Method and apparatus for plating extrusion dies

Abstract

Method and apparatus are set forth for providing a substantially uniform coating on inner wall portions of a die having slots or openings formed in the face of the die. The die is supported by a fixture for up and down movement while it is immersed in a bath of a desired plating solution. A tube or cylinder positioned on an upper surface portion of the die repeatedly collects a column of plating material in a cylinder from the bath on downward movements of the die, so as to provide fresh or replenishment plating solution to the die. The column of plating solution in the cylinder functions as a hydrostatic head and forces the confined solution into the interior of the die on upward movements, thus promoting coating uniformity along inner walls of the die. The die may be rotated 180 degrees so that each face of the die may be subjected to the hydrostatic force flow of the plating solution, also resulting in a more uniform coating.

1 . A method of plating interior wall portions of a die which comprises, 
 immersing a die within a bath of plating solution,    moving said die upwardly and downwardly within said bath,    repeatedly confining a replenished supply of said plating solution above said die during downward movement of said die within said bath, and    flowing said confined supply of replenished plating solution solely into interior portions of said die during upward movement of the die to produce a substantially uniform plating coating on the interior wall portions of said die.    
     
     
         2 . A method as defined in  claim 1  including the step confining a column of the replenished plating solution above the die and within the confines of peripheral portions of the die.  
     
     
         3 . A method as defined in  claim 1  including the step of creating a hydrostatic head of said plating solution within the confined supply of plating solution and forcing said solution into interior portions of the die.  
     
     
         4 . A method as defined in  claim 1  including the step of periodically rotating the die 180 degrees while still being retained within the bath.  
     
     
         5 . A method as defined in  claim 1  including the step of periodically flowing the confined supply of replenished plating solution into interior portions of the die from opposite faces of the die.  
     
     
         6 . A method of nickel plating interior wall portions of a die having slots for extruding ceramic honeycomb structures which comprises, 
 immersing an extrusion die to be coated in a bath of electroless nickel plating solution,    moving said die upwardly and downwardly within the bath solution,    forming a separate confined column of plating solution above the die from the bath, and    creating a hydrostatic head within said separate confined column of plating solution;    whereby the hydrostatic head forces the confined column of plating solution into the slots of said die to provide a substantially uniform nickel coating on the interior wall portions of said slots.    
     
     
         7 . A method as defined in  claim 6  including the step rotating the die 180 degrees while retaining the die within the plating solution.  
     
     
         8 . A method as defined in  claim 7  including the step of flowing the confined supply of plating solution under hydrostatic pressure into the die from opposite faces of the die to provide more uniform coating thickness along the slot length.  
     
     
         9 . A fixture for plating interior wall portions of a die member which comprises, 
 means for supporting said die member in a plating bath solution,    means for moving said die member upwardly and downwardly within said plating bath and,    means for confining a column of said plating solution above said die and for directing the flow of said confined solution solely into interior portions of said die member to provide a substantially uniform coating of plating material along said interior wall portions.    
     
     
         10 . A fixture for plating interior wall portions of a die member as defined in  claim 9 , wherein said confining means includes means for replenishing plating solution to an upper surface of said die member.  
     
     
         11 . A fixture for plating interior wall portions of a die member as defined in  claim 9 , including pivotal means for rotating said die member from one fixed position to another fixed position while said die is in said plating bath.  
     
     
         12 . A fixture for plating interior wall portions of a die member as defined in  claim 9 , wherein said means for supporting said die includes a pair of clamping rings which encircle a peripheral portion of said die member.  
     
     
         13 . A fixture for plating interior wall portions of a die member as defined in  claim 12 , wherein said confining means includes a tubular member removably secured to said support means.  
     
     
         14 . A fixture for plating interior wall portions of a die member as defined in  claim 9  wherein said confining means includes a cylindrical member removably secured to at least one of said clamping rings.  
     
     
         15 . A fixture for plating interior wall portions of a die member as defined in  claim 9  including trunnion means pivotally mounting said die support means and wherein said pivotal means includes a lever secured to said die supporting means for rotating said support means and said die about said trunnion means.  
     
     
         16 . A fixture for plating interior wall portions of a die member as defined in  claim 9  including locking pin means for locking said die in a desired rotated position.  
     
     
         17 . A fixture for plating interior wall portions of a die member as defined in  claim 13  wherein said clamping rings have recessed t-slots and said cylindrical member has a pair of pins for engagement with said slots for securing said cylindrical member on said clamping ring.