Porta N-145 Spindle from a transfer machine
Porta N-145 FMU, 2000 RPM, grease lubrication, belt driven
This spindle is one of several installed on a transfer machine used in the manufacture of driveline components. The bearings in this spindle were very noisy when rotated in assembly incoming. Upon disassembly we observed that the entire spindle interior was heavily contaminated with a brown sludge consisting of part coolant & particulate. This contaminant had degraded the grease in the bearings and caused wear of the races & rotating elements. We also noted degradation of the ball screw unit which controls the Z axis motion. Finally, we decided to address the heavily damaged and stuck tool drive keys & the tooling taper ID which was extremely worn with runout >46µm. The customer retained the drawbar assembly, reinstalling it in their spare spindle to keep production moving.
In preparation for the final assembly of the spindle, we sent the ball screw unit to a reliable vendor for a precision rebuild. We completed a grind, chrome plate and finish grind of the tooling taper ID on our in-house Kellenberger grinding machines. We also machined out the old drive keys and fabricated a new set. After a thorough cleaning of all components, we rebuilt the spindle with all new bearings, drive belt, seals, o-rings and assembly screws, installing the rebuilt ball screw unit and the newly-fabricated drive keys. We finished this rebuild with our final test run, break-in and final QC. Our customer had already shipped another spindle from this machine to us by the time we were finishing up on this one.