Abstract
In the case of internal oscillation grinding of deep straight hole which is longer than a wheel width, a workpiece is finished in a taper shape because of a larger elastic deformation of wheel spindle in grinding process. In this paper, the controlled internal oscillation grinding technique for optimal form accuracy of a deep straight hole is developed, introducing retraction grinding method in which a grinding wheel head rapidly retracts a small amount against infeed direction at the beginning of spark-out grinding. Main conclusions obtained in this paper are as follows; (1) In internal grinding of a deep straight hole with retraction motion, the setting retraction amount is decided by the wheel spindle recovery which is almost in direct proportion to the retraction amount. (2) At the optimal retraction amount finishing a workpiece to a minimum taper error, the elastic deformation of wheel spindle just after retraction motion is constant decided by the grinding system even if the plunge speed or the speed ratio are different. (3) The optimal retraction amount is decided by subtracting the above own elastic deformation of wheel spindle from the elastic deformation of wheel spindle just before the beginning of spark-out grinding process without retraction motion.
