Improvement strategy for machine tool vibration induced from the movement of a counterweight during machining process

The objective of this study is to propose and execute an improvement strategy for machine tool vibration induced from the movement of a counterweight balance system during the machining process. The elastic jump due to the effects of the inertia of a counterweight and of the potential energy released from the connected chain is investigated, firstly by using the dynamic analysis numerical software, Nastran, when the machine tool head makes a sudden stop during different motion types in the machining process. In turn, the vibration energy absorber, such as spring and damper, is assembled together in parallel manner, which is then connected to the counterweight in series, attempting to reduce the phenomenon of induced vibration to the utmost. The design and fabrication of a vibration reduction system for machine tool head during the machining process is performed based on the absorber parameters obtained from the simulation calculations. Milling experiment on aluminum alloy is undertaken in conjunction with various CNC cutting-path planning, such as moderate steps and vertical steps under different feed-rate cutting conditions. No concentric-strip-like waviness was detected on machined surface during the former cutting path. But such kinds of waviness marks left on the machined surface around the corner area between the subsequent steps are very obvious with the vertical-step path. This induced tool vibration phenomenon is remarkably improved through the strategies proposed and implemented in this study.