CUTTING TOOL EDGE HONING USING NON-NEWTONIAN MEDIA

金属切削工具的边缘通常通过称为边缘珩磨的工艺制备成半径为几十微米的近似圆形。除提高刃口强度外，刃口珩磨还延长了刀具寿命，提高了涂层性，对加工表面质量有良好的影响。目前用于边缘珩磨的工艺，如磨料刷和微抛丸，受到制备边缘几何形状的高度可变性的限制，以及它们珩磨复杂几何形状刀具的能力。为此，本研究项目旨在开发一种创新、经济、环保的磨边工艺，以解决上述问题。即将开发的新工艺**是一种自由磨料刃磨工艺，其中磨料悬浮在非牛顿（剪切增稠）流体中，根据其变形的速率和模式，其粘度会发生明显变化。玉米淀粉（约50%重量）和水的混合物就是这样一种液体。在应变速率下端，介质表现为流体，随着应变速率的增大，介质表现接近于固体。考虑到状态的变化是快速的、可逆的和可控的，流体行为的这种巨大变化被用来控制磨料与工具边缘接合的力场。考虑到这种流体响应，可以在这种新工艺中控制工艺的运动学/几何形状，以调节磨料-工件的相互作用，从而调节材料去除的机制和程度。由于刃磨介质是一种流体，因此诸如滚齿刀等复杂几何形状的切削工具可以进一步**容易地加工。拟议的工作将需要简单的边缘准备，直刃工具开始，以便了解工艺行为；随后将对弯曲刃刀具进行研究，并对其在高速钢和超硬刀具珩磨中的效果进行表征。鉴于刃磨对刀具质量和性能的关键影响**，本研究有望显著**提高工业合作伙伴在市场上的竞争优势。

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.