First Plasma Build - 4'x4'+

[IslandSpark]

Hey guys, I'm working on designing my first plasma CNC build. While I'm not new to building/Fabbing (3d printers, PrintNC router etc) This is my first from scratch design and I'm looking for some feedback. Its a 4'x4' (plus a bit of wiggle room) plasma with built-in welding table. I plan to build this machine using rails/ballscrews and servo's. I know its likely overkill but I have access to a lot of near new components with my day job in industrial automation. I'll be running Linux CNC with servo drives over Ethercat and a Mesa 7i76 with THCAD for torch height control and interfacing my hypertherm 45xp to the system.

1) with a 5mm/rev ballscrew and 3000RPM rated festo servo's (up to 6900RPM if req'd) I expect to be able to run with no further gear reduction @ around 600IPM. If required i might be able to snag some 3:1 planetary reducers from work which would put me at ~200IPM (at rated servo speed). Any insight here? I don't expect to need additional reduction for resolution or torque requirements but you may know better?

2) Dual Y Drives allow for some racking and then automated gantry squaring after homing using the prox's and encoders, however i am a little worried about my bottom mount ballscrew and the lever forces it will produce moving the gantry, Initially I've gone with dual carriage rails on the Y axis to help resist this levering force but I'm an electrician not an engineer...?

Further thoughts/feedback?

Plasmax2.PNG

Plasmax1.PNG

[acourtjester]

Welcome aboard
Good start with the other CNC tables, I am not a fan of ball screws for plasma but that's me. You may want to look at the 7I76E as it has more inputs and outputs. I found with the THCAD-10 for THC I had to switch the Hypertherm to 20:1, I hope you have more experiences with LinuxCNC than I had. I am still having minor problems, QTPlasmaC is a great GUI lots of info shown on the screen. But the Z action is controlled by the GUI and the SheetCam tools are called Material and all are selected when in the GUI. The G-codes commands are different from other software. Here is the front page of the GUI.
Have fun
Tom

QTPlasmaC GUI.JPG