Stability prediction in straight turning of a flexible workpiece by collocation method

Chatter vibrations produced during turning of slender parts or boring with flexible tools lead to a wavy work surface, and reduce the spindle headstock life span as well. This study deals with the problem of chatter prediction in straight turning of non-rigid parts, making use of round inserts. A stability model for straight turning has been developed using the Chebyshev collocation method for the first. This algorithm allows the introduction of an accurate round insert edge geometry, discretising the lead position angle and the variable cutting coefficients of the forces model along the edge. The method is applied to a SDOF system by means of a specially designed testpart and demonstrates its usefulness to determine chatter-free conditions.

▶ Stability prediction of straight turning of flexible workpiece with round inserts. ▶ Development of a 1 DOF model to predict chatter due to the radial displacements of the workpiece. ▶ The method considers variable cutting coefficients and variable lead angle along the tool cutting edge. ▶ A testpart has been specially designed for model verification. ▶ The comparisons between experimental results and simulations prove the accuracy of the model.