Chip structure classification based on mechanics of its formation

Understanding chip formation is the first step to good chip control, a necessity for automated machining. Such understanding results in the prediction of chip breakability for a wide range of machining conditions. This paper presents a generalized model of chip formation in metal cutting. The mechanical properties of the workpiece are of prime concern. A new classification of chip structure is proposed, according to which classification, seven different chip structures are distinguished, namely: the regular broken chip, the irregular broken chip, the continuous fragmentary chip, the continuous fragmentary chip with a wedge-shaped texture, the continuous chip, the continuous hump-back chip, and the fragmentary hump-back chip. Unlike the known classifications which often have a post-process nature, the proposed classification considers the chip structure, the chip stress and strains as the results of chip-formation dynamics. The methodology presented in this paper provides a new and viable means to predict chip breakability. The results of this study give clear ideas to the tool designer, technologist, or even to the foreman, as to what kind of chip-breaking should be used for a given set of machining conditions. (C) 1997 Elsevier Science S.A.