there as well.

Thanks!