THREE-DIMENSIONAL PRINTING SYSTEMS AND METHODS OF THEIR USE
The present disclosure describes three-dimensional (3D) printing apparatuses, processes, software, and systems for producing high quality 3D objects. Described herein are printing apparatuses that facilitate control of energy beam characteristics using an optical mask during one or more printing operations.
1 . An apparatus for printing a three-dimensional object, the apparatus comprising:
a platform configured to support a powder bed comprising a powder material;
a layer forming device configured to form multiple layers of the powder as part of the powder bed, which layer forming device comprises a blade or a roller configured to translate in a first direction over an exposed surface of the powder bed to planarize the exposed surface of the powder bed;
an elevator operationally coupled with the platform, wherein the elevator comprises a motor configured to translate the platform in a second direction substantially perpendicular to the first direction;
a processing chamber having an internal volume configured to enclose at least the exposed surface of the powder bed during the printing, wherein the processing chamber includes a ceiling wall;
a laser configured to generate a laser beam that melts at least a portion of the powder bed to a molten material as part of the three-dimensional object during the printing;
a window coupled to the ceiling wall of the processing chamber, which window is configured to permit the laser beam to pass therethrough to the internal volume of the processing chamber;
a gas flow system configured to provide a flow of gas within the internal volume of the processing chamber, which flow of gas provides a stream of particles that progressively deposits an optical mask on an internal surface of the window, which optical mask progressively absorbs energy from the laser beam and modifies a peak power density of the laser beam during melting of at least one of the multiple layers of powder, wherein the optical mask causes the peak power density of the laser beam to vary by (i) at least 5% after forming 3,000 cm 3 of the molten material compared to a variation of the peak power density of the laser beam transmitted through the window excluding the optical mask and (ii) at least 10% after forming 5,000 cm 3 of the molten material compared to the variation of the peak power density of the laser beam transmitted through the window excluding the optical mask;
a galvanometer scanner configured to translate the laser beam across the exposed surface of the powder bed in accordance with a path, wherein the galvanometer scanner is external to the internal volume of the processing chamber; and
one or more controllers operationally coupled with the elevator, the layer forming device and the galvanometer scanner, which one or more controllers is configured to direct (a) the elevator to translate the platform in the second direction, (b) the layer forming device to translate in the first direction, and (c) the galvanometer scanner to direct the laser beam at the powder bed in accordance with the path.
2 . The apparatus of claim 1 , wherein the optical mask causes the peak power density of the laser beam to increase during at least part of the melting of the at least one of the multiple layers of powder.
3 . The apparatus of claim 1 , wherein the optical mask causes the peak power density of the laser beam to decrease during at least part of the melting of the at least one of the multiple layers of powder.
4 . The apparatus of claim 1 , wherein during the printing, the apparatus is configured to melt at least about five (5) cubic centimeters of the molten material per hour.
5 . The apparatus of claim 1 , wherein the varied peak power density of the laser beam in accordance with one or both of (i) and (ii) is associated with forming regions of porosity within the three-dimensional object.
6 . The apparatus of claim 1 , wherein the varied peak power density of the laser beam in accordance with one or both of (i) and (ii) is associated with forming regions of surface roughness on the three-dimensional object.
7 . The apparatus of claim 1 , wherein the stream of particles includes particles that become entrained within the flow of gas at or above the exposed surface of the powder bed.
8 . The apparatus of claim 1 , wherein the one or more controllers is operationally coupled with the gas flow system, which one or more controllers is configured to control a velocity of the stream of particles.
9 . The apparatus of claim 8 , wherein the control is in real time during the printing of the three-dimensional object.
10 . The apparatus of claim 1 , wherein the apparatus is configured generate at least about five (5) milligrams per second (mg/sec) of gas-borne particles during the printing.
11 . The apparatus of claim 1 , wherein the gas flow system is configured to facilitate a turbulent movement of the stream of particles in the internal volume of the processing chamber.
12 . The apparatus of claim 11 , wherein (I) a wall of the processing chamber and/or (II) a baffle in the processing chamber, is configured to facilitate the turbulent movement of the stream of particles.
13 . The apparatus of claim 12 , wherein (III) the wall of the processing chamber and/or (IV) the baffle in the processing chamber, is normal or substantially normal to the internal surface of the window.
14 . The apparatus of claim 11 , wherein the turbulent movement is directly adjacent to the window.
15 . The apparatus of claim 11 , wherein the window is in a recessed portion of the processing chamber, wherein a side wall of the recessed portion causes the turbulent movement of the stream of particles to preferentially deposit particles on a select region of the internal surface of the window.
16 . The apparatus of claim 1 , wherein the gas flow system is configured to provide the flow of gas at a substantially constant velocity within the processing chamber during at least the melting of the at least the portion of the powder bed.
17 . The apparatus of claim 1 , wherein the flow of gas has a velocity ranging from about 0.2 to about 2 meters per second (m/sec).
18 . The apparatus of claim 1 , wherein particles within the stream of particles comprise at least about 10% metal oxide by volume.