Collaborative Research: Full Field Measurement of Cutting Tool Surface Temperatures

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The objective of this project is to measure the temperature distributions along the tool-chip interface and along the tool-workpiece interface, through transparent cutting tools, during the machining of hard to machine alloys. Two non-contact optical thermography techniques, namely, infrared thermography and two-wave laser induced fluorescence, will be used for full-field, high resolution measurements of the temperature fields along the surfaces of cutting tools. Transparent cutting tools of two designs will be used to optically access the rake and flank faces. Tool coatings made of temperature sensitive phosphors will be applied over transparent tools to enable fluorescence thermography. A newly developed split-optic will be used to simultaneously measure the infrared intensity in two wavelengths. The spatial resolution of the measurements will be from one to ten micrometers. With two-wave laser induced fluorescence, temporal resolution as low as one microsecond can be achieved. These capabilities will represent a major improvement over the current state of the art. The development of thin film sensors for high speed, full field, surface temperature measurements will be of use in a variety of applications requiring non-contact temperature monitoring. This study will be the first application of fluorescence thermography to study cutting temperatures and will lead to the first direct observations of the flank face temperature of new and worn tools. Measurement of the variation of the temperature distribution through the thickness of the workpiece will help improve our understanding of the plane stress to plane strain transition. The measured temperatures will help validate finite element simulations of machining, and lead to improved material constitutive models, friction models and tool wear models. Research results and methods will be incorporated into academic courses. A partnership will be formed with the McNair scholars program at Wichita State University to attract underrepresented students.