Apparatus and method for conditioning deposited powder - Patents.com

Abstract

An apparatus and method are provided for conditioning powder deposited on a substrate (e.g., a web) by wetting the powder within a 3D printing apparatus. The wetting device is disposed between the powder dispenser and at least one top calender roller in the direction of movement of the substrate and is configured to apply a wetting agent to the powder on the substrate before the powder passes through the calender rollers. The wetting agent is a material that increases the cohesiveness of the powder and prevents the powder from adhering to the top roller. In a particular embodiment, the wetting agent is a vapor that is trapped in the region of the substrate where the powder passes through the wetting device and does not wet other regions of the substrate that are not within the wetting device.

Description

[Technical field]

[0001] The present disclosure relates to improved apparatus and methods for providing conditioning to powder deposited on a substrate, for example, in a 3D printing apparatus, by lubricating / wetting the powder. [Background technology]

[0002] Specifically, in current binder jet 3D printing, powder can be deposited on a substrate and then the powder on the substrate can be passed through rollers, such as a calender system, for compaction. Conventional techniques suffer from uneven compaction due to powder sticking to the contact rollers or powder splitting between the rollers and the carrier plate or substrate on which the powder is deposited. In all cases, this results in uneven part production. Thus, for example, in 3D printing, particularly powder binder jetting (although the techniques described herein can also be applied to continuous material jetting systems), configurations are needed to compact uniformly and prevent powder sticking and splitting during powder and pattern roller compaction. The practice of applying lubricants and / or wetting agents to the deposited powder to improve powder flowability, thereby aiding compaction uniformity and minimizing or controlling tension between the substrate and subsequently applied layers, is discussed in U.S. Patent Application Serial No. 17 / 375,781. Summary of the Invention

[0003] In one embodiment, an apparatus is provided that includes a powder dispenser configured to dispense a powder onto a substrate (substrate), a calender including a top roller positioned above the powder on the substrate, and a conditioning device positioned between the powder dispenser and the calender in the direction of movement of the substrate, the conditioning device configured to apply a conditioning agent to the powder on the substrate before the powder passes through the calender, the conditioning agent comprising a material that increases the cohesiveness of the powder.

[0004] In another embodiment, a method is provided that includes distributing a powder onto a substrate, applying a conditioning agent to the distributed powder on the substrate before the powder passes through a calender, and compressing the powder after the conditioning agent has been applied, the conditioning agent being comprised of a material that increases the cohesiveness of the powder to provide a uniform compaction of the powder during compaction.

[0005] The drawings illustrate one or more embodiments in accordance with the present teachings, by way of example only, and not by way of limitation. In the drawings, like reference numbers refer to the same or similar elements. It should also be understood that the drawings are not necessarily to scale. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 illustrates a powder conditioning, lubrication, or wetting apparatus positioned above a substrate in a 3D printing apparatus, according to an embodiment of the present disclosure. [Diagram 2] FIG. 13 illustrates another embodiment of a powder conditioning, lubrication, or wetting apparatus positioned above a substrate in a 3D printing apparatus, according to aspects of the present disclosure. [Diagram 3] 1 is a cross-sectional view of an element of a wetting device according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a perspective view of a lift mechanism for lifting a wetting device from a substrate according to an aspect of the present disclosure. [Diagram 5] FIG. 1 illustrates a perspective view of a wetting device that includes the use of a heat sink below the substrate opposite the wetting device above the substrate, in accordance with an aspect of the present disclosure. [Figure 6] 1 illustrates a cutaway end view of a wetting apparatus that includes tilting the table on which the steam handling head is mounted to prevent possible water contamination in the steam chamber, according to an aspect of the present disclosure. [Figure 7] 1 illustrates a system interface for controlling the generation and characteristics of steam applied to a steam treatment head in a wetting apparatus according to an aspect of the present disclosure. [Figure 8] FIG. 1 is a block diagram illustrating an exemplary computer system on which aspects of the present disclosure may be implemented. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] In the following detailed description, numerous specific details are set forth by way of example to provide a thorough understanding of the disclosed subject matter. However, upon reading this disclosure, it may become apparent to one skilled in the art that one or more of the disclosed aspects may be practiced without such details. Furthermore, the description of various exemplary embodiments according to the present disclosure may include references to or to one or more known techniques or operations, and such references may be at a relatively high level to avoid obscuring various concepts, aspects, and features thereof with details that are not specific to the present disclosure and are not necessary to fully understand the present disclosure.

[0008] In the present disclosure, configurations are provided for pre-treating or conditioning powder prior to the calendering operation to ensure uniform compaction and prevent powder adhesion and splitting on the top roller during powder and pattern roller compaction. These configurations are particularly useful in 3D printing devices, for example, and in particular powder binder jetting (although the techniques described herein can also be applied to continuous material jetting or other powder deposition systems).

[0009] In particular, as described in the applicant's related provisional application entitled "Printing Method and Apparatus for Additive Manufacturing, Including In-situ Powder Regeneration" (Application No. 63 / 299,867), filed on January 14, 2022, a platform for additive manufacturing (AM manufacturing) has been developed that is a modular base machine that builds each layer separately. The individual layers pass through several apparatuses, each with a unique function. One of these apparatuses involves compressing the powder in a calendering operation while the deposited powder layer is still in the green uncured stage. Thus, disclosed herein are methods and apparatuses that are particularly adapted to the new platform described in the above-mentioned related application. Specifically, in the platform described in this related application, due to the nature of the platform, the powder layers can be individually conditioned by the techniques described in this disclosure, thus making it possible to improve the calendering of the layers in the platform described in the above-mentioned related application.

[0010] The above-mentioned related applications describe systems and methods for applying powder to a substrate in a powder application device, removing a first portion of the powder to create clean portions of the substrate between the portions of the deposited powder, moving the portions of the deposited powder remaining on the substrate to a wetting device, wetting the powder with a wetting agent in the wetting device, passing the wetted portions of the deposited powder through calender rollers to compress the powder, cutting the substrate at the clean portions to create substrate segments each including one of the portions of the deposited powder, moving the substrate segments with the portions of the deposited powder to a binder application device, applying a binder to the powder in the binder application device, curing the deposited powder into layers, transferring the substrate segments with the attached layers to respective carrier plates, moving the carrier plates with the substrate segments with the attached layers to a lamination device, inverting each of the carrier plates to separate the layers from the substrate segments, and laminating the layers individually on top of each other to form a multi-layer product. The present disclosure can be incorporated into the systems described in the related applications as part of the calendering of the powder while in the green uncured stage of the overall 3D printing operation. It should be noted that although a particular order of steps is described above, the order of steps can be changed as desired without departing from the scope of the present disclosure.

[0011] FIG. 1 shows a powder conditioning, lubrication, or wetting device 10 arranged above a substrate in a 3D printing apparatus according to an embodiment of the present disclosure. FIG. 2 shows another embodiment of such a powder conditioning, lubrication, or wetting device utilizing an alternative configuration for powder compaction. With reference to FIGS. 1 and 2, a spray or inkjet printhead 12 is arranged behind a powder dispenser 14 on a carrier substrate (substrate) 16 (e.g., a carrier conveyor belt) relative to the direction of movement, and sprays or inkjet prints a conditioning agent 18, e.g., a wetting agent, on the powder 20 deposited by the powder dispenser 14 on the substrate 16 (note that a "substrate" is also referred to as a "web" in the art). In the case of lubrication, a lubricant or wetting agent / liquid 18 with a controlled, preferably high, surface tension is uniformly deposited on the deposited powder 20. Thus, the deposited powder 20 is wetted by the controlled wetting agent 18. The wetting agent 18 aids in uniform compaction of the powder 20 by providing sufficient lubrication, increases internal cohesion, and prevents powder splitting by increasing the powder's cohesiveness. As described below with respect to certain embodiments, the wetting agent 18 can be steam generated from water. However, other wetting agents including water or other materials added to organic materials can be used to help improve uniform compaction and internal cohesion of the powder for subsequent processing. Also, in alternative embodiments, the conditioning agent 18 can be applied by evaporation.

[0012] Referring to FIG. 1, to minimize adhesion or splitting of the powder 20 during calendering, a controlled surface energy coating 28 can be applied to the surface of the upper compression roller 24 (including the lower compression roller 26) of the calender 22 to prevent the powder 20 from splitting and sticking to the upper compression roller 24. FIG. 2 shows an alternative arrangement using a coating layer 28', such as a sheet rolled from a distribution sheet roller, with a low surface energy applied to the upper compression roller 24 of the calender 22 or to another coating surface used during calendering. The combination of a coating or coating surface with a controlled surface energy and a wetting agent 18 applied by the spray dispenser of the inkjet printer 12 prevents the powder from splitting and sticking to the compression roller 24. The amount of wetting agent 18 applied to the powder can be less than 10% by weight.

[0013] 1 and 2, after powder compression by calender compression rollers 24 and 26 and prior to patterning, the carrier substrate 16 with the compressed powder 20 applied by spraying or inkjet can be subjected to a drying process by dryer 30 to remove and evaporate the remaining wetting agent 18 that has not yet evaporated. The dryer 30 can be an IR lamp, hot air, or a pulse dryer for faster drying.

[0014] To summarize the above description of FIG. 1 and FIG. 2 regarding the concept of single layer powder compaction, a dispenser 12 (e.g., spray or inkjet printhead) is provided to dispense a conditioner, lubricant or wetting agent 18 onto the layer of deposited powder 20. The conditioner, lubricant or wetting agent 18 can be deposited by using evaporation techniques, inkjet, spray, or vapor as described below with respect to a specific implementation. The conditioner, e.g., lubricant / wetting agent 18, lubricates / wets the deposited powder 20 for uniform compaction and to prevent sticking and splitting, as described above. Furthermore, as described above, in addition to the lubricant / wetting agent 18, a coating can be applied to the top roller 24 of a pair of compaction rollers 24 and 26, as shown in FIG. 1, or a cover sheet 28 can be applied between the top roller 24 and the top surface of the deposited powder 20, as shown in FIG. 2, to further enhance the prevention of the powder 20 from sticking to the top roller 24 or splitting during compaction by the calender rollers 24 and 26. 1 and 2 show a pair of calender rollers 24 and 26, it should be noted that in alternative embodiments, a single top roller 24 can be used to press the powder layer 20 between the top roller 24 and the substrate 16. Alternatively, a solid support such as a rigid plate (not shown) can be provided below the substrate 16 and operated in conjunction with the single upper calender roller 24 to compress the powder 20.

[0015] 3-7, all of which relate to a particular implementation of the above principles, specifically using steam as a lubricant or wetting agent 18 for powder 20. For convenience, the following description uses the term wetting agent 18 rather than conditioner or lubricant, noting that the wetting of powder 20 resulting from the use of wetting agent 18 has a particular conditioning effect, in this case a lubricating effect.

[0016] Regarding the use of steam as a wetting agent 18, in various experiments to perform the wetting of the powder 20 prior to calendering, various approaches were attempted to find a wetting process that would not damage the dispersed powder 20 and provide enough lubrication to improve flowability, but not so much that the wetting agent spread beyond the desired powder boundaries. Experiments were performed with atomizers and fine sprayers with different nozzles and types of nozzles. The use of such atomizers and fine sprayers improved the compaction and uniformity of the powder 20 after compaction on the calender rollers 24 and 26, especially when combined with a coating 28 or cover 28' of the top roller with a low surface energy material, as shown in Figures 1 and 2, but the result of some of these experiments was striations, pockets, and damage to the powder sample 20. Specifically, it was determined from these experiments that it was difficult to control the spray area or the amount of water (or other wetting agent 18) applied to the surface of the powder 20.

[0017] Experiments were then conducted in which water in the form of steam was applied to the surface of the powder 20. It was determined that this method eliminated the above-mentioned problems with grooves, pockets, and damage to the powder sample. The steam created a uniform and controllable method of powder wetting. In other words, the steam acts as a wetting agent in this embodiment, referred to below as steam 18'. The steam region was also very controllable using the steam chamber, as described below, so as not to wet the substrate region of the powder 20 with the portion of the substrate 16 outside the steam chamber. This eliminates powder damage in further downstream processes following powder compression in the calender rollers 24 and 26.

[0018] FIG. 3 shows a cross-sectional view of the elements of a conditioning apparatus, in this example a wetting apparatus 10. As seen in FIG. 3, a moving substrate 16 having a controlled thickness of powder 20 (typically controlled via devices such as blades to flatten the powder and / or rollers to promote uniformity of the deposited powder) enters the wetting apparatus 10. The wetting apparatus 10 (e.g., a vapor housing 32 including a vapor chamber 34) can confine the generated vapor 18' and provide an isolation area through which the substrate 16 having powder 20 thereon can pass. In other words, the vapor 18' is confined to the portion of the substrate 16 within the vapor chamber 34, and the powder 20 on the portion of the substrate 16 outside the vapor chamber 34 remains uncontacted by the vapor 18'.

[0019] As shown in Figure 3, the wetting apparatus 10 can include a vapor housing 32 that houses all of the elements necessary for the wetting process. The vapor housing 32 is optional, but can serve several purposes as described in more detail below, one of which is to provide a safety feature to protect the user from unintentional exposure from the generated vapor 18'. It can also provide a means to protect all of the elements of the wetting process from unexpected damage as the wetting apparatus 10 moves away from the substrate 16.

[0020] The vapor 18' is initially generated using a vapor generator (e.g., using an evaporator as shown in FIG. 7), which, according to one embodiment, continues to generate the vapor 18' until commanded not to. The vapor generator can be selected to provide a minimum vapor flow rate / velocity for applying the vapor to the vapor source input 38, and a desired temperature range for the vapor 18'. The generated vapor 18' is fed to a vapor processing head 36 in the vapor housing 32 via the vapor source input 38. The vapor 18' travels down a heated tube (see FIG. 7) from the vapor generator to the vapor source input 38, and then into the vapor processing head 36 (e.g., a heated vapor delivery wand). The vapor processing head 36 may have one or more vapor distribution heads or nozzles that distribute the vapor 18' into the head 36. The vapor processing head 36 can be a wide triangular object that coats the incoming powder 20 on the substrate 16 with the forced vapor 18'. The dispensed steam 18' wets the powder 20 as it passes under the heated steam dispenser (ie, the steam treatment head 36).

[0021] The width of the vapor-treatment head 36 is preferably at least the width of the powder 20 to be dispensed onto the substrate 16, but slightly less than the width of the substrate 16 itself. Alternatively, the width of the vapor-treatment head 36 may be substantially the same width as the substrate 16. In one embodiment, the vapor-treatment head 36 is configured such that the vapor 18' spreads out in a triangular shape as it travels from the vapor source input 38 to the powder 20 on the substrate 16.

[0022] In some implementations, the heater 40 may be attached to or adjacent to the vapor chamber 34 or alternatively the steaming head 36 to help maintain the vapor 18' within the vapor chamber 34 and / or the steaming head 36. In some implementations, the heater 40 is shaped to match the shape of the vapor processing head 36. In other implementations, the heater 40 may be shaped differently than the steaming head 36 and cover either an area smaller or larger than the width and height of the steaming head 36. The heater 40 may include a heater core passing through the heater 40 that generates heat that spreads throughout the remainder of the heater 40. Sensors (see, e.g., FIG. 7) may be provided within the vapor chamber 34 to activate the heater 40 as needed based on sensing the temperature and level of the vapor 18' being dispersed by the vapor processing head 36. In other implementations, the rate of vapor generation may be related to the speed of the substrate 16 moving through the vapor chamber 34. Sensors and controllers are incorporated inside the vapor chamber 34 to modify the rate of vapor production or the speed of the substrate 16 as needed to ensure that an appropriate amount of vapor 18' is applied to the powder 20 so that the powder 20 remains intact during subsequent compression at the calender rollers 24 and 26. Dynamic modification of the vapor production may be enabled based on data received from various sensors that are fed back to the controller.

[0023] As shown in FIG. 3, the wetting apparatus 10 includes one or more vacuum devices 42 within the steam housing 32, preferably at least one of which is adjacent to the steam treatment head 36, to remove excess steam or any condensation that may occur outside of the steam target area of ​​the powder 20. The steam target area is the powder area of ​​the substrate 16 within the wetting apparatus 10. The vacuum devices 42 can remove excess steam or condensation from the wetting apparatus 10 and / or control the steam pressure / flow rate within the steam chamber 34. This provides further control of the moisture experienced by the deposited powder 20. The vacuum devices 42 may be open to the surface of the powder 20, but not all the way to the substrate 16. In some embodiments, the location of the opening can be changed by the user as directed by the application, or automatically based on data acquired via sensors. The vacuum devices 42 may also incorporate a hydrophilic material (not shown), such as a felt strip, to aid in the extraction of condensed water vapor. The hydrophilic material can be continuously wetted or saturated with an aqueous solution to aid in the operation. The moisture experienced by the powder 20 can be controlled by optimizing various parameters of the wetting apparatus 10 (including the pressure provided by the vacuum apparatus 42 ) and the speed at which the substrate 16 moves through the vapor chamber 34 .

[0024] As the substrate 16 passes through the wetting apparatus 10, if excess moisture is present on the "pure" substrate portions (e.g., areas of the substrate 16 where no powder 20 is supposed to be deposited), this will most likely have evaporated and no additional excess moisture removal operations other than the vacuum apparatus 42 are necessary. However, in one embodiment, as also shown in FIG. 3, a substrate cleaning actuator 44 may be provided at the exit of the wetting apparatus 10 to blow air onto the substrate 16 in areas where no powder 20 is deposited to clean excess powder that may have drifted onto these portions of the substrate 16. In one configuration, the substrate cleaning actuator 44 may distribute air all the way to the surface of the substrate 16.

[0025] In another configuration, as shown in FIG. 3, to accommodate a moving substrate, the substrate cleaning actuator 44 can be actuated to lower to the surface of the substrate 16 only when not positioned over a powder region, and to rise above the surface of the powder 20 at other times. The timing of the rise and fall can be timed based on the speed of the substrate 16, the width of the powder segment, and the width of the non-powdered segment. In other examples, the timing of the rise and fall may be based on data received from a sensor, such as an image capture device, and associated image processing required to determine the edges of the powder, areas of powder, and / or areas of "pure" substrate.

[0026] In an alternative configuration, one or more sensors disposed on the vapor housing 32 can record the edge of the powder 20 as it exits the vapor housing 32. Once the edge is aligned, a cleaning tool (not shown), for example a flexible blade made of a soft "squeegee" style material, can be used to push and remove the liquid from the surface of the substrate 16 where the powder 20 is not deposited. Because the tip of the squeegee style flexible blade is the only material that touches the substrate, the material used for the flexible blade should be selected as a material that prevents damage to the substrate as the tip of the flexible blade scrapes the substrate to remove the powder from the substrate in the desired first portion. The material selected for use as the flexible blade may also depend on the particular chemical nature of the powder 20, where it is desirable to select a blade material to which the powder does not adhere or react. In one embodiment, based on the speed of the moving substrate 16, the approach angle of the blade can be adjusted such that as the blade traverses the substrate 16 from one side to the other while the substrate 16 is moving, the cleaning tool traverses the substrate and moves between two adjacent edges of the powder 20 on the substrate in a direction substantially perpendicular to the longitudinal sides of the substrate 16.

[0027] As shown in FIG. 4, a hydrophilic material may be provided, such as felt strips 46 that run parallel to the edges of the substrate 16. These felt strips 46 capture condensation and allow it to be vacuumed away by the vacuum device 42. Alternatives to felt may include other materials that can collect moisture and do not damage the powder or substrate 16, such as sponges, "squeegee" materials, and the like. In some embodiments, the material strips may include two sides, each side addressing one or more different requirements. For example, one side provides moisture collection and the other aids in sealing.

[0028] In one embodiment, water vapor condensing on the top surface of the hydrophilic material (e.g., felt strip 46) may be transferred through one or more ports 48 at the bottom of the wetting device 10 to a water reservoir (not shown) for eventual reuse / recycling. The condensed water may travel from the port 48 through piping to the water reservoir. In some cases, a user may select which of the one or more ports 48 are utilized, providing an additional method of controlling the flow rate of steam within the steam chamber 34 and allowing an even distribution of water vapor to be maintained. In other examples, which of the one or more ports 48 are utilized may be automatically selected based on data from a sensor identifying the level or condensed water vapor extraction at each of the ports 48. The hydrophilic material may be continuously wetted or saturated with an aqueous solution to allow it to absorb and capture condensed steam while allowing the water vapor to be drawn through a vacuum. In some embodiments, in one or more locations, the hydrophilic material may extend from the top surface to the port 48, providing a mechanism for transporting condensed water to the port 48.

[0029] Additional sensors may be incorporated to ensure that the wetting device 10 is always equipped with a steam source 18' and does not dry out. Additional sensors can also be provided to ensure that the hydrophilic material (e.g., the felt strips 46) maintains the required saturation level so that condensed water vapor can be extracted via the applied vacuum.

[0030] In a further embodiment, also shown in FIG. 4, the wetting apparatus 10 can be lifted using a lifting mechanism 50 which raises the table on which the entire wetting apparatus 10 is placed upward to expose the felt strip 46 which can be replaced or cleaned as necessary, and separates the wetting apparatus 10 from the substrate 16.

[0031] The lifting mechanism 50 may be manually or electronically operated. In another embodiment, the wetting device 10 may be hinged along one edge so that it can be rotated to expose the felt strip 46 so that it can be replaced or cleaned as needed. Rails or location structures (not shown) may be provided on either side of the substrate 16 to provide a defined location for the wetting device 10 to reside so that an edge of the wetting device 10 aligns and seals against the felt 46 when lowered toward the substrate 16. The weight of the wetting device 10 may further help facilitate sealing.

[0032] 5 and 6, a heat sink 52 is provided below the substrate 16 opposite the wetting apparatus 10 and the steaming head 36 to dissipate heat generated by the wetting apparatus 10 from the bottom surface of the support substrate 16. This ensures that the substrate 16, which is typically made of Mylar, is not thermally damaged by the steaming operation. Of course, it is noted that other materials can be used for the substrate 16. The dimensions of the heat sink 52 can be adjusted accordingly to ensure that the substrate 16 itself is not damaged by the steaming operation occurring within the steam housing 32 located directly above the heat sink 52. The heat sink 52 also helps control the temperature of the powder 20 to ensure absorption and condensation of the vapor.

[0033] In one embodiment, a fan 54 may be provided adjacent the heat sink 52 to further enhance heat dissipation from the heat sink 52. Figure 5 also shows a vacuum system 42 for condensation removal and a substrate cleaning actuator 44, which is shown in more detail in Figure 3.

[0034] In another embodiment, a heating device such as a heating pad 56 can be disposed on the top surface of the vapor chamber 34 (see FIG. 3) to reduce or at least minimize moisture condensing above the substrate on the inner surface of the vapor chamber 34. The heating device 56 can be disposed on the exterior surface of the vapor chamber 34, on the inner surface of the top surface of the vapor chamber 34, or can be incorporated therein.

[0035] 6, the mounting platform 60 to which the steaming head 36 is attached is configured to be tilted at an angle θ to ensure that steam dispersed from the steaming head 36 does not condense and remain on the surface of the mounting platform 60, creating the potential for water contamination. In one embodiment, the mounting platform 60 is fixed at the angle θ, while in another embodiment, the mounting platform 60 is configured such that the angle θ is adjustable.

[0036] Referring to FIG. 7, there is shown a system interface 70 for generating and controlling steam used by the steam processing head 36 in the steam housing 32 shown in, for example, FIGS. 3 and 4. Specifically, the system interface 70 includes a precision pump 72 that receives water from a water inlet 74 and pumps a precise, predetermined amount of water to an evaporator 75. The evaporator 75 boils the water from the pump 72 to generate steam 18' and delivers the steam to a steam line 76 that delivers the steam 18' to a steam source input 38 on the steam processing head 36 in the steam housing 32. As shown in FIG. 7, optionally, the steam line 76 can be 1-3 meters long and can be heated (to conserve steam). In an alternative embodiment, a mass flow controller (not shown) can be included after the evaporator 75 to meter and control the flow rate of the steam 18' delivered by the evaporator 75 to the steam chamber 34.

[0037] With further reference to FIG. 7, various sensors can be used to ensure that the proper amount and temperature of steam is produced. Specifically, a temperature sensor 77 can be provided between the evaporator 75 and the steam line 76 to ensure that the steam output of the evaporator 75 is sufficient. If the steam temperature exceeds a predetermined appropriate temperature, the pump 72 and evaporator 75 can be controlled to reduce the steam temperature. Alternatively, if the temperature sensor 77 indicates that the steam temperature is too low, the pump 72 and / or evaporator 75 can be adjusted to increase the steam temperature. As shown in FIG. 7, a display and controller 78 allows an operator to control this. Alternatively, a feedback control system (not shown) can be used to perform this adjustment action automatically. Additionally, the control of the pump 72 and evaporator 75 can also be affected based on the output of an optional external sensor 79 located within the steam housing 32, which can measure the temperature, volume, and pressure of the steam within the steam housing 32, as described above with reference to FIG. 3.

[0038] The rate and temperature of vapor generation, controlled by the system interface 70 of FIG. 7, the temperature range of the heater 40 disposed on the vapor chamber 34 / vapor processing head 36, as well as the speed of the substrate 16, can all be selected based on, for example, the substrate 16 used, the powder material 20 to be deposited on the substrate 16, etc., with the objective being to ensure that the dispersed powder 20 is not damaged and that sufficient lubrication / wetting is provided to improve flowability, but not so much that the wetting agent 18 spreads beyond the desired powder boundaries. In addition, the vapor 18' generated, and the lubrication / wetting provided, should be selected such that a Mylar surface (such as the surface of the calendar roller 24) disposed on the lubricated / wetted powder deposition surface does not "pick up" any of the deposited powder 20, i.e., the powder does not adhere to it. Additional sensors can be incorporated into the system to help control these parameters. For example, sensors may be provided to measure the powder temperature, and a feedback control system (not shown) can be used to regulate the vapor generation and / or the heat sink 52, such that the vapor generator (e.g., evaporator 75) and / or the heat sink 52 can assist in controlling the powder temperature. Such additional sensors can monitor the powder temperature for condensation and absorption. The sensors can also provide information that can be used to automate manufacturing operations, if desired. Heat sink 52 may also be provided with a water cooling mechanism to control the temperature.

[0039] FIG. 8 is a block diagram illustrating an example of a computer system 800 in which aspects of the disclosure, such as the display and controller 78 shown in FIG. 7, or the feedback control system described above, may be implemented. The computer system 800 may include a bus 802 or other communication mechanism for communicating information and a processor 804 coupled to the bus 802 for processing information. The computer system 800 may also include a main memory 806, such as a random access memory (RAM) or other dynamic storage device coupled to the bus 802 for storing information and instructions executed by the processor 804. The main memory 806 may also be used to store temporary variables or other intermediate information during execution of instructions executed by the processor 804. The computer system 800 may be implemented as the display and controller 78 shown in FIG. 7 of the feedback control system described above, for example, to perform the operations described above with reference to FIGS. 1-7.

[0040] Computer system 800 may further include a read only memory (ROM) 808 or other static storage device coupled to bus 802 for storing static information and instructions for processor 804. A storage device 810, such as a flash memory or other non-volatile memory, may be coupled to bus 802 for storing information and instructions.

[0041] Computer system 800 may be coupled via bus 802 to a display 812, such as a liquid crystal display (LCD), for displaying information. One or more user input devices, such as exemplary user input device 814, may be coupled to bus 802 and configured to receive various user inputs, such as user command selections, and communicate these to processor 804 or main memory 806. User input device 814 may include physical structures, or virtual implementations, or both, that provide user input modes or options, and cursor control 816, for example, for controlling a cursor, that is visible to a user through display 812 or through other techniques; such modes or operations may include, for example, a virtual mouse, trackball, or cursor direction keys.

[0042] The computer system 800 may include resources of each of the processors 804 executing their respective program instructions in an overlapping or interleaved manner. Instructions may be read into the main memory 806 from another machine-readable medium, such as the storage device 810. In some examples, hard-wired circuitry may be used in place of or in combination with software instructions. The term "machine-readable medium" as used herein refers to any medium involved in providing data that causes a machine to operate in a specific manner. Such media may take forms including, but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media may include, for example, optical or magnetic disks, such as the storage device 810. Transmission media may include optical paths, or electrical or acoustic signal propagation paths, and may include acoustic or light waves, such as those generated during radio and infrared data communications, capable of carrying instructions detectable by a physical mechanism for input to a machine.

[0043] The computer system 800 also includes a communication interface 818 coupled to the bus 802 for a two-way data communication coupling to a network link 820 that is connected to a local network 822. The network link 820 may provide data communication through one or more networks to other data devices. For example, the network link 820 may provide a connection through the local network 822 to a host computer 824 or to data equipment operated by an Internet Service Provider (ISP) 826 to access a server 830 through the Internet 828 to, for example, obtain application program code.

[0044] It should be noted that while the above description has been presented primarily with respect to wetting powder in a 3D printing environment, the apparatus and methods of the present disclosure are not limited to only powder wetting for 3D printers; they may be used in any situation where it is desirable to wet the powder to keep it intact for subsequent processing.

[0045] Although the embodiments described and illustrated are for a substrate in the form of a conveyor belt or the like or a moving substrate, it will be apparent that the teachings disclosed herein may be applied to individual substrate segments or separate substrate segments.

[0046] Further features, characteristics and advantages of the present invention are described by subsections below.

[0047] Item 1: An apparatus comprising: a powder dispenser configured to dispense a powder onto a substrate; a calender including a top roller arranged above the powder on the substrate; and a conditioning device arranged between the powder dispenser and the calender in a direction of movement of the substrate, the conditioning device being configured to apply a conditioning agent to the powder on the substrate before the powder passes through the calender, the conditioning agent comprising a material that increases the cohesiveness of the powder.

[0048] Item 2: The apparatus of item 1, wherein the top roller has a controlled surface energy coating configured to prevent powder from adhering to the top roller.

[0049] Item 3: The apparatus of item 1 or 2, further comprising a cover layer located between the top roller and a top surface of the powder on the substrate and configured to prevent the powder from adhering to the top roller.

[0050] Item 4: The apparatus according to any one of Items 1 to 3, further comprising a dryer disposed after the calender along the direction of movement of the substrate, the dryer being configured to dry the powder on the substrate after the substrate has passed through the calender.

[0051] Item 5: The apparatus according to any one of items 1 to 4, wherein the conditioning device includes a wetting device, and the wetting device includes a steam treatment head configured to apply steam as a wetting agent to the powder on the substrate.

[0052] Item 6: The apparatus according to any one of items 1 to 5, wherein the steam treatment head is disposed within a steam housing including a steam chamber that covers a portion of the substrate along a direction of movement of the substrate, and the steam chamber is configured to confine steam from the steam treatment head to the portion of the substrate disposed within the steam chamber.

[0053] Item 7: The apparatus according to any one of items 1 to 6, further comprising at least one vacuum device disposed within the steam housing of the wetting apparatus adjacent to the steam treatment head and configured to remove excess steam and condensate generated by the steam treatment head within the steam housing.

[0054] Item 8: The apparatus according to any one of Items 1 to 7, wherein the wetting device is configured to continuously generate steam at the steam treatment head while the substrate moves through the wetting device.

[0055] Item 9: The apparatus according to any one of items 1 to 8, further comprising a sensor for detecting when powder is present on a portion of the substrate below the steaming head, wherein the wetting device is configured to generate steam from the steaming head only when the sensor determines that powder is present on the portion of the substrate below the steaming head.

[0056] Item 10: The apparatus according to any one of Items 1 to 9, further comprising a heater disposed adjacent to the vapor processing head and configured to maintain vapor within the vapor processing head.

[0057] Item 11: The apparatus according to any one of Items 1 to 10, further comprising a lifting mechanism configured to separate the wetting device from the substrate.

[0058] Item 12: The apparatus according to any one of items 1 to 11, further comprising a heat sink located under the substrate on the opposite side of the vapor housing of the wet apparatus.

[0059] Item 13: The apparatus according to any one of items 1 to 12, further comprising a sensor configured to measure a powder temperature.

[0060] Item 14: The device according to any one of items 1 to 13, further comprising a sensor configured to measure a temperature of the steam as the steam enters the steam chamber.

[0061] Item 15: The apparatus according to any one of Items 1 to 14, wherein the heat sink is configured to have a controllable heat capacity for controlling the powder temperature.

[0062] Item 16: The apparatus according to any one of Items 1 to 15, further comprising a lower roller positioned below the substrate on the opposite side of the upper roller such that the substrate is positioned between the upper roller and the lower roller.

[0063] Item 17: The apparatus according to any one of Items 1 to 16, wherein the base material is a conveyor belt.

[0064] Item 18: The apparatus of any of items 1 to 17, further comprising a substrate cleaning actuator configured to blow air onto the substrate in areas where no powder has been deposited to remove any excess powder that may have drifted onto those portions of the substrate.

[0065] Item 19: The apparatus according to any one of Items 1 to 18, wherein the substrate cleaning actuator is configured to be raised and lowered so as to come into contact with and move away from the substrate.

[0066] Item 20: A method comprising distributing a powder on a substrate, applying a conditioning agent to the distributed powder on the substrate before the powder passes through a calender, and compressing the powder after the conditioning agent has been applied, wherein the conditioning agent is comprised of a material that increases the cohesiveness of the powder to provide a uniform compaction of the powder during compaction.

[0067] Item 21: The method according to item 20, further comprising drying the powder after compressing the powder.

[0068] Item 22: The method according to item 20 or 21, wherein the conditioning agent is steam applied by a steaming head.

[0069] Item 23: The method according to any one of Items 20 to 22, wherein the vapor treatment head is disposed in a vapor housing including a vapor chamber that covers a portion of the substrate along a direction of movement of the substrate.

[0070] Item 24: The method according to any one of Items 20 to 23, further comprising applying a vacuum with at least one vacuum device disposed within the steam housing adjacent to the steam treatment head to remove excess steam and condensate generated by the steam treatment head within the steam housing.

[0071] Item 25: The method according to any one of Items 20 to 24, further comprising continuously generating steam with a steam treatment head while the substrate moves through the wetting device.

[0072] Item 26: The method according to any one of Items 20 to 25, further comprising sensing via a sensor when powder is present on a portion of the substrate below the steam treatment head, and steam is generated from the steam treatment head only when the sensor determines that powder is present on the portion of the substrate below the steam treatment head.

[0073] Item 27: The method according to any one of Items 20 to 26, further comprising heating the steam treatment head to maintain steam in the steam treatment head.

[0074] Item 28: The method according to any one of Items 20 to 27, further comprising raising the steam treatment head to separate the wetting device from the substrate.

[0075] Item 29: The method of any of Items 20 to 28, further comprising removing heat from the substrate via a heat sink located below the substrate on the opposite side of the vapor housing.

[0076] Item 30: The method according to any one of Items 20 to 29, further comprising measuring the temperature of the powder with a sensor.

[0077] Item 31: The method according to any one of Items 20 to 30, further comprising measuring the temperature of the steam as it enters the steam chamber.

[0078] Item 32: The method according to any one of Items 20 to 31, further comprising controlling the powder temperature via a heat sink having a controllable heat capacity.

[0079] Item 33: The method according to any one of Items 20 to 32, wherein compressing the powder is carried out by passing the powder through a calendar including a top roller above the substrate and a bottom roller opposite to the top roller and located below the substrate.

[0080] Item 34: The method of any of items 20 to 33, further comprising blowing air onto the substrate using a substrate cleaning actuator in areas where no powder has been deposited to clean any excess powder that may have drifted onto those portions of the substrate.

[0081] Item 35: The method according to any one of Items 20 to 34, further comprising raising and lowering the substrate cleaning actuator to contact and release the substrate.

[0082] Although various embodiments have been described, the description is intended to be illustrative rather than limiting, and it is understood that many more embodiments are possible that are within the scope of the embodiments. Although many possible combinations of features are shown in the accompanying drawings and discussed in this detailed description, many other combinations of the disclosed features are possible. Any feature of any embodiment may be used in combination with or in place of any other feature or element in any other embodiment, unless specifically limited thereto. Thus, it will be understood that any of the features shown and / or discussed in this disclosure may be implemented together in any suitable combination.

[0083] While the above has described what is believed to be the best mode and / or other examples, it will be understood that various modifications can be made therein and that the subject matter disclosed herein can be embodied in a variety of forms and examples and that the teachings can be applied to numerous applications, only a few of which are described herein.

[0084] Unless otherwise indicated, all measurements, values, ratings, positions, dimensions, sizes, and other specifications set forth herein are approximate and not exact, and are intended to have a reasonable range consistent with the functions to which they relate and that which is customary in the art to which they pertain.

[0085] It will be understood that the terms and expressions used herein have the ordinary meanings given to such terms and expressions with respect to their corresponding respective fields of study and research, unless a specific meaning is otherwise set forth herein. Relative terms such as first and second may be used merely to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements may include other elements not expressly listed or inherent to such process, method, article, or apparatus, rather than including only those elements. An element preceded by "a" or "an" does not, without further constraints, preclude the presence of additional identical elements in the process, method, article, or apparatus that includes that element.

Claims

1. An apparatus comprising: a powder dispenser configured to dispense a powder onto the substrate; a calender comprising a top roller positioned above the powder on the substrate; an adjustment device disposed between the powder dispenser and the calender in the direction of movement of the substrate; the conditioning device is configured to apply a conditioning agent to the powder on the substrate before the powder passes through the calender; The apparatus, wherein the modifier is a material that increases the cohesiveness of the powder.

2. 10. The apparatus of claim 1, wherein the top roller has a controlled surface energy coating configured to prevent the powder from adhering to the top roller.

3. 10. The apparatus of claim 1, further comprising a cover layer located between the top roller and a top surface of the powder on the substrate, the cover layer configured to prevent the powder from adhering to the top roller.

4. The apparatus of claim 3 further comprising a dryer disposed after the calender along a direction of movement of the substrate.

5. 10. The apparatus of claim 1, wherein the conditioning device comprises a wetting device, the wetting device comprising a steam head configured to apply steam as a wetting agent to the powder on the substrate.

6. The apparatus of claim 5 , wherein the steam head is disposed within a steam housing that includes a steam chamber that covers a portion of the substrate along a direction of movement of the substrate.

7. 7. The apparatus of claim 6, further comprising at least one vacuum device disposed within the steam housing of the wetting device adjacent the steam head and configured to remove excess steam and condensate generated by the steam head within the steam housing.

8. The apparatus of claim 6 , wherein the wetting device is configured to continuously generate steam at the steam head while the substrate moves through the wetting device.

9. 7. The apparatus of claim 6, further comprising a sensor for sensing when powder is present on a portion of the substrate beneath the steam head, the wetting device being configured to generate steam from the steam head only when the sensor determines that powder is present on the portion of the substrate beneath the steam head.

10. The apparatus of claim 5 , further comprising a heater disposed adjacent the steam head and configured to maintain steam within the steam head.

11. The apparatus of claim 5 , further comprising a lift mechanism configured to separate the wetting device from the substrate.

12. The apparatus of claim 6 , further comprising a heat sink disposed beneath the substrate opposite the vapor housing of the wetting device.

13. The apparatus of claim 1 , further comprising a sensor configured to measure a powder temperature.

14. The apparatus of claim 6 , further comprising a sensor configured to measure a temperature of the steam as it enters the steam chamber.

15. 13. The apparatus of claim 12, wherein the heat sink is configured to have a controllable thermal mass to control a powder temperature.

16. The apparatus of claim 1 , further comprising a lower roller positioned opposite the upper roller and below the substrate such that the substrate is disposed between the upper and lower rollers.

17. The apparatus of claim 1 , wherein the substrate comprises a conveyor belt.

18. 10. The apparatus of claim 1, further comprising a substrate cleaning actuator configured to blow air onto the substrate in areas where no powder has been deposited to remove excess powder that may have drifted onto those portions of the substrate.

19. 20. The apparatus of claim 18, wherein the substrate cleaning actuator is configured to be raised and lowered into and out of contact with the substrate.

20. 1. A method comprising: Distributing a powder onto a substrate; applying a conditioning agent to the powder distributed on the substrate before the powder passes through a calender; and compressing the powder after the conditioning agent has been applied. The method of claim 1, wherein the modifier comprises a material that increases the cohesiveness of the powder to provide a uniform compaction of the powder during compaction.

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