Rounding Process of Workpiece in Through-Feed Centerless Grinding with Large Grinding Allowance

摘要

This paper deals with the computer simulation and experimental investigation of the workpiece rounding process in through-feed centerless grinding with large grinding allowance. In a through-feed centerless grinding operation, when the grinding allowance is extremely large compared with common occasions, the geometrical support conditions for workpiece such as center height will change significantly during grinding. This results in the complication of the workpiece rounding process and embarrasses the operator setting-up the optimum conditions. In order to assist the operator in setting-up the conditions efficiently, the proposal of a way to predict the final profile of workpiece and its roundness is meaningful. For this purpose, a computer simulation method is proposed and actual experiments ware conducted to verify the method. The obtained results showed that (1) The center height of workpiece decreases linearly with grinding time, leading to the linear reduction in workpiece diameter during grinding operation with a larger grinding allowance; (2) The grinding allowance depends on the tilt angle of blade top face, meaning the grinding allowance can be determined by using a blade with the appropriate tilt of top face; (3) During grinding, larger irregularities on workpiece circumference become smaller along with the occurrence of small irregularities, resulting in the eventual improvement in workpiece roundness; (4) The workpiece profile formed and the resultant roundness greatly depends on the difference between the center height angles at the entrance and the exit. When the difference is kept constant, the center height affects significantly the final roundness; the optimum roundness is obtained when letting the average value of the center height angle be around 6.5°.