Improvement of the vibro-acoustic behaviour of vibratory feeders for pasta by modelling and experimental techniques

The competitiveness of the global markets and the restrictive rules on vibro-acoustical emissions have led to design machines that combine high performances and low noise level. Therefore, reduction of vibration and noise in mechanical systems is pivotal. In this scenario, this paper addresses the vibro-acoustical improvement of a pre-drying vibratory feeder for pasta by means of experimental and numerical vibration analysis. The moving parts of the feeder is coupled with the structural base by means leaf springs and the swinging motion is achieved by an eccentric-and-rod mechanism driven by an asynchronous engine. The oscillating motion leads to unacceptable vibrations that induce high noise levels and structural failures. Operational vibrations was measured as well as torsional oscillations of the main shaft by means of laser probe and zebra tape. Furthermore, an experimental modal analysis of key components of the feeder has been carried out. In order to foresee the effects of design changes, an analytical dynamic model has been developed and validated by experimental measurements. Exploiting the experimental and simulation results, several modifications have been carried out for vibration reduction. The vibration level of the system has been significantly reduced and the effectiveness of improvements has been experimentally verified.