Method and apparatus for reliably laser marking articles

Abstract

The invention is a method and apparatus for creating marks 194 on an anodized aluminum specimen 190 with selectable color and optical density. The method includes providing a laser marking system 148 having a laser 150 , laser optics 154 and a controller 160 operatively connected to said laser 150 to control laser pulse parameters. The laser marking system 148 is directed to produce laser pulses 152 having laser pulse parameters associated with the desired color and optical density in the presence of a fluid 168 directed to the surface of the anodized aluminum specimen 158 while marking.

1 . A method for creating a mark on an article, said method comprising:
 providing said article;   cooling at least a portion of the article; and   directing a beam of laser pulses onto said article thereby creating said mark.   
     
     
         2 . The method of  claim 45  wherein said article is an anodized aluminum article. 
     
     
         3 - 4 . (canceled) 
     
     
         5 . The method of  claim 49  wherein said fluid is water. 
     
     
         6 . The method of  claim 49  wherein said fluid is a flowing fluid. 
     
     
         7 . The method of  claim 6  further comprising moving said fluid in relation to said anodized metal article to maintain a relationship between said fluid and said laser pulses. 
     
     
         8 - 17 . (canceled) 
     
     
         18 . The method of  claim 1  wherein said mark has an optical density equal to or less than about L*=40, a*=5, and b*=10. 
     
     
         19 . (canceled) 
     
     
         20 . A laser marking apparatus adapted to produce marks on an article, said apparatus comprising:
 a laser operative to produce laser pulses;   laser optics operative to modify and direct said laser pulses;   a stage operative to hold and position said article;   a fluid operative to absorb heat from said article; and   a controller operative to access predetermined laser pulse parameters and in cooperation with said laser, laser optics and stage, create and direct said laser pulses according to said predetermined laser pulse parameters to impinge upon said article while said fluid absorbs heat created by said laser pulses from said article thereby producing said marks.   
     
     
         21 - 23 . (canceled) 
     
     
         24 . The apparatus of  claim 20  wherein said fluid is water. 
     
     
         25 . The apparatus of  claim 20  further comprising a nozzle configured to direct a flow of said fluid onto said anodized article. 
     
     
         26 . The apparatus of  claim 25  wherein said fluid flow is moveable in relation to said article to maintain a relationship between said fluid and said laser pulses. 
     
     
         27 - 41 . (canceled) 
     
     
         42 . The method of  claim 1 , therein said article includes a substrate. 
     
     
         43 . The method at  claim 42 , wherein said substrate is a metal substrate. 
     
     
         44 . The method of  claim 42 , wherein said article includes a layer on a surface of the substrate. 
     
     
         45 . The method of  claim 1 , wherein
 said article includes a layer having, at a first temperature, a fluence threshold above which said layer tends to become damaged, and   said cooling at least said portion of said article comprises cooling at least said portion of said layer to a second temperature lower than the first temperature.   
     
     
         46 . The method of  claim 45 , wherein directing said beam of laser pulses onto said article comprises directing said beam of laser pulses onto said article at a fluence level above said fluence threshold. 
     
     
         47 . The method of  claim 44 , wherein said layer includes an oxide layer. 
     
     
         48 . The method of  claim 47 , wherein said layer includes an anodic oxide layer. 
     
     
         49 . The method of  claim 1 , wherein cooling at least a portion of said article comprises thermally contacting said article with a fluid. 
     
     
         50 . The method of  claim 1 , wherein cooling at least said portion of said article comprises cooling at least said portion of said article while directing said beam of laser pulses onto said article. 
     
     
         51 . The apparatus of  claim 25 , further comprising a fluid supply coupled to said nozzle, said fluid supply configured to supply said fluid to said nozzle. 
     
     
         52 . An article having a mark created thereon, said mark being created according to a process comprising:
 providing said article;   cooling at least a portion of the article; and   directing a beam of laser pulses onto said article thereby creating said mark.   
     
     
         53 . The article of  claim 52 , wherein said article includes a substrate. 
     
     
         54 . The article of  claim 53 , wherein said substrate includes a metal. 
     
     
         55 . The article of  claim 53 , wherein said article includes a layer on a surface of the substrate. 
     
     
         56 . The article of  claim 55 , wherein said layer includes an oxide layer. 
     
     
         57 . The article of  claim 56 , wherein said layer includes an anodic oxide layer. 
     
     
         58 . The article of  claim 52 , wherein
 said article includes a layer having, at a first temperature, a fluence threshold above which said layer tends to become damaged, and   said cooling at least said portion of said anodized metal article comprises cooling at least said portion of said anodic oxide layer to a second temperature lower than the first temperature.   
     
     
         59 . The article of  claim 56 , wherein directing said beam of laser pulses onto said anodized metal article comprises directing said beam of laser pulses onto said anodized metal article at a fluence level above said fluence threshold. 
     
     
         60 . The article of  claim 52 , wherein said article is an anodized aluminum article. 
     
     
         61 . The article of  claim 52 , wherein said mark has an optical density equal to or less than about L*=40, a*=5, and b*=10.