An Environmentally Friendly Method of Metal Cutting
The challenge for manufacturing is to be able to produce machined products in an environmental and sustainable way without increasing unit costs. This is especially important in metal cutting processes where liquid cutting fluid is used to prolong tool life. Traditionally cutting fluids have been used to remove heat from the work piece due to the high thermal capacity and conductivity of the cutting fluid. Numerous health issues though –for example chronic skin conditions - have been linked to prolonged exposure to hazardous chemicals and the bacterial constituents found in cutting fluids. Removal of the cutting fluid is also an absolute necessity. This is very expensive and requires appropriate regulatory processes put in place to ensure its safe environmental disposal. In the early 1990s the introduction of dry machining was viewed as both an attempt to reduce reliance on cutting fluids and an improvement to the working environment. Reducing unit costs was also an objective. To date these goals have not been met, even with improvements made to cutting tool materials. Success will only be achieved when the metal cutting process is shown to be as effective as traditional methods. Dry machining incorporating passive air is considered in this paper as a possible alternative to harmful liquid-based cooling. However, low convective heat removal rates associated with conventional air-cooling methods have been generally inadequate for dissipating intense heat generation in cutting processes. This paper examines the operational effectiveness of vortex air-cooling, with results obtained comparing favourably with those achieved by liquid cooling. Measurements clearly indicate a highly significant reduction in tool tip temperature with the vortex air-jet used in the metal cutting process.
Keywords: Cutting Fluid, Vortex Air-jet, Tool Life, Heat Generation, Hazardous Chemicals
Dr. Brian Boswell
Lecturer, Mechanical Engineering, Curtin University of Technology
Prof. Tilak Chandratilleke
Head of Department, Mechanical Engineering, Curtin University of Technology