We have an issue of spindle belt slipping on a Pinacho CNC Lathe ST310 with a rather large spindle (A2-11 nose, 16" hydraulic chuck and cylinder with 6" spindle bore). The spindle is driven via V-belts from a gearbox, which is driven by another belt set from Fanuc spindle motor. The slipping happens when the spindle start and stop (we it at around 500~700 RPM), slipping is on either the motor-gearbox belts or gearbox-spindle belt set. When we adjusted/tighten the belts, it get better only for a couple of weeks before it start slipping again. We also tried different brand of belts, but no luck.

During the turning, it usually works just find. So I wonder if the acceleration and deceleration rate of the spindle when it start and stop rotating can be adjust? Would it help with the problem? Or should I not mess with it and look for other solutions?


Thank you all in advance.