Patent ID: 6213691
Filing Date: 2001-04-10
Classification: B23B,B23C,Y10T

Abstract:
A circular drill cutter for producing pockets, elongate slotted holes, through-bores in a solid material with a possibility of relief milling and rearward counterbohring, reaming of already produced openings, wherein the cutter is rotatably driven on CNC-controlled machine-tool and is displaced along a path with a continuous feeding along a Z-axis or, during formation of large pockets and during copy milling, is driven without being fed along the Z-axis, the circular drill cutter comprising a plurality of indexable bits; and a plurality of bit seats for supporting the bits,wherein each indexable bit (1) has three identical cutting engagement regions (2,3,4) offset relative to each other by 120.degree., each cutting engagement region including a main face cutting edge having a short straight main face cutting edge (5), a finishing cutting edge (7), and a circular connection cutting edge (23) extending between the main face cutting edge (6) and the finishing cutting edge (7),wherein the indexable bit (1) has a plurality of cross-cutting edges (11) extending, respectively, between the finishing cutting edges of respective cutting engagement regions and adjacent cutting engagement regions and formed as countersunk cutting edges,wherein the indexable bit (1) has an offset circumferential surface (13) spaced a different distance from a bit circumference and including three contact surfaces (15a, 15b, 15c) associated with the three cutting engagement regions (2, 3, 4), respectively, two respective contact surfaces (15a, 15b) of two adjacent cutting regions (3, 4) being aligned with each other along a straight line (33), andwherein a bit seat (225) has three contact surfaces (13a, 13b, 13c) corresponding to the three contact surfaces (15a, 15b, 15c) of the indexable bit (1) and projecting from a milled surface (16) of the bit seat (25), the bit seat (25), the bit seat (25) being displaced by a negative radial angle (17) and pivoted by a negative axial angle (26a).