Optimization of variable helix cutter for improving chatter stability

Abstract

Chatter during machining process causes tool wear, poor surface finish, limited metal removal rate, and limited productivity. Variable pitch/helix cutters can avoid the occurrence of regenerative chatter by disturbing the phase of vibration between adjacent teeth. However, if the pitch and helix angles are not properly selected, then the stability may be worse than that of a regular cutter. In this study, a stability model of variable helix milling is established, and a simple and effective optimization method is proposed. An index called “suppression factor” is proposed to measure stability quantitatively. In a given cutting parameter area, the best combination of pitch and helix angles improves the absolute stability of the variable helix cutter. The optimal variable helix cutter is customized. The correctness of the stability model and the effectiveness of the optimization method are verified by comparison experiments.