Method of reducing cycle time for metal forming

Abstract

A method for reducing the part-to-part cycle time of quick plastic forming and superplastic forming of a metallic sheet alloy into an automotive sheet metal component by locally modifying a die surface to control friction which militates against undesirable necking and thinning.

What is claimed is:  
     
         1 . A method for tailoring friction characteristics of a die to minimize a cycle time for metal forming, the method comprising the steps of: 
 providing a metal forming die having a die surface to effect metal forming of a structure thereon, the die surface having at least one coefficient of friction; and    modifying a portion of the die surface to change the at least one coefficient of friction on the portion of the die surface.    
     
     
         2 . The method according to  claim 1  wherein the die surface is modified by chemical etching.  
     
     
         3 . The method according to  claim 1  wherein the die surface is modified by laser surface dimpling.  
     
     
         4 . The method according to  claim 1  wherein the die surface is modified by scribing.  
     
     
         5 . The method according to  claim 1  wherein the die surface is modified by sand blasting.  
     
     
         6 . The method according to  claim 1  wherein the die surface is modified by laser particle injection.  
     
     
         7 . The method according to  claim 1  wherein the die surface is modified by inserting dissimilar metal inserts therein.  
     
     
         8 . The method according to  claim 1  wherein the die surface is modified by laser ablation.  
     
     
         9 . The method according to  claim 1  wherein the die surface is modified by local oxidation.  
     
     
         10 . The method according to  claim 1  wherein the metal provided is at least one of aluminum, magnesium, titanium, and stainless steel.  
     
     
         11 . A method of making a structure by metal forming, the method comprising the steps of: 
 providing a metal blank;    providing a metal forming die having a die surface to effect forming of the metal blank thereon, the die surface having at least one coefficient of friction; and    forming the metal structure by applying pressure to the metal blank with the metal forming die;    wherein a portion of the die surface is modified to change the at least one coefficient of friction on the portion of the die surface to minimize a cycle time for said forming and militate against at least one of necking, localized thinning, and splitting of the metal blank during said forming.    
     
     
         12 . The method according to  claim 11  wherein the die surface is modified by chemical etching.  
     
     
         13 . The method according to  claim 11  wherein the die surface is modified by laser surface dimpling.  
     
     
         14 . The method according to  claim 11  wherein the die surface is modified by scribing.  
     
     
         15 . The method according to  claim 11  wherein the die surface is modified by sand blasting.  
     
     
         16 . The method according to  claim 11  wherein the die surface is modified by laser particle injection.  
     
     
         17 . The method according to  claim 11  wherein the die surface is modified by inserting dissimilar metal inserts therein.  
     
     
         18 . The method according to  claim 11  wherein the die surface is modified by laser ablation.  
     
     
         19 . The method according to  claim 11  wherein the die surface is modified by local oxidation.