Dressing and manufacture of outer blade cutting wheel

Abstract

An outer blade cutting wheel ( 1 ) comprising a base and a blade section ( 11 ) of metal or alloy-bonded abrasive grains is dressed by clamping the cutting wheel between a pair of circular jigs ( 2 ) such that the blade section ( 11 ) projects beyond the jigs, immersing the cutting wheel in an electropolishing liquid, positioning counter electrodes ( 4, 5, 6 ) relative to the blade section, and effecting electropolishing for thereby removing part of the metal or alloy bond and chips received in chip pockets until abrasive grains are exposed on the blade section surface.

1 . A method for dressing an outer blade cutting wheel comprising a base in the form of an annular thin disc of cemented carbide having an outer periphery and a blade section formed on the outer periphery of the base, the blade section being an abrasive layer comprising abrasive grains and a metal or alloy for bonding the grains to each other and to the base, said method comprising the steps of:
 clamping the outer blade cutting wheel between a pair of circular jigs to hold the cutting wheel such that the opposed surfaces of the cutting wheel are covered over a predetermined range with the jigs and the blade section projects beyond the outer edge of the circular jigs,   immersing the cutting wheel clamped between the jigs in an electropolishing liquid in an electropolishing tank,   providing an electrode which is spaced apart from and encloses the outer circumference of the blade section and a pair of electrodes which are opposed to and spaced apart from the side surfaces of the blade section, as counter electrodes, and   conducting electricity between the cutting wheel and the counter electrodes for electrolytically dissolving away part of the metal or alloy between abrasive grains and chips received in chip pockets in the blade section surface until abrasive grains are partially raised from the blade section surface.   
     
     
         2 . The dressing method of  claim 1  wherein the counter electrodes include a cage electrode which is spaced apart from and encloses the outer circumference of the blade section and a pair of annular electrodes which are opposed to and spaced apart from the side surfaces of the blade section. 
     
     
         3 . The dressing method of  claim 1  wherein the abrasive grains in the blade section are diamond and/or CBN grains, and the metal or alloy for bonding the grains to each other and to the base is formed by electroplating or electroless plating. 
     
     
         4 . The dressing method of  claim 1  wherein of the metal or alloy for bonding the grains to each other and to the base, the bonding metal is selected from Ni and Cu, and the bonding alloy is selected from the group consisting of Ni—Fe, Ni—Mn, Ni—P, Ni—Co and Ni—Sn alloys. 
     
     
         5 . The dressing method of  claim 1  wherein the blade section further comprises a metal or alloy infiltrated into voids between abrasive grains or between abrasive grains and the base. 
     
     
         6 . The dressing method of  claim 5  wherein the infiltrating metal is Sn and/or Pb, and the infiltrating alloy is selected from the group consisting of Sn—Ag—Cu, Sn—Ag, Sn—Cu, Sn—Zn and Sn—Pb alloys and mixtures thereof. 
     
     
         7 . A method for manufacturing an outer blade cutting wheel comprising a base in the form of an annular thin disc of cemented carbide having an outer periphery and a blade section formed on the outer periphery of the base, said method comprising the steps of:
 effecting electroplating or electroless plating on the base having abrasive grains retained on its outer periphery in a plating bath, to deposit a metal or alloy for bonding the abrasive grains to each other and to the base, for thereby forming an abrasive layer composed of the abrasive grains and the metal or alloy, the abrasive layer constituting the blade section,   tailoring the protrusion, thickness and outer diameter of the abrasive layer by wire electrical discharge machining and/or a grinding wheel, and   dressing the cutting wheel by the method of  claim 1 , using the plating bath in the electroplating or electroless plating step as an electropolishing liquid, for thereby electrolytically dissolving away part of the metal or alloy between abrasive grains and chips received in chip pockets in the blade section surface until abrasive grains are partially raised from the blade section surface.   
     
     
         8 . The method of  claim 7  wherein the abrasive grains are diamond and/or CBN grains. 
     
     
         9 . The method of  claim 7  wherein of the metal or alloy for bonding the grains to each other and to the base, the bonding metal is selected from Ni and Cu, and the bonding alloy is selected from the group consisting of Ni—Fe, Ni—Mn, Ni—P, Ni—Co and Ni—Sn alloys. 
     
     
         10 . The method of  claim 7 , comprising, after the step of electroplating or electroless plating to form an abrasive layer composed of abrasive grains and the metal or alloy, the step of effecting further electroplating or electroless plating to form a plating cover for enhancing the bond strength between abrasive grains and between abrasive grains and the base. 
     
     
         11 . The method of  claim 7 , comprising, after the step of electroplating or electroless plating to form an abrasive layer composed of abrasive grains and the metal or alloy, the step of infiltrating a molten metal and/or alloy into voids between abrasive grains or between abrasive grains and the base and solidifying the metal and/or alloy therein. 
     
     
         12 . The method of  claim 11  wherein the infiltrating metal is Sn and/or Pb, and the infiltrating alloy is selected from the group consisting of Sn—Ag—Cu, Sn—Ag, Sn—Cu, Sn—Zn and Sn—Pb alloys and mixtures thereof.