An efficient liquid cooling system keeps the motor and bearing temperature at a permanent, low and therefore safe operating range.

Motor and bearing cooling

GMN high-speed spindles are equipped with an effective liquid cooling system.

A cooling sleeve in the area of the shaft bearing as well as at the spindle motor minimize increases in operating temperature, which can be caused by bearing friction as well as motor losses.

The reduction in operation-related heat development, increases the detachable spindle performance and provides maximum productivity as well as high machining quality.



Coolant temperature

The maximum detachable performance of the spindle is achieved in a specified coolant temperature range of 20 °C to 25 °C.

The actually available performance depends upon coolant temperature and from the medium used.



High machining precision

Low coolant medium temperature differences reduce axial shaft displacement and improve machining precision.

GMN cooling systems with high control precision are available as accessories.


Coolant supplied through the spindle shaft

The optional “coolant supplied through the spindle shaft” unit provides a significant improvement in tool cooling, when machining displaced bores and blind bores.

  • Shorter cycle times
  • Improved surface quality
  • Improved dimensional accuracy through cooler grinding
  • Reduced risk of fires during high-performance grinding

GMN offers two different systems for coolant feed through the shaft depending on one’s machining requirements:


Low-pressure seals

RPM range to: 120,000 RPM

  • Seal: Sealing gas/air lock
  • Maximum coolant pressure: 4 bar
  • Dry running allowed
  • Insensitive to pressure surges
  • Required filter fineness: < 0.1 mm
  • Spindle insertion position: horizontal (other insertion positions upon request)


High-pressure seal

Speed range to: 75,000 RPM

  • Seal: Touching sealing discs
  • Maximum coolant pressure: depending on the type of spindle, up to a maximum of 50 bar (higher pressures on request)
  • Minimum pressure: 3 bar
  • Dry running allowed
  • Pressure surges must be avoided
  • Required filter fineness: < 0.01 mm
  • Spindle insertion position: horizontal (other insertion positions upon request)