Experimental and Analytical Efforts to Characterize Cutting Fluid Mist Formation and Behavior in Machining

Abstract

The use of cutting fluids in machining operations is being carefully scrutinized by industry for several reasons, including its overall cost in the manufacturing process and its impact on worker health. Given the concerns associated with the use of cutting fluids, a number of experimental and analytical research efforts are being conducted to gain an understanding of the role of these fluids in various machining processes. The knowledge gained by this research will aid in the development and implementation of strategies to reduce or eliminate the negative effects of cutting fluids, while maintaining their beneficial role. This article presents the results of designed experiments focused on determining the significant variables that influence air quality during turning operations, as well as characterize the aerosol emissions associated with wet and dry turning. Air quality is characterized by measuring the mass concentration and particle size distribution of the dust and mist created during a set of machining experiments. The relative importance of vaporization/condensation and atomization as mist-generating mechanisms is also explored. The experiments revealed that spindle speed has a dominating effect on both mist mass concentration and aerodynamic particle size. Analytical models are presented that predict the average droplet size of the mist generated by atomization and are used to investigate droplet size trends for various cutting fluids and machining parameters. The results predicted by the models are consistent with the expected trends.

Particle size distributions of oil mists in workplace atmospheres and their exposure concentrations to workers in a fastener manufacturing industry

“…The manufacture of fasteners involves seven important industrial processes, including the wire drawing, forming, threading, cleaning, heat treatment, surface treatment, and packaging and shipping. Among them mineral oil-based metalworking fluids (MWFs) are used in forming, threading, heat treatment processes for cooling, lubricating, and corrosion inhibition purposes and hence might result in the emission of oil mist to the workplace atmosphere and lead to the exposures of workers [1,2].…”

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

“…(53−58) The type of MWF being used, the presence or absence of additives to reduce misting, the type of machining operations being performed, and the amount of general and local exhaust ventilation employed at the facility all affect the amount of MWF mist generated and released into the employee's breathing zone. Various studies indicate some of the important factors that influence mist generation, including tool spindle speed; (57,58) size and location of the workpiece; (57) speed, feed rate, and depth of cut; (57) pressure of the applied fluid; (58,59) and the proximity of the tool to the part. (59) Due to the complexity of the metalworking fluid environment, a comprehensive systems approach using a combination of fluid management and effective engineering controls has received widespread acceptance.…”

Assessing Long-Term Oil Mist Exposures for Workers in a Fastener Manufacturing Industry Using the Bayesian Decision Analysis Technique

“…Manufacturing fasteners involves seven processes, including the wire drawing, forming, threading, cleaning, heat treatment, surface treatment, and packaging and shipping. Mineral oil-based metal working fluids (MWFs) are involved in the forming, threading, heat treatment for cooling, lubricating, and corrosion inhibition purposes, and hence might result in the exposures of workers to oil mists (Thornburg and Leith, 2000;Michalek et al, 2003). Among these workplaces, the threading was found with the highest exposure level (Chen et al, 2007).…”