Vibration Analysis of High-Precision Machine Tools Mounted on a Passive Vibration Isolation Table

Passive vibration isolation tables have been widely used to reduce the vibration of precision machine tools. However, because vibration isolators have low stiffness, vibrations are easily caused by the counter forces due to the feed motion of the machine tool. The vibration leads to the relative displacement between the tool and the workpiece that occurs in the perpendicular direction to the feed direction. This vibration is called cross talk vibration. This paper describes the analysis of the cross talk vibration by using the dynamic model of a machine tool and a vibration isolation table. First, the mechanism of the cross talk vibration is investigated by the multi-body simulation. Then, dynamic models are constructed from the multi-body simulation model by extracting a dominant structural mode of the machine tool. The analysis with the dynamic model shows that the amplitude of the cross talk vibration is in inverse proportion to the stiffness of the machine structure. The columns of the machine tool are modified to reduce the cross talk vibration. The amplitude of the vibration is reduced to approximately 1/4 as expected from the dynamic model.