Mist generation from metalworking fluids formulated using vegetable oils.

Metalworking fluid emulsion formulations produced from vegetable oils may be less toxic and may reduce disposal costs when compared with fluids formulated with petroleum-based oils. Experiments were performed on experimental emulsions made with unmodified and modified soybean oils to measure rates of mist production by impaction, centrifugal force and evaporation/recondensation mechanisms. Results were compared with measurements made using a commercial metalworking fluid emulsion formulated using vegetable oil and another made from mineral oil. The results indicated that most of the experimental fluids produced about the same amount of mist as the commercial fluids by impaction and more mist than the petroleum-based fluid by centrifugal force. However, an air-oxidized modified soy oil produced less mist by impaction than the petroleum-based fluid and about the same by centrifugal force. The experimental fluids produced between 30 and 90% less mist than the commercial fluids by evaporation/recondensation. The air-oxidized soybean oil was the most promising candidate among the experimental fluids for further testing in more realistic machining conditions.