Self-induced vibration of bandsaw blades during cutting

Abstract

A new interpretation of the washboarding phenomenon found in bandsawing of wood is given in this paper. A theoretical model of the washboarding pattern was derived by considering the motion of the teeth during cutting. The theory of machine tool chatter was adapted to illustrate the mechanism of self-induced vibration in bandsawing and to provide a criterion for its existence. It was found that the whole cutting span of the band should be used to determine the vibration characteristics instead of the previous practice of using the section between the workpiece and the top wheel. It has been found that the frequencies responsible for washboarding are all torsional frequencies and physical explanation for this is suggested by considering the squeeze film damping effect of the air gaps between the blade and the sawn surfaces.