PURPOSE: To extremely minimize and depress local deformation in the thickness direction of a film cutting end surface and to depress a high edge phenomenon by forming the tip of a round edge cutter into a first tip part at its and a second tip part following the first tip part and having an acuter tip angle than the tip angle of the first tip part.
CONSTITUTION: The tip 5 of a round tooth cutter 4 is inserted in a cutting edge receiving groove 3 located at the cutting position of a predetermined film 1 out of many cutting edge receiving grooves 3. The running film 1 is cut by means of the tip 5. The tip 5 of the round edge cutter 4 is formed into two-stage tips, a first tip part 5a at the tip top side, and a second tip part 5b formed by following the first tip part 5a. The tip angle θ2 of the second tip part 5b is set to an acuter tip angle than the tip angle θ1 of the first tip part 5a. Namely, the tip angle θ1 is within a range of 15-20 degrees. The tip angle θ2 is set within a range of 7-13 degrees. Thus cutting action is dramatically enhanced by minimizing and depressing local deformation in the thickness direction of the cutting end surface and by depressing a high edge phenomenon.
KOGA HIROSHI
TAKADA HIROYUKI
