Automatic Tool Changer Problems. 1

[Eoghann]

We manufacture large grinding and cutting equipment. Recently we produced a grinder with an automatic tool changing system but have been experiencing problems with the tools sticking in the taper. We are using a SKF 50 style taper and an OTT Jacob clamp/push cylinder for holding/ejecting the tool in the grinder.
The OTT Jacob cylinder gives about 1000kg of push to eject the tool. The tools are made from EN19 and the tapers have been surface hardened (Nitrided). There is a problem with rust forming on the surface of the tool and the female taper of the grinder, but only where the tool/grinder actually touch.

http://www.blackisle.org.uk/spindle_rust.jpg

This pic shows that the thin end of the taper (in open air inside the grinder) has very little rust compared to the rest of the taper.

http://www.blackisle.org.uk/grinder_rust.jpg

shows the inside of the grinder.
The equipment is working in a fully covered building (main doors always wide open), about 500km from the nearest sea.

Does any know why the rust is building up in these areas? Is it due to fretting?
Is there any lubrication we should be looking at to coat the spindle?
Anyone else have problems with tools not ejecting?

Thank you for any help you can supply.

 

[unclesyd]

I would start looking at my coolant as the grinder has ton of rust visible and looks to be all over the component. One other thing is that the fine grinding dust/residue could be being trapped in the female part of the holder.

There are lubricants that you can use, but I would first get with my coolant supplier as to his recommendations and compatibility problems. Stay away from sulphur containing compounds, like MoS2. Get his recommendations for testing.

Is the operator wiping, with a clean rag, the tapers at some interval?