A METHODOLOGY FOR CHIP BREAKER DESIGN AT LOW FEED TURNING OF ALLOY STEEL USING FINITE ELEMENT MODELING METHODS

Thin chips produced in finish turning, facing and fine boring are very hard to be broken at low feeds because of their flexibility, and cause trouble in chip control. These long chips must be broken into small pieces for easy disposal and to protect the finished surface from coiling chips. In the present paper a methodology to design chip breaker geometry at a low feed of 0.1mm/rev has been discussed. 2D chip breaking criteria based on tensile strain available in literature has been used. Limiting or fracture strain for chip breakage of AISI 4140 Steel has been calculated from experiments. Design has been modified to induce strain in the chip greater than or equal to its fracture strain. Finite element modeling has been used to investigate the effect of V groove and Curved groove on fracture strain. Simulations were conducted at different front groove angles for both configurations of groove. Thirdwave Advantedge has been used for finite element modeling. Curved groove was found to be better than V-groove for chip control in the present study. The chip-tool contact length plays a major role in deciding the configuration of chip breaker. Experiments were conducted for the chip breaker design arrived out of simulations. Chip breakage and chip shape were found to be in good agreement with experiments. Results of this research help to guide the design of chip breaker geometries at low feeds to further enhance productivity in AISI 4140 steel.