Matsuura MC-1500V4 Spindle Repair

The Matsuura MC-1500V4 is a CNC vertical machining center capable of 4-axis cutting.  The spindle in this machine is grease lubricated and gear driven giving it the capability of running up to 3,500 rpm.

CHALLENGE

This spindle has an unusual bearing complement for a vertical machining center, including a tapered roller bearing and an angular contact pair in the front, with an angular contact support pair on the tail. The rear pair had been removed from the spindle shaft prior to arrival at our facility and had obviously suffered catastrophic failure. The cages which normally contain the rolling elements were broken & there was evidence of extremely high temperatures.

Upon disassembly, it was evident that the interior of the front bearing housing as well as the interior of the shaft where the drawbar is located were thoroughly contaminated with coolant. The OD of the spindle shaft behind the front housing also showed signs of contamination and light corrosion. The grease in the front roller bearing was severely degraded from coolant contamination.

We observed wear and damage on several other components which ranged from slight to significant. The BT-45 tooling taper ID had several wear bands resulting in poor tool contact and excessive runout measurements. The gripper ball sleeve was damaged and the gripper balls were heavily worn. The ID of the seal collar at the rear of the front housing had light rubout damage.

SOLUTION

We reworked the rubout damage on the seal collar and corrected the BT-45 taper ID issues with a one-step precision kiss grind. We reassembled the spindle with all new bearings, Belleville springs, o-rings & assembly screws, and installed a brand new gripper assembly which corrected all of the wear and damage issues we had observed. We asked our customer to send us two spindle parts which they did not initially provide with the spindle. We needed the front housing cover & front spacer which are necessary to set bearing capture and to test run this spindle.

RESULT

After reassembly of all components, adjusting bearing preload, and undergoing break-in and testing procedures, this spindle passed our final quality inspection before being returned to our customer with a 1-year warranty.