Food for thought...
If you buy a smaller, used VMC with rails (HAAS, etc.) there's not as much to worry about. Budget replacing all the electronics except for the spindle motor and drive. Even the linear rails can be replaced if necessary.
We're saturated with used VMC's here in the rust belt, but I'd imagine you could find an old HAAS or Brother (or similar) for a few thousand that has an obsolete control that some shop doesn't have time to fiddle with it. Rigging for one of the smaller VMC's isn't going to be that bad, so the only thing to worry about financially is the spindle.
New ballscrews are going to be about the same price whether for a PM940 or for a HAAS VF-0. Same thing for the control hardware, and if you can re-use the axis servos & drives - that's a savings. Just don't count on it and budget for it.
Having done it on a small mill, I don't see much difference between taking a new manual machine and converting it and retrofitting an old VMC. The big difference is that you don't have to fabricate ballscrew mounts or modify any of the major hardware to get it working. The challenge will be getting the control to work with the spindle motor.
If the tool changer is too complicated to figure out at first - don't use it. Just leave yourself some extra inputs/outputs to get it working at some point after you've gotten your CNC Controls Apprenticeship over with.
So instead of spending time researching how to manufacture ballscrew mounts, spend time looking at old VMC user manuals and find one with spindle drive inputs you can connect to with off-the-shelf CNC control hardware.
And look for one that originally ran on single phase - I think there were a few 7.5hp little ones made a while ago that could work.
If you buy a smaller, used VMC with rails (HAAS, etc.) there's not as much to worry about. Budget replacing all the electronics except for the spindle motor and drive. Even the linear rails can be replaced if necessary.
We're saturated with used VMC's here in the rust belt, but I'd imagine you could find an old HAAS or Brother (or similar) for a few thousand that has an obsolete control that some shop doesn't have time to fiddle with it. Rigging for one of the smaller VMC's isn't going to be that bad, so the only thing to worry about financially is the spindle.
New ballscrews are going to be about the same price whether for a PM940 or for a HAAS VF-0. Same thing for the control hardware, and if you can re-use the axis servos & drives - that's a savings. Just don't count on it and budget for it.
Having done it on a small mill, I don't see much difference between taking a new manual machine and converting it and retrofitting an old VMC. The big difference is that you don't have to fabricate ballscrew mounts or modify any of the major hardware to get it working. The challenge will be getting the control to work with the spindle motor.
If the tool changer is too complicated to figure out at first - don't use it. Just leave yourself some extra inputs/outputs to get it working at some point after you've gotten your CNC Controls Apprenticeship over with.
So instead of spending time researching how to manufacture ballscrew mounts, spend time looking at old VMC user manuals and find one with spindle drive inputs you can connect to with off-the-shelf CNC control hardware.
And look for one that originally ran on single phase - I think there were a few 7.5hp little ones made a while ago that could work.