CUTTING TOOL EDGE HONING USING NON-NEWTONIAN MEDIA

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The edges of metal cutting tools are commonly prepared to correspond to an approximately rounded shape of a**radius of several tens of micrometers, by a process known as edge honing. In addition to enhancing edge**strength, edge honing extends tool life, improves coatability and has a favorable influence on the quality of the**machined surface. Processes currently used for edge honing such as abrasive brushing and micro-blasting are**limited by the high variability in the geometry of the prepared edge, and their capability to hone cutting tools of**a complex geometry. To this end, this research project aims to develop an innovative, cost-effective and**environment-friendly edge honing process that has the potential to address the issues above. The novel process**that is to be developed is a free abrasive edge honing process wherein abrasives are suspended in a**non-Newtonian (shear-thickening) fluid that exhibits an appreciable change in its viscosity, depending on the**rate and mode of its deformation. A mixture of corn starch (~50% by weight) and water is one such fluid. The**medium behaves like a fluid at the lower end of strain rate, with the behavior approaching that of a solid with**an increase in strain rate. Such a dramatic change in fluid behavior is harnessed to control the force field that**engages abrasives against a tool edge, given that the change of state is rapid, reversible and controllable. In**consideration of such a fluid response, the process kinematics/geometry may be controlled in this novel process**to regulate the abrasive-workpiece interaction, and thereby the mechanism and extent of material removal. As**the edge honing medium is a fluid, cutting tools of an intricate geometry such as gear hobbing tools can further**be readily processed. The proposed work will entail the edge preparation of simple, straight edge tools to start**with, so as to understand process behavior; this will be followed by investigations on curved edge tools, and**will characterize its efficacy in the honing of high speed steel and superhard tools. Given the critical influence**of edge honing on the quality and performance of cutting tools, this research is expected to significantly**enhance the competitive edge of the industrial partner in the marketplace.