Effects of Tool Edge Shapes on Dynamics of the Metal Cutting Process

The present paper deals with an experimental study of the effects of land shapes and clearance angles on dyamics of the metal cutting process from the view point of chatter control. The dynamics of the metal cutting process is expressed by a stiffness vector of the process, which can be obtained by subtracting the stiffness vector of the structure measured when out of cutting from that measured during cutting. In order to measure those vectors a transfer function analyser and an electromagnetic exciter are used. The measurement of the stiffness vectors during cutting are executed on condition that the tool is excited harmonically in the direction of the thrust force during orthogonally cutting and the regenerative and mode coupling effects are excluded. Chatter control effects are evaluated by the amount of energy expended at the cutting process in a cycle of vibration. Experimental results show that chatter control effects of lands are very large comparing with those of small clearance angles. It is found also that degree of the effects of land shapes solely depend upon the length of the land projected onto the mean cutting direction when the other conditions are retained.