Drill bit and method for grinding a drill bit
AssigneeKennametal Inc.
InventorsBernhard Borschert, Dieter Mühlfriedel
Life of this patent
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Abstract
The invention relates to a drill bit (2), having main cutting edges (4a, 4b) which are connected together by a transversal cutting edge (6). An open surface (7) which extends into a flute (8) lies adjacent to each main cutting edge. The drill bit (2) is ground, in particular, during a continuous three-dimensional grinding process in such a way that the open surface (7) forms a continuous curved surface which follows a radius of curvature (R) running from the main cutting edge (4a) in the direction of the flute (8). The continuous grinding process, in comparison to a conventional two-stage process, produces an improved drill bit geometry which is devoid of ridges (16). The ridge-free configuration reduces the mechanical stress during drilling to a minimum.
Claims20
Drill bit (2), having two major cutting edges (4a, 4b) joined together via a chisel edge (6), adjacent to each of which is a clearance face (7) that transitions into a flute (8), characterized by the fact that the clearance face (7) is realized in the form of a surface with a radius of curvature (R) that is curved without ridges from the major cutting edge (4a, 4b) toward the flute (8).
Method for grinding of a drill bit (2) that has two major cutting edges (4a, 4b) connected via a chisel ridge (6), adjacent to each of which is a clearance face (7) that transitions into a flute (8), characterized by the fact that a grinding wheel (20) and the drill bit (2) are brought together in a continuous grinding process, the grinding wheel being moved to form a clearance face (7) in the form of a surface that has a radius of curvature (R) curved from the major cutting edge (4a, 4b) in the direction toward flute (8).
Dependencies are inferred from the claim text.