Rotary dresser and method of manufacturing the same

Abstract

A rotary dresser has a super-abrasive grain layer including super-abrasive grains bonded in a single layer to a base metal by a plated layer, in which the super-abrasive grains include first super-abrasive grains having a first average grain diameter, and second super-abrasive grains having a second average grain diameter smaller than the first average grain diameter, a plurality of super-abrasive grains exposed at a surface of the super-abrasive grain layer among the first super-abrasive grains and the second super-abrasive grains have working surfaces formed thereon, and in a region with a highest degree of concentration of the super-abrasive grains, a ratio of a total area of the plurality of working surfaces to an area of an imaginary surface smoothly connecting the plurality of working surfaces is 30% or more and 60% or less.

1 . A rotary dresser having a super-abrasive grain layer including super-abrasive grains bonded in a single layer to a base metal by a metal binder, wherein
 the super-abrasive grains include first super-abrasive grains having a first average grain diameter, and second super-abrasive grains having a second average grain diameter smaller than the first average grain diameter,   a plurality of super-abrasive grains exposed at a surface of the super-abrasive grain layer among the first super-abrasive grains and the second super-abrasive grains have working surfaces formed thereon, and   in a region with a highest degree of concentration of the super-abrasive grains, a ratio of a total area of the plurality of working surfaces to an area of an imaginary surface smoothly connecting the working surfaces is 30% or more and 60% or less.   
     
     
         2 . The rotary dresser according to  claim 1 , wherein the second average grain diameter is 30% or more and 80% or less of the first average grain diameter. 
     
     
         3 . The rotary dresser according to  claim 1 , wherein a ratio of a maximum grain diameter to a minimum grain diameter of the first super-abrasive grains and the second super-abrasive grains (a maximum grain diameter D 1  of the first super-abrasive grains/a minimum grain diameter D 3  of the second super-abrasive grains) is 1.3 or more and 4 or less. 
     
     
         4 . The rotary dresser according to  claim 1 , wherein the first average grain diameter is 300 μm or more and 800 μm or less. 
     
     
         5 . The rotary dresser according to  claim 1 , wherein the super-abrasive grains are artificially synthesized diamonds. 
     
     
         6 . The rotary dresser according to  claim 1 , wherein when a cross section of the super-abrasive grain layer is viewed, an average value of distances between the respective first super-abrasive grains and the base metal is smaller than an average value of distances between the respective second super-abrasive grains and the base metal within a certain range. 
     
     
         7 . A method of manufacturing the rotary dresser according to  claim 1 , the method comprising:
 step (1) of making an inverse mold having a prescribed shape formed on an inner surface of the mold, and attaching the first and second super-abrasive grains to the inner surface by using a plating method;   step (2) of further performing overlay plating to embed and fix the first and second super-abrasive grains with a plated metal;   step (3) of setting a cored bar at a center of the inverse mold and joining the first and second super-abrasive grains and the cored bar to each other; and   step (4) of removing an outer inverse mold of the inverse mold.