Investigation of low-frequency chatter during machining with ball end mills

In this study the investigations of low-frequency oscillations of technological system during machining with ball-end mill of inclined surface were made. An influence of non-linear components of cutting process on change of dynamic state of the system was analyzed. An influence of low-frequency chatter at the beginning of the cutting process on technological system transition to steady state of oscillations with frequencies close to the natural frequency was shown. Explanation of mechanics of transition process from one state to another was proposed. Multiple-factor experiments that included inclined surface machining with different values of spindle speed, allowance, direction of feed motion (upward and downward), cutting patterns (conventional and climb) were carried out. Analysis of experimental research showed that downward conventional machining process loses dynamic stability with cutting conditions, for which upward climb machining stays dynamic stable.