Method for fusing a workpiece

Abstract

Various embodiments of the present invention relate to a method for welding a workpiece comprising the steps of: making a first weld at a first position on said workpiece with a high energy beam, deflecting the high energy beam with at least one deflection lens for making a second weld at a second position on said workpiece, focusing the high energy beam on said workpiece with at least one focusing lens, shaping the high energy beam on said workpiece with at least one astigmatism lens so that the shape of the high energy beam on said workpiece is longer in a direction parallel to a deflection direction of said high energy beam than in a direction perpendicular to said deflection direction of said high energy beam. The invention is also related to the use of an astigmatism lens and to a method for forming a three dimensional article.

That which is claimed: 
     
         1 . A method for welding a workpiece, said method comprising the steps of:
 making a first weld at a first position on said workpiece with a high energy beam;   deflecting the high energy beam with at least one deflection lens to make a second weld at a second position on said workpiece;   focusing the high energy beam on said workpiece with at least one focusing lens; and   shaping the high energy beam on said workpiece with at least one astigmatism lens so that the shape of the high energy beam on said workpiece is longer in a direction parallel to a deflection direction of said high energy beam than in a direction perpendicular to said deflection direction of said high energy beam,   wherein a ratio of a length of said high energy beam in said parallel direction and said perpendicular direction is varying as a function of the power of said energy beam on said workpiece.   
     
     
         2 . The method according to  claim 1 , wherein said high energy beam is at least one of an electron beam or a laser beam. 
     
     
         3 . The method according to  claim 1 , wherein said deflection source is at least one of a tiltable mirror or a tiltable lens. 
     
     
         4 . The method according to  claim 1 , wherein said deflection source is a deflection coil. 
     
     
         5 . The method according to  claim 1 , wherein said workpiece is a powder material layer in an additive manufacturing process. 
     
     
         6 . The method according to  claim 1 , wherein a ratio of a length of said high energy beam in said parallel direction and said perpendicular direction is also varying as a function of the position of said high energy beam on said workpiece. 
     
     
         7 . The method according to  claim 1 , wherein said energy beam is at least five (5) times longer in a direction parallel to the deflection direction compared to a direction perpendicular to said deflection direction. 
     
     
         8 . The method according to  claim 1 , wherein said energy beam is at least ten (10) times longer in a direction parallel to the deflection direction compared to a direction perpendicular to said deflection direction. 
     
     
         9 . The method according to  claim 1 , wherein a mean spot size on said workpiece in a direction perpendicular to the scanning direction is smaller than a mean spot size on said workpiece in a direction parallel to the scanning direction for a full scan length, a full cross section and/or for a full 3-dimensional article. 
     
     
         10 . The method according to  claim 1 , wherein one or more of the steps of deflecting, focusing, and shaping the high energy beam are performed via execution of one or more computer processors. 
     
     
         11 . A method of using of an astigmatism lens in additive manufacturing for forming a three-dimensional article through successive fusion, with a high energy beam, of parts of at least one layer of a powder bed provided on a work table, which parts correspond to successive cross sections of the three dimensional article, said method comprising the step of:
 using said astigmatism lens to prolong the size the high energy beam on said layer of powder bed in a direction parallel to a deflection direction more than in a direction perpendicular to said deflection direction,   wherein a ratio of a length of said high energy beam in said parallel direction and said perpendicular direction is varying as a function of the power of said energy beam on said workpiece.   
     
     
         12 . A method for forming a three-dimensional article through successively depositing individual layers of powder material that are fused together so as to form the article, said method comprising the steps of:
 providing at least one high energy beam source for emitting a high energy beam for at least one of heating or fusing said powder material;   providing a deflection source for deflecting the high energy beam on said powder material;   providing a focus lens for focusing said high energy beam on said powder material; and   shaping the high energy beam on said powder layer with at least one astigmatism lens so that the shape of the high energy beam on said layer of powder is longer in a direction parallel to a deflection direction of said high energy beam than in a direction perpendicular to said deflection direction of said high energy beam,   wherein a ratio of a length of said high energy beam in said parallel direction and said perpendicular direction is varying as a function of the power of said energy beam on said workpiece.   
     
     
         13 . The method according to  claim 12 , wherein said high energy beam is at least one of an electron beam or a laser beam. 
     
     
         14 . The method according to  claim 12 , wherein said deflection source is at least one of a tiltable mirror or a tiltable lens. 
     
     
         15 . The method according to  claim 12 , wherein said deflection source is a deflection coil. 
     
     
         16 . The method according to  claim 12 , wherein a ratio of a length of said high energy beam in said parallel direction and said perpendicular direction is also varying as a function of the position of said high energy beam on said workpiece. 
     
     
         17 . The method according to  claim 12 , wherein said energy beam is at least five (5) times longer in a direction parallel to the deflection direction compared to a direction perpendicular to said deflection direction. 
     
     
         18 . The method according to  claim 12 , wherein said energy beam is at least ten (10) times longer in a direction parallel to the deflection direction compared to a direction perpendicular to said deflection direction. 
     
     
         19 . The method according to  claim 12 , wherein a mean spot size on said workpiece in a direction perpendicular to the scanning direction is smaller than a mean spot size on said workpiece in a direction parallel to the scanning direction for a full scan length, a full cross section and/or for a full 3-dimensional article. 
     
     
         20 . The method according to  claim 12 , wherein:
 the method further comprises the step of receiving and storing, within one or more memory storage areas, a model of said at least one three-dimensional article; and   at least the step of shaping the high energy beam is performed via execution of one or more computer processors.   
     
     
         21 . An apparatus for forming a three-dimensional article through successively depositing individual layers of powder material that are fused together so as to form the article, said apparatus comprising:
 at least one high energy beam source for emitting a high energy beam for at least one of heating or fusing said powder material;   a deflection source for deflecting the high energy beam on said powder material;   a focus lens for focusing said high energy beam on said powder material;   at least one astigmatism lens; and   at least one controller configured to control said at least one astigmatism lens so as to shape the high energy beam on said powder layer such that the shape of the high energy beam on said layer of powder is longer in a direction parallel to a deflection direction of said high energy beam than in a direction perpendicular to said deflection direction of said high energy beam, wherein a ratio of a length of said high energy beam in said parallel direction and said perpendicular direction is varying as a function of the power of said energy beam on said workpiece.   
     
     
         22 . The apparatus according to  claim 21 , wherein said high energy beam is at least one of an electron beam or a laser beam. 
     
     
         23 . The apparatus according to  claim 21 , wherein said deflection source is at least one of a tiltable mirror or a tiltable lens or a deflection coil. 
     
     
         24 . The apparatus according to  claim 21 , wherein a ratio of a length of said high energy beam in said parallel direction and said perpendicular direction is also varying as a function of the position of said high energy beam on said workpiece. 
     
     
         25 . The apparatus according to  claim 21 , wherein said energy beam is at least five (5) times longer in a direction parallel to the deflection direction compared to a direction perpendicular to said deflection direction. 
     
     
         26 . The apparatus according to  claim 21 , wherein said energy beam is at least ten (10) times longer in a direction parallel to the deflection direction compared to a direction perpendicular to said deflection direction. 
     
     
         27 . The apparatus according to  claim 21 , wherein a mean spot size on said workpiece in a direction perpendicular to the scanning direction is smaller than a mean spot size on said workpiece in a direction parallel to the scanning direction for a full scan length, a full cross section and/or for a full 3-dimensional article. 
     
     
         28 . An apparatus for welding a workpiece, said apparatus comprising:
 a high energy beam configured to make a first weld at a first position on said workpiece;   at least one deflection lens configured to deflect the high energy beam so as to cause the high energy beam to make a second weld at a second position on said workpiece;   at least one focusing lens configured to focus the high energy beam on said workpiece; and   at least one astigmatism lens; and   at least one controller configured to:
 shape the high energy beam on said workpiece with said at least one astigmatism lens so that the shape of the high energy beam on said workpiece is longer in a direction parallel to a deflection direction of said high energy beam than in a direction perpendicular to said deflection direction of said high energy beam, 
 wherein a ratio of a length of said high energy beam in said parallel direction and said perpendicular direction is varying as a function of the power of said energy beam on said workpiece. 
   
     
     
         29 . A computer program product for forming a three-dimensional article through successively depositing individual layers of powder material that are fused together so as to form the article, the computer program product comprising at least one non-transitory computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising:
 an executable portion configured to provide at least one high energy beam source for emitting a high energy beam for at least one of heating or fusing said powder material;   an executable portion configured to provide a deflection source for deflecting the high energy beam on said powder material;   an executable portion configured to provide a focus lens for focusing said high energy beam on said powder material;   an executable portion configured to shape the high energy beam on said powder layer with at least one astigmatism lens so that the shape of the high energy beam on said layer of powder is longer in a direction parallel to a deflection direction of said high energy beam than in a direction perpendicular to said deflection direction of said high energy beam,   wherein a ratio of a length of said high energy beam in said parallel direction and said perpendicular direction is varying as a function of the power of said energy beam on said workpiece.   
     
     
         30 . A computer program product for welding a workpiece, the computer program product comprising at least one non-transitory computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising:
 an executable portion configured to make a first weld at a first position on said workpiece with a high energy beam;   an executable portion configured to deflect the high energy beam with at least one deflection lens for making a second weld at a second position on said workpiece;   an executable portion configured to focus the high energy beam on said workpiece with at least one focusing lens; and   an executable portion configured to shape the high energy beam on said workpiece with at least one astigmatism lens so that the shape of the high energy beam on said workpiece is longer in a direction parallel to a deflection direction of said high energy beam than in a direction perpendicular to said deflection direction of said high energy beam,   wherein a ratio of a length of said high energy beam in said parallel direction and said perpendicular direction is varying as a function of the power of said energy beam on said workpiece.