Correlation between Idling Vibration of Machine Tool and Machining Chatter

Abstract

Mechanism of the machining chatter caused by the forced vibration on the machine tool is presented with the metal cutting test results. From the presently conceived theory of self-excited chatter, a theory of forced chatter has been derived. According to the theory, the amplification factor of the chatter amplitude to the amplitude of the idle time forced vibration is predicted from the dynamic characteristic of the machine structure, the cutting condition, and the frequency of the forced vibration. The result of turning tests performed with the forced vibration added by a magnetic exciter proves that the amplification factor varies according to the forcing frequency in the way as predicted by the theory. From the theory and the experiment of this study, it is understood that there exist some particular sets of conditions where very high amplification factors are attained although the ratio is not greater than unity except at these conditions. The forcing frequency above the resonance frequency but in the resonance range is particularly unfavorable due to the generation of the forced chatter.