Copper machining and Toolcone rust

Dear Mr. / Mrs.
 
Coppermachining:
We have a problem with staining with a full syntetic on coper/brazz machining. Or actually the problem is only in one machine, it is quite strange. We have done tha same machining with the same fluid on the same material in other machines with no problem. The only difference we have found between the different machines is that on the machine that has staining there is fitted a so called electrostatic airfilter on the air from the machine. The filter creates ozone as a part of the cleaning process of the air, I think. The fluid that is colected in this filter is returned into the coolant sump. Do you think this can cause the staining ?
 
Toolcones:
We have some small dots of rust/corrosion on the toolcones as well with this full syntetich, never had any problems with an oilemulsion. We have talked to different people and they say they have the same problem and they also use a full syntetich. They say it is because of the blowing on the toolcone before it enters the machine or toolmagazine behind the machine. Is this correct ? The supplier of the fluid claim that this is a common problem with all types of syntetichs. Thanks, hope to have some feedback on these matters quite soon.
Best Regards RB 
Filed Under: 
Maintenance / Troubleshooting

Anonymous (not verified)

Fri, 2011-03-11 15:12

Dear Reader,
 
To address your first question in metalworking terms copper is a sensitive metal, by that in mean it will stain easily. The filter you refer to is creating ozone which can be corrosive to certain metals and I have seen ozone stain copper. So to answer your question the ozone can be contributing to your copper staining problem.
 
Regarding your second question without knowing the type of metal these tool cones are made of answering your question will be difficult at best, but I will try, the corrosion you describe can be caused by the surfactant package in the coolant (nonyl-phenols are infamous for this). You say you did not have this problem with a soluble oil, then unless there is some reason why you want to use a synthetic I would return to using the soluble oil. Thank you for two great questions and for reading,
 
All Best
Dom