Cyclic variable timer for additive manufacturing

Abstract

A print engine of an additive manufacturing system may include an XY galvanometer arranged to direct a laser beam toward a plurality of locations on a print bed along a print path. In one embodiment, an XY gantry supporting an XY galvanometer is connected to a motion control system that supports dynamic adjustment of the cycle time of both the XY gantry and the XY galvanometer.

Description

Related Applications

[0001] This disclosure is part of a non - provisional patent application claiming the benefit of priority of U.S. Patent Application No. 63 / 387,617, filed on December 15, 2022, which is incorporated herein by reference in its entirety. Technical Field

[0002] This disclosure generally relates to systems and methods for powder bed preparation for high - throughput additive manufacturing. In one embodiment, high - speed manufacturing is enabled by using a pulsed laser controller that is synchronized with a process system controller and allows scheduling of the timing of laser pulses within an allowed frequency range based on real - time process feedback. Background

[0003] Traditional component machining often relies on removing material by drilling, cutting, or grinding to form parts. In contrast, additive manufacturing (also known as 3D printing) generally involves continuously adding material layer - by - layer to build parts. Starting from a 3D computer model, additive manufacturing systems can be used to form complex parts from a variety of materials.

[0004] One known additive manufacturing technique - powder bed fusion additive manufacturing (PBF - AM) uses one or more focused lasers to draw patterns in a thin layer of powder by melting the powder and bonding it to the underlying layer to gradually form a 3D printed part. The powder can be plastic, metal, glass, ceramic, crystal, other meltable materials, or a combination of meltable and non - meltable materials (i.e., plastic and wood or metal and ceramic).

[0005] Often, pulsed lasers with a fixed clock generated by a laser control system are used. Typically, when not printing, the clock timing can vary or shift, but in order to maintain high - quality laser pulses during printing, the frequency and phase should not change significantly. In practice, this means that if the motion is not completed within the allotted maximum time, the laser control system will "skip" a cycle.

[0006] To increase throughput and print quality, a method for dynamic cycle - time regulation is needed. Advantageously, this can reduce cycle skipping and improve the speed and quality of powder bed printing. Brief Description of the Drawings

[0007] Non - limiting and non - exhaustive embodiments of the present disclosure are described with reference to the following drawings, in which like reference numerals refer to like parts throughout the various views unless otherwise specified.

[0008] Figure 1A An embodiment of a tile printing process is shown; Figure 1B A modified serpentine tile printing path is shown; Figure 1C shows an offset tile overlap; Figure 1D shows a printer control system and a laser control system that can control laser timing during tile printing.

[0009] Figure 1E shows an embodiment of a laser heating cycle; Figure 1F shows a top view and a side view of an XY gantry supporting an XY galvanometer mirror; Figure 2 shows XY gantry movement in two specific use cases; Figure 3 shows an additive manufacturing system capable of providing a one - dimensional or two - dimensional beam to a cartridge; Figure 4 shows a method of operating a cartridge - based additive manufacturing system capable of providing a one - dimensional or two - dimensional beam to a cartridge; and Figure 5 is an additive manufacturing system including a phase - change light valve and a switching station system that can reuse patterned two - dimensional energy. Detailed description

[0010] In the following description, reference is made to the accompanying drawings, which form a part of the description and in which are shown, by way of illustration, specific exemplary embodiments in which the present disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the concepts disclosed herein, and it should be understood that various disclosed embodiments may be modified and other embodiments may be utilized without departing from the scope of the present disclosure. Accordingly, the following detailed description should not be construed as limiting.

[0011] Figure 1A shows an embodiment of a tile printing process 100A. As Figure 1AAs shown, suitable software computer-aided design (CAD) files can be stored in a database accessible by an additive manufacturing printer, and the CAD files provide necessary details regarding printable part parameters and metadata. In one process embodiment, a part definition is selected for printing in a chamber. By using a recipe library, printing parameters are assigned, which include tile parameters, powder type, or nominal laser parameters. A print job is scheduled, and a powder bed and an optional cartridge system can be prepared for printing. Once printing begins, the layers are processed to determine tiling parameters (including size and offset), and laser parameters are set to compensate for support structures or overhang structures. A process print sequence algorithm (optionally including a serpentine path) can be selected, and data is streamed for job execution. Job execution can include: spreading and inspecting a powder layer, receiving tile bitmaps by a projector, receiving tile positions by a motion controller, and receiving tile laser parameters by a laser controller. During execution, the projector is prepared to display tiles, the laser controller prints the tiles, and the motion controller moves between subsequent tile positions until the print job is complete. In some embodiments, each printed layer can be inspected and indexed to the next layer along the Z-axis.

[0012] Figure 1B A modified tile print path 100B is shown, which shows an example print path for a rectangular print bed divided into 81 tiles. The print path moving from tile to tile is indicated by arrows in Figure 1B . Various alternative print paths can also be arranged using tiling parameters such as tile size, tile offset, and width. In some embodiments, the print path can be arranged at least in part based on the pattern to be printed and / or the number of tiles that can be managed by a galvanometer mirror system. In one embodiment, a serpentine path (such as that seen with reference to print path 100B) can be determined. The example serpentine path can be modified based on which tiles need to be printed and which do not. In some embodiments, the serpentine path can be shifted to start at the first corner of the first tile to be printed. In other embodiments, the path can be dynamically adjusted to minimize movement between tiles, or a hybrid serpentine path can be determined that accommodates other process or thermal constraints (e.g., allowing certain tiles to have longer rest times to cool). In some embodiments, those tiles that do not need to be printed can be skipped, advantageously reducing the mechanical movement required of the galvanometer gantry and galvanometer mirrors compared to embodiments that move to each tile position during a conventional linear or serpentine path to each potential tile position.

[0013] Figure 1CShows an offset tile overlap 100C. Typically, the overlap is a small fraction of the tile size and can be measured in units from microns to millimeters. In one embodiment, an x and y offset is provided for a subsequent layer relative to the underlying layer. In effect, this provides tile coverage and ensures that the seams of the stitching do not overlap. In some embodiments, instead of or in addition to the overlap between layers, a tile overlap can be set such that tiles can overlap within the same print layer.

[0014] Figure 1D Shows a printer control system and a laser control system 100D, which can control laser timing during tile printing. As shown, the streamed tile data for printing is continuously supplied to a tile image projector, a tile position motion controller, and a laser controller. In one embodiment, the streaming of the data is configured such that the image projector and the motion controller always have more queued data than the laser controller, thus ensuring that the image projector and the motion controller have sufficient tile information to trigger the laser controller for the upcoming tile to be printed. In some embodiments, the streaming is not real-time and caching is required for the tile image projector, the tile position motion controller, and the laser controller.

[0015] When a minimum amount of tile data is cached, the printer control system passes the data to the laser control system. The light valve cycle and illumination can be configured, the motion controller moves the optics, and the projector provides a display to illuminate the desired tile. The laser heating time is set, the target site temperature is measured, the laser power is set, and the pulsed laser is enabled. Then the pulsed laser can be emitted in various timing or shaping sequences as needed. In some embodiments, the cycle time can be adjusted to help avoid cycle skipping.

[0016] Figure 1E Shows for use with such as reference Figure 1A and Figure 1DAn embodiment of a cyclic variable timer for the laser timing and heating cycle 100E of the described system and process. As shown, in one embodiment, the laser preparation and emission process can be carried out within a nominal 25 millisecond (40 Hz) cycle. A new image trigger can initiate such a process that includes skipping of individual tiles, or includes extended movement for skipping multiple tiles in some cycles. At the same time, the light valve can transition to a new pattern. Once the light valve is ready and the movement has stopped, laser heating can be initialized to bring the powder temperature in the desired pattern close to the melting point, and then a laser pulse is triggered to fully melt the powder in the desired pattern. Then the cycle is repeated until the tile fabrication for each layer is completed. In some embodiments, it is possible to perform dynamic cycle time adjustment within a certain tolerance (i.e., between 35 and 40 Hz). This can avoid some cycle skips, provided that the average frequency of the pulsed laser does not drop enough to cause thermal problems.

[0017] Figure 1F Top and side views of an XY gantry supporting XY galvanometer mirrors are shown. In some embodiments, movements such as those discussed with respect to Figure 1A , Figure 1D and Figure 1E can include both XY galvanometer mirror movement and movement of the XY gantry supporting the XY galvanometer mirrors. This embodiment can be used when the XY galvanometer range is not sufficient to address the entire print bed. As seen in the top view, a patterned or unpatterned laser beam can be directed by a fixed mirror towards a movable XY galvanometer mirror, which in turn directs the laser beam towards the print bed. Typically, an XY galvanometer mirror can rotate 0.5 degrees in 5 milliseconds or less, which is much faster than XY gantry movement.

[0018] Figure 2 XY gantry movement 200 in two specific usage scenarios of an XY gantry for supporting XY galvanometer mirrors as discussed with respect to Figure 1F is shown. In one embodiment, the XY gantry is sent to a set point with a determined acceleration and velocity. The distance between the set point and the actual XY gantry position is sent to the XY galvanometer. If this distance is within the range of XY galvanometer laser beam redirection, the tile target is within range and laser processing of the tile on the print can begin. This is shown for case 1 with respect to Figure 2 . If this distance is not within range, the XY gantry is moved (or continues to move) until the XY galvanometer is within range, as seen for case 2 with respect to Figure 2 . Note that in some embodiments, it is not necessary to stop the XY gantry movement before laser processing begins. Additionally, in some embodiments, new set point targets can be dynamically supplied to the XY gantry or XY galvanometer at any time.

[0019] In the embodiment shown with respect to Figure 3 the additive manufacturing system may be represented by various modules that form an additive manufacturing method and system 300, which is adapted to be used in conjunction with a tile printing process that may optionally use an XY galvanometer stage and a galvanometer mirror system with a cycle-variable timer. As Figure 3 seen, the laser source and amplifier 312 may be configured as a continuous laser or a pulsed laser. In other embodiments, the laser source includes a pulsed electrical signal source, such as an arbitrary waveform generator or an equivalent that acts on a continuous laser source, such as a laser diode. In some embodiments, this may also be achieved via a fiber laser or a fiber-emitted laser source that is then modulated by an acousto-optic or electro-optic modulator. In some embodiments, a high-repetition-rate pulsed source using a Pockels cell may be used to create a pulse sequence of any length.

[0020] Possible laser types include, but are not limited to: gas lasers, chemical lasers, dye lasers, metal vapor lasers, solid-state lasers (e.g., fiber), semiconductor (e.g., diode) lasers, free-electron lasers, gas dynamic lasers, "nickel-like" samarium lasers, Raman lasers, or nuclear-pumped lasers.

[0021] Gas lasers may include lasers such as helium-neon lasers, argon lasers, krypton lasers, xenon ion lasers, nitrogen lasers, carbon dioxide lasers, carbon monoxide lasers, or excimer lasers.

[0022] Chemical lasers may include lasers such as hydrogen fluoride lasers, deuterium fluoride lasers, COIL (chemical oxygen iodine laser), or Agil (all-gas-phase iodine laser).

[0023] Metal vapor lasers may include lasers such as: helium-cadmium (HeCd) metal vapor lasers, helium-mercury (HeHg) metal vapor lasers, helium-selenium (HeSe) metal vapor lasers, helium-silver (HeAg) metal vapor lasers, strontium vapor lasers, neon-copper (NeCu) metal vapor lasers, copper vapor lasers, gold vapor lasers, or manganese (Mn / MnC l2 ) vapor lasers. Rubidium or other alkali metal vapor lasers may also be used. Solid-state lasers may include lasers such as: ruby lasers, Nd:YAG lasers, NdCrYAG lasers, Er:YAG lasers, neodymium YLF (Nd:YLF) solid-state lasers, neodymium-doped yttrium orthovanadate (Nd:YVO4) lasers, neodymium-doped yttrium calcium oxyborate Nd:YCa4O(BO3) 3Or simply referred to as Nd:YCOB, neodymium glass (Nd:Glass) lasers, titanium sapphire (Ti:sapphire) lasers, thulium YAG (Tm:YAG) lasers, ytterbium YAG (Yb:YAG) lasers, ytterbium:2O3 (glass or ceramic) lasers, ytterbium-doped glass lasers (rods, plates / chips (chip), and optical fibers), holmium YAG (Ho:YAG) lasers, chromium zinc selenide (Cr:ZnSe) lasers, cerium-doped lithium strontium (or calcium) aluminum fluoride (Ce:LiSAF, Ce:LiCAF), promethium-147 phosphate glass (147Pm +3 :Glass) solid-state lasers, chromium-doped beryllium aluminate (chrysoberyl) lasers, erbium-doped and erbium-ytterbium co-doped glass lasers, uranium(III)-doped calcium fluoride (U:CaF2) solid-state lasers, samarium(II)-doped calcium fluoride (Sm:CaF2) lasers, or F-Center lasers.

[0024] Semiconductor lasers can include laser medium types such as: GaN, InGaN, AlGaInP, AlGaAs, InGaAsP, GaInP, InGaAs, InGaAsO, GaInAsSb, lead salts, vertical-cavity surface-emitting lasers (VCSELs), quantum cascade lasers, hybrid silicon lasers, or combinations thereof.

[0025] Such as Figure 3As shown, the additive manufacturing system 300 uses a laser that can provide one-dimensional or two-dimensional directed energy as part of the energy patterning system 310. In some embodiments, the one-dimensional patterning can be directed as a linear or curved strip, grating line, helix, or any other suitable form. The two-dimensional patterning can include discrete or overlapping tiles, or an image with varying laser intensity. A two-dimensional image pattern with non-square boundaries can be used, overlapping or interpenetrating images can be used, and the images can be provided by two or more energy patterning systems. The energy patterning system 310 uses a laser source and amplifier 312 to direct one or more continuous or intermittent energy beams toward beam shaping optics 314. After shaping, if desired, the beam is patterned by the energy patterning unit 316, and typically some energy is directed to the waste energy processing unit 318. The patterned energy is relayed by the image repeater 320 toward the article processing unit 340, and in one embodiment, as a two-dimensional image 322 focused near the bed 346. The article processing unit 340 can include a cartridge such as those discussed previously. The article processing unit 340 has a plate or bed 346 (with walls 348), which together form a sealed cartridge chamber that houses the material 344 (such as metal powder) dispensed by a powder hopper or other material dispenser 342. The dispensed powder can be generated or recycled as discussed in this disclosure. The patterned energy directed by the image repeater 320 can melt, fuse, sinter, amalgamate, change the crystal structure, affect the stress pattern, or otherwise chemically or physically alter the dispensed and distributed material 344 to form a structure with desired properties. The control processor 350 can be connected to various sensors, actuators, heating or cooling systems, monitors, and controllers to coordinate the operation of the laser source and amplifier 312, beam shaping optics 314, laser patterning unit 316, and image repeater 320, as well as any other components of the system 300. As will be understood, the connections can be wired or wireless, continuous or intermittent, and include the ability for feedback (e.g., heating can be adjusted in response to sensed temperature).

[0026] In some embodiments, the beam shaping optical device 314 can include a variety of imaging optics to combine, focus, diverge, reflect, refract, homogenize one or more laser beams received from the laser source and amplifier 312, adjust the intensity of one or more laser beams received from the laser source and amplifier 312, adjust the frequency of one or more laser beams received from the laser source and amplifier 312, or otherwise shape one or more laser beams received from the laser source and amplifier 312 and direct the one or more laser beams toward the laser patterning unit 316. In one embodiment, a wavelength selective mirror (e.g., a dichroic mirror) or a diffractive element can be used to combine multiple beams, each beam having a different optical wavelength. In other embodiments, a multi-faceted mirror, a microlens, and refractive or diffractive optical elements can be used to homogenize or combine multiple beams.

[0027] In addition to the monolithic embodiments described with respect to Figure 1A , Figure 1B , Figure 2 A, and Figure 2 B, the laser patterning unit 316 can also include static or dynamic energy patterning elements. For example, the laser beam can be blocked by a mask having fixed or movable elements. To increase the flexibility and simplicity of image patterning, pixel-addressable masking, image generation, or transmission can be used. In some embodiments, the laser patterning unit includes an addressable light valve that provides patterning either alone or in combination with other patterning mechanisms. The light valve can be transmissive, reflective, or use a combination of transmissive and reflective elements. Electrical addressing or optical addressing can be used to dynamically change the pattern. In one embodiment, a transmissive optically addressed light valve is used to rotate the polarization of light passing through the valve, where the optically addressed pixels form a pattern defined by the light projection source. In another embodiment, a reflective optically addressed light valve includes a write beam for changing the polarization of a read beam. In certain embodiments, non-optically addressed light valves can be used. These can include, but are not limited to, electrically addressable pixel elements, movable mirrors or micro-mirror systems, piezoelectric or micro-actuated optical systems, fixed or movable masks or shields, or any other conventional system capable of providing high-intensity light patterning.

[0028] The waste energy handling unit 318 is used to disperse, redirect, or utilize energy that is not patterned and passes through the image repeater 320. In one embodiment, the waste energy handling unit 318 can include passive or active cooling elements that remove heat from both the laser source and amplifier 312 and the laser patterning unit 316. In other embodiments, the waste energy handling unit can include a "beam dump" to absorb any beam energy not used in defining the laser pattern and convert it to heat. In still other embodiments, beam shaping optics 314 can be used to recycle the waste laser beam energy. Alternatively or additionally, the waste beam energy can be directed to the article handling unit 340 for heating or further patterning. In certain embodiments, the waste beam energy can be directed to an additional energy patterning system or article handling unit.

[0029] In one embodiment, a "switchyard" - type optical system can be used. The switchyard system is adapted to reduce light waste in an additive manufacturing system due to unwanted light being discarded for the pattern to be printed. The switchyard involves the redirection of a complex pattern from where it is generated (in this case, the plane where a spatial pattern is imparted to a structured or unstructured beam) to where it is delivered through a series of switching points. Each switching point can optionally change the spatial distribution of the incident beam. The switchyard optical system can be used in, for example but not limited to, laser - based additive manufacturing techniques where a mask is applied to light. Advantageously, in various embodiments in accordance with the present disclosure, the discarded energy can be recycled in a homogenized form or as patterned light for maintaining high power efficiency or high productivity. Additionally, the discarded energy can be recycled and reused to increase the strength of more difficult - to - print materials.

[0030] The image repeater 320 can receive the patterned image (one-dimensional or two-dimensional) from the laser patterning unit 316 directly or through a switching station and direct it to the article handling unit 340. In a manner similar to the beam shaping optics 314, the image repeater 320 can include optics for combining, focusing, diverging, reflecting, refracting the patterned light, adjusting the intensity of the patterned light, adjusting the frequency of the patterned light, or otherwise shaping and guiding the patterned light. Movable mirrors, prisms, diffractive optical elements, or solid-state optical systems that do not require substantial physical movement can be used to guide the patterned light. One of the plurality of lens assemblies can be configured to provide incident light with a magnification ratio, where the lens assembly has both a first set of optical lenses and a second set of optical lenses, and the second set of optical lenses can be exchanged from the lens assembly. The rotation of one or more sets of mirrors mounted on a compensation gantry and a final mirror mounted on a build platform gantry can be used to direct the incident light from a precursor mirror to a desired location. Translational movement of the compensation gantry and the build platform gantry can also ensure that the distance between the incident light and the precursor mirror and the article handling unit 340 is substantially equal to the image distance. In effect, this enables the beam delivery size and intensity for different materials to be rapidly varied over the location of the build area while ensuring high availability of the system.

[0031] A material dispenser 342 (e.g., a powder hopper) in the article handling unit 340 (e.g., a cartridge) can dispense material, remove material, mix material, provide a grading or variation in material type or particle size, or adjust the layer thickness of the material. The material can include metals, ceramics, glass, polymer powders, other fusible materials capable of undergoing a thermally induced phase change from solid to liquid and back to solid, or combinations thereof. The material can also include a composite of a fusible material and a non-fusible material, where one or both components can be selectively targeted by the imaging relay system to melt the fusible component while leaving the non-fusible material intact or subjecting the non-fusible material to evaporation / destruction / combustion or other destruction processes. In certain embodiments, slurries, sprays, coatings, wires, strips, or sheets of the material can be used. Unwanted material can be removed for disposal or recycling by using a blower, a vacuum system, sweeping, vibration, shaking, tilting, or inverting the bed 346.

[0032] In addition to the material handling components, the article handling unit 340 can include components for holding and supporting the 3D structure, mechanisms for heating or cooling the chamber, auxiliary optics or support optics, and sensors and control mechanisms for monitoring or regulating the material or environmental conditions. The article handling unit can support a vacuum or inert gas atmosphere, in whole or in part, to reduce unwanted chemical interactions and mitigate the risk of fire or explosion (especially for reactive metals). In some embodiments, various pure other atmospheres or mixtures of other atmospheres can be used, including those containing the following: Ar, He, Ne, Kr, Xe, CO2, N2, O2, SF6, CH4, CO, N2O, C2H2, C2H4, C2H6, C3H6, C3H8, i-C4H 10 、C4H 10 、1-C4H8、cic-2、C4H7、1,3-C4H6、1,2-C4H6、C5H 12 、n-C5H 12 、i-C5H 12 、n-C6H 14 、C2H3Cl、C7H 16 、C8H 18 、C 10 H 22 、C 11 H 24 、C 12 H 26 、C 13 H 28 、C 14 H 30 、C 15 H 32 、C 16 H 34 、C6H6、C6H5-CH3、C8H 10 、C2H5OH、CH3OH、iC4H8. In some embodiments, refrigerants or large inert molecules (including but not limited to sulfur hexafluoride) can be used. A closed atmospheric composition with at least about 1% He by volume (or by number density) and a selected percentage of inert / non-reactive gas can be used.

[0033] In certain embodiments, multiple article handling units, cartridges, or build chambers (each having a build platform that houses a powder bed) can be used in combination with multiple optomechanical assemblies that are arranged to receive one or more incident energy beams and direct them into the cartridges. Multiple cartridges allow for simultaneous printing of one or more print jobs.

[0034] In another embodiment, one or more article handling units, cartridges, or build chambers may have a cartridge held at a fixed height while the optics are vertically movable. The distance between the final optics of the lens assembly and the top surface of the powder bed can be managed to be substantially constant by indexing the final optics upward by a distance equivalent to the powder layer thickness while holding the build platform at a fixed height. Advantageously, it may be easier to fabricate large and heavy objects compared to a vertically movable build platform as there is no need for precise micron-scale movement of the build platform's varying mass. Generally, build chambers intended for metal powders with a volume greater than about 0.1 - 0.2 cubic meters (i.e., greater than 100 - 200 liters or heavier than 500 - 1,000 kg) will most benefit from holding the build platform at a fixed height.

[0035] In one embodiment, a portion of the powder bed layer in a cartridge may be selectively melted or fused to form one or more temporary walls from the fused portion of the powder bed layer to accommodate another portion of the powder bed layer on the build platform. In selected embodiments, fluid channels may be formed in one or more first walls to enable improved thermal management.

[0036] In some embodiments, an additive manufacturing system may include an article handling unit or cartridge that supports a powder bed that can be tilted, inverted, and shaken to substantially separate the powder bed from the build platform in a hopper. The powder material forming the powder bed can be collected in the hopper for reuse in later print jobs. The powder collection process can be automated, and a vacuum system or gas injection system can also be used to assist in powder removal and evacuation.

[0037] In some embodiments, an additive manufacturing system may be configured to easily handle parts that are longer than the available build chamber or cartridge. A continuous (long) part can sequentially advance from a first region to a second region in a longitudinal direction. In the first region, selected particles of particulate material can be consolidated. In the second region, unconsolidated particles of the particulate material can be removed. The first portion of the continuous part can advance from the second region to a third region while the last portion of the continuous part is formed within the first region, and the first portion remains in the same position in the lateral and transverse directions as the position it occupied within the first and second regions. In effect, additive manufacturing and scavenging (e.g., separation and / or reuse of unused or unconsolidated granular material) can occur in parallel (i.e., simultaneously) at different locations or regions on a part conveyor without the need to stop for removal of granular material and / or the part.

[0038] In another embodiment, additive manufacturing capabilities can be enhanced by using an enclosure that limits the exchange of gaseous species between the interior and exterior of the enclosure. An airlock provides an interface between the interior and exterior; the interior having a plurality of additive manufacturing chambers, including a chamber that supports powder bed fusion. A gas management system maintains the gaseous oxygen within the interior at or below a limiting oxygen concentration, thereby increasing the types of powders that can be used and the flexibility of processing within the system.

[0039] In another manufacturing embodiment, capabilities can be enhanced by housing an article handling unit, cartridge, or build chamber within an enclosure, the build chamber being capable of creating parts weighing greater than or equal to 2,000 kilograms. A gas management system can maintain the gaseous oxygen within the enclosure at a concentration below atmospheric levels. In some embodiments, a wheeled vehicle can transport parts from within the enclosure through the airlock, since the airlock is used to buffer between the gaseous environment within the enclosure and the gaseous environment exterior to the enclosure, and transport to a location external to both the enclosure and the airlock.

[0040] Other manufacturing embodiments relate to the in-process collection of powder samples from a powder bed. An ingestion system is used for the collection and characterization of the powder samples during the process. The collection can be performed periodically, and the results of the characterization lead to the adjustment of the powder bed fusion process. The ingestion system can optionally be used for one or more of auditing, process adjustment, or actions such as modifying printer parameters or verifying the proper use of licensed powder materials.

[0041] Another improvement to the additive manufacturing process is described, which can be provided by using a manipulator device such as a crane, lift gantry, robotic arm, or similar device that allows manipulation of parts that are difficult or impossible for a human to move. The manipulator device can grip various permanently or temporarily additively manufactured manipulation points on the part to enable repositioning or manipulation of the part.

[0042] A control processor 350 can be connected to control any of the components of the additive manufacturing system 300 described herein, including lasers, laser amplifiers, optics, thermal controls, build chambers, and manipulator devices. The control processor 350 can be connected to various sensors, actuators, heating or cooling systems, monitors, and controllers to coordinate operations. A wide range of sensors, including imagers, light intensity monitors, thermal sensors, pressure sensors, or gas sensors, can be used to provide information used in control or monitoring. The control processor can be a single central controller, or alternatively, can include one or more independent control systems. The controller processor 350 is provided with an interface that allows input of manufacturing instructions. The use of a wide range of sensors allows for various feedback control mechanisms to improve quality, manufacturing throughput, and energy efficiency.

[0043] Figure 4An embodiment of operating a manufacturing system applicable to additive or subtractive manufacturing is shown. In this embodiment, flowchart 400 illustrates an embodiment of a manufacturing process supported by the described optical and mechanical components. In step 401, a material powder generated or recycled as discussed in this disclosure is formed. In step 402, the powder material is positioned in a cartridge, bed, chamber, or other suitable support. In some embodiments, the material can be a metal plate that is laser cut using subtractive manufacturing techniques, or a powder that can be melted, fused, sintered, induced to change crystal structure, have an affected stress distribution pattern, or otherwise be chemically or physically altered to form a structure with desired properties by additive manufacturing techniques.

[0044] In step 404, unpatterned laser energy is emitted by one or more energy emitters including but not limited to solid-state or semiconductor lasers, and then amplified by one or more laser amplifiers. In step 406, the unpatterned laser energy is shaped and altered (e.g., intensity modulation or focusing). In step 408, the unpatterned laser energy is patterned, where the energy that does not form part of the pattern is processed in step 410 (this can include conversion to waste heat, recovery as patterned or unpatterned energy, or waste heat generated by cooling the laser amplifier in step 404). In step 412, the patterned energy that now forms a one-dimensional or two-dimensional image is relayed towards the material. In step 414, the image is applied to the material, either for subtractive processing or for additively building a part of a 3D structure. For additive manufacturing, these steps can be repeated (loop 418) until the image (or different subsequent images) has been applied to all necessary areas of the top layer of the material. When the application of energy to the top layer of the material is complete, a new layer can be applied (loop 416) to continue building the 3D structure. These process loops continue until the 3D structure is complete, at which point the remaining excess material can be removed or recycled.

[0045] Figure 5is an embodiment of an additive manufacturing system that includes a phase change light valve and a switching station system that enables the reuse of patterned two-dimensional energy. The additive manufacturing system 520 has an energy patterning system that has a laser and amplifier source 512 that directs one or more continuous or intermittent laser beams toward beam shaping optics 514. Excess heat can be transferred to a waste energy processing unit 522, which can include an active light valve cooling system. After shaping, the beam is two-dimensionally patterned by an energy patterning unit 530, and generally some energy is directed to the waste energy processing unit 522. The patterned energy is relayed by one of a plurality of image relays 532 toward one or more article processing units 534A, 534B, 534C, or 534D, typically as a two-dimensional image focused near a movable or fixed height bed. The bed is located within a cartridge that includes a powder hopper or similar material dispenser. The patterned laser beam directed by the image relay 532 can melt, fuse, sinter, combine, change crystal structure, affect stress distribution patterns, or otherwise chemically or physically alter the dispensed material to form a structure having desired properties.

[0046] In this embodiment, the waste energy processing unit has multiple components to allow the reuse of wasted patterned energy. The coolant fluid from the laser amplifier and source 512 can be directed to one or more of a generator 524, a heating / cooling thermal management system 525, or an energy dump 526. Additionally, relays 528A, 528B, and 528C can transfer energy to the generator 524, the heating / cooling thermal management system 525, or the energy dump 526, respectively. Optionally, relay 528C can direct the patterned energy into the image relay 532 for further processing. In other embodiments, the patterned energy can be directed by relay 528C to relays 528B and 528A for insertion into the laser beam provided by the laser and amplifier source 512. The image relay 532 can also be used to reuse the patterned image. The image can be redirected, inverted, mirrored, sub-patterned, or otherwise transformed for distribution to one or more article processing units 534A - 534D. Advantageously, the reuse of patterned light can improve the energy efficiency of the additive manufacturing process and, in some cases, increase the energy intensity directed at the bed or reduce the manufacturing time.

[0047] Many modifications and other embodiments of the present invention will come to the mind of those skilled in the art who benefit from the teachings given in the foregoing description and the related drawings. Therefore, it is to be understood that the present invention is not limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims. It is also to be understood that other embodiments of the present invention may be practiced without the elements / steps specifically disclosed herein.

Claims

1. A print engine for an additive manufacturing system, comprising: An XY galvanometer, which is arranged to direct a laser beam to a plurality of positions on a print bed along a print path; An XY gantry, which supports the XY galvanometer; And A motion control system for the XY gantry and the XY galvanometer, which supports dynamic adjustment of the cycle time.

2. The print engine of the additive manufacturing system according to claim 1, further comprising a laser, which is capable of directing a two-dimensional laser image towards the print bed.

3. The printing engine of the additive manufacturing system according to claim 1, wherein, The print bed is a powder bed.

4. The printing engine of the additive manufacturing system according to claim 1, wherein, The print path is at least partially defined according to a pattern to be printed.

5. The printing engine of the additive manufacturing system according to claim 1, wherein, The print path is at least partially serpentine.

6. A print engine for an additive manufacturing system, comprising: An XY galvanometer, which is arranged to direct a laser beam to a plurality of positions on a print bed; An XY gantry, which supports the XY galvanometer; And A motion control system for the XY gantry and the XY galvanometer, which controls the movement to provide a serpentine pattern on a tile having a pattern to be printed.

7. The print engine of the additive manufacturing system according to claim 6, further comprising a laser, which is capable of directing a two-dimensional laser image towards the print bed.

8. The printing engine of the additive manufacturing system according to claim 6, wherein, The print bed is a powder bed.

9. A print engine for an additive manufacturing system, comprising: An XY galvanometer, which is arranged to direct a laser beam to a plurality of positions on a print bed; An XY gantry, which supports the XY galvanometer; And A motion control system for the XY gantry and the XY galvanometer, which controls the movement to provide offset printing of tiles between layers.

10. The print engine of the additive manufacturing system according to claim 9, further comprising a laser, which is capable of directing a two-dimensional laser image towards the print bed.

11. The printing engine of the additive manufacturing system according to claim 9, wherein, The print bed is a powder bed.

12. A print engine for an additive manufacturing system, comprising: An XY gantry, An XY galvanometer, which is supported by the XY gantry and is arranged to direct a two-dimensional laser beam to a plurality of tiles defined as positions on a print bed according to a defined print path.

13. The print engine of the additive manufacturing system according to claim 9, further comprising a motion control system for the XY gantry and the XY galvanometer, which supports dynamic adjustment of the cycle time.

14. The printing engine of the additive manufacturing system according to claim 9, wherein, The print bed is a powder bed.

Images