I was in a crankshaft grinding area in which a water and soluble-oil solution was used for cooling at the grinding station when I was asked if I could help the engineer design a ventilation system to remove the smoke and haze that filled the room. My answer was that I could, but wouldn't.
When asked why I wouldn't design a ventilation system, I asked, “When you first replace the cooling solution, is there any smoke or haze?”
After some thinking, the answer was no. I asked if there was any objectionable odor when the cooling solution first was replaced. Again, the answer was no. I then explained I believed the problem of both the haze and odor was the result of tramp hydraulic oil that leaked from the production machines into the coolant. I further stated I believed the amount of tramp oil at which problems become apparent should be determined.
Determinations of the percentage of tramp oil in the solution were made daily. It was found that when the tramp oil reached 6 percent, both the odors and haze became noticeable. A centrifugal separator was installed, and the tramp oil was reduced to and kept below 4 percent. It then was found that the same cutting oil could run almost indefinitely without complaints or replacement.
There was, of course, more interest in this compound than before. As a result, a program was started to determine if the amount of the soluble oil could be reduced without affecting operations. Much to everyone's surprise, the percentages of expensive cutting oil being added to the water could be reduced as much as 50 percent without any ill effects on the grinding. By determining and eliminating the cause of the problem, instead of trying to control it, the overall operating cost was reduced, rather than increased, with more satisfactory results.
Kenneth E. Robinson, CIH
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