Vibration and Noise Reduction of C-Frame Turret Punch Press by Applying Turret as Impact Mass Damper.

Abstract

We applied a set of turrets, which are used for providing punches and dies, to a damper for a C-frame turret punch press to reduce the vibration and noise. The upper-and lower-turret dampers have same characteristics as an impact mass damper. The damping characteristics can be changed by adjusting the preload. Those can effectively reduce the noise and the vibration although the contact area between the damper and the frame is small. In a wide frequency range, the effect of the sound pressure level reduction is the same for either one turret or a set of trurrets. In the lower frequency range, however, the set of the turret dampers can reduce the sound pressure level more effectively than one turret damper. As a result, the amplitude of the first tuning vibration, which is a natural vibration mode of C-type structures, is reduced up to 1/9 of the original structure, and the reduction in the sound pressure level is over 6dB. Furthermore, the complex structure of the turret damper and the double wall eliminates the first tuning vibration, and is estimated to reduce the sound pressure level in the actual punching by about 11dB.