Papers by Keyword: Grinding Cracks

Abstract: The high efficiency deep grinding is widely used in manufacturing. The experiments were carried out to study on the high speed deep grinding force and grinding burn and cracks in grinding 40Cr steel specimen with Al₂O₃ wheel. The experimental studies demonstrate that the grinding force increases with the grinding layer depth. The trail of grinding on space surface is blurred progressively, the surface topography deteriorates gradually. When the depth of grinding increases to the certain value, grinding burn appears, and micro-cracks emerge. Selecting the optimization parameter in high speed deep grinding can avoid the grinding burn and grinding cracks.

Abstract: Grinding may create flaws that control strength and limit the performance of finished ceramics. Machining cracks sometimes have been difficult or impossible to find especially in toughened ceramics with interlocking grain microstructures that create rough fracture surfaces. Our fractographic examinations show that machining damage leaves telltale markings on fracture surfaces that may be easily detected using common fractographic techniques. A comprehensive study with over 400 ground rods and rectangular bars was conducted on several commercial silicon nitrides to study the effects of various machining conditions. Similarities and differences in behavior were observed. A paradoxical finding was that tougher silicon nitrides developed deeper grinding cracks. Machining crack size and shape strongly depended on the grinding wheel grit size.