I have a bridgeport VMC412 with SEM servo motors and BOSCH drives.
we have had this machine for a good 25 years running. Some years ago I dismantled the Z motor and found the commutator segments paper thin.... I found a sem motor over e-bay and this was not exactly like the one on the machine but ran OK.
eventually started getting gross positioning error in Z and I reduced the Z max feed in parameters and it cannot go more than F5000. I tried tweaking the bosch control card but cannot get it any better. I need the machine to run faster....but can`t. what are the options? the machine parameters need modifications? I can`t use the motor I have? The machine is still giving out valuable output so worth spending a bit to get it to its original glory.... Any help appreciated.