Ok, well I took the plunge and purchased a mid-80's vintage comet CNC knee mill with a dead control for a retrofit. I've been doing a lot of reading on here and have learned quite a bit so far, but the problem with learning is that the more you learn the less you actually know. I have not decided which path to take yet for the retrofit, buy a kit or assemble my own, so here I am looking for a bit more specific insight. I haven't received the mill yet so I am not able to take stock of what exactly I have as of yet. I do know it has Fanuc servo's and a velocity drive system ( the old control is a Fanuc system 10 MA controller), a 3 phase 3HP 4 pole 230V spindle motor and that is about all I know about the control so far. What I would like to do is build a high quality retrofit, retain the original servos, possibly add a VFD to increase the spindle speed (max is 4200RPM right now, I would like to try and get 5-6K rpm if this is possible).
Now if I where to build up my own kit, from the hardware side of it I know I need encoders, servo drives a motion control card for the PC. What else do I need? The current configuration for the spindle motor appears to use a motor to control the hand wheel to change the motor speed, do I even need this if I am going to use a VFD? What all am I miising here guys?