Additive manufacturing system with gas flow head

Abstract

An additive manufacturing system may include a build surface, one or more laser energy sources, and an optics assembly. Exposure of a layer of material on the build surface to laser energy from the optics assembly melts at least a portion of the layer of material. A gas flow head is coupled to the optics assembly and defines a partially enclosed volume between the optics assembly and the build surface. The gas flow head includes a gas inflow through which a supply gas flows into the gas flow head, a gas outflow through which a return gas flows out of the gas flow head, and an aperture arranged to permit transmission of the laser energy through the gas flow head to the build surface. The supply gas and return gas define a gas flow profile within the gas flow head.

1 . An additive manufacturing system comprising:
 a build surface;   one or more laser energy sources;   an optics assembly movable relative to the build surface and configured to direct laser energy from the one or more laser energy sources toward the build surface to melt at least a portion of a layer of material on the build surface; and   a gas flow head coupled to the optics assembly and defining a partially enclosed volume between the optics assembly and the build surface, the gas flow head comprising:
 a gas inflow through which a supply gas flows into the gas flow head during operation of the gas flow head; 
 a gas outflow through which a return gas flows out of the gas flow head during operation of the gas flow head; and 
 an aperture configured to permit transmission of the laser energy through the gas flow head to the build surface, wherein the supply gas and return gas define a gas flow profile during operation of the gas flow head, wherein at least a portion of the gas flow profile flows from a first side of the melted portion of the layer of material to a second side of the melted portion of the layer of material during operation of the gas flow head. 
   
     
     
         2 . The additive manufacturing system of  claim 1 , wherein the gas inflow is configured to be disposed on the first side of the melted portion and the gas outflow is configured to be disposed on the second side of the melted portion during operation of the gas flow head. 
     
     
         3 . The additive manufacturing system of  claim 1 , wherein the gas flow head and optics assembly are configured to be moved across the build surface at substantially a same velocity. 
     
     
         4 . The additive manufacturing system of  claim 1 , wherein the aperture has an area ranging from between about 10 and about 10,000 times a beam area of the one or more laser energy sources. 
     
     
         5 . The additive manufacturing system of  claim 4 , wherein the gas flow head has an area ranging from between about 10 to about 100 times the area of the aperture. 
     
     
         6 . The additive manufacturing system of  claim 5 , wherein the area of the gas flow head is about 0.05 to about 0.2 times an area of the build surface. 
     
     
         7 . The additive manufacturing system of  claim 1 , wherein a maximum dimension of the aperture is less than  15  millimeters larger than a maximum beam width of the one or more laser energy sources. 
     
     
         8 . The additive manufacturing system of  claim 1 , wherein the gas flow head further comprises a lower surface adjacent to the build surface and an upper surface positioned between the optics assembly and the lower surface. 
     
     
         9 . The additive manufacturing system of  claim 8 , wherein at least a portion of the gas flow profile flows between the lower surface and the upper surface. 
     
     
         10 . The additive manufacturing system of  claim 8 , wherein the aperture is a first aperture positioned on the upper surface, and wherein the gas flow head further comprises a second aperture positioned on the lower surface. 
     
     
         11 . The additive manufacturing system of  claim 10 , wherein the first aperture and the second aperture are aligned with one another. 
     
     
         12 . The additive manufacturing system of  claim 10 , wherein the first aperture has a first maximum dimension ranging from 1 to 2 millimeters (mm) larger than a beam width of the one or more laser energy sources, and the second aperture has a second maximum dimension ranging from 5 to 15 mm larger than the first maximum dimension. 
     
     
         13 . The additive manufacturing system of  claim 10 , further comprising an optical window covering the first aperture and arranged to permit transmission of laser energy through the first aperture. 
     
     
         14 . The additive manufacturing system of  claim 1 , wherein the gas flow profile within the gas flow head is configured to entrain ejected particles and/or fumes generated by exposure of the layer of material to the laser energy. 
     
     
         15 . The additive manufacturing system of  claim 1 , wherein the gas flow head further comprises a pair of baffle plates extending towards the build surface, wherein each baffle plate is substantially parallel to a scan direction of the gas flow head. 
     
     
         16 . The additive manufacturing system of  claim 15 , wherein each baffle plate is selectively actuatable between an extended position and a retracted position. 
     
     
         17 . A method for additive manufacturing comprising:
 directing laser energy from one or more laser energy sources through an optics assembly and toward a build surface, wherein the optics assembly is movable in a scan direction relative to the build surface;   exposing a layer of material on the build surface to the laser energy;   melting at least a portion of the layer of material due to exposure of the portion to the laser energy;   generating a flow of gas through a gas flow head in a direction that flows from a first side of the melted portion of the layer of material to a second side of the melted portion of the layer of material during operation of the gas flow head, the gas flow head being coupled to the optics assembly and movable with the optics assembly and defining a partially enclosed volume between the optics assembly and the build surface.   
     
     
         18 . The method of  claim 17 , wherein generating the flow of gas through the gas flow head comprises flowing a supply gas into the gas flow head through a gas inflow on the first side of the melted portion and flowing a return gas out of the gas flow through a gas outflow on the second side of the melted portion. 
     
     
         19 . The method of  claim 17 , further comprising moving the gas flow head and the optics assembly in the scan direction at substantially a same velocity. 
     
     
         20 . The method of  claim 17 , wherein exposing a layer of material on the build surface to the laser energy comprises directing the laser energy through at least one aperture of the gas flow head. 
     
     
         21 . The method of  claim 20 , wherein directing the laser energy through the at least one aperture of the gas flow head comprises directing the laser energy through an aperture having an area ranging from between about 10 and about 10,000 times a beam area of the one or more laser energy sources. 
     
     
         22 . The method of  claim 20 , wherein directing the laser energy through the at least one aperture of the gas flow head comprises directing the laser energy through an aperture having an area ranging from about 1% to about 10% of an area of the gas flow head. 
     
     
         23 . The method of  claim 20 , wherein directing the laser energy through the at least one aperture of the gas flow head comprises directing the laser energy through an aperture having a maximum dimension less than 15 millimeters larger than a maximum beam width of the one or more laser energy sources. 
     
     
         24 . The method of  claim 20 , wherein directing the laser energy through the at least one aperture further comprises directing the laser energy through an optical window covering the at least one aperture and arranged to permit transmission of the laser energy through the at least one aperture. 
     
     
         25 . The method of  claim 17 , wherein generating the flow of gas through the gas flow head comprises generating the flow of gas between a lower surface of the gas flow head and an upper surface of the gas flow head, the lower surface positioned adjacent to the build surface and the upper surface positioned between the optics assembly and the lower surface. 
     
     
         26 . The method of  claim 25 , wherein exposing a layer of material on the build surface to the laser energy comprises directing the laser energy through a first aperture in the upper surface of the gas flow head and a second aperture in the lower surface of the gas flow head. 
     
     
         27 . The method of  claim 26 , wherein directing the laser energy through the first and second apertures further comprises directing laser energy through the first and second aperture, the first and second aperture being aligned with one another. 
     
     
         28 . The method of  claim 26 , wherein directing the laser energy through the first and second apertures further comprises the first aperture having a first maximum dimension ranging from 1 to 2 millimeters (mm) larger than a beam width of the one or more laser energy sources, and the second aperture having a second maximum dimension ranging from 5 to 15 mm larger than the first maximum dimension. 
     
     
         29 . The method of  claim 17 , further comprising entraining ejected particles and/or fumes in the flow of gas, the ejected particles and/or fumes being generated by exposure of the layer of material to the laser energy. 
     
     
         30 . The method of  claim 17 , further comprising selectively actuating at least one of a pair of baffle plates of the gas flow head between an extended position and a retracted position.