Abrasive article, apparatus and process for finishing glass or glass-ceramic recording disks

Abstract

A process, multi-functional grinding wheel and apparatus for mirror-finishing the edge of at least one of a cut unfinished glass recording disk or a cut unfinished glass-ceramic recording disk. The process includes (a) rough grinding the edge of the at least one of the unfinished glass recording disk or the unfinished glass ceramic recording disk with a diamond abrasive wheel to shape the edge into a trapezoid cross section; (b) grinding the trapezoid-shaped edge of the at least one of the glass recording disk or the unfinished glass ceramic recording disk with a first resin bonded grinding wheel which comprises abrasive grains having an average particle size in the range from about 75 micrometers to about 15 micrometers and has an axis of rotation and an annular shape with an inside curved surface and an outside curved surface extending along the axis of rotation; and (c) grinding the edge of the trapezoid-shaped recording disk with a second resin bonded grinding wheel which comprises abrasive grains having an average particle size in the range from about 3 micrometers to about 0.2 micrometer and has an axis of rotation and an annular shape with an inside curved surface and an outside curved surface extending along the axis of rotation. The multi-functional grinding wheel comprises the first grinding wheel coaxially attached to the second grinding wheel.

What is claimed is:  
     
         1 . A process for mirror-finishing the edge of at least one of a cut unfinished glass recording disk or an unfinished glass or glass-ceramic recording disk, said process comprising the steps of: 
 a. rough grinding the edge of the at least one of the unfinished glass recording disk or the unfinished glass-ceramic recording disk with a diamond abrasive wheel to shape the edge into a trapezoid cross section;    b. grinding the trapezoid-shaped edge of the at least one of the glass recording disk or the unfinished glass-ceramic recording disk with a first resin bonded grinding wheel which comprises abrasive grains having an average particle size in the range from about 53 micrometers to about 9.5 micrometers and has an axis of rotation and an annular shape with an inside curved surface and an outside curved surface extending along the axis of rotation; and    c. after step b, grinding the edge of the trapezoid-shaped recording disk with a second resin bonded grinding wheel which comprises abrasive grains having an average particle size in the range from about 2.5 micrometers to about 0.45 micrometer and has an axis of rotation and an annular shape with an inside curved surface and an outside curved surface extending along the axis of rotation.    
     
     
         2 . The process of  claim 1  wherein the abrasive grains of the first resin bonded grinding wheel are graded according to one JIS#220, JIS#240, JIS#280, JIS#320, JIS#360, JIS#500, JIS#600, JIS#700, JIS#800, JIS#1000, or JIS#1200, and wherein the abrasive grains of the second resin bonded grinding wheel are graded according to one JIS#5000, JIS#6000, JIS#8000, JIS#10000, JIS#15000, or JIS#20000.  
     
     
         3 . The process of  claim 2  wherein the first and second resin bonded grinding wheels have a shore D hardness of not less than about 80.  
     
     
         4 . The process of  claim 2  wherein the first and second resin bonded grinding wheels each have an axial groove having an inverted trapezoid cross-sectional shape in at least one of the inside curved surface or the outside curved surface.  
     
     
         5 . The process of  claim 4  wherein the groove is on the inside curved surface.  
     
     
         6 . The process of  claim 2  wherein said first resin bonded grinding wheel is coaxially attached to said second resin bonded grinding wheel.  
     
     
         7 . The process of  claim 2  wherein said grinding is carried out in the presence of a water stream.  
     
     
         8 . The process of  claim 2  wherein said grinding wheels have a density in the range of about 1.6 to about 2.5 g/cm 3 .  
     
     
         9 . The process of  claim 2  wherein said abrasive material is selected from the group consisting of SiC, Al 2 O 3 , CeO 2 , and combinations thereof.  
     
     
         10 . The process of  claim 2  wherein said wheel shore D hardness is in the range of about 85 to 95.  
     
     
         11 . The process of  claim 2  wherein said resin bonded abrasive wheels are bonded with a polyurethane resin.  
     
     
         12 . The process of  claim 2  wherein the resin bonded grinding wheel is rotated at a peripheral velocity in one direction in the range of about 1000 to 3000 n/min. and the glass disk is rotated in an opposite direction at a peripheral velocity in the range of about 20 to 500 m/min.  
     
     
         13 . The process of  claim 2  wherein said grinding is carried out under a load between the grinding wheel and the disk edge in the range of about 0.2 to 5 kg.  
     
     
         14 . The process of  claim 2  wherein the grinding time in each of steps a, b and c is in the range of about 5 to 60 seconds.  
     
     
         15 . The process of  claim 2  wherein further comprising between steps a and b, the step of: 
 grinding the trapezoid-shaped edge of the at least one of the glass recording disk or the unfinished glass-ceramic recording disk with a resin bonded grinding wheel which comprises abrasive grains having an average particle size in the range from about 106 micrometers to about 53 micrometers and has an axis of rotation and an annular shape with an inside curved surface and an outside curved surface extending along the axis of rotation.  
 
     
     
         16 . The process of  claim 2  wherein further comprising between steps a and b, the step of: 
 grinding the trapezoid-shaped edge of the at least one of the glass recording disk or the unfinished glass-ceramic recording disk with a resin bonded grinding wheel which comprises abrasive grains graded according to one of JIS#120, JIS#150, JIS#180, or JIS#220 and has an axis of rotation and an annular shape with an inside curved surface and an outside curved surface extending along the axis of rotation.  
 
     
     
         17 . A multi-functional grinding wheel comprising at least one resin bonded grinding wheel annular segment which has an axis of rotation and an inside curved surface and an outside curved surface extending along its axis of rotation and which comprises first abrasive grains having an average particle size in the range from about 53 micrometers to about 9.5 micrometers coaxially attached to at least one other grinding wheel annular segment which comprises second abrasive grains having an average particle size from about 2.5 micrometers to about 0.45 micrometer.  
     
     
         18 . The multi-functional grinding wheel of  claim 17  wherein the first abrasive grains are graded according to one of JIS#220, JIS#240, JIS#280, JIS#320, JIS#360, JIS#500, JIS#600, JIS#700, JIS#800, JIS#1000, or JIS#1200, and wherein the second abrasive grains are graded according to one of JIS#5000, JIS#6000, JIS#8000, JIS#10000, JIS#15000, or JIS#20000.  
     
     
         19 . The multi-functional grinding wheel of  claim 18 , wherein at least one of the resin bonded grinding wheel segments has a groove which is an inverted trapezoid in cross-sectional shape.  
     
     
         20 . The multi-functional grinding wheel according to  claim 19 , wherein said groove is the inside curved surface.  
     
     
         21 . The multi-functional grinding wheel of  claim 18  wherein said grinding wheels have a density in the range of about 1.6 to about 2.5 g/cm 3 .  
     
     
         22 . The multi-functional grinding wheel of  claim 18  wherein said abrasive material is selected from the group consisting of SiC, Al 2 O 3 , CeO 2 , and combinations thereof.  
     
     
         23 . The multi-functional grinding wheel of  claim 18  wherein the and resin bonded grinding wheel segments comprising the first and second abrasive grains each have a shore D hardness of at least 80.  
     
     
         24 . The multi-functional grinding wheel of  claim 23  wherein the and resin bonded grinding wheel segments comprising the first and second abrasive grains each have a shore D hardness is in the range of about 85 to 95.  
     
     
         25 . The multi-functional grinding wheel of  claim 18  wherein said resin bonded abrasive wheel segments are bonded with a polyurethane resin.  
     
     
         26 . A multi-functional grinding wheel comprising at least one resin bonded grinding wheel annular segment which has an axis of rotation and an inside curved surface and an outside curved surface extending along its axis of rotation and which comprises first abrasive grains having an average particle size in the range from about 106 micrometers to about 53 micrometers coaxially attached to at least one other grinding wheel annular segment which comprises second abrasive grains having an average particle size from about 53 micrometers to about 9.5 micrometers coaxially attached to at least one other grinding wheel annular segment which comprises third abrasive grains having an average particle size from about 2.5 micrometers to about 0.45 micrometer.  
     
     
         27 . The multi-functional grinding wheel of  claim 26  wherein the first abrasive grains are graded according to one of JIS#120, JIS#150, JIS#180, and JIS#220, wherein the second abrasive grains are graded according to one of JIS#220, JIS#240, JIS#280, JIS#320, JIS#360, JIS#500, JIS#600, JIS#700, JIS#800, JIS#1000, or JIS#1200, and wherein the third abrasive grains are graded according to one of JIS#5000, JIS#6000, JIS#8000, JIS#10000, JIS#15000, or JIS#20000.  
     
     
         28 . An apparatus for grinding a glass disk having a diamond ground trapezoid-shaped pitted edge comprising: 
 a multi-functional grinding wheel comprising at least one resin bonded grinding wheel annular segment which has an axis of rotation and an inside curved surface and an outside curved surface extending along its axis of rotation and which comprises first abrasive grains having an average particle size in the range from about 53 micrometers to about 9.5 micrometers coaxially attached to at least one other grinding wheel annular segment which comprises second abrasive grains having an average particle size from about 2.5 micrometers to about 0.45 micrometer;    a motor for rotating the multi-functional grinding wheel about its axis of rotation in at least one direction;    a clamp for transversely holding the glass disk on a rotatable shaft;    a motor for peripherally rotating the transversely deployed glass disk in a direction opposite to that of the grinding wheel; and    a lift mechanism for causing the glass disk to move vertically and horizontally to sequentially contact the first and second segments of the rotating grinding wheel under load to cause the grinding wheel segments to remove pits from the pitted surface of the disk edge.    
     
     
         29 . The multi-functional grinding wheel of  claim 28  wherein the first abrasive grains are graded according to one of JIS#220, JIS#240, JIS#280, JIS#320, JIS#360, JIS#500, JIS#600, JIS#700, JIS#800, JIS#1000, or JIS#1200, and wherein the second abrasive grains are graded according to one of JIS#5000, JIS#6000, JIS#8000, JIS#10000, JIS#15000, or JIS#20000.  
     
     
         30 . An apparatus for grinding a glass disk having a diamond ground trapezoid-shaped pitted edge comprising: 
 a multi-functional grinding wheel comprising at least one resin bonded grinding wheel annular segment which has an axis of rotation and an inside curved surface and an outside curved surface extending along its axis of rotation and which comprises first abrasive grains having an average particle size in the range from about 106 micrometers to about 53 micrometers coaxially attached to at least one other grinding wheel annular segment which comprises second abrasive grains having an average particle size from about 53 micrometers to about 9.5 micrometers coaxially attached to at least one other grinding wheel annular segment which comprises third abrasive grains having an average particle size from about 2.5 micrometers to about 0.45 micrometer;    a motor for rotating the multi-functional grinding wheel about its axis of rotation in at least one direction;    a clamp for transversely holding the glass disk on a rotatable shaft;    a motor for peripherally rotating the transversely deployed glass disk in a direction opposite to that of the grinding wheel; and    a lift mechanism for causing the glass disk to move vertically and horizontally to sequentially contact the first, second, and third segments of the rotating grinding wheel under load to cause the grinding wheel segments to remove pits from the pitted surface of the disk edge.    
     
     
         31 . The apparatus of claim  30  wherein the first abrasive grains are graded according to one of JIS#120, JIS#150, JIS#180, and JIS#220, wherein the second abrasive grains are graded according to one of JIS#220, JIS#240, JIS#280, JIS#320, JIS#360, JIS#500, JIS#600, JIS#700, JIS#800, JIS#1000, or JIS#1200, and wherein the third abrasive grains are graded according to one of JIS#5000, JIS#6000, JIS#8000, JIS#10000, JIS#15000, or JIS#20000.