Method of manufacturing a cold plate heat exchanger assembly having a metallic compliant gasket

Abstract

The subject invention provides a method of manufacturing an all-metal cold plate heat exchanger assembly for removing excess heat from a heat generating electronic component. The cold plate assembly includes a base plate having micro-channels and associated micro-fins, a manifold plate having alternating channels, and a manifold cover, wherein the manifold plate cooperates with the micro-channels to form an engineered pathway for coolant flow. This method assures a tight interface sealing between the contact surfaces of the alternating channels of the manifold plate and the coplanar surfaces of the micro-fins that would prevent coolant by-pass flow, but without clogging or jeopardizing the flow through the micro-channels. This method utilizes a layer of recast metallic particulates, which is a natural by-product of laser machining, as a compliant gasket material between the coplanar edges of the alternating channels and the coplanar edges of the micro-fins.

1 . A method of manufacturing a cold plate heat exchanger assembly for a heat-producing component, comprising the steps of:
 providing a base plate formed of a material suitable for laser machining, wherein said base plate has an interior surface that is substantially planar;   providing a manifold cover;   providing a manifold plate having alternating inlet-outlet channels, wherein said inlet-outlet channels have coplanar surfaces;   laser machining a pattern of alternating substantially parallel micro-channels and micro-fins into said base plate interior surface, wherein each of said micro-fins have a micro-fin edge, and wherein said laser machining includes controlling laser energy and ambient temperature to produces aerosol particulate matter that rises from said micro-channels and deposits onto said micro-fin edges to form a recast layer;   arranging said cover manifold onto said base plate with said manifold plate in between such that said inlet-outlet channel coplanar surfaces are disposed adjacent to said micro-fin edges with said recast layer in between;   pressing said manifold cover toward said base plate to compress the recast layer to form a compliant gasket in between; and   hermetically sealing said base plate to said manifold cover.   
   
   
       2 . The method of manufacturing a cold plate assembly of  claim 1  wherein the step of said laser machining further comprises the steps of:
 blanketing said base plate interior surface with an inert cover gas having a predetermined temperature below dew point of said vaporized base plate material; and   focusing and maneuvering a laser beam onto said base plate interior surface, wherein said laser beam has sufficient intensity to vaporize said base plate material into said aerosol particulate matter, thereby forming said micro-channels and said micro-fins;   wherein said vaporized base plate material rises from said micro-channels into said cover gas and condenses into micro-droplets, which then deposit onto said micro-fin edges to form said recast layer.   
   
   
       3 . The method of manufacturing a cold plate assembly of  claim 1 , wherein said recast layer has a height less than 65 microns. 
   
   
       4 . The method of manufacturing a cold plate assembly of  claim 3 , wherein said recast layer has a height in the range 30 to 64 microns. 
   
   
       5 . The method of manufacturing a cold plate assembly of  claim 1 , where said recast layer has a coverage ratio in the range 0.3 to 1.0 
   
   
       6 . The method of manufacturing a cold plate assembly of  claim 1 , wherein said manifold plate is formed integrally with manifold cover. 
   
   
       7 . The method of manufacturing a cold plate assembly of  claim 1 , wherein said base plate is formed of copper. 
   
   
       8 . A method of manufacturing a cold plate heat exchanger assembly for an electronic component, comprising the steps of:
 providing a base plate formed of copper, wherein said base plate has an interior surface that is substantially planar;   providing a manifold cover and alternating inlet-outlet channels, wherein said inlet-outlet channels have coplanar surfaces;   providing a blanket of inert cover gas on to said base plate;   laser machining a pattern of alternating substantially parallel micro-channels and micro-fins into said base plate interior surface, wherein each of said micro-fins have a micro-fin edge, and wherein said laser machining includes controlling laser energy to produce aerosol particulate matter that rises from said micro-channels into said cover gas and controlling temperature of said cover gas so that said aerosol particulate matter condenses onto said micro-fin edges to form a recast layer;   arranging said cover manifold onto said base plate such that said inlet-outlet channel coplanar surfaces are disposed adjacent to said micro-fin edges with said recast layer in between;   pressing said manifold cover toward said base plate to compress the recast layer to form a compliant gasket in between; and   hermetically sealing said base plate to said manifold cover.   
   
   
       9 . The method of manufacturing a cold plate assembly of  claim 8 , wherein said recast layer has a height in the range 30 to 64 microns. 
   
   
       10 . The method of manufacturing a cold plate assembly of  claim 9 , where said recast layer has a coverage ratio in the range 0.3 to 1.0. 
   
   
       11 . The method of manufacturing a cold plate assembly of  claim 10 , wherein said coplanar surfaces of said inlet-outlet channels are in intimate contact with coplanar edges of micro-fins forming a checker board flow pattern.