The Application of Active Control to Improve Boring Bar Performance

Abstract

A previously established theoretical basis for controlling both the static stiffness as well as dynamic vibrations and regenerative chatter in particular was implemented in the work described by this paper. It was found that the experimental boring bar setup did exhibit two principal modes but that the controller could be synthesized largely independent of these modes. Cutting tests were performed using Delrin acetal plastic on a lathe equipped with a pivoted boring bar which was controlled by an electro-hydraulic servo system. It was found that the theory established earlier did in fact predict qualitatively the new stability borderline. Width of cut was improved by a factor of twelve and equivalent static stiffness was increased without bound.