Loop Variable Timer for Additive Manufacturing

Abstract

The print engine of the additive manufacturing system may include an XY galvanometer arrangement positioned to direct a laser beam toward multiple locations on the print bed along a print path, hi one embodiment, an XY gantry supporting the XY galvanometer arrangement is connected to a motion control system that facilitates dynamic adjustment of the cycle time for both the XY gantry and the XY galvanometer arrangement.

Description

[Technical Field]

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

[0002] [Technical field] The present disclosure relates generally to systems and methods for powder bed preparation for high throughput additive manufacturing. In one embodiment, high speed manufacturing is supported by the use of a pulsed laser controller that is synchronized with a processing system controller and allows the timing of laser pulses to be scheduled within an allowed frequency range based on real-time process feedback. [Background technology]

[0003] Traditional component fabrication often relies on the removal of material by drilling, cutting, or grinding to form a part. In contrast, additive manufacturing, also known as 3D printing, typically involves the sequential layer-by-layer addition of material to build a part. Starting with a 3D computer model, additive manufacturing systems can be used to create complex parts from a variety of materials.

[0004] One additive manufacturing technique, known as powder bed fusion additive manufacturing (PBF-AM), uses one or more focused lasers to write a pattern into a thin layer of powder, melting the powder and bonding it to the layer below, gradually forming a 3D printed part. The powder can be plastic, metal, glass, ceramic, quartz, other fusible materials, or a combination of fusible and infusible materials (i.e., plastic and wood or metal and ceramic).

[0005] Pulsed laser devices are often used that have a fixed clock generated by the laser control system. Typically, the clock timing can be changed or shifted when not printing, but the frequency and phase should not be changed significantly to maintain high quality laser pulses while printing. In practice, this means that the laser control system will "skip" a cycle if a move is not completed within the maximum allotted time.

[0006] What is needed to improve throughput and print quality is a way to dynamically adjust cycle times, which can advantageously reduce skipped cycles and improve the speed and quality of powder bed printing. [Brief explanation of the drawings]

[0007] Non-limiting, non-exhaustive embodiments of the present disclosure are described with reference to the following figures, in which like reference numerals refer to like parts throughout the different figures unless otherwise stated. [Figure 1A] 1 illustrates an embodiment of a tile printing process. [Figure 1B] 1 illustrates a modified serpentine tile printing path. [Figure 1C] Illustrates offset tile overlap. [Figure 1D] 1 illustrates a press control system and a laser control system capable of controlling laser timing during tile printing. [Figure 1E] 1 illustrates one embodiment of a laser heating cycle. [Figure 1F] 10A and 10B show top and side views of an XY gantry supporting an XY galvanometer mirror. [Figure 2] 1 illustrates the movement of the XY gantry in two specific use cases. [Figure 3] 1 illustrates an additive manufacturing system capable of providing a one-dimensional or two-dimensional light beam to a cartridge. [Figure 4] 1 illustrates a method of operating a cartridge-based additive manufacturing system capable of providing a one-dimensional or two-dimensional light beam to a cartridge. [Figure 5] 1 illustrates an additive manufacturing system including a phase change light valve and switchyard system that enables patterned two-dimensional energy recycling. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the following description, reference is made to the accompanying drawings that form a part hereof, 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, it being understood that modifications may be made to the various disclosed embodiments and other embodiments may be utilized without departing from the scope of the present disclosure. Accordingly, the following detailed description is not to be taken in a limiting sense.

[0009] FIG. 1A illustrates an embodiment of a tile printing process 100A. As seen in FIG. 1A, computer-aided design (CAD) files of appropriate software providing necessary details regarding printable part parameters and metadata can be stored in a database accessible by the additive manufacturing printer. In one process embodiment, a part definition is selected for printing in a chamber. A recipe library is used to assign printing parameters, including tile parameters, powder type, or nominal laser parameters. A print job can be scheduled, and the powder bed and optional cartridge system can be prepared for printing. Once printing begins, layers are processed to determine tile parameters, including size and offset, with laser parameters set to compensate for support material or overhangs. A processing print sequence algorithm, optionally including a serpentine path, can be selected, and data can be streamed for job execution. Job execution can include spreading and inspecting powder layers, receiving tile bitmaps by a projector, receiving tile positions by a motion controller, and receiving tile laser parameters by a laser controller. The laser controller prints the tile while the execution projector is prepared for display of the tile, 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 the Z axis can be indexed to the next layer.

[0010] FIG. 1B illustrates a modified tile printing path 100B showing an example printing path for a rectangular printing bed divided into 81 tiles. The printing path moving from tile to tile is indicated by arrows in FIG. 1B. Various alternative printing paths can also be arranged using tile parameters such as tile size, tile offset, and tile width. In some embodiments, the printing 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 the galvo mirror system. In one embodiment, a serpentine path, such as that shown for printing path 100B, can be determined. This example serpentine path can be modified based on which tiles need to be printed and which tiles do not. In some embodiments, the serpentine path can be staggered to start at a 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 accounts for other process or thermal constraints (e.g., allowing longer dwell times for certain tiles to cool). In some embodiments, tiles that do not need to be printed may be skipped, advantageously reducing the required mechanical movement of the galvo gantry and galvo mirrors compared to embodiments that move to all tile positions during a conventional linear or serpentine path that moves to all possible tile positions.

[0011] FIG. 1C illustrates offset tile overlap 100C. Typically, the overlap is a small percentage of the tile size and may be measured in microns to millimeters. In one embodiment, an x- and y-offset is provided for the subsequent layer relative to the underlying layer. In effect, this provides a tile overlay and ensures that seams (boundaries, joins where adjacent tiles join) do not overlap. In some embodiments, the tile overlap may be configured so that tiles may overlap on the same print layer in addition to or instead of overlapping between layers.

[0012] FIG. 1D illustrates a printer control system and laser control system 100D capable of controlling laser timing during tile printing. As shown, streaming tile data for printing is continuously provided to the tile image projector, tile position motion controller, and laser controller. In one embodiment, the data stream is structured so that the image projector and motion controller always have more queued data than the laser controller, ensuring that the image projector and motion controller have enough tile information to allow the laser controller to be triggered for the next tile that needs to be printed. In some embodiments, the stream is not real-time, requiring buffering of the tile image projector, tile position motion controller, and laser controller.

[0013] Once the minimum amount of tile data has been buffered, the press control system passes the data to the laser device. 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 spot temperature is measured, the laser power is set, and the pulsed laser device is enabled. The pulsed laser can then be fired in various timing or shaped sequences as needed. In some embodiments, the cycle time can be adjusted to help avoid skipped cycles.

[0014] FIG. 1E illustrates one embodiment of a loop-variable timer for laser timing and heating cycle 100E, which is possible using the system and process described with respect to FIGS. 1A and 1D. As shown, in one embodiment, the laser arming and firing process can occur over a nominal 25 millisecond (40 Hz) period. A new image trigger can initiate the process, including a single tile skip or, in some periods, a longer period for multiple tile skips. Simultaneously, the light valves can transition to a new pattern. Once the light valves are armed and stopped, laser heating can be initiated to bring the powder temperature near the melting point in the required pattern, after which a laser pulse is triggered to fully melt the powder in the required pattern. The cycle is then repeated until tile production is complete for each layer. In some embodiments, dynamic cycle time adjustment within a certain tolerance range (e.g., between 35 Hz and 40 Hz) can be possible. This can avoid skipping some cycles, provided that the average frequency of the pulsed laser does not decrease enough to cause thermal issues.

[0015] FIG. 1F illustrates a top view and a side view of the XY gantry supporting the XY galvanometer mirrors. In some embodiments, the movements described with respect to FIGS. 1A, 1D, and 1E can include both the XY galvanometer mirrors and the XY gantry supporting the galvanometer mirrors. This embodiment can be used when the range of the XY galvanometer device is not sufficient to process the entire print bed. As seen in the top view, a patterned or unpatterned laser beam can be directed by a fixed mirror toward the movable XY galvanometer mirrors, which then direct the laser beam toward the print bed. Typically, the XY galvanometer mirrors can rotate 0.5 degrees in 5 milliseconds or less, which is significantly faster than the movement of the XY gantry.

[0016] FIG. 2 illustrates XY gantry movement 200 in two specific use cases for an XY gantry supporting an XY galvo mirror as described with respect to FIG. 1F. In one embodiment, the XY gantry is moved to a setpoint with a defined acceleration and velocity. The distance between the setpoint and the actual XY gantry position is sent to the XY galvo device. If this distance is within the redirection range of the XY galvo laser beam, the tile target is in range and laser processing of tiles on the print bed can begin. This is shown with respect to Case 1 in FIG. 2. If this distance is not within range, as seen with respect to Case 2 in FIG. 2, the XY gantry moves (or continues to move) until the XY galvo device is in range. It should be noted that in some embodiments, the XY gantry movement does not need to stop before laser processing begins. Also, in some embodiments, a new setpoint target can be dynamically provided to the XY gantry or XY galvo device at any time.

[0017] In the embodiment illustrated with respect to FIG. 3 , the additive manufacturing system can be represented by various modules forming an additive manufacturing method and system 300 suitable for use in connection with a tile printing process procedure that may optionally utilize an XY galvanometer gantry and a galvanometer mirror system with a loop variable timer. As seen in FIG. 3 , the laser source and amplifier 312 can be fabricated as a continuous or pulsed laser device. In other embodiments, the laser source includes a pulsed electrical signal source, such as an arbitrary waveform generator or equivalent that operates on a continuous laser source, such as a laser diode. In some embodiments, this can also be achieved via a fiber laser source or a fiber launched laser source that is subsequently modulated by an acousto-optic or electro-optic modulator. In some embodiments, a high-repetition-rate pulse source using a Pockels cell can be used to create pulse trains of any length.

[0018] 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.

[0019] 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.

[0020] Chemical lasers may include lasers such as hydrogen fluoride lasers, deuterium fluoride lasers, COIL (chemoenzymatic iodine lasers), or Agil (all vapor phase iodine lasers).

[0021] Metal vapor lasers include 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, and manganese (Mn / MnC l2) vapor lasers. Rubidium or other alkali metal vapor lasers can also be used. Solid-state lasers include 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 oxoborate Nd:YCa4O(BO3)3 or simply 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 (rod, plate, etc.). The lasers may include lasers such as fluorine-doped fluoride (F:Cu ...

[0022] The semiconductor laser may include laser media such as GaN, InGaN, AlGaInP, AlGaAs, InGaAsP, GaInP, InGaAs, InGaAsO, GaInAsSb, lead salt, vertical cavity surface emitting laser (VCSEL), quantum cascade laser, hybrid silicon laser, or combinations thereof.

[0023] As shown in FIG. 3 , additive manufacturing system 300 uses a laser device capable of providing one-dimensional or two-dimensional directed energy as part of energy patterning system 310. In some embodiments, one-dimensional patterning can be directed as straight or curved strips, as rastered lines, as spiral lines, or in other suitable forms. Two-dimensional patterning can include separate or overlapping tiles or images with varying laser intensity. Two-dimensional image patterns with non-rectangular boundaries can be used, overlapping or interpenetrating images can be used, and images can be provided by two or more energy patterning systems. 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, the beam is patterned, if necessary, by energy patterning unit 316, and generally some energy is directed to waste energy processing unit 318. The patterned energy is relayed by image relay 320 toward article processing unit 340. In one embodiment, two-dimensional image 322 is focused near floor 346. Article processing unit 340 may include a cartridge as described above. Article processing unit 340 has a plate or floor 346 (with walls 348) that together form an enclosed cartridge chamber containing material 344 (e.g., metal powder) to be dispensed by a powder hopper or other material dispenser 342. The dispensed powder may be crafted or recycled as described herein. The patterned energy directed by image relay 320 may melt, melt, sinter, fuse, change crystalline structure, affect stress patterns, or otherwise chemically or physically alter the dispensed or dispersed material 344 to form a structure with desired properties.Control processor 350 may be connected to various sensors, actuators, heating or cooling systems, monitors, and controllers to coordinate the operation of laser source and amplifier 312, beam shaping optics 314, laser patterning unit 316, and image relay 320, as well as any other components of system 300. As will be understood, connections may be wired or wireless, may be continuous or intermittent, and may have feedback capability (e.g., thermal heating may be adjusted in response to a sensed temperature).

[0024] In some embodiments, the beam shaping optics 314 may include a variety of imaging optics to combine, focus, diverge, reflect, refract, homogenize, intensity adjust, frequency adjust, or otherwise shape one or more laser beams received from the laser source and amplifier 312 and direct them toward the laser patterning unit 316. In one embodiment, multiple light beams, each having a different optical wavelength, may be combined using wavelength-selective mirrors (e.g., dichroic) or diffractive elements. In other embodiments, multiple beams may be homogenized or combined using polygonal mirrors, microlenses, and refractive or diffractive optical elements.

[0025] In addition to the monolithic embodiments described with respect to FIGS. 1A, 1B, and 2, the laser patterning unit 316 can include static or dynamic energy patterning elements. For example, the laser beam can be interrupted by a mask with fixed or movable elements. Pixel-addressable masking, image generation, or transmission can be used for greater flexibility and ease of image patterning. In some embodiments, the laser patterning unit includes addressable light valves alone or in combination with other patterning devices to provide patterning. Light valves can be transmissive, reflective, or use a combination of transmissive and reflective elements. Patterns can be dynamically changed using electrical or optical addressing. In one embodiment, a transmissive optically addressed light valve acts to rotate the polarization of light passing through the valve, with optically addressed pixels forming a pattern defined by an optical projection source. In another embodiment, a reflective optically addressed light valve includes a write beam to modify the polarization of a read beam. In some embodiments, non-optically addressed light valves can be used. These may include, but are not limited to, electrically addressable pixel elements, movable mirror or micromirror systems, piezoelectric or micro-actuated optical systems, fixed or movable masks or shielding plates, or other conventional systems capable of providing high intensity patterning.

[0026] The waste energy processing unit 318 can be used to dissipate, redirect, and utilize energy that was not patterned and passed through (skipped) the image relay 320. In one embodiment, the waste energy processing unit 318 can include passive or active cooling elements to remove heat from both the laser source and amplifier 312 and the laser patterning unit 316. In other embodiments, the waste energy processing unit can include a "beam dump" to absorb and convert to heat any beam energy not used to define the laser pattern. In yet other embodiments, the wasted laser beam energy can be recycled using the beam shaping optics 314. Alternatively or additionally, the wasted beam energy can be directed to the article processing unit 340 for heating or further patterning. In some embodiments, the wasted beam energy can be directed to an additional energy patterning system or article processing unit.

[0027] In one embodiment, a "switchyard" type optical system may be used. The switchyard system is suitable for reducing light wasted in additive manufacturing systems due to unwanted light waste from the printed pattern. The switchyard involves redirecting a complex pattern from its generation (in this case, a plane where a spatial pattern is imparted to a structured or unstructured beam) to its transmission through a series of switch points. Each switch point may optionally modify the spatial profile of the incident beam. The switchyard optical system may be utilized in, for example, but not limited to, laser-based additive manufacturing techniques where a mask is applied to the light. Advantageously, in various embodiments of the present disclosure, wasted energy may be recycled, either in a homogenized form used to maintain high power efficiency or high throughput, or as patterned light. Furthermore, wasted energy may be recycled and reused to increase intensity for printing more challenging materials.

[0028] The image relay 320 may receive the patterned image (whether one-dimensional or two-dimensional) from the laser patterning unit 316 directly or through a switchyard and direct it toward the article processing unit 340. In a manner similar to the beam shaping optics 314, the image relay 320 may include optics to combine, focus, split, reflect, refract, adjust intensity, adjust frequency, or otherwise shape and direct the patterned light. The patterned light may be directed using moveable mirrors, prisms, diffractive optical elements, or solid-state optical systems that do not require substantial physical movement. One of the lens assemblies may be configured to provide incident light having the magnification at both the first set of optical lenses and the second set of optical lenses, and at the second set of optical lenses that are interchangeable from the lens assemblies. Rotation of a set of one or more mirrors mounted on a compensating gantry and a final mirror mounted on the build platform gantry can be used to direct the light from the leading mirror to the desired location. Translational movement of the compensating gantry and the build platform gantry can also ensure that the distance of the incident light from the leading mirror to the article handling unit 340 is substantially equal to the image distance. In practice, this allows for rapid change of the optical beam transmission size and intensity across the build zone location for different powder materials while ensuring high system availability.

[0029] A material dispenser 342 (e.g., a powder hopper) within the article processing unit 340 (e.g., a cartridge) can disperse, remove, or mix materials, provide gradations or variations in material type or particle size, or adjust the thickness of a material layer. Materials can include metals, ceramics, glasses, polymer powders, other dissolvable materials capable of undergoing a heat-induced phase change from solid to liquid and vice versa, or combinations thereof. Materials can also include composites of dissolvable and indissolvable materials, in which either or both components can be selectively targeted with an image relay system to melt the dissolvable component, while either leaving only the indissolvable material or subjecting it to evaporation, destruction, combustion, or other destructive processes. In certain embodiments, slurries, sprays, coatings, wires, strips, or sheets of material can be used. Unwanted material may be removed by using a blower, a vacuum system, sweeping, vibrating, shaking, sloping, or inverting the floor 346 for disposal or recycling.

[0030] In addition to material processing components, the article processing unit 340 may include components for holding and supporting three-dimensional structures, devices for heating or cooling the chamber, auxiliary or supporting optics, and sensors and controls for monitoring or adjusting material or environmental conditions. The article processing unit may, in whole or in part, support a vacuum or inert gas atmosphere to reduce unwanted chemical interactions and reduce the risk of fire or explosion (especially with reactive metals). In some embodiments, the article processing unit may support a vacuum or inert gas atmosphere, such as Ar, He, Ne, Kr, Xe, CO, N, O, SF, CH, CO, N0, C2H2, C2H4, C2H6, C3H6, C3H8, i-C4H 10 , C4H 10 , 1-C4H8, cic-2,C4H7, 1,3-C4H6, 1,2-C4H6, C5H 12 , n-CH 12 , i-C5H 12 , n-CH 14 , C2H3Cl, C7H 16 , C8H 18 , C10 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 Various pure or mixtures of other atmospheres may be used, such as atmospheres containing iCHOH, CHOH, CHOH, iCH. In some embodiments, refrigerants or large, inert molecules (including, but not limited to, sulfur hexafluoride) may be used. An enclosure atmospheric composition may be used that will have at least about 1% helium by volume (or number density) and a selected percentage of an inert / non-reactive gas.

[0031] In some embodiments, multiple article processing units, cartridges, or build chambers, each having a build platform for holding a powder bed, can be used with multiple opto-mechanical assemblies arranged to receive and direct one or more incident energy beams into the cartridges, allowing for the simultaneous printing of one or more print jobs.

[0032] In another embodiment, one or more article processing units, cartridges, or build chambers can have cartridges maintained at a fixed height, with the optics vertically movable. The distance between the last optic of the lens assembly and the top surface of the powder bed can be managed to be essentially constant by maintaining the build platform at a fixed height and moving the last optic upward a distance equivalent to the thickness of the powder layer. Advantageously, compared to vertically moving the build platform, large, heavy objects can be manufactured more easily because the ever-changing mass of the build platform does not need to be moved to precise micron increments. Typically, build chambers intended for metal powders with volumes greater than 0.1 cubic meters to 0.2 cubic meters (i.e., heavier than 100 liters to 200 liters or 500 kg to 1000 kg) will benefit most from keeping the build platform at a fixed height.

[0033] In one embodiment, a portion of the powder bed layer in the cartridge may be selectively melted or fused to form one or more temporary walls out from the melted portion of the powder bed layer to contain another portion of the powder bed layer on the build platform. In selected embodiments, fluid passages may be formed in one or more of the first walls to allow for improved thermal management.

[0034] In some embodiments, an additive manufacturing system, which may include an article handling unit or cartridge supporting a powder bed, may be tiltable, invertable, and vibrable to substantially separate the powder bed from the build platform at a hopper. The powder material forming the powder bed may be collected in the hopper for reuse in subsequent print jobs. The powder collection process may be automated, and vacuum or gas injection systems may also be used to assist in powder removal or removal.

[0035] In some embodiments, an additive manufacturing system can be configured to easily process parts longer than the available build chamber or cartridge. A continuous (long) part can advance sequentially longitudinally from a first zone to a second zone. In the first zone, selected particles of granular material can be fused. In the second zone, unfused particles of granular material can be removed. A first portion of the continuous part can advance from the second zone to a third zone, while a final portion of the continuous part is formed in the first zone and the first portion is maintained in the same lateral and transverse position occupied by the first portion in the first and second zones. Indeed, additive manufacturing and cleaning (e.g., separation and / or recovery of unused or unfused granular material) can be performed in parallel (i.e., simultaneously) at different positions or zones on the part conveyor without the need to stop for removal of granular material and / or parts.

[0036] In another embodiment, additive manufacturing capabilities may be enhanced through the use of an enclosure that limits the exchange of gas between the interior of the enclosure and the exterior of the enclosure. An airtight chamber provides an interface between the interior and exterior, the interior having multiple additive manufacturing chambers, including additive manufacturing chambers that support the melting of the powder bed. A gas management system maintains gaseous oxygen within the interior below a critical oxygen concentration, allowing for increased flexibility in the types of powders and processes that can be used within the system.

[0037] In another manufacturing embodiment, capacity can be increased by having an article processing unit, cartridge, or build chamber within the enclosure, where the build chamber can produce parts weighing over 2000 kilograms. A gas management system can maintain gaseous oxygen within the enclosure at concentrations below atmospheric levels. In some embodiments, a vehicle (conveyor) can transport parts from inside the enclosure to a location outside both the enclosure and the airtight chamber, as the chamber acts as a buffer between the gaseous environment within the enclosure and the gaseous environment outside the enclosure.

[0038] In other manufacturing embodiments, real-time powder sample collection from the powder bed is performed. A suction system is used for in-process collection and characterization of powder samples. The collection can be performed periodically, and the results of the characterization can result in adjustments to the powder bed fusion process. The suction system can optionally be used for one or more audits, process adjustments, or actions, such as changing printer parameters or verifying proper use of certified powder materials.

[0039] Yet another improvement to additive manufacturing processes can be provided and described by the use of manipulation devices such as cranes, lifting gantries, robotic arms, or the like that allow manipulation of parts that are difficult or impossible to move by humans. The manipulation devices can grasp various permanent or temporary additive manufacturing manipulation points on a part so that the part can be repositioned or manipulated.

[0040] The control processor 350 can be connected to control any component of the additive manufacturing system 300 described herein, including the laser, laser amplifiers, optics, heating controls, build chamber, and manipulation devices. The control processor 350 can be connected to various sensors, actuators, heating or cooling systems, monitors, and controllers to coordinate their operation. A wide range of sensors can be used to provide information used for control or monitoring, including imaging devices, light intensity monitors, heat, pressure, or gas sensors. The control processor can be a single central controller, or alternatively, can include one or more independent control systems. The control processor 350 is provided with an interface that allows for input of manufacturing instructions. The use of a wide range of sensors enables a variety of feedback control mechanisms that improve quality, manufacturing throughput, and energy efficiency.

[0041] One embodiment of the operation of a manufacturing system suitable for additive or subtractive manufacturing is illustrated in FIG. 4. In this embodiment, a flowchart 400 illustrates one embodiment of a manufacturing process assisted by the described optical and mechanical components. In step 401, a powder of material, created or recycled as described 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 may be a metal plate for laser cutting using subtractive manufacturing techniques, or a powder that can be melted, fused, sintered, altered by additive manufacturing techniques to change crystal structure, affect stress patterns, or otherwise chemically or physically modified to form a structure with desired properties.

[0042] In step 404, unpatterned laser energy is emitted by one or more energy emitters, including, but not limited to, solid-state or semiconductor laser devices, and then amplified by one or more laser amplifiers. In step 406, the unpatterned laser energy is shaped and modified (e.g., intensity modulated or focused). In step 408, the unpatterned laser energy is patterned, whereby energy that does not form part of the pattern is disposed of in step 410 (this may include conversion to waste heat, recycling as patterned or unpatterned energy, or waste heat generated in cooling the laser amplifiers in step 404). In step 412, the patterned energy, now forming a one- or two-dimensional image, is relayed toward a material. In step 414, the image is applied to the material to produce a portion of a 3D structure, whether by subtractive or additive manufacturing. In the case of additive manufacturing, these steps may be repeated (loop 418) until the image (or another subsequent image) has been applied to all required areas of the top layer of material. Once the application of energy to the top layer of material is complete, a new layer may be applied (loop 416) to continue fabricating the 3D structure. These processing loops continue until any remaining excess material can be removed or recycled and the 3D structure is complete.

[0043] FIG. 5 illustrates one embodiment of an additive manufacturing system including a phase-change light valve and switchyard system that enables patterned two-dimensional energy recycling. Additive manufacturing system 520 includes an energy patterning system with a laser source and amplifier 512 that directs one or more continuous or intermittent laser beams into shaping optics 514. Residual heat can be conducted into a waste energy processing unit 522, which may include an active light valve cooling system. After shaping, the beam is patterned in two dimensions by an energy patterning unit 530, with some energy typically directed into the waste energy processing unit 522. The patterned energy is relayed by multiple image relays 532 to one or more article processing units 534A, 534B, 534C, or 534D, typically as a two-dimensional image focused near a movable or fixed-height floor. The floor can be in a cartridge containing a powder hopper or similar material dispenser. The patterned laser beam directed by the image relay 532 may melt, melt, sinter, fuse, change the crystal structure, affect stress patterns, or otherwise chemically or physically modify the dispensed material to form a structure with desired properties.

[0044] In this embodiment, the waste energy processing unit has multiple components to enable reuse of the patterned waste energy. Coolant from the laser amplifier and source 512 can be directed to one or more of the generator 524, the heating / cooling thermal management system 525, or the energy dump 526. Additionally, repeaters 528A, 528B, and 528C can each transmit energy to the generator 524, the heating / cooling thermal management system 525, or the energy dump 526. Optically, repeater 528C can direct the patterned energy to image repeater 532 for further processing. In other embodiments, the patterned energy can be directed by repeater 528C to repeaters 528B and 528A for insertion into the laser beam provided by the laser source and amplifier 512. Using image repeater 532, reuse of the patterned image is also possible. The image may be redirected, inverted, reflected, sub-patterned, or transformed for distribution to one or more article processing units 534A-D. Advantageously, recycling patterned light may improve the energy efficiency of the additive manufacturing process and, in some cases, may improve the intensity of energy directed to the floor or reduce manufacturing time.

[0045] Many modifications and other embodiments of the invention will occur to those skilled in the art having the benefit of the teachings presented in the foregoing description and the associated drawings. It is understood, therefore, that the 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 understood that other embodiments of the invention may be practiced that exclude elements / steps not specifically disclosed herein.

Claims

1. 1. A print engine for an additive manufacturing system, comprising: an XY galvanometer arrangement positioned to direct the laser beam towards a plurality of locations on the print bed according to the print path; an XY gantry supporting the XY galvanometer device; and a motion control system for supporting dynamic adjustment of cycle times for the XY gantry and the XY galvanometer device; The print engine.

2. 10. The print engine of claim 1, further comprising a laser device capable of directing a two-dimensional laser image to the print bed.

3. 10. The print engine of claim 1, wherein the print bed is a powder bed.

4. 10. The print engine of claim 1, wherein the printing paths are defined at least in part according to a pattern to be printed.

5. 10. The print engine of claim 1, wherein the printing path is at least partially serpentine.

6. 1. A print engine for an additive manufacturing system, comprising: an XY galvanometer arrangement positioned to direct the laser beam towards a plurality of locations on the print bed; an XY gantry supporting the XY galvanometer device; and a motion control system that controls the motion of the XY gantry and the XY galvanometer device to provide a serpentine pattern across a tile having a pattern to be printed; The print engine.

7. 10. The print engine of claim 6, further comprising a laser device capable of directing a two-dimensional laser image against the print bed.

8. 7. The print engine of claim 6, wherein the print bed is a powder bed.

9. 1. A print engine for an additive manufacturing system, comprising: an XY galvanometer arrangement positioned to direct the laser beam towards a plurality of locations on the print bed; an XY gantry supporting the XY galvanometer device; and a motion control system that controls the motion of the XY gantry and the XY galvanometer device to provide offset printing of tiles between layers; The print engine.

10. 10. The print engine of claim 9, further comprising a laser device capable of directing a two-dimensional laser image against the print bed.

11. 10. The print engine of claim 9, wherein the print bed is a powder bed.

12. 1. A print engine for an additive manufacturing system, comprising: XY gantry, an XY galvanometer device supported by the XY gantry, the XY galvanometer device being positioned to direct a two-dimensional laser beam toward a plurality of tiles defined as locations on a print bed according to a defined print path; and The print engine.

13. 10. The print engine of claim 9, further comprising a motion control system for the XY gantry and XY galvanometer device that supports dynamic adjustment of cycle times.

14. 10. The print engine of claim 9, wherein the print bed is a powder bed.

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