Study on movement forming methods for the machining of elliptic-shaped holes

Abstract

The movement forming methods for the machining of elliptic-shaped holes are presented. These methods can make the tool nose orbit, which is the synthesis of revolution of the hydrostatic shaft center around bearing center and rotation of the tool nose around shaft center, become an ellipse. Thus, the machining of elliptical holes can be achieved. Necessary conditions and sufficient conditions for forming elliptic tool nose orbit, under the condition that multiple shaft center orbits and the tool nose’s rotation orbit take synchronous forward synthesis and synchronous backward synthesis, are studied. The influence of initial phase angle of the tool nose on the formation of elliptic tool nose orbit has also been investigated. Characteristics and control equations of elliptic tool nose orbit under the conditions of multiple shaft center orbits and different initial phase angles of the tool nose are given. These studies will lay a theoretical foundation for the realization of the movement forming methods. Traditional machining methods for elliptic-shaped holes require auxiliary feed mechanism installed on the machine tool, and machining efficiency is limited by the frequency response characteristic of the servo bar. The forming methods presented in this article can overcome these shortcomings and provide a new approach for precision machining of elliptic-shaped holes.