Technique for online controlling the cutting process stability

Abstract

Nowadays techniques for online controlling the cutting process stability are based on the use of a sensor, in order to identify the occurrence of self-excited relative vibration between tool and part. A disadvantage of these techniques is that dynamic stability control system reacts only after passing over the stability limit, and the self-excited vibrations have already appeared. Hence, any reaction to the instability occurrence is delayed. This paper presents a novel technique for dynamic stability online control in cutting processes. According to it, the current operating point of the machining system is not only permanently brought into the stability domain, for maintaining the process stable, but also kept near the stability limit, for reaching the maximum level of productivity. The new technique has the following advantages:<b><span style="mso-bidi-font-family:Helvetica" lang="EN-GB"> </span></b>(i) provides to permanently use the entire processing capacity of the machining system, in optimal terms of dynamic stability; (ii) in the designing stage, allows to satisfy the specific requirements of both dedicated and flexible machining systems. The equipment required for implementing it can be designed as independent unit that can be attached to a machining system, or as integrated unit on a CNC machining system. The paper includes tests proving the possibility of applying the technique for turning processes stability control.