Tool, apparatus, and method for precision polishing of lenses and lens molds

Abstract

A tool for polishing objects having a wide variety of materials and shapes including precision optical surfaces, injection mold inserts, and thin film coating dies. The tool has an elastic solid bladder with a curved surface, upon which is disposed an abrasive band. The curved bladder surface is produced by compressing the bladder between two parallel plates. The apparatus comprises a multi-axis computer controlled machine to which the tool is attached.

1 . A polishing tool comprising: 
 a) a mandrel having a drive shank at a proximal end thereof, a threaded shank, a mandrel shank, and a flange at a distal end thereof;    b) a solid elastic annular bladder comprising a bore, an outer surface, a lower surface, and an upper surface, said bladder disposed upon said mandrel with said lower surface of said bladder in contact with said flange of said mandrel and said mandrel shank passing through said bore in said bladder;    c) a compression flange comprising a compression washer and a compression collar, said compression washer comprising a lower surface in contact with said upper surface of said bladder, and said compression collar comprising a bore slidingly engaged with said threaded shank of said mandrel; and    d) a compression nut threadedly engaged with said threaded shank of said mandrel, wherein when said compression nut is tightened upon said threaded shank, said solid bladder is compressed between said flange of said mandrel and said compression washer, causing said outer surface of said bladder to have an arcuate shape.    
   
   
       2 . The polishing tool as recited in  claim 1 , wherein said arcuate shape of said bladder resulting from said solid bladder being compressed between said flange of said mandrel and said compression washer is further ground to a different arcuate shape.  
   
   
       3 . The polishing tool as recited in  claim 2 , wherein said different arcuate shape is a spherical shape.  
   
   
       4 . The polishing tool as recited in  claim 1 , wherein said solid elastic annular bladder consists essentially of an elastomer.  
   
   
       5 . The polishing tool as recited in  claim 4 , wherein said elastomer is selected from the group consisting of gum rubber, nitrile rubber, and polyurethane.  
   
   
       6 . The polishing tool as recited in  claim 4 , wherein said elastomer has a Shore A durometer of between about 10 and about 90.  
   
   
       7 . The polishing tool as recited in  claim 6 , wherein said elastomer has a Shore A durometer of about 40.  
   
   
       8 . The polishing tool as recited in  claim 1 , wherein said solid elastic annular bladder consists essentially of an elastomeric closed cell foam.  
   
   
       9 . The polishing tool as recited in  claim 1 , wherein said compression collar of said compression flange comprises an inner stop, and said mandrel comprises a shoulder stop, and wherein when said compression nut is tightened upon said threaded shank, said inner stop of said compression collar contacts said shoulder stop of said mandrel.  
   
   
       10 . The polishing tool as recited in  claim 1 , further comprising means for locking said compression flange to said mandrel.  
   
   
       11 . The polishing tool as recited in  claim 10 , wherein means for locking said compression flange to said mandrel comprises a setscrew in said compression collar engaged with said mandrel.  
   
   
       12 . The polishing tool as recited in  claim 1 , further comprising a polishing band engaged with said outer surface of said bladder.  
   
   
       13 . The polishing tool as recited in  claim 12 , wherein said polishing band comprises an outer surface impregnated with abrasive particles.  
   
   
       14 . The polishing tool as recited in  claim 13 , wherein said abrasive particles are selected from the group consisting of ceria, alumina, silica, diamond, and mixtures thereof.  
   
   
       15 . A polishing tool comprising: 
 a) a mandrel having a drive shank at a proximal end thereof, a threaded shank, a mandrel shank, and a flange at a distal end thereof;    b) a solid elastic annular bladder comprising a bore, an outer surface, a lower surface, and an upper surface, said bladder disposed upon said mandrel with said lower surface of said bladder in contact with said flange of said mandrel and said mandrel shank passing through said bore in said bladder;    c) a compression flange comprising a compression washer and a compression collar, said compression washer comprising a lower surface in contact with said upper surface of said bladder, and said compression collar comprising a bore slidingly engaged with said threaded shank of said mandrel;    d) a polishing band engaged with said outer surface of said bladder; and    e) a compression nut threadedly engaged with said threaded shank of said mandrel, wherein when said compression nut is tightened upon said threaded shank, said solid bladder is compressed between said flange of said mandrel and said compression washer, causing said outer surface of said bladder and said polishing band to have an arcuate shape.    
   
   
       16 . The polishing tool as recited in  claim 15 , wherein said polishing band comprises an outer surface impregnated with abrasive particles.  
   
   
       17 . A polishing tool comprising: 
 a) a mandrel having a drive shank at a proximal end thereof, a threaded shank, a mandrel shank, and a flange at a distal end thereof;    b) a solid elastic annular bladder comprising a bore, an outer surface, a lower surface, and an upper surface, said bladder disposed upon said mandrel with said lower surface of said bladder in contact with said flange of said mandrel and said mandrel shank passing through said bore in said bladder; and    c) means for compressing said lower surface of said bladder toward said upper surface of said bladder, thereby causing said outer surface of said bladder to have an arcuate shape.    
   
   
       18 . The polishing tool as recited in  claim 17 , wherein said means for compressing said lower surface of said bladder toward said upper surface of said bladder comprises a compression flange comprising a compression washer and a compression collar, said compression washer comprising a lower surface in contact with said upper surface of said bladder, and said compression collar comprising a bore slidingly engaged with said threaded shank of said mandrel; and a compression nut threadedly engaged with said threaded shank of said mandrel.