Kennametal Beyond MR geometry smoothes stainless steel turning issues

Double-sided indexable inserts commonly feature four cutting edges per side with cutting edges facing away from each other. A chip step consisting of an inlet region and an outlet region usually separates each cutting edge. Kennametal, explaining the reasoning behind the Beyond MR design, points out that while these chip steps help to control chip flow and cutting action, the common fluted design of incremental inlet and outlet regions tends to be an area of concentrated stresses during cutting, shortening tool life. In Beyond MR the chip step geometry is designed in a continuous curve so that alternating stresses are reduced. The radius of curvature of the chip step surface is initially very large, becoming appreciably smaller, constituting the inlet region of the chip step. From the lowest point of the chip step, the small radius of curvature grows larger, constituting the outlet region. As the surface of the chip step always has a curve, uniform chip forming occurs. Chips tend to deform continuously within the chip step, minimising the chip on tool face friction. Rake angle, the incline of the top surface of the cutting edge that makes contact with the chip, also helps control the degree of cutting forces and cutting edge strength. The Beyond MR insert has a high positive rake angle that works with the smoothly curved cutting edge to reduce cutting forces and extend tool life. Beyond MR's rake profile without points of load concentration also provides stability even in high depth-of-cut applications. Additionally, formed-in channels deliver flood coolant to the cutting edge for cooler, smoother cutting. Beyond MR is available in six grades to cover all stainless turning applications. Grades are also available for steels and cast irons.