Clarification of Grinding Crack Mechanism

摘要

The importance of improving vehicle performance necessitates constant increases in the accuracy and strength of shafts such as the crankshaft, which is a key part of the engine. Grinding is used as a finish method for bearings and other parts where the required accuracy is particularly high, but a crucial issue in this process is solving quality problems caused by so-called grinding cracks. Conventional wisdom states that the most important factors in grinding cracks are surplus grinding heat generated at the grinding point and the cooling that occurs when coolant is applied, but no general solutions have been formulated. This article describes how the temperature generated during grinding on a high-speed cylindrical grinding machine was measured successfully, thereby enabling the grinding crack mechanism to be demonstrated quantitatively. As a result, the necessary conditions for ensuring that no cracks are generated have been defined, regardless of variations in material composition or process location, making it possible to develop more efficient methods of grinding.