Slip-line solutions for orthogonal machining with a step-type chip breaker and experimental validation of cutting parameters

Slip-line field models for orthogonal cutting with step -type chip breaker assuming adhesion friction at chip -tool interface are developed using those proposed by Dewhurst and Kudo. The analytical results predict that with decrease in distance of chip breaker from the cutting edge of the tool, the breaking strain increases. The variation of radius of curvature of chip, cutting ratio, cutting and thrust forces with position of chip breaker for a constant height of chip breaker is studied by conducting orthogonal turning tests on mild steel bar of 40 mm diameter, using a HSS tool. It is found that radius of curvature of chip, cutting ratio, cutting and thrust forces decrease with decrease in distance of the chip breaker from the cutting edge of the tool. For higher feeds, the calculated results from Dewhurst's field are found to be in good agreement with experimental observations, whereas the same is found to be true for Kudo's first field for lower feeds.