PURPOSE: To provide a throwaway tip for a front face milling cutter of a cutting angle of 90° which is high in edge strength and economical by using four corners not receiving limitation of a cutting amount.
CONSTITUTION: On acute-angled corner parts of an upper surface 11 of a parallelogram as its fundamental shape, auxiliary cutting blades 15 connected to a main cutting blade 14 out of a parallelogramic frame at a roughly 90° corner angle to the main cutting blade 14 are formed in point symmetry with the center of the surface. Additionally, the bottom surface is made in the same shape and measurement as the upper surface and the upper surface is reversed by 180° and additionally, the bottom surface is turned to be in a position rotated by 3° to 7° around the surface center as its fulcrum against the upper surface. Consequently, it is possible to form two pieces each of cutting blade corners on the upper and bottom surfaces, that is four pieces in total of the cutting blade corners which are high in blade point strength and sharp.
MORI YOSHIKATSU
MAEDA YOSHIKI
YANAI SHIGETO
