Issues Associated With MQL Implementation: Effect on Peripheral Milling Process Performance and Impact on Machining Economics

Abstract

The copious use of metal working fluids in machining applications carries with it worker health, environmental, and cost concerns. Driven by these concerns, minimum quantity lubrication (MQL) technology has been proposed as an intermediate alternative between flood and dry machining applications. However, widespread use of MQL is inhibited by worries related to unknown costs, thermal distortions, chip flushing problems, flammability of airborne metal dust, and system reliability/repeatability. More information is needed on the effects of lubricant flow rate and droplet characteristics on the cutting performance. One challenge associated with implementing MQL technology has been the difficulty in reconfiguring dedicated transfer line systems. To address some of the above issues, tests have been conducted to investigate the effects of lubricant flow rate and droplet characteristics on cutting performance in terms of cutting force, workpiece temperature, surface finish, and air quality. Comparisons are made among dry, MQL, and fluid flood applications to show that MQL and flood application provide similar benefit in terms of work temperature. Machining cost analysis for both multistage and single-stage operations provides insight into the relative difference between transfer line and FMS machining systems in terms of costs for different fluid applications.

Comparative Economic Analysis and Investigation of Micro Lubrication Over Conventional Cooling in Manufacturing

“…Few studies have performed an economic analysis of MQL versus conventional cooling in milling operations. Ju et al (2005) performed a cost analysis for a machining center and a transfer line for MQL and traditional cooling drilling, boring, and face filling operations.…”

“…The cost of flooded coolant was significantly higher than that of the MQL. The cost of flooded coolant was 22% higher than that of MQL (Ju et al, 2005). Amrita et al compared the costs of two systems that used low-and high-pressure compressed air with nanocutting fluid at 5 mL/min and 1 mL/min, respectively.…”

Nanofluids as a potential solution for Minimum Quantity Lubrication: A review

“…Peripheral milling tests were recently performed to examine the effects of fluid application strategy (dry, MQL, and fluid flood), axial depth of cut, flow rate, and air pressure. 38 The work concluded that while MQL application was not as successful as flood application in reducing the workpiece temperature, it did provide a sizeable improvement over dry machining. Increases in fluid flow rate and air pressure were found to reduce temperature and improve surface finish.…”

An Experimental Investigation on Vegetable Oils as a Cutting Fluid under Minimum Quantity Lubrication: A Sustainable Machining Approach

“…Reduction in cutting temperature under the application of MQL attributed to increasing fluid flow rate and air pressure; was observed by Juet. al, 2005 [14]. Attanasioet.…”