Characterization of vibratory finishing using the Almen system

Abstract

The Almen system was adapted to a vibratory finishing process to characterize the effect of varying process parameters for the purposes of process development and control. Saturation curves for two types of aluminum Almen strips were obtained by finishing at two distinct conditions using a tub type vibratory finisher and steel spherical media. Comparison with the normal contact forces and effective impact velocities, measured for both these conditions in a previous study [D. Ciampini, M. Papini, J.K. Spelt, Impact velocity measurement of media in a vibratory finisher, J. Mater. Process. Technol., 183 (2007) 347–357], provided insight into the mechanics of the vibratory finishing process. An electromagnetic apparatus was constructed to simulate the normal impacts in the vibratory finisher. It was found that surface-normal impacts at velocities comparable to the higher range in the vibratory finisher produced Almen saturation curves similar to those created in the vibratory finisher. This provided support for the modeling approximation of treating all contact events in a vibratory finisher as effective surface-normal impacts, and the accuracy of the effective impact velocity measurement employed in [D. Ciampini, M. Papini, J.K. Spelt, Impact velocity measurement of media in a vibratory finisher, J. Mater. Process. Technol., 183 (2007) 347–357].