Variable thickness golf club head and method of manufacturing the same

Abstract

A method of forming a crown of a golf club head including casting the crown of the golf club head, the crown including an internal surface adjacent a hollow interior of the golf club head, and an external surface opposite the internal surface, the crown including a first region and a second region adjacent the first region, the first region including a recess formed in the internal surface, the first region including a sacrificial protrusion on the external surface extending outwards beyond the second region; applying a mask to the external surface of the second region; exposing the crown of the golf club head to an etching chemical, wherein the etching chemical removes the sacrificial protrusion from the external surface of the crown; removing the etching chemical from the crown of the golf club head; and removing the mask from the second region.

What is claimed is: 
     
         1 . A method of forming a crown of a golf club head, comprising:
 casting said crown of said golf club head, said crown of said golf club head comprising an internal surface adjacent a hollow interior of said golf club head, and an external surface opposite said internal surface, said crown of said golf club head comprising a first region and a second region adjacent said first region, said second region substantially surrounding said first region, said first region comprising a recess formed in said internal surface, said first region comprising a sacrificial protrusion on said external surface extending outwards beyond said second region, wherein said first region of has an as-cast thickness T 1 , and thickness T 1  is greater than or equal to 0.48 mm;   applying a mask to said external surface of said second region;   exposing said crown of said golf club head to an etching chemical, wherein said etching chemical removes said sacrificial protrusion from said external surface of said crown;   removing said etching chemical from said crown of said golf club head; and   removing said mask from said second region.   
     
     
         2 . A method of forming a portion of a golf club head, comprising:
 casting said portion of said golf club head, said portion of said golf club head comprising an internal surface adjacent a hollow interior of said golf club head, and an external surface opposite said internal surface, said portion of said golf club head comprising a first region and a second region adjacent said first region, said first region comprising a recess formed in said internal surface, said first region comprising a sacrificial protrusion on said external surface extending outwards beyond said second region;   applying a mask to said external surface of said second region;   exposing said portion of said golf club head to an etching chemical;   removing said etching chemical from said portion of said golf club head; and   removing said mask from said second region.   
     
     
         3 . The method of  claim 2 , further comprising polishing said external surface of said portion of said golf club head. 
     
     
         4 . The method of  claim 2 , wherein said first region of has an as-cast thickness T 1 , and thickness T 1  is greater than or equal to 0.48 mm. 
     
     
         5 . The method of  claim 4 , wherein said thickness T 1  of said first region, after exposing said portion of said golf club head to an etching chemical, is reduced to less than or equal to 0.45 mm. 
     
     
         6 . The method of  claim 4 , wherein said thickness T 1  of said first region, after exposing said portion of said golf club head to an etching chemical, is reduced to less than or equal to 0.35 mm. 
     
     
         7 . The method of  claim 4 , wherein said thickness T 1  of said first region, after exposing said portion of said golf club head to an etching chemical, is reduced to less than or equal to 0.25 mm. 
     
     
         8 . The method of  claim 2 , wherein exposing said portion of said golf club head to an etching chemical removes said sacrificial protrusion from said first region. 
     
     
         9 . The method of  claim 2 , wherein exposing said portion of said golf club head to an etching chemical is completed when said external surface is substantially flush at the intersection of said first region and said second region. 
     
     
         10 . The method of  claim 2 , wherein said second region substantially surrounds said first region. 
     
     
         11 . The method of  claim 2 , wherein said second region has a thickness T 2 , and wherein said recess has a depth D r , and wherein D r  is greater than or equal to T 2 /2. 
     
     
         12 . A method of forming a crown of a golf club head, comprising:
 casting said crown of said golf club head, said crown of said golf club head comprising an internal surface adjacent a hollow interior of said golf club head, and an external surface opposite said internal surface, said crown of said golf club head comprising a first region and a second region adjacent said first region, said first region comprising a recess formed in said internal surface, said first region comprising a sacrificial protrusion on said external surface extending outwards beyond said second region;   applying a mask to said external surface of said second region;   exposing said crown of said golf club head to an etching chemical, wherein said etching chemical removes said sacrificial protrusion from said external surface of said crown;   removing said etching chemical from said crown of said golf club head; and   removing said mask from said second region.   
     
     
         13 . The method of  claim 12 , further comprising polishing said external surface of said crown of said golf club head. 
     
     
         14 . The method of  claim 12 , wherein said first region of has an as-cast thickness T 1 , and thickness T 1  is greater than or equal to 0.48 mm. 
     
     
         15 . The method of  claim 14 , wherein said thickness T 1  of said first region, after exposing said crown of said golf club head to an etching chemical, is reduced to less than or equal to 0.45 mm. 
     
     
         16 . The method of  claim 14 , wherein said thickness T 1  of said first region after exposing said crown of said golf club head to an etching chemical is reduced to less than or equal to 0.35 mm. 
     
     
         17 . The method of  claim 14 , wherein said thickness T 1  of said first region after exposing said crown of said golf club head to an etching chemical is reduced to less than or equal to 0.25 mm. 
     
     
         18 . The method of  claim 12 , wherein exposing said crown of said golf club head to an etching chemical is completed when said external surface is substantially flush at the intersection of said first region and said second region. 
     
     
         19 . The method of  claim 12 , wherein said second region substantially surrounds said first region. 
     
     
         20 . The method of  claim 12 , wherein said second region has a thickness T 2 , and wherein said recess has a depth D r , and wherein D r  is greater than or equal to T 2 /2.