PURPOSE: To extend maintenance of accuracy of twisting remarkably in manufacture of chip by extruding a flat chip while heating it using ceramics excellent in heat resistance for a twist forming die.
CONSTITUTION: For instance, a twisted chip for a built-up end mill having twist of 30° is manufactured in following process. a flat chip, 40×30×50mm, made of sintered hard alloy is put in a linear groove 2 of a twist foming die 1 made by forming Si3N4 group ceramics by slip cast process, and pressed by a punch 4 to a twist groove 3. A zone in which the chip is plastic deformed profiling the groove 3 is heated by a high frequency coil 5 to a temperature at which the chip material obtain sufficient deformability. Consequently, by using ceramics excellent in heat resistance for a twist forming die, the wear of the die can be reduced remarkably, and the maintenance of accuracy of twist can be improved remarkably compared with conventional method that uses a carbon die.
HARA HISAO
TAKAHASHI NORIO
KONYA YASUO
NIHON KOUGU SEISAKUSHO KK
Next Patent: PLASTIC WORKING METHOD OF DISTORTED PLATE BY FREE DISTORTION