Method and Apparatus for Roll Grinding

Abstract

In one aspect, a process for roll grinding employs a grinding wheel that is porous and permeable. In another aspect, a process for grinding mill rolls includes dressing the grinding wheel as the wheel traverses the surface of a mill roll. Other aspects relate to a system, e.g., a mill roll grinding machine, or parts thereof, in which a dressing tool contacts the wheel as the wheel grinds the surface of the mill roll. In specific examples, the wheel and a rotary dressing tool are maintained in contact as the wheel traverses the surface of the mill roll.

1 . A process for grinding mill rolls, the process comprising:
 a. mounting a grinding wheel on a roll grinding machine;   b. bringing the grinding wheel into contact with a rotating mill roll;   c. traversing the grinding wheel across a surface of the mill roll while maintaining continuous contact of the grinding wheel with the surface of the mill roll;   d. dressing the grinding wheel while the grinding wheel is in contact with the mill roll; and   e. grinding the surface of the mill roll.   
     
     
         2 . The process of  claim 1 , wherein the grinding wheel is dressed with a rotary dressing tool. 
     
     
         3 . The process of  claim 1 , wherein the dressing tool is rotated continuously. 
     
     
         4 . The process of  claim 1 , wherein the dressing tool is rotated intermittently. 
     
     
         5 . The process of  claim 1 , wherein the process is under computer numerical control. 
     
     
         6 . The process of  claim 1 , wherein the grinding wheel includes a vitrified bond. 
     
     
         7 . The process of  claim 1 , wherein the grinding wheel comprises about 55% to about 80%, by volume, interconnected porosity defined by a matrix of fibrous particles, the fibrous particles having a length to diameter aspect ratio of at least 5:1, and abrasive grain and bond in amounts effective for roll grinding, and having an air permeability measured in cc air/second/inch of water of at least 0.44 times the cross-sectional width of the abrasive grain, wherein the interconnected porosity provides an open structure of channels permitting passage of fluid or debris through the abrasive article during grinding, and wherein the fibrous particles consist of materials selected from the group consisting of abrasive grain, filler, combinations thereof, and agglomerates thereof. 
     
     
         8 . The process of  claim 1 , wherein the grinding wheel has an air permeability measured in cc air/second/inch of water of at least 0.44 times the cross-sectional width of the abrasive grain, and comprises: (i) prior to curing the grinding wheel, a matrix of fibrous particles, the fibrous particles having a length to diameter aspect ratio of at least 5:1; (ii) after curing the grinding wheel, about 55% to about 80%, by volume, interconnected porosity, the interconnected porosity being defined by the matrix of fibrous particles; and (iii) abrasive grain and bond in amounts effective for grinding, wherein the interconnected porosity provides an open structure of channels permitting passage of fluid or debris through the abrasive article during grinding and wherein the matrix of fibrous particles is at least one layer of structured filler selected from the group consisting of glass mat, organic mat, ceramic fiber mat, and combinations thereof. 
     
     
         9 . The process of  claim 1 , wherein the grinding wheel comprises about 40% to about 54%, by volume, interconnected porosity defined by a matrix of fibrous particles, the fibrous particles having a length to diameter aspect ratio of at least 5:1, and abrasive grain and bond in amounts effective for grinding, and having an air permeability measured in cc air/second/inch of water of at least 0.22 times the cross-sectional width of the abrasive grain, wherein the interconnected porosity provides an open structure of channels permitting passage of fluid or debris through the abrasive article during grinding, and wherein the fibrous particles consist of materials selected from the group consisting of abrasive grain, filler, combinations thereof, and agglomerates thereof. 
     
     
         10 . The process of  claim 1 , wherein the grinding wheel has an air permeability measured in cc air/second/inch of water of at least 0.44 times the cross-sectional width of the abrasive grain, and comprises: (i) prior to curing the abrasive article, a matrix of fibrous particles, the fibrous particles having a length to diameter aspect ratio of at least 5:1; (ii) after curing the abrasive article, about 55% to about 80%, by volume, interconnected porosity, the interconnected porosity being defined by the matrix of fibrous particles; and (iii) abrasive grain and bond in amounts effective for grinding, wherein the interconnected porosity provides an open structure of channels permitting passage of fluid or debris through the abrasive article during grinding, and wherein the matrix of fibrous particles is at least one layer of structured filler selected from the group consisting of glass mat, organic mat, ceramic fiber mat, and combinations thereof. 
     
     
         11 . The process of  claim 1 , wherein the wheel comprising:
 a blend of abrasive grains including: i) a filamentary sol-gel alumina abrasive grain having a length-to-cross-sectional-width aspect ratio of greater than about 1.0, or an agglomerate thereof; and ii) agglomerated abrasive grain granules including a plurality of abrasive grains held in a three-dimensional shape by a binding material;   a bond; and   at least about 35 volume percent porosity.   
     
     
         12 . The process of  claim 1 , wherein the wheel comprises:
 an agglomerate including: i) a filamentary sol-gel alumina abrasive grain having a length-to-cross-sectional-width aspect ratio of greater than about 1.0; ii) a non-filamentary abrasive grain; and iii) a binding material, wherein the non-filamentary abrasive grain and filamentary sol-gel alumina abrasive grain are held in a three-dimensional shape by the binding material;   a bond; and   at least about 35 volume percent porosity.   
     
     
         13 . (canceled) 
     
     
         14 . A method for dressing a wheel grinding a mill roll, the method comprising:
 maintaining contact between the wheel and a rotary dressing tool as the wheel traverses a surface of the mill roll.   
     
     
         15 .- 35 . (canceled) 
     
     
         36 . An apparatus for grinding mill rolls includes a dressing tool that is operationally linked to a grinding wheel to maintain contact between the dressing tool and the grinding wheel as the grinding wheel traverses a surface of the mill roll. 
     
     
         37 . The process of  claim 1 , wherein the surface of the mill roll that is ground in step (e) is a cylindrical surface.