Patent ID: 11878350
Assignee: 3D SYSTEMS, INC.
Field: Materials, metallurgy (Chemistry)
Classification: CPC B  Y | IPC B

Claim 16:
17. A method of fabricating a three dimensional (3D) article comprising:
providing a 3D print engine including:
a plurality of walls laterally defining a build chamber;
a build box including a build plate coupled to a vertical positioning apparatus, the build plate defining a lateral area;
a powder dispenser;
a beam system configured to generate a plurality of energy beams that scan over a build plane within the lateral area of the build plate and that is at a fixed height for powder fusion;
a peripheral plate disposed between the build plate and the plurality of walls, the peripheral plate having an upper surface;
a gas inlet that ejects a gas flow stream at an inlet end of the build chamber and passes over the build plane and at least part of the upper surface of the peripheral plate;
a gas outlet at an outlet end of the build chamber and receives the gas flow stream from the gas inlet;
a plurality of projecting structures mounted to and extending above the upper surface of the peripheral plate, the plurality of projecting structures shaping the flow field of the gas flow stream to provide a more uniform velocity of gas flow velocities above the build plane;
the upper surface of the peripheral plate includes an outlet surface which is laterally disposed between the build plate and the gas outlet, the plurality of projecting structures including a dam wall projecting above the outlet surface and having a major axis along an axis Y that is perpendicular to a general flow direction X of the gas stream, the dam wall includes two dam walls that individually span a portion of a width of the build chamber and have a gap between them along the axis Y; and
a gas handling system coupled to the gas inlet and gas outlet;

operating the vertical positioning system to position the build plate for receiving a new layer of powder;
operating the powder dispenser to dispense the new layer of powder over the build plate or a previously dispensed layer of powder, the new layer of powder having an upper surface proximate to the build plane;
operating the gas handling system to emit the gas flow stream from the gas inlet;
shaping the gas flow stream with the plurality of projecting structures to shape the flow field of the gas flow stream to provide a more uniform velocity of gas flow velocities above the build plane;
operating the beam system to selectively fuse the new layer of powder; and
repeating operation of the vertical positioning system, the powder dispenser, the gas handling system, and the beam system to complete fabrication of the 3D article.