Shank drill

Abstract

A shank cutter has plural circumferential cutting edges which run in a helical manner in the region of its cutting section and of which at least one critical number are equipped in each case with a preferably essentially flattened roughing profile with chip-separating grooves with rounded bases, so that the chip-separating grooves of cutter ridges which are adjacent in the circumferential direction are axially offset relative to each other. To create a tool which provides long service life by combined advantages of a vibration-stabilized finishing cutter and a conventional roughing cutter, at least one circumferential cutting edge has an angle of twist which differs from that of another circumferential cutting edge. In addition, the chip-separating grooves of the circumferential cuffing edges which are equipped with a roughing profile in each case merge into a preferably essentially flattened central section of the roughing profile by means of a predefined flank radius.

1 . Shank cutter, which has a plurality of circumferential cutting edges which run in a helical manner in the region of a cutting section of the shank cutter and of which at least one critical number are equipped in each case with a roughing profile with chip-separating grooves with rounded bases, in such a manner that the chip-separating grooves of cutter ridges which are adjacent in the circumferential direction are axially offset with respect to each other, wherein at least one circumferential cutting edge has an angle of twist which differs from the angle of twist of another circumferential cutting edge, and that the chip-separating grooves in each case merge into a central section of the roughing profile by means of a predefined flank radius. 
   
   
       2 . A shank cutter according to  claim 1 , wherein the angles of twist of adjacent circumferential cutting edges are different. 
   
   
       3 . A shank cutter according to  claim 1 , wherein there are an even number of circumferential cutting edges, of which in each case two lie diametrically opposite each other and have the same angle of twist. 
   
   
       4 . A shank cutter according to  claim 1 , wherein the pitch of the cutter is equal in a radial plane which lies in the region of the cutting section. 
   
   
       5 . A shank cutter according to  claim 1 , wherein the angles of twist of the circumferential cutting edges differ by 1° to 6°. 
   
   
       6 . A shank cutter according to  claim 1 , wherein the flank radius lies in the range from 0.1 to 1.0 mm. 
   
   
       7 . A shank cutter according to  claim 1 , wherein the flank radius which in each case faces away from the cutter shank is smaller than the other flank radius of the chip-separating groove. 
   
   
       8 . A shank cutter according to  claim 1 , wherein the chip-separating grooves are angled towards a plane, which is perpendicular to a longitudinal axis of the shank cutter, of the shank cutter. 
   
   
       9 . A shank cutter according to  claim 8 , wherein the chip-separating grooves in each case follow in sections the course of a helix, the lead of which corresponds to the pitch of the roughing profile which is formed with the chip-separating groove. 
   
   
       10 . A shank cutter according to  claim 1 , wherein the chip-separating grooves are parallel with a plane, which is perpendicular to a longitudinal axis of the shank cutter, of the shank cutter. 
   
   
       11 . A shank cutter according to  claim 10 , wherein the chip-separating grooves of cutter ridges which are adjacent in the circumferential direction are axially offset with respect to each other by the dimension V, where:
     V=T/n      
     and T means the pitch of the roughing profile which is formed by the chip-separating grooves and n means the number of circumferential cutting edges. 
   
   
       12 . A shank cutter according to  claim 1 , wherein the flank radius is smaller than the smallest radius in the base of the rounded chip-separating grooves. 
   
   
       13 . A shank cutter according to  claim 1 , wherein the angles of twist are between 20 and 55°. 
   
   
       14 . A shank cutter according to  claim 1 , it wherein the shank cutter consists of a hard material, at least in the region of the cutting section. 
   
   
       15 . A shank cutter according to  claim 1 , it wherein the shank cutter is provided with a coating, at least in the region of the cutting section. 
   
   
       16 . A shank cutter according to  claim 1 , wherein the geometry of the roughing profile of the central section and/or the ratio of the pitch to the depth of the chip-separating groove is selected as a function of the physical properties of the material to be chipped. 
   
   
       17 . A shank cutter according to  claim 1 , wherein the roughing profile is essentially identical in all the sectional planes which contain a longitudinal axis of the shank cutter. 
   
   
       18 . A shank cutter according to  claim 1 , wherein the central section which lies between the chip-separating grooves has a convexly curved surface. 
   
   
       19 . A shank cutter according to  claim 18 , wherein the radius of curvature of the central section is essentially greater than the flank radius. 
   
   
       20 . Use of a shank cutter according to  claim 1  for chipping with large cutting widths, in particular for cutting flanks, grooves, diagonal drill holes or spiral shapes.