Strip supported anodized heat sink

Abstract

Heat sink suitable for use, for example, as semiconductor heat sinks are formed from a unitary precision stamping consisting of at least one rail to which are attached a plurality of heat sink elements. Each of the heat sink elements is attached to the rail by a bridge region of reduced thickness. The heat sinks, supported by the rail member, may be subjected to the anodizing treatment or other surface coating treatment while still attached to the rail. The thickness of the area of reduced thickness is chosen to correspond to the design thickness of the anodized coating. Since the anodized coating penetrates the surface of the part being anodized, by selecting the appropriate thickness for the region of the reduced thickness, the anodized coating can be made to fully penetrate the bridge region such that when the heat sink is separated from the rail member, the anodic film completely covers the heat sink, without the presence of bare spots typical of prior art rack-anodized heat sinks.

What is claimed is:  
     
         1 . A unitary precision stamping comprising: 
 a frame comprising an elongate rail having a length dimension, a width dimension and a first thickness dimension;    a plurality of heat sinks, each of said plurality of heat sinks comprising a metal member having at least partially planar front and rear surfaces and a perimeter surface joining said front surface with said rear surface, said front and rear surfaces defining a second thickness dimension therebetween proximal said perimeter surface, each of said plurality of heat sinks further comprising a bridge member forming a unitary attachment between said perimeter surface and said frame, said bridge member comprising a region of reduced thickness relative to said second thickness dimension.    
     
     
         2 . The unitary precision stamping of  claim 1 , wherein: 
 said bridge member further comprises a necked region having a lateral dimension parallel to said length dimension of said frame that is smaller than a lateral dimension of said perimeter surface proximal said bridge member.    
     
     
         3 . The unitary precision stamping of  claim 1 , wherein: 
 said region of reduced thickness comprises a region coined to a reduced thickness.    
     
     
         4 . The unitary precision stamping of  claim 1 , further comprising: 
 a surface of said region of reduced thickness has a region of minimum thickness, said region of minimum thickness defining a chord that is substantially orthogonal to said rear surface    
     
     
         5 . The unitary precision stamping of  claim 4 , wherein: 
 said region of minimum thickness is in contact with said perimeter surface.    
     
     
         6 . The unitary precision stamping of  claim 1 , wherein: 
 said region of reduced thickness has a predetermined thickness dimension corresponding to twice the anticipated anodized coating thickness.    
     
     
         7 . The unitary precision stamping of  claim 1 , wherein: 
 each of said plurality of heat sinks comprises a thin polygonal plate having planar front and rear surfaces.    
     
     
         8 . The unitary precision stamping of  claim 1 , wherein: 
 said frame comprises a first and a second elongate rail disposed in a parallel spaced-apart configuration with said plurality of heat sinks disposed therebetween.    
     
     
         9 . The unitary precision stamping of  claim 8 , wherein: 
 each of said plurality of heat sinks comprise two bridge members, one of said bridge members forming a unitary attachment between said first elongate rail and a selected one of said plurality of heat sinks and the other of said two bridge members forming a unitary attachment between said second elongate rail and said selected one of said plurality of heat sinks.    
     
     
         10 . A method of forming a plurality of anodized heat sinks comprising 
 providing a strip of metallic material having a length dimension, a width dimension and a first thickness dimension;    stamping a plurality of apertures in said strip of metallic material to form a plurality of heat sinks disposed adjacent at least one rail member, each of said plurality of heat sinks comprising a member having at least a partially planar front surface, a partially planar rear surface and a perimeter surface joining said front surface with said rear surface, said front and rear surfaces defining a second thickness dimension proximal said perimeter surface, each of said plurality of heat sinks being attached to said at least one rail member by a bridge member having a front and a rear surface, said front and rear surfaces of said bridge member facing substantially parallel to said front and rear surfaces of a proximal one of said plurality of heat sinks, said bridge member comprising a region of reduced thickness relative to said second thickness dimension;    immersing said plurality of heat sinks in a solvent bath;    exposing said plurality of heat sinks to an electric current while in said solvent bath to form an anodic film on said plurality of heat sinks, said anodic film penetrating said front and rear surfaces of said plurality of heat sinks and said front and rear surfaces of said bridge member by a predetermined amount; and    thereafter detaching said plurality of heat sinks from said at least one rail member by separating said bridge members.    
     
     
         11 . The method of  claim 10 , wherein: 
 the step of stamping a plurality of apertures comprises forming a first and a second rail member disposed in a parallel, spaced-apart configuration with said plurality of heat sinks disposed therebetween.    
     
     
         12 . The method of  claim 10 , wherein: 
 said region of reduced thickness is formed by coining a portion of said bridge member.    
     
     
         13 . The method of  claim 10 , wherein 
 said region of reduced thickness is formed such that said front and rear surfaces of said bridge member meet said perimeter surface at an angle substantially equal to ninety degrees.    
     
     
         14 . The method of  claim 10 , wherein: 
 the step of separating said bridge members comprises breaking said bridge members.