Cutting tool

Abstract

The present disclosure relates to cutting tools and cutting inserts in general, and more particularly to the specific shapes of cutting edges on cutting tools and cutting inserts. In an embodiment, a cutting tool with a cutting edge formed as a sinusoidal curve is provided. In an embodiment, a rotary drill bit including a cutting insert comprising a sinusoidal curve is provided.

1 . A cutting insert comprising: a pair of cutting webs inclined relative to each other so as to converge at a point region; each cutting web including an inner cutting edge, an outer cutting edge and a transition point disposed between the inner and outer cutting edges; wherein the inner cutting edge extends from the point region to the transition point and has a sinusoidal configuration described by y=sin(2*π*x+π), with x describing an x coordinate on an x axis, y describing a y coordinate on a y axis that is perpendicular to the x axis, the point (0,0) defined as the point region, and the point (z,0) defined as the transition point, where z is at least 0.5 or greater. 
     
     
         2 . The cutting insert of  claim 1 , wherein z is no more than 1.5. 
     
     
         3 . The cutting insert of  claim 1 , wherein the cutting insert has a diameter and each inner cutting edge has an inner cutting edge length that extends from the point region to the transition point, and the inner cutting edge length is less than 0.49 times the diameter. 
     
     
         4 . The cutting insert of  claim 1 , wherein the sinusoidal configuration of each inner cutting edge has an amplitude of no more than 0.5 millimeters. 
     
     
         5 . The cutting insert of  claim 1 , wherein each outer cutting edge has an outer slope at the transition point, each inner cutting edge has an inner slope at the transition point, and the outer slope is equivalent to the inner slope. 
     
     
         6 . The cutting insert of  claim 1 , wherein each inner cutting edge has a positive rake. 
     
     
         7 . The cutting insert of  claim 1 , wherein each outer cutting edge has a positive rake. 
     
     
         8 . A cutting tool assembly comprising: a drill body having a rotational axis extending longitudinally through a forward end and a rear end, wherein the rear end is configured to be secured to a machine and the forward end comprises a slot; and the cutting insert of  claim 1  disposed in the slot. 
     
     
         9 . The cutting insert of  claim 1 , further comprising a notch having a first face, a curved second face and a curved valley, the curved valley connecting the first face and the second face, wherein the first face is bounded by the curved valley and the inner cutting edge. 
     
     
         10 . The cutting insert of  claim 10 , further comprising a chisel defined by the first face, the valley, the second face and the inner cutting edge of each of the cutting webs converging to the point region. 
     
     
         11 . The cutting insert of  claim 1 , wherein the cutting insert has a diameter and each inner cutting edge has an inner cutting edge length that extends from the point region to the transition point, and the inner cutting edge length is less than 0.249 times the diameter.