Grooving, conditioning and micromechanics of grinding wheels

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Grinding is a strategic manufacturing process; the Canadian aerospace, automotive, oil and gas, and forestry industries are all users of grinding technology. Virtually all parts made of hard materials that require fine surface finishes or tight tolerances are ground. One of the fundamental difficulties with conducting research in grinding is a lack of knowledge of the geometry of the cutting tool. A grinding wheel has a multitude of geometrically undefined cutting points which are irregularly distributed on its working surface and which are presented to the workpiece at random orientations. Prior to any grinding operation, the surface of a grinding wheel needs to be conditioned by cutting the wheel surface with a diamond tool in order to sharpen the grinding wheel and ensure that it has a circular cross-section. This operation modifies the number and the size of cutting edges on the grinding wheel and significantly affects the grinding process. Fine dressing conditions produce very smooth surfaces but also result in low energy efficiency with high forces, high power consumption and a high probability of workpiece damage, while coarse dressing conditions have the opposite effects. While the effects of wheel conditioning have been studied indirectly by measuring the workpiece surface roughness, grinding power, forces and temperatures, the link between the wheel surface topography and these outcomes has not been adequately quantified because a technology does not exist that can completely and accurately define all of the cutting edges on a grinding wheel. Thus, the first objective of the proposed research is to develop a measuring system that, for the first time, can completely map the entire surface of an industrial sized grinding wheel. This information will be used to improve the cost effectiveness and productivity of the grinding process in the same way that learning how tool geometry affects turning and milling has benefited those manufacturing processes. Next, a novel and inexpensive wheel conditioning technology called wheel grooving will be developed that can alter the surface of a grinding wheel in a selective manner and produce the desired surface roughness using less energy with higher material removal rates.