Modelling and experimental analysis of surface roughness in spherical grinding

A new method for predicting the surface roughness in spherical grinding was developed. Spherical grinding typically uses a cup grinding wheel containing segmented abrasive blocks that continually engage the surface of the sphere workpiece during grinding. In this study, the trajectory of the abrasive grain, undeformed chip thickness, and the grinding mechanism are considered separate from the surface grinding process. Therefore, the traditional method used to determine surface roughness based on surface grinding cannot be applied to predict the surface roughness in spherical grinding. A new analytical spherical surface roughness model was developed based on chip thickness, and the effect of overlapping of triangle grooves produced by multiple abrasive grains was considered to improve the precision of the roughness model. The process parameters that affect spherical surface roughness are theoretically analysed and experimentally studied. Comparison of the experimental results with the predicted results derived from the developed roughness model validates the proposed model and demonstrates the effects of the fundamental factors on surface roughness in spherical grinding.