This is part of a much larger project to replace an ageing Westwind Air Bearing Spindle with a more modern type.

 

The existing high frequency drive wasn't suitable so a Control Techniques drive was fitted along with a bespoke interlock board I designed. This board monitors the tacho in the spindle to make sure that the air operated collet can't open while the spindle is running.

 

The retrofit involved using part of the existing support for the old spindle, which was considerably smaller in size, and utilising a linear Air Bearing sleeve (pictured in orange) to provide the axial bearing. These parts are readily available from commercial drilling machines.

 

Two machines were converted and they share a common water cooling unit. The control boxes for each spindle are set up in a Master/Slave configuration so that the master contols the cooler pump and fan while the Slave notifies it that it requires cooling. There is also a pressure sensor in the emergency stop circuit to ensure that the spindle stops if the air supply is lost.

 

All of the parts were made from the 3D model data on my CNC milling machine, as were the cutouts in the boxes and the engraving on the hand control pictured.

 

The motor drive, control logic and power supply were mounted in a separate box, not pictured here.