Relief-face friction in vibration tapping

One of the key problems in the tapping process for difficult-to-cut materials such as titanium alloys is that the relief-face friction of the tap is very large. In this paper, the vibration tapping process, in which the spring-back of the machined surface can be removed, has been analyzed with elasto-plasticity. Thus the reason why vibration tapping can reduce the tapping torque has been explained qualitatively, and a theoretical basis for choosing reasonable values for the cutting parameters for vibration tapping has been provided. The theoretical analysis shows good agreement with the experimental results obtained when tapping a titanium alloy.