Metalworking Fluid Mist—Strategies to Reduce Exposure: A Comparison of New and Old Transmission Case Transfer Lines

Abstract

Three studies were performed to assess the effectiveness of various techniques to control metalworking fluid (MWF) mist. The studies consisted of a detailed main study that determined the effect of degree of enclosure on personal exposures and area concentrations of MWF mist on two machining transfer lines. One ancillary study was conducted to determine the effect of shutting off MWF delivery during down time; the second ancillary study investigated the effectiveness of improved retrofitted enclosure. In the main study, the two operations were identical except for degree of enclosure. Personal and area sampling results for the new line were about half those found in the old line. Measurements at the new operation exhibited significantly less variability. Personal exposures and area concentrations were significantly less at the new operation than at the older, less enclosed operation, demonstrating that the total enclosure in the new operation provides better and more consistent control of the mist. The first ancillary study was conducted to determine if shutting off MWF delivery to the parts being machined reduced area MWF mist concentration during downtime at a partially enclosed transfer machining line. A significant reduction in concentration of 80% was measured with machining off/MWF off. Mist concentrations measured with machining off/MWF on were not significantly different from mist levels measured during machining on/MWF on. The second ancillary study investigated the reduction of mist concentration achieved through improved enclosure of an existing set of machines. Area mist concentrations were measured at a machining operation before and after the installation of an improved enclosure. Area mist concentrations were reduced by 87% with the improved enclosure.