Patent Description:
In additive manufacturing processes, recoat assemblies may be used to smooth or distribute powder across a build area, for instance. As build material or powder is aerosolized throughout a build process, the powder and other contaminants may deposit on the surface of the roller, contaminating the roller and reducing its efficiency in smoothing powder in subsequent passes over a build area.

<CIT> discloses a build material spreading apparatus for additive manufacturing including a movable spreader to spread build material over a build area, the spreader having a top, a bottom, a front, and a back, and a cover movable with the spreader covering the front, top and back of the spreader.

<CIT> discloses an additive manufacturing apparatus that may include a recoat head for distributing build material in a build area, a print head for depositing material in the build area, one or more actuators for moving the recoat head and the print head relative to the build area, and a cleaning station for cleaning the print head.

<CIT> discloses a recoat assembly for an additive manufacturing system that includes a base member that is movable in a lateral direction and a powder spreading member coupled to the base member.

<CIT> discloses a powder laying device for electron beam titanium alloy powder fusion forming.

The invention is defined by the subject matter of the appending claims which are to be construed under consideration of the description and the drawings. The present disclosure relates to recoat assemblies for additive manufacturing systems, additive manufacturing systems comprising such recoat assemblies, and methods of using the same. Rollers of recoat assemblies may become contaminated with depositions of build material or powder. Therefore, it may be necessary to be able to visually and/or physically access the rollers of recoat assemblies to identify and/or replace a contaminated roller. Current recoat assemblies include fully exposed rollers. Fully exposed rollers may be visually accessible at all times during a build process. However, in being fully exposed, the remainder of the manufacturing apparatus becomes frequently contaminated with aerosolized powder depositions. Other current recoat assemblies may include enclosed rollers, that may contain aerosolized powder, but also include one or more parts that must be disassembled from the recoat assembly in order to visually or physically access the roller. Such recoat assemblies may greatly reduce overall build efficiency and require disturbing the inert environment of the build are to disassemble the recoat assembly. Other current recoat assemblies may include articulating recoat assemblies that may move or rotate in multiple axes to allow the roller to be visually accessed without disassembling the recoat assembly. However, such assemblies may feature reduced repeatability and accuracy throughout a build process, as the articulating nature of the recoat assembly in multiple axes reduces the structural stability of critical components of the recoat assembly, such as the roller.

Embodiments described herein address one or more of the above-noted shortcomings. Particularly, embodiments herein provide recoat assemblies having rollers located within a powder containment section to reduce powder contamination. To visually or physically access the roller, select portions of the recoat assembly are pivotable to expose the roller within the powder containment section. To enhance repeatability, critical components of the recoat assembly, such as the roller, are not pivotable. In addition, the critical components of the recoat assembly may only be movable along one coordinate axes, increasing stability and repeatability in build processes.

Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment.

Directional terms as used herein - for example, up, down, right, left, front, back, top, bottom - are made only with reference to the figures as drawn and are not intended to imply absolute orientation unless otherwise expressly stated.

The phrase "communicatively coupled" is used herein to describe the interconnectivity of various components and means that the components are connected either through wires, optical fibers, or wirelessly such that electrical, optical, and/or electromagnetic signals may be exchanged between the components.

Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

As used herein, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a" component includes aspects having two or more such components, unless the context clearly indicates otherwise.

Referring now to <FIG>, an additive manufacturing system <NUM> is schematically depicted. The additive manufacturing system <NUM> includes, but is not limited to, a supply platform <NUM>, a build platform <NUM>, a print assembly <NUM>, a cleaning station <NUM>, and a recoat assembly <NUM>. The additive manufacturing system <NUM> may be arranged such that the build platform <NUM> is located proximate (e.g., next to) the supply platform <NUM> so that build feedstock (e.g., powder) can be delivered by the supply platform <NUM> to the build platform <NUM>, as described herein.

The supply platform <NUM> is generally a surface that supports the build feedstock for the purposes of moving the feedstock to a location that is accessible by the recoat assembly <NUM> to move the feedstock to the build platform <NUM>. Accordingly, the supply platform <NUM> is movable within a supply receptacle <NUM> to receive build feedstock from a first position (e.g., a supply origin position, a receiving position) to a second position (e.g., a position in an area that is reachable by the recoat assembly <NUM> to push the build feedstock to the build platform <NUM>, a supply position). To affect such a movement of the supply platform <NUM>, the supply platform may be coupled to a supply platform actuator <NUM>. The supply platform actuator <NUM> is movable/actuatable in a vertical direction (e.g., the +/- Z direction of the coordinate axes depicted in <FIG>) such that the supply platform <NUM> may be raised or lowered within the supply receptacle <NUM> (e.g., raised from the first position to the second position or lowered from the second position to the first position). As noted herein, the build platform <NUM> is located adjacent to the supply platform <NUM>.

The build platform <NUM> generally provides a surface upon which an object is formed during an additive manufacturing process. As is generally understood, objects in additive manufacturing are formed by means of a successive layerwise deposition of feedstock material that is fused together using the print assembly <NUM>. As such, to make room for each successive layer of material for fusing, the build platform <NUM> is movable within a build receptacle <NUM> to make room for each successive layer. To affect such a movement of the build platform <NUM>, the build platform <NUM> may be coupled to a build platform actuator <NUM>. The build platform actuator <NUM> is movable/actuatable in the vertical direction (e.g., the +/- Z direction of the coordinate axes depicted in <FIG>) such that the build platform <NUM> is raised or lowered within the build receptacle <NUM>.

The print assembly <NUM> is generally a device, system, component, or the like that contains elements for fusing build materials in the additive manufacturing system <NUM>. That is, the print assembly <NUM> includes, but is not limited to, at least one binder deposition component that provides a layer of curable binder material. Various other components and functionality of the print assembly <NUM> should generally be understood and is not described in further detail herein. In some embodiments, the additive manufacturing system <NUM> may also include at least one light emitting component that emits light (e.g., a laser or the like) toward build materials and/or binder to cause fusing and/or curing of materials.

The recoat assembly <NUM> is generally a device, system, component, or the like that is movable within the additive manufacturing system <NUM> to push material between locations, to spread a layer of material across an area, to smooth a layer of material that has been spread, and/or the like. Additional details regarding the recoat assembly will be described herein.

In operation, build material <NUM> obtained from the build feedstock, such as organic or inorganic powder, is positioned on the supply platform <NUM> when the supply platform <NUM> is located at the first position (e.g., a receiving position). The supply platform <NUM> is moved from the first position to the second position (e.g., the supply position) by the supply platform actuator <NUM> to present a layer of the build material <NUM> in a movement path of the recoat assembly <NUM>. The recoat assembly <NUM> is then actuated along a working axis <NUM> of the additive manufacturing system <NUM> towards the build platform <NUM>. In some embodiments, the working axis <NUM> may be generally parallel to a horizontal axis (e.g., the +X/-X axis of the coordinate axes of <FIG>). However, the present disclosure is not limited to such embodiments. As the recoat assembly <NUM> traverses the working axis <NUM> from a home region <NUM> over the supply platform <NUM> towards the build platform <NUM>, the recoat assembly <NUM> distributes the layer of build material <NUM> in the path of the recoat assembly <NUM> from the supply platform <NUM> to the build platform <NUM> (e.g., pushes the layer of build material <NUM> from the supply platform <NUM> to the build platform <NUM>, spreads the layer of build material <NUM>, smooths the layer of build material <NUM>, etc.).

Thereafter, the print assembly <NUM> moves along the working axis <NUM> over the build platform <NUM> and may deposit a layer of binder <NUM> in a predetermined pattern on the layer of build material <NUM> that has been distributed on the build platform <NUM>. After the binder <NUM> is deposited, an energy source may be utilized to cure the deposited binder <NUM>, as described in greater detail herein. The print assembly <NUM> can then move to a home position <NUM> where at least a portion of the print assembly <NUM> is positioned over the cleaning station <NUM>. While the print assembly <NUM> is in the home position <NUM>, the print assembly <NUM> works in conjunction with the cleaning station <NUM> to provide cleaning and maintenance operations on the elements of the print assembly <NUM> to ensure the elements are not fouled or otherwise clogged. This may assist in ensuring that the print assembly <NUM> is capable of depositing the binder <NUM> in the desired pattern during a subsequent deposition pass.

During this maintenance interval, the supply platform <NUM> is actuated in an upward vertical direction (e.g., towards the +Z direction of the coordinate axes depicted in the figure) as indicated by arrow <NUM> to present a new layer of build material <NUM> in the path of the recoat assembly <NUM>. The build platform <NUM> is actuated in the downward vertical direction (e.g., in the -Z direction of the coordinate axes depicted in the figure) as indicated by arrow <NUM> to prepare the build platform <NUM> to receive a new layer of build material <NUM> from the supply platform <NUM>. The recoat assembly <NUM> is then actuated along the working axis <NUM> of the additive manufacturing system <NUM> again to add another layer of build material <NUM> and binder <NUM> to the build platform <NUM>. This sequence of steps is repeated a plurality of times to build an object on the build platform <NUM> in a layerwise manner.

While the embodiment depicted in <FIG> and described above describes the recoat assembly <NUM> and the print assembly <NUM> as being different components, it should be understood that recoat assembly <NUM> and the print assembly <NUM> may be included in a common assembly that is movable along the working axis <NUM>. Further, while reference is made herein to additive manufacturing systems including a print assembly <NUM> that dispenses a binder <NUM>, it should be understood that this is merely an example. For example, in some embodiments, instead of building objects with a curable binder <NUM> applied to the build material <NUM>, in some embodiments, a laser or other energy source may be applied to the build material <NUM> to fuse the build material <NUM>.

Referring to <FIG>, to form an object, layers of build material 31AA, 31BB, 31CC, 31DD may be sequentially positioned on top of one another. In the example provided in <FIG>, sequential layers of binder 50AA-50CC are positioned on the layers of build material 31AA-31DD. By curing the layers of binder 50AA-50CC, a finished product may be formed.

Referring to <FIG>, a perspective view of one embodiment of the recoat assembly <NUM> is schematically depicted. The recoat assembly <NUM>, in embodiments, may include a transverse actuator <NUM> that moves the recoat assembly <NUM> in the lateral direction (e.g., in the +X/-X-direction as depicted in <FIG>). Particularly, the transverse actuator <NUM> may be movably disposed within a first guide <NUM> of the additive manufacturing system <NUM> (<FIG>) and coupled to a first lateral edge <NUM> of the recoat assembly <NUM>. Accordingly, the transverse actuator can move the recoat assembly <NUM> in the lateral direction along the first guide <NUM>. In some embodiments, the additive manufacturing system <NUM> (<FIG>) may further include a second guide <NUM> extending substantially parallel to the first guide <NUM> and positioned opposite the first guide <NUM> across the supply platform <NUM> (<FIG>) and the build platform <NUM> (<FIG>). The recoat assembly <NUM> may be movably coupled to the second guide <NUM> along a second lateral edge <NUM> of the recoat assembly <NUM> such that the second lateral edge <NUM> slides along the second guide <NUM> when the recoat assembly <NUM> is moved via the transverse actuator <NUM>. In some embodiments, the second lateral edge <NUM> may be retained within the second guide <NUM> such that the second lateral edge <NUM> slides within the second guide <NUM>. In other embodiments, the second lateral edge <NUM> may be disposed on the second guide <NUM> so that the second lateral edge <NUM> moves overtop of the second guide <NUM>.

Referring to <FIG> and <FIG>, perspective views of an embodiment of the recoat assembly <NUM> are depicted. More specifically, <FIG> depicts the recoat assembly <NUM> in a closed configuration, and <FIG> depicts the recoat assembly <NUM> in an open configuration. The recoat assembly <NUM> generally includes a first portion <NUM> and a second portion <NUM>. The second portion <NUM> is pivotally coupled to the first portion <NUM> (e.g., via a hinge or the like (not depicted)). The second portion <NUM> is pivotable with respect to the first portion <NUM> from a first, closed position, depicted in <FIG>, to a second, open position depicted in <FIG>. In some embodiments, the first portion <NUM> of the recoat assembly may not be pivotable. As shown in <FIG>, the first portion <NUM> of the recoat assembly <NUM> includes a roller <NUM> that rotates around a central roller axis to contact, move, spread, and/or smooth the build material <NUM> (<FIG>) as described herein.

The first portion <NUM> and/or the second portion <NUM> are encasement portions that define one or more internal cavities. In some embodiments, at least one of the one or more internal cavities defined by the first portion <NUM> and/or the second portion <NUM> may contain the roller <NUM>. Such encasement portions may define a barrier that contains materials (e.g., build material <NUM> (<FIG>) within at least one of the one or more internal cavities and/or prevents or reduces an amount of environmental materials (e.g., airborne particulate matter) from contacting the roller <NUM> when the first portion <NUM> and the second portion <NUM> are arranged in the closed configuration shown in <FIG>.

In embodiments, the second portion <NUM> of the recoat assembly <NUM> may include a shield <NUM>. The shield <NUM> may be a component that shields at least one of the one or more internal cavities from an external environment and be constructed of any plastic, polymer, metal, and/or combinations thereof that provides shielding properties (e.g., shielding from airborne particles, shielding from temperatures that exceed a threshold, etc. The shield <NUM> may be integrated with the second portion <NUM> (e.g., constructed as at least a section of the second portion <NUM>), or may be disposed on at least a section of the second portion <NUM>. In embodiments, the shield <NUM> may be transparent, e.g., such that at least a portion of the one or more internal cavities can be viewed from a location outside the second portion <NUM> of the recoat assembly <NUM>. In some embodiments, the shield <NUM> may include a handle <NUM> disposed on or integrated within an outer surface thereof to allow for manual manipulation of the shield <NUM>, and the remainder of the second portion <NUM> of the recoat assembly, as will be discussed in greater detail below.

Still referring to <FIG> and <FIG>, the second portion <NUM> of the recoat assembly <NUM> may further include a powder plow assembly <NUM> in some embodiments. The powder plow assembly <NUM> may generally be a component that assists in moving excess build material <NUM> (<FIG>) and/or debris positioned in or along the path of the recoat assembly <NUM> as the recoat assembly <NUM> moves along the working axis <NUM>. The powder plow assembly <NUM> may include a powder plow <NUM>, which may be formed from any suitable material with a wear resistant low coefficient of friction coating. As a non-limiting example, the powder plow <NUM> may be formed from electroless nickel with co-deposited polytetrafluoroethylene (PTFE) or may be electropolished. The powder plow assembly <NUM>, including the powder plow <NUM>, may be fixedly secured to, and extend from, a bottom edge of the shield <NUM>.

As noted, the first portion <NUM> and/or the second portion <NUM> of the recoat assembly <NUM> may define one or more internal cavities therein. <FIG> and <FIG> depict cross-sectional views of various internal cavities defined by the first portion <NUM> and/or the second portion <NUM> of the recoat assembly <NUM>. More specifically, <FIG> depicts the recoat assembly <NUM> in the closed configuration, and <FIG> depicts the recoat assembly <NUM> in the open configuration.

As particularly depicted in <FIG> and <FIG>, the second portion <NUM> of the recoat assembly <NUM> may further include a base frame <NUM> extending a distance inward (e.g., in the +X direction of the coordinate axes of <FIG>) from and coupled to an interior surface <NUM> of the shield <NUM>. As shown in <FIG>, the base frame <NUM> may extend from the interior surface <NUM> of the shield <NUM> in a direction toward the first portion <NUM> when the recoat assembly <NUM> is in the closed configuration. The base frame <NUM> of the second portion <NUM> provides a surface (e.g., a base surface, a shelf, or the like) or a support by which one or more other components may be coupled to or supported by the second portion <NUM> of the recoat assembly <NUM>. In some embodiments, the base frame <NUM> may be a planar support or frame.

Still referring to <FIG> and <FIG>, in some embodiments, the first portion <NUM> of the recoat assembly <NUM> may include a first base frame <NUM> (e.g., a horizontal base frame) and/or a second base frame <NUM> (e.g., a vertical base frame). More specifically, the second base frame <NUM> may extend a distance downward (e.g., towards the -Z direction of the coordinate axes of <FIG>) from the first portion <NUM>, such as, for example, in a direction towards the roller <NUM>. The first base frame <NUM> may extend a distance from the second base frame <NUM> (e.g., extend from a distal portion of the second base frame <NUM> in the -X direction of the coordinate axes of <FIG>). In some embodiments, the first base frame <NUM> and the second base frame <NUM> may form an L-shape configuration. In some embodiments, the first base frame <NUM> and the second base frame <NUM> may be a single base frame having two sections that extend in different directions (e.g., a first portion extending in the -Z direction and a second portion extending in the -X direction of the coordinate axes of <FIG>). The first base frame <NUM> and/or the second base frame <NUM> provides a surface (e.g., a base surface, a shelf, or the like) or a support by which one or more other components may be coupled to or supported by the first base frame <NUM> and/or the second base frame <NUM>. In some embodiments, the first base frame <NUM> and/or the second base frame <NUM> may be planar supports or frames. In some embodiments, the first base frame <NUM> and/or the second base frame <NUM> generally provide one or more surfaces for attachment of various components of the recoat assembly <NUM> to the first portion <NUM> of the recoat assembly <NUM>.

Still referring to <FIG> and <FIG>, the one or more cavities defined by the first portion <NUM> and the second portion <NUM> of the recoat assembly <NUM> may include a powder containment region <NUM> in some embodiments. The powder containment region <NUM> is generally an area defined by one or more components of the recoat assembly <NUM> that includes one or more powder shields or shrouds, such as, for example, an inner shroud <NUM> and/or an outer shroud <NUM>. The inner shroud <NUM> may include a first shroud segment <NUM> and a second shroud segment <NUM> that surround at least a portion of the roller <NUM>. The first shroud segment <NUM> may define a first end <NUM> of the inner shroud <NUM>. The second shroud segment <NUM> may define a second end <NUM> of the inner shroud <NUM>. The first end <NUM> of the inner shroud <NUM> and the second end <NUM> of the inner shroud <NUM> may be adjacent opposite sides of the roller <NUM>, such that the inner shroud <NUM> at least partially surrounds the roller <NUM>. In some embodiments, the first shroud segment <NUM> of the inner shroud <NUM> and the second shroud segment <NUM> of the inner shroud <NUM> may each be quarter spheres, such that when the recoat assembly <NUM> is in the closed configuration, the inner shroud <NUM> substantially forms a hemisphere around the roller <NUM>, as can be seen in <FIG>.

The first shroud segment <NUM> of the inner shroud <NUM> may be coupled to the first base frame <NUM> of the first portion <NUM> of the recoat assembly <NUM> by means of a shield hanger <NUM> (see <FIG>) coupled to an underside of the first base frame <NUM>. That is, the shield hanger <NUM> extends in a direction (e.g., vertically, in the -Z direction of the coordinate axes of <FIG>) from the first base frame <NUM> to a location adjacent to the roller <NUM> such that the first shroud segment <NUM> coupled thereto is also located adjacent to the roller <NUM> as described herein. The second shroud segment <NUM> of the inner shroud <NUM> may be coupled to the base frame <NUM> of the second portion <NUM> of the recoat assembly <NUM>, or one or more other surfaces of the second portion <NUM> of the recoat assembly, such that, when the second portion <NUM> is pivoted away from the first portion <NUM> to the open position as shown in <FIG>, the second shroud segment <NUM> of the inner shroud <NUM> separates from the first shroud segment <NUM> of the inner shroud <NUM> to expose the roller <NUM>.

Still referring to <FIG>, the powder containment region <NUM> may further include an outer shroud <NUM> encasing the inner shroud <NUM> and the roller <NUM>. The outer shroud <NUM> may include, for example, a first outer shroud wall <NUM> nearest to the first end <NUM> of the inner shroud <NUM> and a second outer shroud wall <NUM> nearest to the second end <NUM> of the inner shroud <NUM> in some embodiments. The first outer shroud wall <NUM> may be coupled to an underside of the first base frame <NUM> of the first portion <NUM> of the recoat assembly <NUM> in some embodiments. The second outer shroud wall <NUM> may be coupled to an underside of the base frame <NUM> of the second portion <NUM> of the recoat assembly <NUM> in some embodiments. That is, the outer shroud walls <NUM>, <NUM> extend in a direction (e.g., vertically, in the -Z direction of the coordinate axes of <FIG>) from the first base frame <NUM> and the base frame <NUM>, respectively. In some embodiments, the outer shroud walls <NUM>, <NUM>, together with the first base frame <NUM> and base frame <NUM>, respectively, may substantially surround the inner shroud <NUM> and the roller <NUM> when the recoat assembly <NUM> is in the closed configuration as shown in <FIG> and may expose the roller <NUM> when in the open configuration as shown in <FIG>. Further, in some embodiments, the various components of the outer shroud <NUM> may define the outer limits of the powder containment region <NUM>.

Still referring to <FIG>, the first portion <NUM> of the recoat assembly <NUM> further includes a first powder blocker component <NUM> and a second powder blocker component <NUM>. The first powder blocker component <NUM> and the second powder blocker component <NUM> may each be coupled to one or more components of the first portion <NUM> of the recoat assembly <NUM>, such as the first base frame <NUM> and/or the second base frame <NUM>. The first powder blocker component <NUM> and the second powder blocker component <NUM> may provide support for the roller <NUM> and/or further contain powder within the powder containment region <NUM>. For example, the first powder blocker component <NUM> may extend laterally (e.g., in the +X/-X directions of the coordinate axes of <FIG>) over the inner shroud <NUM> and the second powder blocker component <NUM> may extend downward (e.g., in the -Z direction of the coordinate axes of <FIG>) between the first shroud segment <NUM> and the second shroud segment <NUM> of the inner shroud <NUM> such that the second powder blocker component <NUM> is compressed between the first shroud segment <NUM> and the second shroud segment <NUM> of the inner shroud <NUM> when the recoat assembly <NUM> is in the closed position as shown in <FIG>. In some embodiments, the second powder blocker component <NUM> extends such that it contacts the roller <NUM> so that, as the roller <NUM> rolls, excess material clinging to the roller <NUM> is scraped off by the second powder blocker component <NUM>.

Still referring to <FIG>, the recoat assembly <NUM> may include at least one pneumatic actuator <NUM>. The pneumatic actuator <NUM> includes a base <NUM> that is fixedly coupled to a portion of the recoat assembly <NUM> to provide support for the pneumatic actuator <NUM>. For example, the base <NUM> may be coupled to the first portion <NUM> of the recoat assembly <NUM>, such as, for example, the first base frame <NUM> and/or the second base frame <NUM> of the first portion <NUM> of the recoat assembly <NUM>. An actuatable head <NUM> (<FIG>) of the pneumatic actuator <NUM> is coupled to the shield <NUM> of the second portion <NUM> of the recoat assembly <NUM> (e.g., the interior surface <NUM> of the shield <NUM>). The head <NUM> of the pneumatic actuator <NUM> may particularly be coupled to the shield <NUM> at a junction between a horizontal support arm <NUM> (<FIG>) extending across an upper interior wall <NUM> of the shield <NUM> and a vertical support arm (not shown) positioned along an interior surface of the interior surface <NUM> of the shield <NUM>. The horizontal support arm <NUM> of the second portion <NUM> is pivotally coupled to a vertical support arm <NUM> of the first portion <NUM> of the recoat assembly <NUM>. Therefore, as the pneumatic actuator <NUM> is actuated such that the head <NUM> extends away from the base <NUM>, the head <NUM> applies an upward (e.g., in the +Z direction of the coordinate axes of <FIG>) force on the horizontal support arm <NUM> of the second portion <NUM> toward the position of the interior surface <NUM> of the shield <NUM>, the second portion <NUM>, including the shield <NUM> and all components coupled thereto, rotate about the pivotable connection between the horizontal support arm <NUM> of the second portion <NUM> and the vertical support arm <NUM> of the first portion <NUM>. Therefore, the shield <NUM>, powder plow assembly <NUM>, second outer shroud wall <NUM> of the outer shroud <NUM>, and the second shroud segment <NUM> of the inner shroud <NUM> may pivot upwardly into a second position to expose the roller <NUM> from within with powder containment region <NUM>, as shown in <FIG>. In addition, various components of the recoat assembly <NUM>, including the roller <NUM>, first lateral edge <NUM>, and second lateral edge <NUM> (<FIG>) remain stationary with respect to the second portion <NUM> as the roller <NUM> is exposed from within the powder containment region <NUM>. The exposed roller <NUM> can be inspected without disturbing the position of the various components of the recoat assembly <NUM> coupled to the first portion <NUM>, allowing for a build process to subsequently resume with stability and repeatability.

Still referring to <FIG>, in embodiments the recoat assembly <NUM> may include a lift assist arm <NUM>. The lift assist arm <NUM> may be pivotally coupled to the first portion <NUM> of the recoat assembly <NUM> at a first end <NUM> of the lift assist arm <NUM>. The lift assist arm <NUM> may further be pivotally coupled to the second portion <NUM> of the recoat assembly <NUM> at a second end <NUM> of the lift assist arm <NUM>. The first end <NUM> of the lift assist arm <NUM> may be pivotally coupled to the vertical support arm <NUM> of the first portion <NUM> in some embodiments. The second end <NUM> of the lift assist arm <NUM> may be pivotally coupled to the vertical support arm (not shown) positioned along the interior surface <NUM> of the shield <NUM> in some embodiments. The lift assist arm <NUM> may include a spring biased to expand in length, thereby providing a biasing force that assists in transitioning the second portion <NUM> of the recoat assembly <NUM> from the closed configuration to the open configuration. Actuation of the pneumatic actuator <NUM> may overcome the bias of the lift assist arm <NUM> to maintain the second portion <NUM> in the closed configuration when desired.

<FIG> depicts an embodiment of the recoat assembly <NUM> that includes a locking bar <NUM> in lieu of the lift assist arm <NUM> depicted in <FIG> and <FIG>. Referring to <FIG>, in conjunction with <FIG>, a first end <NUM> of the locking bar <NUM> is pivotally coupled to the first portion <NUM> of the recoat assembly <NUM>. The first end <NUM> of the locking bar <NUM> may be pivotally coupled to a horizontal support arm <NUM> positioned along the second base frame <NUM>. A second end <NUM> of the locking bar <NUM> is selectively couplable to the second portion <NUM> of the recoat assembly <NUM> when the second portion <NUM> of the recoat assembly <NUM> is in the open configuration as shown in <FIG>. The second end <NUM> of the locking bar <NUM> is selectively couplable to a rod <NUM> positioned along the interior surface <NUM> of the shield <NUM>. That is, the second end <NUM> of the locking bar <NUM> is a free end that can be engaged with the rod <NUM>. After the second portion <NUM> is pneumatically or manually pivoted to the second open configuration, a user may rotate the locking bar <NUM> about the horizontal support arm <NUM> and couple the second end <NUM> of the locking bar <NUM> with the rod <NUM>. In such cases, the locking bar <NUM> may lock the second portion <NUM> in the open configuration as an additional measure to ensure the second portion <NUM> does not fall on a user servicing the roller <NUM>, for instance.

In operation, the recoat assemblies described herein facilitate access to the roller. In some embodiments, a method of accessing the roller of the recoat assembly includes pivoting the second portion of the recoat assembly with respect to the first portion of the recoat assembly from a first position to a second position to expose the roller from within the powder containment section, as described herein. In some aspects, the method further includes moving the recoat assembly to an access position in a build chamber prior to pivoting the second portion. That is, the recoat assembly may be moved to a location such as, for example, the home region <NUM> depicted in <FIG>. Such a moving step may include driving the recoat assembly along a first guide at a first longitudinal edge of the recoat assembly by a transverse actuator as described herein, as well as guiding the recoat assembly along a second guide at a second longitudinal edge of the recoat assembly. In some aspects, pivoting the second portion includes pneumatically or manually actuating the second portion about a pivot point, as described herein with respect to <FIG>. In some aspects, the method may further include pivoting a locking bar to engage a free end of the locking bar with the second portion of the recoat assembly, as described herein with respect to <FIG>.

Claim 1:
A recoat assembly (<NUM>) for an additive manufacturing system (<NUM>), comprising:
a first encasement portion (<NUM>) comprising a roller (<NUM>) to contact, move, spread, and/or smooth a build material (<NUM>); and
a second encasement portion (<NUM>) pivotally coupled to the first encasement portion (<NUM>) and pivotable with respect to the first encasement portion (<NUM>) from a first position to a second position,
an internal cavity of the second encasement portion (<NUM>) defined in part by a base frame (<NUM>, <NUM>) of the first encasement portion (<NUM>) when the second encasement portion (<NUM>) is in the first position, wherein:
the roller (<NUM>) is enclosed in a powder containment section of the recoat assembly (<NUM>) when the second encasement portion (<NUM>) is in the first position; and
a rotating surface of the roller (<NUM>) is exposed when the second encasement portion (<NUM>) pivots away from the base frame (<NUM>, <NUM>) of the first encasement portion (<NUM>) to the second position.