Haas DT-1 Spindle Repair

The Haas DT-1 is a vertical machining center, fitted with a grease lubricated inline direct-drive spindle.  This specific spindle is the high performance option capable of operating at 20,000 RPM and a BT30 tooling taper.

CHALLENGE

This Haas DT-1 spindle arrived to NTE after around 1,000 hours of high speed cutting of aluminum.  The customer stated there were no significant crashes to be reported, but upon initial inspection the spindle was noisy when spun by hand.  After disassembly of the spindle it was found that the rear radial bearing had catastrophically failed and the bearing cage was completely destroyed.  Because of the rear bearing failure, the bearing journal shoulder was worn and had high runout at 7µm.  The BT30 taper had good runout and fair contact was found after a bluing test, but was in very poor condition visually.  No other significant dimensional deviations were noted on any critical dimensions (bearing journals/shoulders, housing bores).

SOLUTION

The following actions were performed on this Haas DT-1 spindle:

• Cleaning of all parts
• Replace Bearings, Bolts, O-rings, Bellevilles, and Gripper Balls
• Kiss grind bearing journal shoulder
• Kiss grind 30 ID taper

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.