JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME, vol.141, no.9, 2019 (SCI-Expanded)
The objective of this work is to fabricate thermocouples directly on the rake face of a commercially available tungsten carbide cutting insert for accurately measuring the tool-chip interface temperature during metal cutting. The thermocouples are sputtered onto the cutting insert using micromachined stencils, are electrically isolated with layers of Al2O3, and receive a top coating of AlTiN for durability. The result is a nonsacrificial thermocouple junction that is approximately 1.3 mu m below the rake face of the tool and 30 mu m from the cutting edge. Experimental and numerical characterization of the temperature measurement accuracy and response time are presented. The instrumented cutting tool can capture the tool-chip interface temperature transients at frequencies of up to 1 MHz, which enables the observation of serrated chip formation and adiabatic shear events. Temperature measurements from oblique machining of 4140 steel are presented and compared with three-dimensional, transient numerical simulations using finite element analysis, where cutting speed and feed are varied. This method of measuring the tool-chip interface temperature shows promise for future research and smart manufacturing applications.