Abstract

The impact of plastic scraps against the inside walls of plastic shredders results in high noise levels and constitutes a significant occupational hazard.

A model of the propagation of noise generated by impacts against a flat surface was developed and used to effect source reduction of noise emitted by plastic shredders.

Through modelling and experimentation, the initial solution was optimized, resulting in a 8 dB (A) reduction in noise. Because this solution involves the modification of the inside walls of the shredder, it is inexpensive and compatible with other aspects of production. It may therefore be easily implemented throughout the plastics transformation and fabrication sector, in which 3 000 shredders are estimated to be in operation. The scientific and technical foundation which this project provided will facilitate studies of impact noise in other sectors.