Toyoda FH630 Spindle Repair

The Toyoda FH630 is a CNC horizontal machining center.  It comes fitted with an oil mist lubricated and stator driven spindle capable of running up to 6,000 rpm.

CHALLENGE

This Toyoda FH630 spindle was seized when it arrived at NTE. The OD of the shaft nose had rubbed out on the ID of the front cover, and the ID of the taper insert had poor tool contact with excessive runout. The tool retention force was very low incoming and we observed that the gripper fingers were damaged and had significant wear. We also noted that the rear actuator bolts and the sensor covers were loose, and that the spindle-side ceramic seal surface of the rotary union was chipped. We suspected that the front bearings had lost preload in a crash, which may have resulted in much of the previously-mentioned damage.

SOLUTION

The 100mm front bearing journal of the spindle shaft was manufactured to be oversized +32/+35µ to accommodate the special preload of the front quad set of proprietary OEM angular contact bearings. Normal ISO tolerance for that journal when using non-proprietary bearings would be ±9µ. The decision was made to reduce the OD of the journal to make possible the use of non-proprietary high-precision bearings in this, and any subsequent rebuilds.

We performed a kiss grind of the OD of the shaft nose, the ID of the taper insert and the 100mm front bearing journal. After a thorough cleaning of all the other spindle components, we reassembled the spindle with all new bearings, Bellevilles, grippers, rotary union, seals, o-rings, and assembly screws. Tool retention force was checked and found to be improved to be within the correct range.

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.