Sabre 500 spindle fan mysteriously packed with grease?

I have a Sabre 500 which I recently bought, and it's FILTHY. I'm cleaning it up during my retrofit, and I came across something odd.

Attachment 253050

The red cap on top of the spindle motor contains a cooling fan. The top of that housing was covered in cakey grease, so much so that the airflow through it must be restricted.
I pulled the fan housing to clean it, and discovered that it is PACKED with grease inside. Not just greasy, but like an inch thick layer around the inside of the housing, with the fan blade tips dragging through the grease. It seems like clean, fresh grease, so it must be there intentionally. There doesn't seem to be a zerk on it anywhere, so it seems like it was packed with clean black grease, then the fan was installed.

Attachment 253052

This is after taking it apart and starting to clean it up. I've literally taken handfuls of grease out of there at this point.

The fan itself is a pretty normal pancake style fan, although it's 3 phase:

Attachment 253054


I really can't imagine why that grease would be there, what purpose it serves. The top of the spindle motor is a sealed case, so there's no need for grease for it. The only thing I could possibly guess is to catch chips or dust or something?

I found another similar fan on ebay, and it's grease-free:

Attachment 253056

Looks like 1/2 dried coolant. Pretty normal really on non well maintained machines. Seen it more than once.

Sounds like some misguided maintenance person to me?
Fans are usually kept as clear as possible to be effective.
Al.

I washed the housing out real well and re-assembled. It seems to run quietly and happily without the grease, so that's how I'll leave it. Best explanation I've heard yet is that the fan is sucking grease and crud up from below and slinging it centrifugally to the outside of that housing, and that's just decades of buildup.

tmbg

As the other poster said, it is coolant, this is very normal with machining centers, cutting fluid/coolant ( Mist ) some are worse than others, most machines never get cleaned in this area until something fails, just think the operator was breathing that same gunk in as well

To help prevent this Coolant Mist, they have Coolant Mist Collectors mounted above the machines & around the shop to help clear/clean the air

The fan on this Fanuc motor pulls air from the bottom of the motor and sends it out the top of the motor. Was the sheet metal guard that goes around this area installed on the machine ??? Did you look at the baffles in the motor and the bottom of the motor?? If it is clean, then someone got crazy with a grease gun.

Mike cncmachineservices (dot) com