Analysis of motion between rolling die and workpiece in thread rolling process with round dies

Abstract

Exploring the motion characteristics in thread rolling process under varied center distance between rotation axes of workpiece and rolling die is important for accuracy evaluation and process control, and provides a basis for further study on motion compatibility condition in the thread and spline synchronous rolling process. The motion characteristics between the die and workpiece under varied center distance in the thread rolling process were investigated. Related mathematical models in the rolling process, such as the rotation angle and the angular velocity for workpiece, the transmission ratio, and the axodes of workpiece and die, were established. The results indicated that: (1) the relationship between rotation angle of workpiece and rolling time is approximately linearly dependent, transmission ratio almost presents the same change as angular velocity of workpiece; (2) the cross sections of the axodes of workpiece and rolling die are similar to Archimedes line, where the polar radius reduces with the reduction of center distance; (3) however, the changes of the angular velocity of workpiece, the transmission ratio, and the axodes are closely related to the shape of tooth profile.