Patent Description:
In powder bed fusion additive manufacturing, a source image of an optical beam of sufficient energy is directed to locations on the top surface of a powder bed (print surface) to form an integral object when a powdered material is processed (with or without chemical bonding). The resolution (or a pixel size) of an optical system used for powder bed fusion additive manufacturing depends on whether the print surface coincides with the focal plane of the final optics in the optical system, or in term for imaging systems, depending on whether the distance between lenses and image planes for optics performing an imaging operation stays substantially a constant distance for a given lens configuration. To be able to print large objects in powder bed fusion additive manufacturing, accurate control of the image location on the print surface, and distance between lenses is necessary to maintain the resolution or the pixel size on every possible location of the top surface of the powder bed. Different powdered materials may require different intensities or energies of the optical beam as the respective thresholds of bonding energies are different. If a change in the intensity is required when changing the powder type or the powder size distribution, the optical system may need to be shut down for re-installation and re-alignment of the imaging lenses.

Cited reference <CIT> relates to a laser sintering apparatus for forming a three-dimensional model comprising a powder sintered body obtained by exposing a powdered body with a continuously-driven or pulse-driven laser beam in a predetermined-wavelength region that includes ultraviolet and sintering the powdered body.

The present invention is defined by independent claims <NUM> and <NUM>.

Non-limiting and non-exhaustive embodiments of the present disclosure are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various figures unless otherwise specified.

In the following description, reference is made to the accompanying drawings that form a part thereof, and in which is shown by way of illustrating specific exemplary embodiments in which the 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 is to be understood that modifications to the various disclosed embodiments may be made, and other embodiments may be utilized, without departing from the scope of the present disclosure. The following detailed description is, therefore, not to be taken in a limiting sense.

The present disclosure describes a dynamic optical assembly in a powder bed fusion additive three-dimensional manufacturing system suitable for on-the-fly swapping of imaging lens(es) and high-resolution imaging of high average power light sources in forming a large three-dimensional object. Swapping can include both physically replacing, or the modification of a lens such that it has the effect of being a different lens.

In various embodiments in accordance with the present disclosure, a dynamic optical assembly may allow swapping of imaging lens without the need to disassemble the optical assembly to enable different magnification ratios between the source image plane and locations on the top surface of a powder bed. Different magnification ratios entail that the same amount of laser power is distributed over different areas, the specific degree of which may be tuned according to different material types. In some embodiments, the same optical beam may be used for different chambers containing different powdered materials, the dynamic optical assembly of the present disclosure may deliver an appropriate power flux to each chamber while fully utilizing the power capabilities of the light source.

An additive manufacturing system is disclosed which has one or more energy sources, including in one embodiment, one or more laser or electron beams, positioned to emit one or more energy beams. Beam shaping optics may receive the one or more energy beams from the energy source and form a single beam. An energy patterning unit receives or generates the single beam and transfers a two-dimensional pattern to the beam, and may reject the unused energy not in the pattern. An image relay receives the two-dimensional patterned beam and focuses it as a two-dimensional image to a desired location on a height fixed or movable build platform (e.g. a powder bed). In certain embodiments, some or all of any rejected energy from the energy patterning unit is reused.

In some embodiments, multiple beams from the laser array(s) are combined using a beam homogenizer. This combined beam can be directed at an energy patterning unit that includes either a transmissive or reflective pixel addressable light valve. In one embodiment, the pixel addressable light valve includes both a liquid crystal module having a polarizing element and a light projection unit providing a two-dimensional input pattern. The two-dimensional image focused by the image relay can be sequentially directed toward multiple locations on a powder bed to build a 3D structure.

As seen in <FIG>, an additive manufacturing system <NUM> has an energy patterning system <NUM> with an energy source <NUM> that can direct one or more continuous or intermittent energy beam(s) toward beam shaping optics <NUM>. After shaping, if necessary, the beam is patterned by an energy patterning unit <NUM>, with generally some energy being directed to a rejected energy handling unit <NUM>. Patterned energy is relayed by image relay <NUM> toward an article processing unit <NUM>, typically as a two-dimensional image <NUM> focused near a bed <NUM>. The bed <NUM> (with optional walls <NUM>) can form a chamber containing material <NUM> dispensed by material dispenser <NUM>. Patterned energy, directed by the image relay <NUM>, can melt, fuse, sinter, amalgamate, change crystal structure, influence stress patterns, or otherwise chemically or physically modify the dispensed material <NUM> to form structures with desired properties.

Energy source <NUM> generates photon (light), electron, ion, or other suitable energy beams or fluxes capable of being directed, shaped, and patterned. Multiple energy sources can be used in combination. The energy source <NUM> can include lasers, incandescent light, concentrated solar, other light sources, electron beams, or ion beams. 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 laser, Gas dynamic laser, "Nickel-like" Samarium laser, Raman laser, or Nuclear pumped laser.

A Gas Laser can include lasers such as a Helium-neon laser, Argon laser, Krypton laser, Xenon ion laser, Nitrogen laser, Carbon dioxide laser, Carbon monoxide laser or Excimer laser.

A Chemical laser can include lasers such as a Hydrogen fluoride laser, Deuterium fluoride laser, COIL (Chemical oxygen-iodine laser), or Agil (All gas-phase iodine laser).

A Metal Vapor Laser can include lasers such as a Helium-cadmium (HeCd) metal-vapor laser, Helium-mercury (HeHg) metal-vapor laser, Helium-selenium (HeSe) metal-vapor laser, Helium-silver (HeAg) metal-vapor laser, Strontium Vapor Laser, Neon-copper (NeCu) metal-vapor laser, Copper vapor laser, Gold vapor laser, or Manganese (Mn/MnCl<NUM>) vapor laser.

A Solid State Laser can include lasers such as a Ruby laser, Nd:YAG laser, NdCrYAG laser, Er:YAG laser, Neodymium YLF (Nd:YLF) solid-state laser, Neodymium doped Yttrium orthovanadate(Nd:YVO<NUM>) laser, Neodymium doped yttrium calcium oxoborateNd:YCa<NUM>O(BO<NUM>)<NUM> or simply Nd:YCOB, Neodymium glass(Nd:Glass) laser, Titanium sapphire(Ti:sapphire) laser, Thulium YAG (Tm:YAG) laser, Ytterbium YAG (Yb:YAG) laser, Ytterbium:2O<NUM> (glass or ceramics) laser, Ytterbium doped glass laser (rod, plate/chip, and fiber), Holmium YAG (Ho:YAG) laser, Chromium ZnSe (Cr:ZnSe) laser, Cerium doped lithium strontium (or calcium)aluminum fluoride(Ce:LiSAF, Ce:LiCAF), Promethium <NUM> doped phosphate glass(147Pm+<NUM>:Glass) solid-state laser, Chromium doped chrysoberyl (alexandrite) laser, Erbium doped anderbium-ytterbium co-doped glass lasers, Trivalent uranium doped calcium fluoride (U:CaF<NUM>) solid-state laser, Divalent samarium doped calcium fluoride(Sm:CaF<NUM>) laser, or F-Center laser.

A Semiconductor Laser can include laser medium types 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.

For example, in one embodiment a single Nd:YAG q-switched laser can be used in conjunction with multiple semiconductor lasers. In another embodiment, an electron beam can be used in conjunction with an ultraviolet semiconductor laser array. In still other embodiments, a two-dimensional array of lasers can be used. In some embodiments with multiple energy sources, pre-patterning of an energy beam can be done by selectively activating and deactivating energy sources.

Beam shaping unit <NUM> can include a great variety of imaging optics to combine, focus, diverge, reflect, refract, homogenize, adjust intensity, adjust frequency, or otherwise shape and direct one or more energy beams received from the energy source <NUM> toward the energy patterning unit <NUM>. In one embodiment, multiple light beams, each having a distinct light wavelength, can be combined using wavelength selective mirrors (e.g. dichroics) or diffractive elements. In other embodiments, multiple beams can be homogenized or combined using multifaceted mirrors, microlenses, and refractive or diffractive optical elements.

Energy patterning unit <NUM> can include static or dynamic energy patterning elements. For example, photon, electron, or ion beams can be blocked by masks with fixed or movable elements. To increase flexibility and ease of image patterning, pixel addressable masking, image generation, or transmission can be used. In some embodiments, the energy patterning unit includes addressable light valves, alone or in conjunction with other patterning mechanisms to provide patterning. The light valves can be transmissive, reflective, or use a combination of transmissive and reflective elements. Patterns can be dynamically modified using electrical or optical addressing. In one embodiment, a transmissive optically addressed light valve acts to rotate polarization of light passing through the valve, with optically addressed pixels forming patterns defined by a light projection source. In another embodiment, a reflective optically addressed light valve includes a write beam for modifying polarization of a read beam. In yet another embodiment, an electron patterning device receives an address pattern from an electrical or photon stimulation source and generates a patterned emission of electrons.

Rejected energy handling unit <NUM> is used to disperse, redirect, or utilize energy not patterned and passed through the energy pattern image relay <NUM>. In one embodiment, the rejected energy handling unit <NUM> can include passive or active cooling elements that remove heat from the energy patterning unit <NUM>. In other embodiments, the rejected energy handling unit can include a "beam dump" to absorb and convert to heat any beam energy not used in defining the energy pattern. In still other embodiments, rejected beam energy can be recycled using beam shaping optics <NUM>. Alternatively, or in addition, rejected beam energy can be directed to the article processing unit <NUM> for heating or further patterning. In certain embodiments, rejected beam energy can be directed to additional energy patterning systems or article processing units.

Image relay <NUM> receives a patterned image (typically two-dimensional) from the energy patterning unit <NUM> and guides it toward the article processing unit <NUM>. In a manner similar to beam shaping optics <NUM>, the image relay <NUM> can include optics to combine, focus, diverge, reflect, refract, adjust intensity, adjust frequency, or otherwise shape and direct the patterned image.

Article processing unit <NUM> can include a walled chamber <NUM> and bed <NUM>, and a material dispenser <NUM> for distributing material. The material dispenser <NUM> can distribute, remove, mix, provide gradations or changes in material type or particle size, or adjust layer thickness of material. The material can include metal, ceramic, glass, polymeric powders, other melt-able material capable of undergoing a thermally induced phase change from solid to liquid and back again, or combinations thereof. The material can further include composites of melt-able material and non-melt-able material where either or both components can be selectively targeted by the imaging relay system to melt the component that is melt-able, while either leaving along the non-melt-able material or causing it to undergo a vaporizing/destroying/combusting or otherwise destructive process. In certain embodiments, slurries, sprays, coatings, wires, strips, or sheets of materials can be used. Unwanted material can be removed for disposable or recycling by use of blowers, vacuum systems, sweeping, vibrating, shaking, tipping, or inversion of the bed <NUM>.

In addition to material handling components, the article processing unit <NUM> can include components for holding and supporting 3D structures, mechanisms for heating or cooling the chamber, auxiliary or supporting optics, and sensors and control mechanisms for monitoring or adjusting material or environmental conditions. The article processing unit can, in whole or in part, support a vacuum or inert gas atmosphere to reduce unwanted chemical interactions as well as to mitigate the risks of fire or explosion (especially with reactive metals).

Control processor <NUM> can be connected to control any components of additive manufacturing system <NUM>. The control processor <NUM> can be connected to variety of sensors, actuators, heating or cooling systems, monitors, and controllers to coordinate operation. A wide range of sensors, including imagers, light intensity monitors, thermal, pressure, 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 <NUM> is provided with an interface to allow input of manufacturing instructions. Use of a wide range of sensors allows various feedback control mechanisms that improve quality, manufacturing throughput, and energy efficiency.

<FIG> is a cartoon illustrating a bed <NUM> that supports material <NUM>. Using a series of sequentially applied, two-dimensional patterned energy beam images (squares in dotted outline <NUM>), a structure <NUM> is additively manufactured. As will be understood, image patterns having non-square boundaries can be used, overlapping or interpenetrating images can be used, and images can be provided by two or more energy patterning systems. In other embodiments, images can be formed in conjunction with directed electron or ion beams, or with printed or selective spray systems.

<FIG> is a flow chart illustrating one embodiment of an additive manufacturing process supported by the described optical and mechanical components. In step <NUM>, material is positioned in a bed, chamber, or other suitable support. The material can be a powder capable of being melted, fused, sintered, induced to change crystal structure, have stress patterns influenced, or otherwise chemically or physically modified to form structures with desired properties.

In step <NUM>, unpatterned energy is emitted by one or more energy emitters, including but not limited to solid state or semiconductor lasers, or electrical power supply flowing electrons down a wire. In step <NUM>, the unpatterned energy is shaped and modified (e.g. intensity modulated or focused). In step <NUM>, this unpatterned energy is patterned, with energy not forming a part of the pattern being handled in step <NUM> (this can include conversion to waste heat, or recycling as patterned or unpatterned energy). In step <NUM>, the patterned energy, now forming a two-dimensional image is relayed toward the material. In step <NUM>, the image is applied to the material, building a portion of a 3D structure. These steps can be repeated (loop <NUM>) until the image (or different and subsequent image) has been applied to all necessary regions of a top layer of the material. When application of energy to the top layer of the material is finished, a new layer can be applied (loop <NUM>) to continue building the 3D structure. These process loops are continued until the 3D structure is complete, when remaining excess material can be removed or recycled.

<FIG> is one embodiment of an additive manufacturing system <NUM> that uses multiple semiconductor lasers as part of an energy patterning system <NUM>. A control processor <NUM> can be connected to variety of sensors, actuators, heating or cooling systems, monitors, and controllers to coordinate operation of multiple lasers <NUM>, light patterning unit <NUM>, and image relay <NUM>, as well as any other component of system <NUM>. These connections are generally indicated by a dotted outline <NUM> surrounding components of system <NUM>. As will be appreciated, connections can be wired or wireless, continuous or intermittent, and include capability for feedback (for example, thermal heating can be adjusted in response to sensed temperature). The multiple lasers <NUM> can emit a beam <NUM> of light at a <NUM> wavelength that, for example, is <NUM> wide by <NUM> tall. The beam <NUM> is resized by imaging optics <NUM> to create beam <NUM>. Beam <NUM> is <NUM> wide by <NUM> tall, and is incident on light homogenization device <NUM> which blends light together to create blended beam <NUM>. Beam <NUM> is then incident on imaging assembly <NUM> which reshapes the light into beam <NUM> and is then incident on hot cold mirror <NUM>. The mirror <NUM> allows <NUM> light to pass, but reflects <NUM> light. A light projector <NUM> capable of projecting low power light at 1080p pixel resolution and <NUM> emits beam <NUM>, which is then incident on hot cold mirror <NUM>. Beams <NUM> and <NUM> overlay in beam <NUM>, and both are imaged onto optically addressed light valve <NUM> in a <NUM> wide, <NUM> tall image. Images formed from the homogenizer <NUM> and the projector <NUM> are recreated and overlaid on light valve <NUM>.

The optically addressed light valve <NUM> is stimulated by the light (typically ranging from <NUM>-<NUM>) and imprints a polarization rotation pattern in transmitted beam <NUM> which is incident upon polarizer <NUM>. The polarizer <NUM> splits the two polarization states, transmitting p-polarization into beam <NUM> and reflecting s-polarization into beam <NUM> which is then sent to a beam dump <NUM> that handles the rejected energy. As will be understood, in other embodiments the polarization could be reversed, with s-polarization formed into beam <NUM> and reflecting p-polarization into beam <NUM>. Beam <NUM> enters the final imaging assembly <NUM> which includes optics <NUM> that resize the patterned light. This beam reflects off of a movable mirror <NUM> to beam <NUM>, which terminates in a focused image applied to material bed <NUM> in an article processing unit <NUM>. The depth of field in the image selected to span multiple layers, providing optimum focus in the range of a few layers of error or offset.

The bed <NUM> can be raised or lowered (vertically indexed) within chamber walls <NUM> that contain material <NUM> dispensed by material dispenser <NUM>. In certain embodiments, the bed <NUM> can remain fixed, and optics of the final imaging assembly <NUM> can be vertically raised or lowered. Material distribution is provided by a sweeper mechanism <NUM> that can evenly spread powder held in hopper <NUM>, being able to provide new layers of material as needed. An image <NUM> wide by <NUM> tall can be sequentially directed by the movable mirror <NUM> at different positions of the bed.

When using a powdered ceramic or metal material in this additive manufacturing system <NUM>, the powder can be spread in a thin layer, approximately <NUM>-<NUM> particles thick, on top of a base substrate (and subsequent layers) as the part is built. When the powder is melted, sintered, or fused by a patterned beam <NUM>, it bonds to the underlying layer, creating a solid structure. The patterned beam <NUM> can be operated in a pulsed fashion at <NUM>, moving to the subsequent <NUM> x <NUM> image locations at intervals of <NUM> to <NUM> (with <NUM> to <NUM> being desirable) until the selected patterned areas of powder have been melted. The bed <NUM> then lowers itself by a thickness corresponding to one layer, and the sweeper mechanism <NUM> spreads a new layer of powdered material. This process is repeated until the 2D layers have built up the desired 3D structure. In certain embodiments, the article processing unit <NUM> can have a controlled atmosphere. This allows reactive materials to be manufactured in an inert gas, or vacuum environment without the risk of oxidation or chemical reaction, or fire or explosion (if reactive metals are used).

<FIG> illustrates in more detail operation of the light patterning unit <NUM> of <FIG>. As seen in <FIG>, a representative input pattern <NUM> (here seen as the numeral "<NUM>") is defined in an 8x12 pixel array of light projected as beam <NUM> toward mirror <NUM>. Each grey pixel represents a light filled pixel, while white pixels are unlit. In practice, each pixel can have varying levels of light, including light-free, partial light intensity, or maximal light intensity. Unpatterned light <NUM> that forms beam <NUM> is directed and passes through a hot/cold mirror <NUM>, where it combines with patterned beam <NUM>. After reflection by the hot/cold mirror <NUM>, the patterned light beam <NUM> formed from overlay of beams <NUM> and <NUM> in beam <NUM>, and both are imaged onto optically addressed light valve <NUM>. The optically addressed light valve <NUM>, which would rotate the polarization state of unpatterned light <NUM>, is stimulated by the patterned light beam <NUM>, <NUM> to selectively not rotate the polarization state of polarized light <NUM>, <NUM> in the pattern of the numeral "<NUM>" into beam <NUM>. The unrotated light representative of pattern <NUM> in beam <NUM> is then allowed to pass through polarizer mirror <NUM> resulting in beam <NUM> and pattern <NUM>. Polarized light in a second rotated state is rejected by polarizer mirror <NUM>, into beam <NUM> carrying the negative pixel pattern <NUM> consisting of a light-free numeral "<NUM>".

Other types of light valves can be substituted or used in combination with the described light valve. Reflective light valves, or light valves base on selective diffraction or refraction can also be used. In certain embodiments, non-optically addressed light valves can be used. These can include but are not limited to electrically addressable pixel elements, movable mirror or micro-mirror systems, piezo or micro-actuated optical systems, fixed or movable masks, or shields, or any other conventional system able to provide high intensity light patterning. For electron beam patterning, these valves may selectively emit electrons based on an address location, thus imbuing a pattern on the beam of electrons leaving the valve.

<FIG> is one embodiment of an additive manufacturing system that includes a switchyard system enabling reuse of patterned two-dimensional energy. Similar to the embodiment discussed with respect to <FIG>, an additive manufacturing system <NUM> has an energy patterning system with an energy source <NUM> that directs one or more continuous or intermittent energy beam(s) toward beam shaping optics <NUM>. After shaping, the beam is two-dimensionally patterned by an energy patterning unit <NUM>, with generally some energy being directed to a rejected energy handling unit <NUM>. Patterned energy is relayed by one of multiple image relays <NUM> toward one or more article processing units 234A, 234B, 234C, or 234D, typically as a two-dimensional image focused near a movable or fixed height bed. The bed (with optional walls) can form a chamber containing material dispensed by material dispenser. Patterned energy, directed by the image relays <NUM>, can melt, fuse, sinter, amalgamate, change crystal structure, influence stress patterns, or otherwise chemically or physically modify the dispensed material to form structures with desired properties.

In this embodiment, the rejected energy handling unit has multiple components to permit reuse of rejected patterned energy. Relays 228A, 228B, and 22C can respectively transfer energy to an electricity generator <NUM>, a heat/cool thermal management system <NUM>, or an energy dump <NUM>. Optionally, relay 228C can direct patterned energy into the image relay <NUM> for further processing. In other embodiments, patterned energy can be directed by relay 228C, to relay 228B and 228A for insertion into the energy beam(s) provided by energy source <NUM>. Reuse of patterned images is also possible using image relay <NUM>. Images can be redirected, inverted, mirrored, sub-patterned, or otherwise transformed for distribution to one or more article processing units. Advantageously, reuse of the patterned light can improve energy efficiency of the additive manufacturing process, and in some cases improve energy intensity directed at a bed, or reduce manufacture time.

<FIG> is a cartoon <NUM> illustrating a simple geometrical transformation of a rejected energy beam for reuse. An input pattern <NUM> is directed into an image relay <NUM> capable of providing a mirror image pixel pattern <NUM>. As will be appreciated, more complex pixel transformations are possible, including geometrical transformations, or pattern remapping of individual pixels and groups of pixels. Instead of being wasted in a beam dump, this remapped pattern can be directed to an article processing unit to improve manufacturing throughput or beam intensity.

<FIG> is a cartoon <NUM> illustrating multiple transformations of a rejected energy beam for reuse. An input pattern <NUM> is directed into a series of image relays 237B-E capable of providing a pixel pattern <NUM>.

<FIG> illustrates a non-light based energy beam system <NUM> that includes a patterned electron beam <NUM> capable of producing, for example, a "P" shaped pixel image. A high voltage electricity power system <NUM> is connected to an optically addressable patterned cathode unit <NUM>. In response to application of a two-dimensional patterned image by projector <NUM>, the cathode unit <NUM> is stimulated to emit electrons wherever the patterned image is optically addressed. Focusing of the electron beam pattern is provided by an image relay system <NUM> that includes imaging coils 246A and 246B. Final positioning of the patterned image is provided by a deflection coil <NUM> that is able to move the patterned image to a desired position on a bed of additive manufacturing component <NUM>.

In another embodiment supporting light recycling and reuse, multiplex multiple beams of light from one or more light sources are provided. The multiple beams of light may be reshaped and blended to provide a first beam of light. A spatial polarization pattern may be applied on the first beam of light to provide a second beam of light. Polarization states of the second beam of light may be split to reflect a third beam of light, which may be reshaped into a fourth beam of light. The fourth beam of light may be introduced as one of the multiple beams of light to result in a fifth beam of light. In effect, this or similar systems can reduce energy costs associated with an additive manufacturing system. By collecting, beam combining, homogenizing and re-introducing unwanted light rejected by a spatial polarization valve or light valve operating in polarization modification mode, overall transmitted light power can potentially be unaffected by the pattern applied by a light valve. This advantageously results in an effective re-distribution of the light passing through the light valve into the desired pattern, increasing the light intensity proportional to the amount of area patterned.

Combining beams from multiple lasers into a single beam is one way to increasing beam intensity. In one embodiment, multiple light beams, each having a distinct light wavelength, can be combined using either wavelength selective mirrors or diffractive elements. In certain embodiments, reflective optical elements that are not sensitive to wavelength dependent refractive effects can be used to guide a multiwavelength beam.

Patterned light can be directed using movable mirrors, prisms, diffractive optical elements, or solid state optical systems that do not require substantial physical movement. In one embodiment, a magnification ratio and an image distance associated with an intensity and a pixel size of an incident light on a location of a top surface of a powder bed can be determined for an additively manufactured, three-dimensional (3D) print job. One of a plurality of lens assemblies can be configured to provide the incident light having the magnification ratio, with the lens assemblies both a first set of optical lenses and a second sets of optical lenses, and with the second sets of optical lenses being swappable from the lens assemblies. Rotations of one or more sets of mirrors mounted on compensating gantries and a final mirror mounted on a build platform gantry can be used to direct the incident light from a precursor mirror onto the location of the top surface of the powder bed. Translational movements of compensating gantries and the build platform gantry are also able to ensure that distance of the incident light from the precursor mirror to the location of the top surface of the powder bed is substantially equivalent to the image distance. In effect, this enables a quick change in the optical beam delivery size and intensity across locations of a build area for different powdered materials while ensuring high availability of the system.

In certain embodiments, a plurality of build chambers, each having a build platform to hold a powder bed, can be used in conjunction with multiple optical-mechanical assemblies arranged to receive and direct the one or more incident energy beams into the build chambers. Multiple chambers allow for concurrent printing of one or more print jobs inside one or more build chambers. In other embodiments, a removable chamber sidewall can simplify removal of printed objects from build chambers, allowing quick exchanges of powdered materials. The chamber can also be equipped with an adjustable process temperature controls.

In another embodiment, one or more build chambers can have a build chamber that is maintained at a fixed height, while optics are vertically movable. A distance between final optics of a lens assembly and a top surface of powder bed a may be managed to be essentially constant by indexing final optics upwards, by a distance equivalent to a thickness of a powder layer, while keeping the build platform at a fixed height. Advantageously, as compared to a vertically moving the build platform, large and heavy objects can be more easily manufactured, since precise micron scale movements of the build platform are not needed. Typically, build chambers intended for metal powders with a volume more than ~ <NUM> - <NUM> cubic meters (i.e., greater than <NUM> - <NUM> liters or heavier than <NUM> - <NUM>,<NUM>) will most benefit from keeping the build platform at a fixed height.

In one embodiment, a portion of the layer of the powder bed may be selectively melted or fused to form one or more temporary walls out of the fused portion of the layer of the powder bed to contain another portion of the layer of the powder bed on the build platform. In selected embodiments, a fluid passageway can be formed in the one or more first walls to enable improved thermal management.

Improved powder handling can be another aspect of an improved additive manufacturing system. A build platform supporting a powder bed can be capable of tilting, inverting, and shaking to separate the powder bed substantially from the build platform in a hopper. The powdered material forming the powder bed may be collected in a hopper for reuse in later print jobs. The powder collecting process may be automated, and vacuuming or gas jet systems also used to aid powder dislodgement and removal.

Some embodiments of the disclosed additive manufacturing system can be configured to easily handle parts longer than an available chamber. A continuous (long) part can be sequentially advanced in a longitudinal direction from a first zone to a second zone. In the first zone, selected granules of a granular material can be amalgamated. In the second zone, unamalgamated granules of the granular material can be removed. The first portion of the continuous part can be advanced from the second zone to a third zone, while a last portion of the continuous part is formed within the first zone and the first portion is maintained in the same position in the lateral and transverse directions that the first portion occupied within the first zone and the second zone. In effect, additive manufacture and clean-up (e.g., separation and/or reclamation of unused or unamalgamated granular material) may be performed in parallel (i.e., at the same time) at different locations or zones on a part conveyor, with no need to stop for removal of granular material and/or parts.

In another embodiment, additive manufacturing capability can be improved by use of an enclosure restricting an exchange of gaseous matter between an interior of the enclosure and an exterior of the enclosure. An airlock provides an interface between the interior and the exterior; with the interior having multiple additive manufacturing chambers, including those supporting power bed fusion. A gas management system maintains gaseous oxygen within the interior at or below a limiting oxygen concentration, increasing flexibility in types of powder and processing that can be used in the system.

In another manufacturing embodiment, capability can be improved by having a 3D printer contained within an enclosure, the printer able to create a part having a weight greater than or equal to <NUM>,<NUM> kilograms. A gas management system may maintain gaseous oxygen within the enclosure at concentrations below the atmospheric level. In some embodiments, a wheeled vehicle may transport the part from inside the enclosure, through an airlock, since the airlock operates to buffer between a gaseous environment within the enclosure and a gaseous environment outside the enclosure, and to a location exterior to both the enclosure and the airlock.

Other manufacturing embodiments involve collecting powder samples in real-time in a powder bed fusion additive manufacturing system. An ingester system is used for in-process collection and characterizations of powder samples. The collection may be performed periodically and the results of characterizations result in adjustments to the powder bed fusion process. The ingester system can optionally be used for one or more of audit, process adjustments or actions such as modifying printer parameters or verifying proper use of licensed powder materials.

Yet another improvement to an additive manufacturing process can be provided by use of a manipulator device such as a crane, lifting gantry, robot arm, or similar that allows for the manipulation of parts that would be difficult or impossible for a human to move is described. The manipulator device can grasp various permanent or temporary additively manufactured manipulation points on a part to enable repositioning or maneuvering of the part.

<FIG> is an example apparatus of dynamic optical assembly <NUM> capable of configuring a magnification ratio on the fly for different powdered materials without shutting down the additive manufacturing system and re-installing the optics assembly. Dynamic optical assembly <NUM> may perform various functions related to techniques, methods and systems described herein, including those described below with respect to process <NUM>. Dynamic optical assembly <NUM> may be installed in, equipped on, connected to or otherwise implemented in a laser-based powder bed fusion additive manufacturing system as described above with respect to <FIG> to effect various embodiments in accordance with the present disclosure. Dynamic optical assembly <NUM> may include at least some of the components illustrated in <FIG>.

Dynamic optical assembly <NUM> may include a mechanical assembly <NUM> which may include a set of lens assemblies <NUM>(<NUM>) - <NUM>(K), with K being a positive integer. Each of the lens assemblies <NUM>(<NUM>) - <NUM>(K) may be associated with a respective magnification ratio which magnifies a first image in a specified precursor image plane <NUM> located before the first lens of lens assemblies <NUM>(<NUM>) - <NUM>(K) to a second image of the same or different size on the print surface - final image plane <NUM>. Mechanical assembly <NUM> may be operable to select, switch, or position one of the lens assemblies <NUM>(<NUM>) - <NUM>(K) to receive an incident light beam provided by an energy source <NUM> (e.g., solid state or semiconductor laser). The operation of mechanical assembly <NUM> described above may result in no interruptions of additive manufacturing when changing the powdered materials and, therefore, ensue high availability of the additive manufacturing system.

The lens assemblies <NUM>(<NUM>) - <NUM>(K) may include a plurality of first sets of optical lenses <NUM>(<NUM>) - <NUM>(K) and a plurality of second sets optical lens <NUM>(<NUM>) - <NUM>(K), respectively. That is, each lens assembly <NUM>(Y) of lens assemblies <NUM>(<NUM>) - <NUM>(K) may respectfully include a respective first set of optical lenses <NUM>(Y) and a respective second set of optical lenses <NUM>(Y), where Y is between <NUM> and K. Second sets of optical lenses <NUM>(<NUM>) - <NUM>(K) may be detachable from the lens assemblies <NUM>(<NUM>) - <NUM>(K) to allow a swap or a removal of second sets of optical lenses <NUM>(<NUM>) - <NUM>(K) from the lens assemblies <NUM>(<NUM>) - <NUM>(K). A swap or a removal of second sets of optical lenses <NUM>(<NUM>) - <NUM>(K) may allow further tuning in configuring a magnification ratio for a powdered material since each powdered material may have a different threshold of bonding energy. Swapping or removing of second sets of optical lenses <NUM>(<NUM>) - <NUM>(K) may be performed manually or, alternatively, automatically by operations of mechanical assembly <NUM>.

In some embodiments, dynamic optical assembly <NUM> may further include a precursor mirror <NUM> and a build platform gantry <NUM> with a final mirrors <NUM> mounted on build platform gantry <NUM>. Build platform gantry <NUM> may be mounted at a vertical distance above a powder bed. Precursor mirror <NUM> may be capable of rotations and may direct an incident light received from one of the lens assemblies <NUM>(<NUM>) - <NUM>(K) to final mirror <NUM>. Final mirror <NUM> on build platform gantry <NUM> may be capable of translational movements in two degrees of freedom and rotations in one degree of freedom to receive the incident light from precursor mirror <NUM> and direct the incident light toward the powder bed, e.g., the build area of a printed object.

<FIG> illustrates a lens assembly <NUM> for laser-based powder bed fusion additive manufacturing showing 4x de-magnification. Lens assembly <NUM> may be an implementation of lens assembly <NUM>(<NUM>) - <NUM>(K) in apparatus <NUM>. In the example shown in <FIG>, a beam of <NUM> laser light <NUM>, <NUM> wide and <NUM> tall, contains image information in plane <NUM>. Lens assembly <NUM>, which includes a convex lens <NUM>, a convex lens <NUM>, and a convex lens <NUM> aligned along an optical axis of lens assembly <NUM>, causes a 4x de-magnification in the laser beam and re-creates the image of plane <NUM> on plane <NUM>. Beam <NUM> passes through convex lens <NUM> to form beam <NUM> which passes through convex lens <NUM> to form beam <NUM> which passes through convex lens <NUM> to form beam <NUM> which is incident on a top surface of a powder bed at plane <NUM> in a <NUM> wide by <NUM> tall square.

<FIG> illustrates a lens assembly <NUM> for laser-based powder bed fusion additive manufacturing showing 25x de-magnification. Lens assembly <NUM> may be an implementation of lens assembly <NUM>(<NUM>) - <NUM>(K) in apparatus <NUM>. In the example shown in <FIG>, a beam of <NUM> laser light <NUM>, <NUM> wide and <NUM> tall, contains image information in plane <NUM>. Lens assembly <NUM>, which includes a convex lens <NUM>, a convex lens <NUM>, and a convex lens <NUM> aligned along an optical axis of lens assembly <NUM>, causes a 4x de-magnification in the laser beam and re-creates the image of plane <NUM> on plane <NUM>. Beam <NUM> passes through convex lens <NUM> to form beam <NUM> which passes through convex lens <NUM> to form beam <NUM> which passes through convex lens <NUM> to form beam <NUM> which is incident on a top surface of the powder bed at plane <NUM> in a <NUM> wide and <NUM> tall square.

<FIG> illustrates a system <NUM> having a lens assembly <NUM> for laser-based powder bed fusion additive manufacturing showing 4x magnification. Lens assembly <NUM> may be an implementation of lens assembly <NUM>(<NUM>) - <NUM>(K) in apparatus <NUM>. In the example shown in <FIG>, a beam of <NUM> laser light <NUM>, <NUM> wide and <NUM> tall, contains image information in plane <NUM>. Lens assembly <NUM>, which includes a concave lens <NUM>, a concave lens <NUM>, and a concave lens <NUM> aligned along an optical axis of lens assembly <NUM>, causes a 4x magnification in the laser beam and re-creates the image of plane <NUM> on plane <NUM>. Beam <NUM> passes through concave lens <NUM> to form beam <NUM> which passes through concave lens <NUM> to form beam <NUM> which passes through concave lens <NUM> to form beam <NUM> which is incident on a top surface of the powder bed at plane <NUM> in a <NUM> by <NUM> square.

<FIG> illustrates a lens assembly swapping mechanism <NUM> for changing out optics by rotating new ones into place. This mechanism <NUM> uses rotations to swap out various lens assemblies <NUM>, <NUM>, and <NUM> which are installed in barrel <NUM>. The rotations of barrel <NUM> may be performed with respect to the longitudinal axis of barrel <NUM>, which is also parallel to the optical axes of the lens assemblies <NUM>, <NUM>, and <NUM>. Lens assembly <NUM> contains convex lens <NUM>, convex lens <NUM>, and convex lens <NUM> as shown in <FIG>; lens assembly <NUM> contains convex lens <NUM>, convex lens <NUM>, and convex lens <NUM> as shown in <FIG>; and lens assembly <NUM> contains concave lens <NUM>, concave lens <NUM>, and concave lens <NUM> as shown in <FIG>. In certain embodiments, the lens assembly swapping mechanism may not require physical replacement of lenses in the lens assemblies. Instead, the image size and/or shape may be dynamically modulated by exerting electromagnetic or mechanical effects on special lenses of which the reflective/refractive properties may respond to such effects and cause a change of the magnification ratio. That is, in some embodiments in accordance with the present disclosure, "swapping out" of the optics may be achieved not by physically replacing the optics, but by dynamically changing the optics. For example, a lens capable of modulating its shape under the control of electric, magnetic and/or optic drive effect may be utilized.

In some embodiments, linear translational movements of lenses <NUM>, <NUM>, and <NUM> inside lens assembly <NUM> (or lenses <NUM>, <NUM>, and <NUM> inside lens assembly <NUM>, or lenses <NUM>, <NUM>, and <NUM> inside lens assembly <NUM>) may be used to change the magnification ratios for the respective lens assembly. When the distance between a pair of lenses among lenses <NUM>, <NUM>, and <NUM> changes, the magnification ratio of lens assembly <NUM> may change accordingly.

<FIG> illustrates a swap of two sets of optical lenses for laser-based powder bed fusion additive manufacturing showing 4x de-magnification changing to 25x de-magnification when a first set of optical lenses <NUM> and a second set of optical lenses <NUM> are swapped. Another set of optical lenses including convex lens <NUM> may be non-detachable or non-swappable. In the example shown in <FIG>, a beam of <NUM> laser light <NUM>, in a <NUM> wide and <NUM> tall beam, contains image information in plane <NUM>. A swappable lens assembly <NUM>, which includes a convex lens <NUM> and a convex lens <NUM>, causes a 4x de-magnification in the laser beam and re-creates the image of plane <NUM> on plane <NUM>. Beam <NUM> passes through convex lens <NUM> to form beam <NUM> which passes through convex lens <NUM> to form beam <NUM> which passes through convex lens <NUM> to form beam <NUM> which is incident on the top surface of the powder bed at plane <NUM> in a <NUM> wide and <NUM> tall square. The first set of optical lenses <NUM> is swappable with the second set of optical lenses <NUM> to allow for different projected intensities on a top surface of the powder bed. When swapped, a convex lens <NUM> and a convex lens <NUM> are swapped in to take place of convex lens <NUM> and convex lens <NUM>, thus converting beam <NUM> and beam <NUM> to beam <NUM> and beam <NUM> at a new image plane <NUM>, thereby converting the image into a <NUM> wide and <NUM> tall square at plane <NUM>.

<FIG> illustrates a swap of two sets of optical lenses for laser-based powder bed fusion additive manufacturing showing 4x de-magnification changing to 2x magnification when a first set of optical lenses <NUM> and a second set of optical lenses <NUM> are swapped. Another set of optical lenses including convex lens <NUM> and convex lens <NUM> may be non-detachable or non-swappable. In the example shown in <FIG>, a beam of <NUM> laser light <NUM>, in a <NUM> wide and <NUM> tall beam, contains image information in plane <NUM>. A swappable first set of optical lenses <NUM>, which includes convex lens <NUM>, causes a 4x de-magnification in the laser beam and re-creates the image of plane <NUM> on plane <NUM>. Beam <NUM> passes through convex lens <NUM> to form beam <NUM> which passes through convex lens <NUM> to form beam <NUM> which passes through convex lens <NUM> to form beam <NUM> which is incident on a top surface of the powder bed at plane <NUM> in a <NUM> wide and <NUM> tall square. The second set of optical lenses <NUM> is swappable with the first set of optical lenses <NUM> to allow for different projected intensities on the top surface of the powder bed. When swapped, concave lens <NUM> is swapped in to take place of convex lens <NUM>, thus converting beam <NUM> and beam <NUM> to beam <NUM> and beam <NUM> at a new image plane <NUM>, thereby resulting in a converted image at plane <NUM> of a <NUM> wide and <NUM> tall square.

<FIG> illustrates a removal of second sets of optical lenses for laser-based powder bed fusion additive manufacturing showing 4x de-magnification changing to 2x magnification when a first set of optical lenses <NUM> is removed. Another set of optical lenses including convex lens <NUM> and convex lens <NUM> may be non-detachable or non-swappable. In the example shown in <FIG>, a beam of <NUM> laser light <NUM>, in a <NUM> wide and <NUM> tall beam, contains image information in plane <NUM>. A swappable first set of optical lenses <NUM>, which includes a convex lens <NUM>, causes a 4x de-magnification in the laser beam and re-creates the image of plane <NUM> on plane <NUM>. Beam <NUM> passes through lens <NUM> to form beam <NUM> which passes through convex lens <NUM> to form beam <NUM> which passes through convex lens <NUM> to form beam <NUM> which is incident on the powder bed at plane <NUM> in a <NUM> wide and <NUM> tall square. The first set of optical lenses <NUM> is swappable with a second set of optical lenses <NUM> to allow for different projected intensities on a top surface of the powder bed. In the example shown in <FIG>, the second set of optical lenses <NUM> contains no lens. When swapped, convex lens <NUM> is removed, thus converting beam <NUM> and beam <NUM> to beam <NUM>, and beam <NUM> to beam <NUM> at a new image plane <NUM>, thereby resulting in a converted image at plane <NUM> of a <NUM> wide and <NUM> tall square.

As powder bed fusion additive manufacturing systems grow in speed and size for larger objects, the optical system in laser-based powder bed fusion additive manufacturing systems need to be adjusted to handle resolution requirements. When operating on a light source that is highly divergent and un-collimated, such as with laser lasers, care must be used to ensure that high resolution imaging is maintained. The dynamic optical assembly of the present disclosure is capable of high-resolution image relay operations over large distances and large print surface. A part of the dynamic optical assembly may focus on the translational position control of the optics over the powder bed to maintain high-resolution imaging while directing the laser beam to all possible locations on the powder bed.

The distances between lenses are designed for a specific focal length over a focal plane in an optical system. If the print surface (where an image of the object is formed) coincides with the focal plane of the final optics in the optical system, then a good resolution of the printed object may be obtained. The focal plane may not be a flat plane but with a curvature, and in cases of forming a large object in laser-based powder bed fusion additive manufacturing, some locations on the top surface of the powder bed may lie outside of the focal plane. In some embodiments, a dynamic optical assembly in accordance with the present disclosure may control an imaging distance (or a focal length, or a depth of field) between a source imaging plane and locations on the top surface of the powder bed by adjusting the distance between lens to compensate for the change of the imaging distance due to different locations. The control of the imaging distance may be realized by translational movements and rotations of mirrors and lens mounted on a set of gantries capable of moving along a plane parallel to the top surface of the powder bed (print surface).

<FIG> illustrates an example apparatus of dynamic optical assembly <NUM> capable of controlling an image distance for high resolution imaging on locations over an entire print surface accordance with an embodiment of the present disclosure. Dynamic optical assembly <NUM> may perform various functions related to techniques, methods and systems described herein, including those described below with respect to process <NUM>. Dynamic optical assembly <NUM> may be installed in, equipped on, connected to or otherwise implemented in a laser-based powder bed fusion additive manufacturing system as described above with respect to <FIG> to effect various embodiments in accordance with the present disclosure. Dynamic optical assembly <NUM> may include at least some of the components illustrated in <FIG>.

In some embodiments, dynamic optical assembly <NUM> may include a precursor mirror <NUM>, at least one compensating gantry, build platform gantry <NUM>. For illustrative purpose and without limitation, the at least one compensating gantry is shown in <FIG> as a set of compensating gantries <NUM>(<NUM>) - <NUM>(X), with X being a positive integer greater than <NUM>. The compensating gantries <NUM>(<NUM>) - <NUM>(X) may include sets of mirrors <NUM>(<NUM>) - <NUM>(N), <NUM>(<NUM>) - <NUM>(N),. , 125X(<NUM>) - 125X(N), with N a positive integer. Each set of the mirrors <NUM>(<NUM>) - <NUM>(N), <NUM>(<NUM>) - <NUM>(N),. , 125X(<NUM>) - 125X(N) may be mounted on the respective compensating gantries <NUM>(<NUM>) - <NUM>(X). In some embodiments, at least one set of mirrors <NUM>(<NUM>) - <NUM>(N) may be mounted on the one of the compensating gantries <NUM>(<NUM>) - <NUM>(X). Build platform gantry <NUM> may include a final set of mirrors <NUM>(<NUM>) - <NUM>(J), with J a positive integer. In some embodiments, build platform gantry <NUM> may further include final lens <NUM>. Build platform gantry <NUM> may be mounted at a vertical distance above the print surface and the compensating gantries <NUM>(<NUM>) - <NUM>(X) may be mounted at a horizontal distance next to build platform gantry <NUM>. Precursor mirror <NUM> may reflect off an incident light containing an image at a precursor image plane towards compensating gantries. Sets of mirrors <NUM>(<NUM>) - <NUM>(N), <NUM>(<NUM>) - <NUM>(N),. , 125X(<NUM>) - 125X(N) on the compensation gantries <NUM>(<NUM>) - <NUM>(X) may be capable of translational movements and rotations so as to direct the incident light received from precursor mirror <NUM> towards build platform gantry <NUM>. Final set of mirrors <NUM>(<NUM>) - <NUM>(J) on build platform gantry <NUM> may be capable of translational movements and rotations so as to direct the incident light received from compensating gantries <NUM>(<NUM>) - <NUM>(X) towards the print surface. The translational movements of sets of mirrors <NUM>(<NUM>) - <NUM>(N), <NUM>(<NUM>) - <NUM>(N),. , 125X(<NUM>) - 125X(N) on compensating gantries <NUM>(<NUM>) - <NUM>(X) and final set of mirrors <NUM>(<NUM>) - <NUM>(J) on build platform gantry <NUM> may serve to control a constant image distance between lenses for maintaining an image resolution during the image relay from the precursor image plane and the print surface. The rotations of sets of mirrors <NUM>(<NUM>) - <NUM>(N), <NUM>(<NUM>) - <NUM>(N),. , 125X(<NUM>) - 125X(N) on compensating gantries <NUM>(<NUM>) - <NUM>(X) and final set of mirrors <NUM>(<NUM>) - <NUM>(J) on build platform gantry <NUM> may serve to direct the incident light to various locations on the print surface.

In some embodiments, dynamic optical assembly <NUM> may include one compensating gantry <NUM>(<NUM>) mounted with one mirror <NUM>(<NUM>). Dynamic optical assembly <NUM> may further include precursor mirror <NUM> and build platform gantry <NUM> mounted with one final mirror <NUM>(<NUM>) and final lens <NUM>. Precursor mirror <NUM>, directing the incident light from the precursor image plane, may be incapable of rotations and translational movements. Precursor mirror <NUM>, directing the incident light from the precursor image plane, may direct an incident light towards mirror <NUM>(<NUM>) on compensating gantry <NUM>(<NUM>). Mirror <NUM>(<NUM>) may be capable of a rotation in one degree of freedom and a translational movement in one degree of freedom. Mirror <NUM>(<NUM>) may further direct light towards final mirror <NUM>(<NUM>) on build platform gantry <NUM>. Final mirror <NUM>(<NUM>) may be capable of rotations in two degrees of freedom and translational movements in two degree of freedom so as to direct the incident light passing through final lens <NUM> to all locations on the print surface. Final lens <NUM> may be fixed below relative to final mirror <NUM>(<NUM>) and moves synchronously with final mirror <NUM>(<NUM>).

In some embodiments, dynamic optical assembly <NUM> may further include a processor <NUM> and a memory <NUM> to facilitate controlling of positions and rotations of sets of mirrors <NUM>(<NUM>) - <NUM>(N), <NUM>(<NUM>) - <NUM>(N),. , 125X(<NUM>) - 125X(N) on compensating gantries <NUM>(<NUM>) - <NUM>(X) and final mirror <NUM> on build platform gantry <NUM>. Memory <NUM> storing instructions or programs for configuring relative positons and angles of sets of mirrors <NUM>(<NUM>) - <NUM>(N), <NUM>(<NUM>) - <NUM>(N),. , 125X(<NUM>) - 125X(N) and final set of mirrors <NUM>(<NUM>) - <NUM>(J) to maintain a constant image distance across the entire print surface.

In some embodiments, dynamic optical assembly <NUM> may further include a plurality of lens assemblies <NUM>(<NUM>) - <NUM>(K) and a mechanical assembly <NUM> of apparatus <NUM> to be able to change magnification ratios on-the-fly for different powdered materials. Lens assemblies <NUM>(<NUM>) - <NUM>(K) may include first sets of optical lenses <NUM>(<NUM>) - <NUM>(K) and second sets of optical lenses <NUM>(<NUM>) - <NUM>(K) respectively as in apparatus <NUM>.

<FIG> illustrates an example scenario <NUM> as in embodiments described above in accordance with the present disclosure. Scenario <NUM> illustrates a near-point print as to how compensating gantry and build platform gantry may compensate for a change of the imaging location. In <FIG>, build platform gantry is made of rail <NUM>, rail <NUM>, and rail <NUM>. Final mirror <NUM> is mounted on podium <NUM> and supports fixed final lens <NUM>. Final mirror <NUM> is capable of rotations in two degrees of freedom. Build platform gantry (rail <NUM>, rail <NUM>, and rail <NUM>) is mounted above a powder bed <NUM>, and is capable of a translational motion in the x-direction <NUM> on rail <NUM> and in the y-direction <NUM> on rail <NUM>. Y-directional rail <NUM> and rail <NUM> are mounted on wall <NUM> and wall <NUM> respectively, which sandwich a build platform <NUM> therebetween. Build platform <NUM> is capable of a vertical translational motion up and down. A patterned beam of light <NUM>, which includes a <NUM> x <NUM> beam of <NUM> light containing <NUM> kW of power, may be emanated from an energy source (e.g., semiconductor laser), may contain image information in a precursor image plane <NUM>, and may then reflect off of precursor mirror <NUM> mounted on post <NUM> which is incapable of movements and rotations. The beam of light <NUM> leaving the precursor mirror <NUM> reflects a second time off of mirror <NUM> which is mounted to podium <NUM> on compensating gantry platform of rail <NUM>, and capable of rotation in one axis, and horizontal translation in the x-direction <NUM> on rail <NUM>. The beam of light <NUM> leaving mirror <NUM> reflects off of final mirror <NUM> passes through final lens <NUM> which focuses the light in beam <NUM> to a <NUM> x <NUM> square achieving intensities of <MAT> at the top surface of powder bed <NUM> (print surface) to melt a pattern in a printed image <NUM>. The current position of podium <NUM> is such that the distance the light travels is constant and that the distance <NUM> of <NUM> between precursor mirror <NUM> and mirror <NUM> plus the distance <NUM> of <NUM> between mirror <NUM> and final mirror <NUM> is at a constant value (<NUM>) for every x and y position of podium <NUM> and corresponding x-position of podium <NUM>. It is noteworthy that the dimensions and values referenced herein are for illustrative purposes and without limitation. That is, the scope of the present disclosure is limited to the specific example shown and described in <FIG>.

<FIG> illustrates an example scenario <NUM> as in embodiments described above in accordance with the present disclosure. Scenario <NUM> illustrates a fart-point print as to how compensating gantry and build platform gantry may compensate for a change of the imaging location. In <FIG>, build platform gantry is made of rail <NUM>, rail <NUM>, and rail <NUM>. Final mirror <NUM> is mounted on podium <NUM> also supporting fixed final lens <NUM>. Final mirror <NUM> is capable of rotations in two degrees of freedom. Build platform gantry (rail <NUM>, rail <NUM>, and rail <NUM>) is mounted above a powder bed <NUM>, and is capable of translational motion in the x-direction <NUM> on rail <NUM> and in the y-direction <NUM> on rail <NUM>. Y-directional rail <NUM> and rail <NUM> are mounted on wall <NUM> and wall <NUM> respectively, which sandwich the main build platform <NUM> therebetween. Build platform <NUM> is capable of relative translational motion up and down. A patterned beam of light <NUM>, which includes a <NUM> x <NUM> beam of <NUM> light containing <NUM> kW of power, may emanate from the additive manufacturing optical system, may contain image information in a precursor image plane <NUM>, and may reflect off of precursor mirror <NUM> mounted on post <NUM> which is incapable of movements and rotations. The beam of light <NUM> leaving precursor mirror <NUM> reflects a second time off of mirror <NUM> which is mounted to podium <NUM>, and capable of rotation in one axis, and horizontal translation in the x-direction <NUM> on compensating gantry of rail <NUM>. The beam of light <NUM> leaving mirror <NUM> reflects off of final mirror <NUM> passes through final lens <NUM> which focuses the light in beam <NUM> to a <NUM> x <NUM> square achieving intensities of <MAT> at the top surface of powder bed <NUM> (print surface) to melt a pattern in a printed image <NUM>. The current position of the podium <NUM> is such that the distance the light travels is constant and that the distance <NUM> of <NUM> between precursor mirror <NUM> and mirror <NUM> plus the distance <NUM> of <NUM> between mirror <NUM> and final mirror <NUM> is at a constant value (<NUM>) for every x and y position of podium <NUM> and corresponding x-position of podium <NUM>. It is noteworthy that the dimensions and values referenced herein are for illustrative purposes and without limitation. That is, the scope of the present disclosure is limited to the specific example shown and described in <FIG>.

<FIG> illustrates an example scenario <NUM> as in embodiments described above in accordance with the present disclosure. Scenario <NUM> illustrates a near-point print as to how compensating gantry and build platform gantry may compensate for a change of the imaging location. In <FIG>, build platform gantry is made of rail <NUM>, rail <NUM>, and rail <NUM>. Final mirror <NUM> is mounted on podium <NUM> also supporting fixed final lens <NUM>. Final mirror <NUM> is capable of a rotation in one degree of freedom. Build platform gantry (rail <NUM>, rail <NUM>, and rail <NUM>) is mounted above a powder bed <NUM>, and is capable of translational motion in the x-direction <NUM> on rail <NUM> and in the y-direction <NUM> on rail <NUM>. Y-directional rail <NUM> and rail <NUM> are mounted on wall <NUM> and wall <NUM>, which sandwich the main build platform <NUM> therebetween. Build platform <NUM> is capable of relative translational motion up and down. A patterned beam of light <NUM>, which includes a <NUM> x <NUM> beam of <NUM> light containing <NUM> kW of power, may emanate from the additive manufacturing optical system, may contain image information in a precursor image plane <NUM>, and may reflect off of precursor mirror <NUM> mounted on post <NUM> which is capable of rotation in one degree of freedom. The beam of light <NUM> leaving precursor mirror <NUM> reflects a second time off of mirror <NUM> which is mounted to podium <NUM>, and capable of rotation in one axis, horizontal translation in the x-direction <NUM> on compensating gantry of rail <NUM>, as well as translation in the y-direction <NUM> on rail <NUM>. The beam of light <NUM> leaving mirror <NUM> reflects off of final mirror <NUM> passes through final lens <NUM> which focuses the light in beam <NUM> to a <NUM> x <NUM> square achieving intensities of <MAT> at the top surface of powder bed <NUM> (print surface) to melt a pattern in a printed image <NUM>. The current position of the podium <NUM> is such that the distance the light travels is constant and that the square root of the square of the distance <NUM> in the x-direction <NUM> of <NUM> between precursor mirror <NUM> and mirror <NUM> plus the square of distance <NUM> in the y-direction <NUM> of <NUM> ( <MAT>) plus the distance <NUM> of <NUM> between mirror <NUM> and mirror <NUM> is at a constant value (<NUM>) for every x and y position of podium <NUM> and corresponding x and y positions of podium <NUM>. It is noteworthy that the dimensions and values referenced herein are for illustrative purposes and without limitation. That is, the scope of the present disclosure is limited to the specific example shown and described in <FIG>.

<FIG> illustrates an example scenario <NUM> as in embodiments described above in accordance with the present disclosure. Scenario <NUM> illustrates a far-point print as to how compensating gantry and build platform gantry may compensate for a change of the imaging location. In <FIG>, build platform gantry is made of rail <NUM>, rail <NUM>, and rail <NUM>. Final mirror <NUM> is capable of a rotation in one degree of freedom. Build platform gantry (rail <NUM>, rail <NUM>, and rail <NUM>) is mounted above a powder bed <NUM>, and is capable of translational motion in the x-direction <NUM> on rail <NUM> and in the y-direction <NUM> on rail <NUM>. Y-directional rail <NUM> and rail <NUM> are mounted on wall <NUM> and wall <NUM>, which sandwich the main build platform <NUM> therebetween. Build platform <NUM> is capable of relative translational motion up and down. A patterned beam of light <NUM>, which includes a <NUM> x <NUM> beam of <NUM> light containing <NUM> kW of power, may emanate from the additive manufacturing optical system, may contain image information in a precursor image plane <NUM>, and may reflect off of precursor mirror <NUM> mounted on post <NUM> which is capable of rotation in one degree of freedom. The beam of light <NUM> leaving precursor mirror <NUM> reflects a second time off of mirror <NUM> which is mounted to podium <NUM>, and capable of rotation in one axis, horizontal translation in the x-direction <NUM> on compensating gantry of rail <NUM>, as well as translation in the y-direction <NUM> on rail <NUM>. The beam of light <NUM> leaving mirror <NUM> reflects off of final mirror <NUM> passes through final lens <NUM> which focuses the light in beam <NUM> to a <NUM> x <NUM> square achieving intensities of <MAT> at the top surface of powder bed <NUM> (print surface) to melt a pattern in a printed image <NUM>. The current position of podium <NUM> is such that the distance the light has to travel is constant and that the square root of the square of the distance <NUM> in the x-direction <NUM> of <NUM> between precursor mirror <NUM> and mirror <NUM> plus the square of distance <NUM> in the y-direction <NUM> of <NUM> ( <MAT>) plus the distance <NUM> of <NUM> between mirror <NUM> and final mirror <NUM> is at a constant value (<NUM>) for every x and y position of podium <NUM> and corresponding x and y positions of podium <NUM>. It is noteworthy that the dimensions and values referenced herein are for illustrative purposes and without limitation. That is, the scope of the present disclosure is limited to the specific example shown and described in <FIG>.

<FIG> illustrates an example process <NUM> in accordance with the present disclosure. Process <NUM> may be utilized to print an object in a laser-based powder bed fusion additive manufacturing system in accordance with the present disclosure. Process <NUM> may include one or more operations, actions, or functions shown as blocks such as <NUM>, <NUM>, <NUM>, and <NUM>. Although illustrated as discrete blocks, various blocks of process <NUM> may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation, and may be performed or otherwise carried out in an order different from that shown in <FIG>. Process <NUM> may be implemented by a combination of dynamic optical assembly <NUM> and dynamic optical assembly <NUM>. For illustrative purposes and without limiting the scope of process <NUM>, the following description of process <NUM> is provided in the context of dynamic optical assembly <NUM>. Process <NUM> may begin with block <NUM>.

At <NUM>, process <NUM> may involve processor <NUM> of dynamic optical assembly <NUM> obtaining or otherwise determining information of intensity of light (or energy) required for a powdered material to be bonded in a powder bed fusion additive manufacturing system as described in <FIG>. Process <NUM> may further involve processor <NUM> obtaining or otherwise determining a minimum resolution (a pixel size of an incident light) for an object to be printed in the powder bed fusion additive manufacturing system. According to the intensity and resolution requirements, process <NUM> may involve processor <NUM> determining a magnification ratio of the incident light containing an image information and an image distance of dynamic optical assembly <NUM> associated with the intensity and resolution requirements respectively. The magnification ratio may transfer a first size of the image at a precursor image plane to a second size of the image at the print surface (top surface of a powder bed). The incident light may be originated from energy source <NUM> and passes through the precursor image plane at which the image information may be created. Process <NUM> may involve memory <NUM> of dynamic optical assembly <NUM> storing geometrical data of the object, positional and rotational control data of precursor mirror <NUM>, sets of mirrors <NUM>(<NUM>) - <NUM>(N), <NUM>(<NUM>) - <NUM>(N),. , 125X(<NUM>) - 125X(N), and final set of mirrors <NUM>(<NUM>) - <NUM>(J) in each successive step of powder bed fusion additive manufacturing. Process <NUM> may proceed from <NUM> to <NUM>.

At <NUM>, process <NUM> may involve processor <NUM> configuring mechanical assembly <NUM> and one or more of lens assemblies <NUM>(<NUM>) - <NUM>(K) of dynamic optical assembly <NUM> to achieve the magnification ratio obtained at <NUM> suitable for the powdered material. The configuring of mechanical assembly <NUM> and one of lens assemblies <NUM>(<NUM>) - <NUM>(K) may involve a rotation of mechanical assembly <NUM>, a swap of second sets of optical lenses <NUM>(<NUM>) - <NUM>(K), or a removal of a second set of optical lenses <NUM>(<NUM>) - <NUM>(K). Process <NUM> may proceed from <NUM> to <NUM>.

At <NUM>, process <NUM> may involve processor <NUM> controlling precursor mirror <NUM>, sets of mirrors <NUM>(<NUM>) - <NUM>(N), <NUM>(<NUM>) - <NUM>(N),. , 125X(<NUM>) - 125X(N), final set of mirrors <NUM>(<NUM>) - <NUM>(J) of dynamic optical assembly <NUM> to perform a plurality of rotations to direct the incident light from the precursor image plane to the print surface at a desired location on the print surface (e.g., top surface of a powder bed) in each successive step of powder bed fusion additive manufacturing. Process <NUM> may proceed from <NUM> to <NUM>.

At <NUM>, process <NUM> may involve processor <NUM> controlling sets of mirrors <NUM>(<NUM>) - <NUM>(N), <NUM>(<NUM>) - <NUM>(N),. , 125X(<NUM>) - 125X(N), final set of mirrors <NUM>(<NUM>) - <NUM>(J) of dynamic optical assembly <NUM> to perform a plurality of translational movements to maintain a constant image distance from the precursor image plane to every location of the print surface (e.g., top surface of a powder bed) in each successive step of powder bed fusion additive manufacturing. At <NUM> and <NUM>, processor <NUM> may control the vertical motion of the powder bed to maintain a fixed separation with final lens <NUM>.

Moreover, process <NUM> may involve processor <NUM> performing steps <NUM> and <NUM> in parallel or in reverse order. Alternatively, process <NUM> may involve processor <NUM> performing either step <NUM> or step <NUM> only, or none of steps <NUM> and <NUM>.

<FIG> illustrates an example implementation of dynamic optical assembly <NUM> according to process <NUM> in accordance with the present disclosure. A layer of a powdered material is dispensed on a top surface of a powder bed <NUM> supported by a build platform <NUM>. Source image <NUM> of an incident light located at a precursor image plane is incident upon lens assembly <NUM> in barrel <NUM>. Lens assembly <NUM> may be configured by a rotation <NUM> of barrel <NUM> that effect a swap of a second set of optical lenses (e.g. lenses <NUM>), a removal of a second set of optical lenses, use of dynamic lenses that change shape, electronic lens swapping, beam redirect systems, electro-optically controlled refractive beam steering devices, or a combination thereof, to have a suitable magnification ratio for the powdered material. The beam containing image information of <NUM> is incident on precursor mirror <NUM> and is directed to mirror <NUM> mounted on compensating gantry <NUM> where it reflects off mirror <NUM> and then is incident on final mirror <NUM> mounted on build platform gantry <NUM>. Final mirror <NUM> directs the beam containing image information <NUM> through a final lens <NUM> toward a top surface of a powder bed <NUM> and object image <NUM> is recreated and magnified in image plane <NUM> which may be formed thereon. Alternatively, a transmissive beam steering device can be used in place of <NUM> to direct the beam around the build platform. Object image <NUM> may be of a size different than source image <NUM> after passing through lens assembly <NUM> and traversing the optical path from precursor mirror <NUM> to the top surface of powder bed <NUM> and may be modified according to the magnification ratios of lens assembly <NUM> and/or final lens <NUM>. The powdered material on powder bed <NUM> may melt to form a shape of object image <NUM>. Build platform gantry <NUM> then moves to a next location until designated locations on the top surface of powder bed <NUM> are bonded for that layer. A new layer of the powdered material is dispensed again and the build platform <NUM> may move down a distance equal to the thickness of the layer of the powdered material to keep a constant distance to the build platform gantry <NUM>. The cycle starts for the new layer in continuing the additive printing process.

In the above disclosure, reference has been made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific implementations in which the present disclosure may be practiced. It is understood that other implementations may be utilized and structural changes may be made without departing from the scope of the present disclosure.

Implementations of the systems, apparatuses, devices, and methods disclosed herein may comprise or utilize a special purpose or general-purpose computer including computer hardware, such as, for example, one or more processors and system memory, as discussed herein. Implementations within the scope of the present disclosure may also include physical and other computer-readable media for carrying or storing computer-executable instructions and/or data structures. Such computer-readable media may be any available media that may be accessed by a general purpose or special purpose computer system. Computer-readable media that store computer-executable instructions are computer storage media (devices). Thus, by way of example, and not limitation, implementations of the present disclosure may comprise at least two distinctly different kinds of computer-readable media: computer storage media (devices) and transmission media.

Computer storage media (devices) includes RAM, ROM, EEPROM, CD-ROM, solid state drives ("SSDs") (e.g., based on RAM), Flash memory, phase-change memory ("PCM"), other types of memory, other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which may be used to store desired program code means in the form of computer-executable instructions or data structures and which may be accessed by a general purpose or special purpose computer.

An implementation of the devices, systems, and methods disclosed herein may communicate over a computer network. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or any combination of hardwired or wireless) to a computer, the computer properly views the connection as a transmission medium. Transmissions media may include a network and/or data links, which may be used to carry desired program code means in the form of computer-executable instructions or data structures and which may be accessed by a general purpose or special purpose computer.

Computer-executable instructions comprise, for example, instructions and data which, when executed at a processor, cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. The computer executable instructions may be, for example, binaries, intermediate format instructions such as assembly language, or even source code.

Further, where appropriate, functions described herein may be performed in one or more of: hardware, software, firmware, digital components, or analog components. For example, one or more application specific integrated circuits (ASICs) may be programmed to carry out one or more of the systems and procedures described herein. Certain terms are used throughout the description and claims to refer to particular system components. As one skilled in the art will appreciate, components may be referred to by different names. This document does not intend to distinguish between components that differ in name, but not function.

It should be noted that the sensor embodiments discussed above may comprise computer hardware, software, firmware, or any combination thereof to perform at least a portion of their functions. For example, a sensor may include computer code configured to be executed in one or more processors, and may include hardware logic/electrical circuitry controlled by the computer code. These example devices are provided herein purposes of illustration, and are not intended to be limiting. Embodiments of the present disclosure may be implemented in further types of devices, as would be known to persons skilled in the relevant art(s).

At least some embodiments of the present disclosure have been directed to computer program products comprising such logic (e.g., in the form of software) stored on any computer useable medium. Such software, when executed in one or more data processing devices, causes a device to operate as described herein.

Claim 1:
An apparatus (<NUM>), comprising:
one or more lens assemblies (<NUM>(<NUM>)-<NUM>(K));
a build platform gantry (<NUM>);
a build platform positioned under the build platform gantry (<NUM>);
a plurality of mirrors comprising a precursor mirror (<NUM>), an intermediary mirror (<NUM>), and a final mirror (<NUM>) configured to direct incident light emanating from the one or more lens assemblies (<NUM>(<NUM>)-<NUM>(K)) to a specific location on the build platform;
an energy patterning unit (<NUM>) configured to provide a two-dimensional patterned beam;
an image relay configured to receive and direct the two-dimensional patterned beam to the one or more lens assemblies (<NUM>(<NUM>)-<NUM>(K)); and
wherein the final mirror (<NUM>) is mounted on a first podium (<NUM>) of the build platform gantry (<NUM>) which is movable in both of a first direction and a second direction perpendicular to the first direction and rotatable about a first axis,
wherein the intermediary mirror (<NUM>) is mounted on a second podium (<NUM>) of a compensation gantry which is translatable only in the first direction and rotatable about at least a second axis,
wherein the incident light travels a first distance from the precursor mirror (<NUM>) to the intermediary mirror (<NUM>),
wherein the incident light travels a second distance from the intermediary mirror (<NUM>) to the final mirror (<NUM>), and
wherein the build platform gantry (<NUM>) is configured to translate the first podium (<NUM>) in the first direction and in the second direction and to rotate the final mirror (<NUM>) about the first axis in order to direct the two-dimensional patterned beam at different areas of the build platform to fabricate a part;
wherein the compensation gantry is configured to translate the second podium (<NUM>) only in the first direction and rotate the intermediary mirror (<NUM>) about the second axis to maintain a constant value of a sum of the first distance and the second distance for every position of the first podium (<NUM>) and a corresponding position of the second podium (<NUM>).