Analysis of natural resting aspects of parts in a vibratory bowl feeder ? Validation of ?drop test?

Abstract

This paper seeks to verify that the existing hypotheses, which predict the natural resting aspects of small engineering parts on soft and hard surfaces, are able to predict the orientation of parts on the track of a vibratory bowl at different vibrating amplitude levels. Most of the existing hypotheses developed were verified using the “drop test” method in which parts were repeatedly dropped from a certain height onto a surface in order to analyse the natural resting behaviour of parts. This paper describes an attempt to conduct accurate experiments in the laboratory to examine the probabilities of the feed orientation of square and rectangular components of different aspect ratios by varying the vibration amplitude levels and surface textures of the vibratory bowl. The experimental results were compared with the predictions of the hypotheses postulated first by Ngoi, Lye and Chen [1], secondly by Boothroyd [2] and thirdly by Ngoi, Lim and Lee [3]. The experimental results were found to agree well with those predicted by the hypotheses. Moreover, it is also observed that the vibrating amplitude of the vibratory bowl does not significantly affect the orientation of the parts.