Estimation of Sound Pressure Level in C-Frame Turret Punch Press Using a Scale Model.

Abstract

A method for estimation of the noise level of a C-frame turret punch press is proposed using the results of its scale model. Scale models are often used in the experimental analysis of noise since their structural design can be easily varied. However, the waveform of a punching force is more complex than that of an impulsive force from an impulse hammer, and the supporting exeiting conditions of the scale model are different from those of the actual machine. It is, therefore, difficult to directly apply the similarity law to the experimental results obtained using a scale model. In this study, various waveforms of punching force reported previously have been analyzed in the frequency domain and a method for simulation of the punching force using an impulse hammer has been investigated. The difference between the supporting and exciting conditions of the actual machine and those of its scale model has been analyzed by a finite element method. It is found that two kinds of impulse hammers are necessary for the simulation of the punching force, and that the volumetric acceleration of the scale model is necessary for the estimation of the sound pressure level of the actual machine.