Abrasive fluid jet cutting composition, method and apparatus

Abstract

An abrasive fluid jet cutting composition, method and apparatus for cutting an object from a sheet. In one embodiment, a fluid jet stream is directed against a glass sheet to cut a disk substrate for use in a data storage device. An abrasive slurry is delivered to a fluid jet head from a slurry tank. The slurry is formed by mixing water, abrasive particles, a surfactant or surfactants, and an acid or base. The head also receives a pressurized fluid from a fluid pump. The abrasive slurry and the pressurized fluid are mixed in the head to form the fluid jet stream. Preferably, the abrasive particles are 8-64 microns and may include recycled scrap. The slurry may also contain polishing particles that are smaller than the abrasive particles to affect polishing. In addition to reducing surface tension, the surfactant may cause the abrasive particles to flocculate or disperse.

What is claimed is:  
     
         1 . An abrasive fluid jet cutting composition for delivery to a fluid jet head, the fluid jet head being adapted to mix the abrasive fluid jet cutting composition and a pressurized fluid to form a fluid jet stream and to direct the fluid jet stream against a sheet from which an object is to be cut by the fluid jet stream, the abrasive fluid jet cutting composition comprising a slurry formed by mixing water, abrasive particles, a surfactant, and an acid or a base.  
     
     
         2 . The abrasive fluid jet cutting composition as recited in  claim 1 , wherein the sheet is a glass and the object to be cut is a disk substrate.  
     
     
         3 . The abrasive fluid jet cutting composition as recited in  claim 1 , wherein the sheet is a ceramic and the object to be cut is a disk substrate.  
     
     
         4 . The abrasive fluid jet cutting composition as recited in  claim 2 , wherein the abrasive particles include glass particles.  
     
     
         5 . The abrasive fluid jet cutting composition as recited in  claim 3 , wherein the abrasive particles include ceramic particles.  
     
     
         6 . The abrasive fluid jet cutting composition as recited in  claim 1 , wherein the abrasive particles have a nominal particle size between about 8-64 microns.  
     
     
         7 . The abrasive fluid jet cutting composition as recited in  claim 6 , wherein the abrasive particles have a nominal particle size between about 8-49 microns.  
     
     
         8 . The abrasive fluid jet cutting composition as recited in  claim 6 , wherein the slurry further comprises small polishing particles having a nominal particle size smaller than that of the abrasive particles.  
     
     
         9 . The abrasive fluid jet cutting composition as recited in  claim 8 , wherein the small polishing particles comprise cerium oxide particles having a nominal particle size of about 3 microns.  
     
     
         10 . The abrasive fluid jet cutting composition as recited in  claim 6 , wherein the slurry further comprises lanthanide oxide particles having a nominal particle size smaller than that of the abrasive particles.  
     
     
         11 . The abrasive fluid jet cutting composition as recited in  claim 1 , wherein the surfactant is effective in surface tension reduction, and wherein the surfactant and/or an additional surfactant is effective in causing the abrasive particles to flocculate.  
     
     
         12 . The abrasive fluid jet cutting composition as recited in  claim 1 , wherein the surfactant is effective in surface tension reduction, and wherein the surfactant and/or an additional surfactant is effective in causing the abrasive particles to disperse.  
     
     
         13 . The abrasive fluid jet cutting composition as recited in  claim 11 , wherein the slurry further comprises cerium oxide particles.  
     
     
         14 . The abrasive fluid jet cutting composition as recited in  claim 13 , wherein the abrasive particles include garnet particles.  
     
     
         15 . The abrasive fluid jet cutting composition as recited in  claim 14 , wherein the garnet particles have a nominal particle size between about 8-64 microns and the cerium oxide particles have a nominal particle size of about 3 microns.  
     
     
         16 . An abrasive fluid jet cutting method for cutting an object from a sheet, comprising the steps of: 
 supporting the sheet on a support member;    delivering an abrasive fluid jet cutting composition to a fluid jet head, said fluid jet cutting composition comprising a slurry formed by mixing water, abrasive particles, a surfactant, and an acid or a base;    delivering a pressurized fluid to the fluid jet head;    mixing the slurry and a pressurized fluid received by the fluid jet head to form a fluid jet stream; and    cutting through the sheet by directing the fluid jet stream against the sheet.    
     
     
         17 . The abrasive fluid jet cutting method as recited in  claim 16 , wherein the sheet is a glass and the object to be cut is a disk substrate.  
     
     
         18 . The abrasive fluid jet cutting method as recited in  claim 16 , wherein the sheet is a ceramic and the object to be cut is a disk substrate.  
     
     
         19 . The abrasive fluid jet cutting method as recited in  claim 17 , further comprising the step of grinding a scrap portion of the glass sheet resulting from the cutting step to produce glass particles for subsequent use as abrasive particles in the slurry.  
     
     
         20 . The abrasive fluid jet cutting method as recited in  claim 18 , further comprising the step of grinding a scrap portion of the ceramic sheet resulting from the cutting step to produce ceramic particles for subsequent use as abrasive particles in the slurry.  
     
     
         21 . The abrasive fluid jet cutting method as recited in  claim 16 , wherein the abrasive particles have a nominal particle size between about 8-64 microns.  
     
     
         22 . The abrasive fluid jet cutting method as recited in  claim 21 , wherein the abrasive particles have a nominal particle size between about 8-49 microns.  
     
     
         23 . The abrasive fluid jet cutting method as recited in  claim 21 , wherein the slurry further comprises small polishing particles having a nominal particle size smaller than that of the abrasive particles, and the abrasive jet cutting method further comprising a step of polishing a cut surface of the sheet produced during the cutting step, wherein the polishing step occurs as the fluid jet stream passes through the sheet.  
     
     
         24 . The abrasive fluid jet cutting method as recited in  claim 23 , wherein the small polishing particles comprise cerium oxide particles having a nominal particle size of about 3 microns.  
     
     
         25 . The abrasive fluid jet cutting method as recited in  claim 21 , wherein the slurry further comprises lanthanide oxide particles having a nominal particle size smaller than that of the abrasive particles, and the abrasive jet cutting method further comprising a step of polishing a cut surface of the sheet produced during the cutting step, wherein the polishing step occurs as the fluid jet stream passes through the sheet.  
     
     
         26 . The abrasive fluid jet cutting method as recited in  claim 16 , wherein the surfactant is effective in surface tension reduction, and wherein the surfactant and/or an additional surfactant is effective in causing the abrasive particles to flocculate.  
     
     
         27 . The abrasive fluid jet cutting method as recited in  claim 16 , wherein the surfactant is effective in surface tension reduction, and wherein the surfactant and/or an additional surfactant is effective in causing the abrasive particles to disperse.  
     
     
         28 . The abrasive fluid jet cutting method as recited in  claim 26 , wherein the slurry further comprises cerium oxide particles, and the abrasive jet cutting method further comprising a step of polishing a cut surface of the sheet produced during the cutting step, wherein the polishing step occurs as the fluid jet stream passes through the sheet.  
     
     
         29 . The abrasive fluid jet cutting method as recited in  claim 28 , wherein the abrasive particles include garnet particles.  
     
     
         30 . The abrasive fluid jet cutting method as recited in  claim 29 , wherein the garnet particles have a nominal particle size between about 8-64 microns and the cerium oxide particles have a nominal particle size of about 3 microns.  
     
     
         31 . An abrasive fluid jet cutting apparatus for cutting an object from a sheet, comprising: 
 a support member provided to support the sheet;    a slurry tank containing a slurry formed by mixing water, abrasive particles, a surfactant, and an acid or a base,    a slurry line connecting the slurry tank to a fluid jet head;    a fluid pump providing a source of high pressure fluid to the fluid jet head;    the fluid jet head being adapted to mix the slurry received from the slurry line and the high pressure fluid received from the fluid pump to form a fluid jet stream and to direct the fluid jet stream against the sheet from which the object is to be cut by the fluid jet stream.    
     
     
         32 . The abrasive fluid jet cutting apparatus as recited in  claim 31 , further comprising a slurry pump provided to pump the slurry through the slurry line toward the fluid jet head.  
     
     
         33 . The abrasive fluid jet cutting apparatus as recited in  claim 31 , wherein the slurry tank comprises a stirring mechanism to stir the slurry.  
     
     
         34 . The abrasive fluid jet cutting apparatus as recited in  claim 31 , wherein the sheet is a glass and the object to be cut is a disk substrate.  
     
     
         35 . The abrasive fluid jet cutting apparatus as recited in  claim 31 , wherein the sheet is a ceramic and the object to be cut is a disk substrate.  
     
     
         36 . The abrasive fluid jet cutting apparatus as recited in  claim 34 , wherein the abrasive particles include glass particles.  
     
     
         37 . The abrasive fluid jet cutting apparatus as recited in  claim 35 , wherein the abrasive particles include ceramic particles.  
     
     
         38 . The abrasive fluid jet cutting apparatus as recited in  claim 31 , wherein the abrasive particles have a nominal particle size between about 8-64 microns.  
     
     
         39 . The abrasive fluid jet cutting apparatus as recited in  claim 38 , wherein the abrasive particles have a nominal particle size between about 8-49 microns.  
     
     
         40 . The abrasive fluid jet cutting apparatus as recited in  claim 38 , wherein the slurry further comprises small polishing particles having a nominal particle size smaller than that of the abrasive particles.  
     
     
         41 . The abrasive fluid jet cutting apparatus as recited in  claim 40 , wherein the small polishing particles comprise cerium oxide particles having a nominal particle size of about 3 microns.  
     
     
         42 . The abrasive fluid jet cutting apparatus as recited in  claim 38 , wherein the slurry further comprises lanthanide oxide particles having a nominal particle size smaller than that of the abrasive particles.  
     
     
         43 . The abrasive fluid jet cutting apparatus as recited in  claim 31 , wherein the surfactant is effective in surface tension reduction, and wherein the surfactant and/or an additional surfactant is effective in causing the abrasive particles to flocculate.  
     
     
         44 . The abrasive fluid jet cutting apparatus as recited in  claim 31 , wherein the surfactant is effective in surface tension reduction, and wherein the surfactant is and/or an additional surfactant is effective in causing the abrasive particles to disperse.  
     
     
         45 . The abrasive fluid jet cutting apparatus as recited in  claim 43 , wherein the slurry further comprises cerium oxide particles.  
     
     
         46 . The abrasive fluid jet cutting apparatus as recited in  claim 45 , wherein the abrasive particles include garnet particles.  
     
     
         47 . The abrasive fluid jet cutting apparatus as recited in  claim 46 , wherein the garnet particles have a nominal particle size between about 8-64 microns and the cerium oxide particles have a nominal particle size of about 3 microns.