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Broken power feed gearbox on manual mill. VFD or BLDC?


Nov 1, 2006

I have an old H/V milling machine that has a problem in its power feed gearbox. The gear selector and speeds were working fine, but the high/low mechanism was getting stuck. It reached a point where it was completely jammed. I decided to dig in and see if I can repair it. Had to remove the table along with all the gearbox-related parts. Part of the gearbox housing is integrated into the Y-axis ways. The gearbox itself has parts that cannot be removed (gears held with roll pins that cannot be pushed through.)

Anyway, I'm thinking that the best way forward is to either run a VFD to the power feed motor or use a brushless DC motor to provide variable speed into the system. Would one option function better than the other? Cost probably won't be a whole lot different, and both will require custom work and fiddling around. I'm just trying to figure out if functionality might be very different between the two (for this application). Thank you for any insight or advice you might be able to offer!
If you want rapids I would go for a 3000rpm DC motor
Ratio between rapids and slowes

t feedrate is 300 on a Deckel FP3 (5-1500mm/min)
Keep that in mind if you pck any