Chip Breaker Design, Theory and Practice: Machining with a Step-type Chip Breaker

The present tendency towards machining at high cutting speeds has increased the demand on the use of chip breakers and it has become necessary to ascertain in advance how a chip breaker will perform under a given set up machining conditions. This has initiated a number of studies on the mechanism of chip breaking in machining with both obstruction and groove type chip breakers and has prompted researchers to formulate different breakability criteria which can be used to evaluate the performance of these devices. The present text analyses the problem of chip breaking while machining with a step-type chip breaker using the rigid-plastic slip line field theory. An Attempt has been made to identify the parameters contributing to chip breaking and to study the validity of the different breakability criteria through orthogonal cutting tests. Shear strains in the primary and the secondary deformation zones are estimated and a method is suggested for chip breaker design from the bending strain in chips. The analysis and the accompanying experimental results will no doubt be of value to professionals engaged in metal cutting research