Forced cooling mod for 2.2kW air cooled square CNC spindles

Our 2.2kW air-cooled square spindle from "Rattmmotor" on one of the CNC machines at Stockholm Makerspace had lots of problems with running super hot on lower speeds, since the small impeller-style fan is running directly of the spindle shaft, and provides very little flow under about 10-15krpm.

We decided to change this to forced cooling instead.

So we removed the original back cover and the impeller, then I took the cover with me to 3DVerkstan and got it scanned in super high detail in the Shining3D Autoscan Inspec.

Imported the file into Fusion 360, aligned it, and drew up a new back cover with an integrated mount for a super high flow Delta 60mm fan (PFR0612XHE).

After we added this, we have no problem with cooling at any spindle speed.

The design is made to have four M4 heat-set inserts, but you can mount the fan with screws and nuts, or just glue if you don't have any.