Internally cooled tools and cutting temperature in contamination-free machining

Whilst machining heat is generated by the friction inherent into the sliding of the chip on the rake face of the insert, the temperature in the cutting zone of both the insert and the chip rises, facilitating adhesion and diffusion. These effects accelerate the insert wear, ultimately undermining the tool life. Therefore, a number of methods have been developed to control the heat generation. Most typically, metal working fluids are conveyed onto the rake face in the cutting zone, with negative implications on the contamination of the part. Many applications for instance in health care and optics are often hindered by this contamination. In this study, microfluidics structures internal to the insert were examined as a means of controlling the heat generation. Conventional and internally cooled tools were compared in dry turning of AA6082-T6 aluminium alloy in two 33 factorial experiments of different machining conditions. Statistical analyses supported the conclusion that the chip temperature depends only on the depth of cut but not on the feed rate or on the cutting speed. They also showed that the benefit of cooling the insert internally increases while increasing the depth of cut. Internally cooled tools can therefore be particularly advantageous in roughing operations.