JPS6434607A - Rotary knife - Google Patents

Abstract

PURPOSE:To maintain the good cutting quality of a cutting edge without any contact between the radial external face of the cutting edge and a workpiece, and without any re-polishing of the cutting edge by forming a recess open to a radial external side from the cutting edge of each cutter tip to the rear side thereof in the direction of chip thickness. CONSTITUTION:A chip 6 is brazed to a notch part 5 formed at the cutout part 2 of a plate 1, the external surface 7 of the chip 6 is formed to have a slope projected by an angle gamma with the tangential direction l of the external surface of the plate 1 and a corner part at the front 8 of the chip 6 in a rotational direction is polished, thereby forming a cutting edge 9. A V-shape recess 10 open to the external surface 7 is formed at a position backward of the cutting edge 9 in the rotational direction thereof, extending over the thickness of the chip 6. When the external surface 7 of the chip 6 wears and the cutting edge 6 becomes blunt due to cutting process, the external surface 7 nears a workpiece but the wear reaches the recess 10 before the external surface 7 comes in contact with the workpiece. As a result, the cutting edge 9 continues to maintain the cutting effect thereof and the cutting quality is maintained until the corner part of the back face of the recess 10 and the external surface 7 come in contact with the workpiece.