Contribution to cylindrical grinding of interrupted surfaces of hardened steel with medium grit wheel

Abstract

Grinding is generally the first choice to provide combination of both superior surface finish and closer dimensional tolerances in a machined component. This process can be employed in manufacturing of continuous and interrupted surfaces. Crankshafts and engine piston rings are examples of ground precision mechanical components having interrupted surfaces. However, the specific literature about grinding of interrupted surfaces is still scarce. In this context, aiming to further contribute to the understanding of the behavior of surface integrity of interrupted surfaces during grinding, this paper presents an experimental investigation of interrupted surfaces ground with white aluminum oxide grinding wheel. Discs of AISI 4340 hardened steel with different number of grooves (2, 6, and 12) on the external surface were tested. Experiments with discs without interrupted surface were also carried out for comparisons. In addition to the number of grooves, three values of infeed rate (0.25, 0.50, and 0.75 mm/min) were used as input parameters. The output parameters investigated were the geometric errors (surface roughness and roundness) of the workpiece material as well as the diametric wheel wear. Analysis of variance (ANOVA) test was performed to verify any statistical difference among the output variables. Results showed that both surface finish and roundness of workpieces with interrupted surfaces were higher than those obtained for continuous surface. These parameters also increased with infeed rate up to 0.50 mm/min, whereas the grinding wheel wear was more sensitive to number of grooves and infeed rate. No thermal damages were observed on the machined workpieces under the conditions investigated.

Research on selection of abrasive grain size and cutting parameters when grinding of interrupted surface using aluminum oxide grinding wheel with ceramic binder

“…The research of external cylindrical plunge grinding on interrupted surface of AISI 4340 steel has been carried out in a number of studies, using different types of grinding wheels, such as using aluminum oxide grinding wheel with pine resin binder [6], using aluminum oxide grinding wheel with epoxy resin binder [7], using aluminum oxide grinding wheel with vitrified binder [8], and using CBN grinding wheel [9]. The results of these studies together have made the following Engineering conclusions: (1) both surface roughness and roundness error in interrupted surface grinding are higher than those in continuous surface grinding; (2) when increasing plunge-feed rate, both surface roughness and roundness error increase; (3) both surface roughness and roundness error increase when the number of grooves in the workpiece increases; (4) grinding wheel wear also increases when increasing plunge-feed rate and when increasing number of grooves on the grinding wheel; (5) and no damage to the grinding surface due to the impact of cutting heat was observed.…”