Weiss 176162 Spindle Repair
Weiss, 15000 RPM, CAT-40, grease injection bearing lubrication, stator drive
Installed in a Hardinge Bridgeport XR500 5AX (5-axis vertical machining center)
When our customer first contacted us about this spindle, they were limiting the spindle speed to 4-5000 RPM because it was emitting a loud, high-pitched squeal if run any faster. A week later, they were unable to go past 1000 RPM without it screaming, and the tools were coming out hot. This busy aerospace manufacturer needed to complete an order for a customer so they proceeded to run the spindle for another several months. When they finally pulled the spindle and sent it to us, they requested an expedited turn time as the orders were stacked up and they could not afford significant downtime.
Once the spindle arrived in our facility, we observed that it turned very stiffly when rotated by hand. Upon breakdown it was apparent that the front quad set of bearings was heavily contaminated with coolant, especially the #1 bearing. Our dimensional inspection uncovered excessive runout in the tooling taper, and we also noticed that the specialized rotary union was leaking, which had caused significant corrosion to components at the rear of the spindle. Fortunately, there was no other damage which would require further corrective action. Because the OEM bearings for the grease-injection lubrication system are not available, we advised our customer that we would be converting the spindle to use readily available high-speed grease for life bearings.
Unfortunately, a replacement rotary union was not available and had to be manufactured. Our customer approved their quote with the best turn time we could offer, given our vendor’s lead time. In the interim, we kiss ground the shaft taper, reducing the runout to less than 2µ. We rebuilt the spindle with all new ultra high speed grease for life bearings, Belleville washers, quad seals, o-rings & screws. By the time the rotary union arrived, the spindle run-in and QC were already completed. We were able to assemble the rotary union to the spindle, perform a final test run to check for balance and rub, and ship the spindle back to our customer who is making complex parts at high speed once again.