Additive Manufacturing Machine

Abstract

The present invention is an additive manufacturing machine and associated method for building parts layer by layer by first using additive manufacturing to build a mold to define spaces for the layers and then filling the spaces with paste to build the layers of the part. The machine includes a first mold-building station with an inkjet nozzle for building the mold using standard 3D printing, a second paste-dispensing station spaced from the first station, and a dispensing die slot for dispensing the paste into the spaces to build the layers. The machine operates multiple parts simultaneously, with each part being transported along a path through the stations.

Description

[Technical Field]

[0001] In some embodiments, the present invention relates to machines for additive manufacturing, and more particularly, but not exclusively, to machines that print a mold for each layer of a product or part to be manufactured and then fill the mold to form the next additive layer.

[0002] [Related Applications] This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 935,658, filed November 15, 2019, the contents of which are incorporated herein by reference in their entirety.

[0003] Such manufacturing methods are disclosed in International Patent Application No. IL2018 / 050475, filed April 30, 2018, which teaches, inter alia, combining additive manufacturing with molding techniques to build shapes that were previously impossible with conventional molding or machining techniques, or to use materials that are difficult or impossible to use with known additive manufacturing techniques, or to build shapes more quickly than is possible with known additive manufacturing techniques.

[0004] Additive manufacturing is used to fabricate molds, which are then filled with the material of the final product. In some embodiments, layers of the final product are built separately in individual molds, with subsequent layers being fabricated on top of the previous layer. The previous layer may actually support the mold for the new layer and also provide a floor for the new layer. In an example, two separate applicators are provided: one for printing the mold, with three degrees of freedom as required for 3D printing, and one for filling the mold after it is formed.

[0005] In one example, an inkjet printhead prints a mold using wax or any other heat-melting or heat-setting or UV-curable material, and then fills the mold with a paste, which is then leveled with a mechanical tool such as a squeegee or blade to fill and level the mold.

[0006] Israeli application IL2019 / 050957, filed August 27, 2019, discloses the use of reduced pressure (vacuum) to aid in drying, and more specifically, to effect hardening of paste or other filler used in molds to form layers. More specifically, for each layer, a mold is formed and then filled with paste or other substance, and the newly filled layer surface is then placed in a vacuum, resulting in a rapid reduction in pressure and changing the boiling point of the liquid in the paste that forms the layer. The liquid thus evaporates, hardening the paste and rapidly forming a hard layer. After hardening, the vacuum is released and the volume is evacuated.

[0007] Not all shapes are freestanding; U.S. Provisional Patent Application No. 62 / 780,273, filed December 16, 2018, discloses a method in which a sintered support is manufactured in the same process as the component requiring sintering. In one example, both the component and the support can be provided in an integrated process involving additive manufacturing. In this manner, the mold and support are both manufactured using 3D printing techniques to create the supported shape, and the mold is then filled with a paste or the like, which is dried.

[0008] U.S. Provisional Patent Application No. 62 / 873,909, filed July 14, 2019, discloses a lamination device that aims to fill a mold and eliminate or significantly reduce separate smoothing steps for each layer of the mold. This is accomplished by setting up a blade or squeegee that spreads the paste in the same plane defined by a roller that smooths the mold.

[0009] Thus, a roller can be used to press the mold. An applicator then applies the paste into the mold, and a blade is used to spread the paste. The blade is adjusted to the height and orientation of the roller so that both the roller and the blade define the same plane within the mold. Thus, the roller, in combination with the paste applicator and blade, forms a layer-forming device that can work as part of a 3D printer or additive manufacturing device. The height of the paste distributor can be coordinated with the roller and the blade.

[0010] Thus, the blade may be attached to the same mount as the roller to form such a layer forming device, and one or both of the blade and roller may have provisions for fine adjustment, or may be one or more point dispensers that apply paste to designated points. The point dispensers may be moved from side to side to fill the mold shape.

[0011] When mounted, changing the height of the roller simultaneously changes the height of the blade. Relative movement between the product or part being printed and the single mount holding the blade and roller does not affect the plane that both the roller and blade together define.

[0012] It should be noted that the three processes of pressing the mold after printing, applying the paste, and spreading the paste inside the mold are all done in one pass at a single location. Optionally, a further process of smoothing the paste may be performed.

[0013] However, because each layer is very thin and many layers are required to complete a part, additive manufacturing is known to be slow compared to other manufacturing techniques. As a result, despite its great appeal, additive manufacturing has not made significant progress in mass production and has generally been reserved for prototyping and small-scale production. Summary of the Invention

[0014] The present embodiment aims in particular to provide a machine that can improve manufacturing throughput using a mold-filling variant of additive manufacturing. To date, additive manufacturing has used a single station where a single product is gradually built up layer by layer. The present embodiment provides a manufacturing process that uses different stations for different parts of the process, thus making it possible to manufacture several items in parallel on a single machine. The machine may be closed-loop or linear.

[0015] According to an aspect of some embodiments of the present invention there is provided an additive manufacturing machine for building a part in layers by first using additive manufacturing to build a mold to define spaces for the layers and then filling the spaces with paste to build the layers of the part, the additive manufacturing machine comprising: a first mold forming station having a nozzle configured to form a mold; a second paste dispensing station spaced from the first station, the second paste dispensing station including a dispensing die slot for dispensing paste within the space; Equipped with The additive manufacturing machine is configured to operate on multiple parts simultaneously, with each part being transported along a path that passes through each of the stations.

[0016] The embodiment may include a frame, with the station being fixed on the frame.

[0017] In some embodiments, the stations each form a bridge on the path between a first station side and a second station side, and the fixation is on the first and second station side.

[0018] In one embodiment, the paste dispensing station comprises a roller preceding the dispensing die slot and a cutter following the dispensing die slot, the roller configured to level the mold to a predetermined level and the cutter configured to level the paste, and the roller and cutter are mounted at the same level.

[0019] In one embodiment, the stations are arranged around a perimeter.

[0020] In one embodiment, the stations are arranged so that rotation of the part around the stations provides a total number of completed layers for the part.

[0021] Some embodiments may include a rotary table for transporting manufacturing trays between stations.

[0022] In one embodiment, a rotary table is connected to the frame via a central axle, which provides rotation to the table.

[0023] In one embodiment, the rotation is controlled by an indexer to stop the table when the part is aligned at each station.

[0024] In one embodiment, the periphery of the table is supported vertically from the frame.

[0025] In one embodiment, the periphery of the table includes rails and the frame includes cam followers that extend upwardly towards the rails, thereby providing vertical support.

[0026] In one embodiment, cam followers are aligned with the stations, thereby holding the table vertically and securely at each station.

[0027] Some embodiments may include one or more additional paste dispensing stations.

[0028] Some embodiments may include a drying station.

[0029] Some embodiments may include a vacuum station.

[0030] One embodiment may include a viewing station.

[0031] In one embodiment, the observation station is configured to control the machine to remove layers that are found to be damaged so that the layers can be reconstructed.

[0032] According to one embodiment, the stations are aligned on a linear path, which is traversed by a linear conveyor.

[0033] Some embodiments allow the height of the mold to vary so that different layers are of different thicknesses.

[0034] Some embodiments may create two or more layers in a single revolution of the timetable.

[0035] In some embodiments with at least one additional paste dispensing station, pastes of different compositions can be dispensed for different parts, or parts made of composite materials can be formed.

[0036] According to a second aspect of the present invention there is provided an additive manufacturing method comprising: A path is provided, stations are provided along the path, a build tray is provided, the build tray is moved across the path while pausing at each station, and different stages of additive manufacturing are performed in parallel at each of the stations during the pauses so that a part traversing the path is built in layers.

[0037] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of this invention, exemplary methods and / or materials are described below. In case of conflict, the present patent specification, including definitions, will control. Furthermore, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

[0038] Implementation of the method and / or system embodiments of the present invention may involve performing or completing selected tasks manually, automatically, or a combination thereof. Further, depending on the actual instrumentation and equipment of the method and / or system embodiments of the present invention, some selected tasks may be performed by hardware, software, or firmware, as well as a combination thereof using an operating system.

[0039] For example, hardware for performing selected tasks according to embodiments of the present invention may be implemented as a chip or circuit. As software, selected tasks according to embodiments of the present invention may be implemented as a plurality of software instructions executed by a computer using any suitable operating system. In exemplary embodiments of the present invention, one or more tasks according to exemplary embodiments of the methods and / or systems described herein are performed by a data processor, such as a computing platform for executing a plurality of instructions. Optionally, the data processor includes volatile memory for storing instructions and / or data, and / or non-volatile storage, such as a magnetic hard disk and / or removable media, for storing instructions and / or data. Optionally, a network connection is provided as well. A display and / or user input device, such as a keyboard or mouse, are also optionally provided. [Brief explanation of the drawings]

[0040] Some embodiments of the present invention are described herein, by way of example only, with reference to the accompanying drawings. Referring now specifically to the drawings in detail, it is emphasized that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description with reference to the drawings will make apparent to those skilled in the art how embodiments of the present invention may be practiced.

[0041] [Figure 1] FIG. 1 is a simplified diagram showing a top view of a machine for additive manufacturing of the inside of a cover, according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of a frame for the machine of FIG. 1 having a rotatable shaft for mounting a turntable; [Figure 3A] FIG. 3 is a perspective view of the frame of FIG. 2 with a turntable attached. [Figure 3B] FIG. 3B is a view of the turntable of FIG. 3A as seen from above. [Figure 4] FIG. 1 is a simplified diagram of a build tray and slidable mounting according to an embodiment of the present invention. [Figure 5] FIG. 1 is a top perspective view of a turntable with supports from a frame to the periphery of the turntable. [Figure 6] 6 is a detail of the cam follower structure of the support of FIG. 5. [Figure 7] FIG. 7 is a perspective view of a detail of FIG. 6. [Figure 8] FIG. 4 is a perspective view according to FIG. 3 showing the stations installed around the turntable. [Figure 9] FIG. 9 is a top view of the turntable with the stations installed according to FIG. 8. [Figure 10] FIG. 10 is a side view of the paste dispensing unit of FIG. 9. [Figure 11A] FIG. 10 is a side view of the vacuum station of FIG. 9 in a withdrawn position. [Figure 11B] FIG. 10 is a side view of the vacuum station of FIG. 9 in a vacuum position. [Figure 12]FIG. 10 is a perspective view of the inspection station of FIG. 9. [Figure 13] FIG. 10 is a simplified diagram illustrating an alternative embodiment of the present invention using a linear layout. [Figure 14] 10 is a simplified diagram illustrating an alternative embodiment of the present invention using multiple linear axes. DETAILED DESCRIPTION OF THE INVENTION

[0042] In some embodiments thereof, the present invention relates to a machine for additive manufacturing, and more particularly, but not exclusively, to a machine that prints a mold for each layer of a product or part to be manufactured and then fills the mold to form the next additive layer.

[0043] According to this embodiment, an additive manufacturing machine and associated method are provided for building parts layer by layer by first using additive manufacturing to create a mold to define the space for the layer, and then filling the space with paste to build the part's layers. The machine includes a first mold-building station with inkjet nozzles for creating the mold in three dimensions using standard 3D printing, a second paste-dispensing station spaced from the first station, and a dispensing die slot for dispensing the paste into the space to form the layer. The machine operates on multiple parts simultaneously, with each part transported along a path through the stations. The additive manufacturing machine can be based on either a linear track or a rotating plate design with a closed-loop track, more specifically an endless conveyor. A build tray moves along the track to stations performing different parts of the additive manufacturing process. The endless conveyor concept allows multiple trays to be built in parallel, thereby dramatically increasing throughput.

[0044] There are at least the following stations: a mold printing station, and a paste deposition station. In addition, a drying station, a vacuum station, an optical inspection station, and a station for natural or enhanced cooling may be provided. If not provided as separate stations, some or all of the latter functions may be integrated into, for example, the paste deposition station. The sequence of stations may be provided once, twice, or more times along the track, depending on the amount of throughput required, so that two, three, or more layers may be added to the part for a single revolution. As discussed elsewhere herein, one or more paste deposition stations can enable production using different materials simultaneously.

[0045] This method can be based on the techniques outlined in the background, i.e., inkjet printing of a mold and filling the mold with a paste containing ceramic or metal, typically as a powder, with a water-based or solvent-based binder. The process of adding layers is repeated until the product or part is complete, and various finishing processes are carried out, such as removing the wax from the mold, followed by debinding and sintering to leave a dense product or part.

[0046] Before describing at least one embodiment of the present invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and arrangement of components and / or methods set forth in the following description and / or illustrated in the drawings and / or examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.

[0047] Referring now to the drawings, FIG. 1 illustrates an additive manufacturing machine 10 according to an embodiment of the present invention. The machine is housed in an exterior cover 12 and includes a round turntable 14 and a tray positioned on the turntable that rotates with the turntable. In the embodiment shown in the drawings, rotation is counterclockwise. Stations are arranged around the turntable and are described in more detail below but will be briefly discussed here. A 3D printing station 18 builds the mold to define an internal cavity for filling. A paste dispensing station 20 fills the cavity with paste to provide a smooth surface. Drying stations 22 and 24 provide natural and forced thermal drying, respectively, for the part after the paste is applied. A vacuum station 26 provides vacuum to further dry and harden the part, and an observation station 28 checks for layer inaccuracies. If inaccuracies are found, in some embodiments, layers can be removed and reapplied.

[0048] Referring now to Figure 2, the machine is based on a chassis made from a rigid welded bar 101 supported on leveling pads 102. Mounted on top of the chassis 101 is a motorized indexer system 103, including a motor. As an alternative to the indexer, other controlled rotation stages known in the industry, such as direct motor systems, or pinion tables, as well as other conventional rotation mechanisms, can be substituted. A central shaft 104 is connected to the indexer 103 or the chassis 101 and extends upward. The central shaft 104 is stationary, while the plate 105 is rotated by the indexer 103.

[0049] 3A and 3B, which are top perspective and top plan views of the assembly on the chassis. Mounted above the indexer top plate 105 is a large diameter circular turntable 14 which rotates with the plate 105. The turntable 14 is reinforced by ribs 106 as a primary means of preventing flexing.

[0050] Systems on the turntable may require an on-board power supply for power and communications. As such, a slip ring system 107, such as the Moflon MT series, can be installed. In a slip ring system, a stationary ring is attached to the shaft 104 and a movable ring is attached to the plate 105 or turntable 14. The slip ring system 107 allows current from a power or electronic source to be distributed to the rotation electronic controller and motor that rotates with the turntable 14.

[0051] Alongside the turntable 14, a controlled linear Z stage 108 is provided for the build tray. The Z axis allows for vertical translation of the stage during the part building process.

[0052] Reference is now made to Figure 4, which illustrates an exemplary configuration of stages for build trays according to this embodiment. As mentioned above, mounted on top of each Z stage is a process table assembly 109. The table assembly 109 includes a plate 109a with a sealing surface, a slotted bar 109b that allows horizontal sliding, and a process tray 109c on which the additively manufactured part is built.

[0053] Each of the trays 109c may be separated from the assembly 109 to allow the parts to be removed from the machine for later stages in the process, eg, removal of the mold, etc.

[0054] Process stations can be positioned along and outside the turntable 14. The process stations can perform different processes for building parts on trays 109c. The indexer 103 rotates the trays by a predetermined angle after each operation and then locks all trays in place at the next station for the next operation. In this way, several trays can be built in parallel rather than manufactured serially. Throughput increases accordingly. In one embodiment, a full rotation (360 degrees) of the turntable represents one complete layer build of a part. In other possible embodiments, a full rotation can represent two, three, or more layers.

[0055] 5, 6, and 7, to counteract deflection of the turntable 14 due to the weight of parts or external forces, cam followers 300 are attached to the chassis 101 to support the underside of the turntable 14 in place depending on the level of precision required. Deflection can lead to inaccurate builds. The cam followers 300, which can be located at each station, can provide the support needed to prevent deflection of the table without interfering with the rotation of the turntable.

[0056] In mechanism 300, cam follower 301 is connected to bar 302, which is fixed to the chassis. Cam follower 301 may be a roller bearing. The counter surface that contacts the cam follower is attached to turntable 14. In this embodiment, the counter surface is a hardened, flat, straight rail 303, which may be made from a high chromium steel alloy. Rail 303 may be machined in a way that allows the cam to gently contact the rail, eliminating any shock at the engagement point, but providing support to keep the plate at its designed level at the station. Such machining can be done, for example, by chamfering the rail at ends 310 and 311.

[0057] Reference is now made to Figures 8 and 9, which show details of two stations around the closed loop. The mold build station 18 is an inkjet printer that jets solid ink or any other ink onto the top of the tray to form a mold using additive manufacturing. The mold build station allows for the building of thicker or thinner layers, so that any part can include layers of different thicknesses. More specifically, the height of the mold can be varied, thus allowing different Z resolutions of the layers to be obtained.

[0058] Where the nature of the design allows, it saves time to print thicker layers, while using thinner layers also allows for the production of finer parts where needed. The height of the mold can be determined by varying the print resolution in X and Y coordinates, so that, for example, 1800x1800dpi will be thicker than 1200x1200dpi because more droplets of solid ink are jetted per square inch.

[0059] Furthermore, it should be noted that during the paste drying process, water and solvents may evaporate, potentially reducing the height of the paste layer. In certain cases, this reduction may be as much as 20%, for example, or even more. Therefore, if the required precision of the layer is very high, the filling process may be repeated in the same mold. This may be particularly necessary for the final layer of the part. Specifically, the filling process is repeated, followed by drying, vacuuming, and inspection.

[0060] The mold build station 18 is peripherally supported via supports 500 on a precise flat surface 111 on the chassis 101 (see Figures 3A-3B). The station 18 is centrally supported on the shaft 104 via beams 501 and is held stable over its length to provide stable and precise positioning. In this embodiment, three beams 501 are used to provide stable fixation.

[0061] The inkjet printhead 112 is attached to a head plate 113, which allows droplets of solid ink, for example based on molten wax, to be applied precisely to predetermined locations on the tray to build up the mold. The ink flows from a main ink reservoir 114 to the printhead. The head plate 113 is movable in two non-parallel and typically orthogonal horizontal directions, for example the long axis of the tray and the short axis of the tray, achieving the freedom to deposit droplets anywhere required on the tray. It may be recalled that the tray itself moves vertically so that the printed layer is always at the same height.

[0062] According to one embodiment, the head array is movable along the length of station 18 by a linear motor system (not shown) and vertically by a ball screw system (not shown) to print the mold.

[0063] Thus, in this embodiment, the mold printing station 18 is suspended as a bridge over the path of the trays as they pass, providing a print head that is supported on both sides and movable in the X and Y directions.

[0064] The paste station 20 is similarly suspended as a bridge over the tray path and attached to the main chassis 101 via supports (not shown) and also to the shaft 104. A further paste station 20 may be located around the turntable 14 after the mold printing station in the direction of indexer rotation.

[0065] Station 20 includes a motor-driven linear axis 160 along the radius of the indexing system, along which application unit 121 can move back and forth. If necessary, multiple pasting stations can be provided, for example if a part requires more than one material, so that more than one different paste is required. In this way, parts with multiple materials can also be composed of different materials, for example on different trays.

[0066] 10, which is a side view of application unit 121 mounted on paste dispensing station 20. Roller 122, die slot 123, and blade 124 provide a paste filling mechanism to fill the space inside the mold walls with paste. More specifically, roller 122 presses against the printed mold to ensure a flat and accurate mold surface. Die slot 123 applies the paste by pressure or by other means such as a peristaltic pump, movable syringe, etc.

[0067] The blade 124 then removes excess paste from the layer mold surface. Further details of this method can be found in applicant's co-pending application Ser. No. 62 / 873,909 (filed July 14, 2019), discussed briefly above, the contents of which are incorporated herein by reference.

[0068] Additionally, a cutter assembly 130 can be installed in the unit 121. The cutter assembly 130 can include a circular cutter 131, such as a wood planer. The cutter can be motor-driven by a spindle or any controllable circular motor. The cutter 131 is mounted on a vertical shaft 132, which allows the cutter to be elevated while the paste is being applied, eliminating collisions between the cutter and the part. The shaft 132 can be a pneumatic linear stage or a motorized stage. If desired, the building tray can be moved vertically to the exact required position as the cutter is lowered into the cutting position. The cutting assembly can move along the vertical axis of the station 20 to polish an existing surface, for example, before laying a new surface or to remove an undesired layer.

[0069] Returning now to Figures 8 and 9, drying stations 22 and 24 are the next stations the tray encounters in the part preparation process. At these stations, the parts undergo either natural or forced drying. Forced drying can include any known drying process, such as hot air drying, IR drying, or microwave drying. In one embodiment, drying stations 22 and 24 are forced hot air drying stations, in which a hot air blower 143 forces air toward the parts. According to one embodiment, the user can choose to turn off the air at either station 22 or 24, resulting in natural drying, which refers to drying based on natural air convection. The tray remains in place for a fixed time, allowing water or solvent to evaporate, either forcibly or naturally, from the last filled layer. Pipes (not shown) lead from the blower 143 to the associated station. In one embodiment, the temperature of the hot air is below the wax melting point, since the previous layer mold structure may still be required.

[0070] Here, station 26, immediately following the drying station, provides vacuum drying and curing. The vacuum curing process is described in the applicant's co-pending International Patent Application No. IL2019 / 050957, filed August 27, 2019. FIGS. 11A and 11B show side views of the vacuum station. FIG. 11A shows the vacuum chamber elevated before or after use, while FIG. 11B shows the chamber in use, applying a vacuum to dry the current part. More specifically, at curing station 26, a vacuum cap 151 covers the flat plate 109a, resulting in a cap volume enclosing the process tray 109c and the parts contained therein. The vacuum cap 151 is then pumped down to remove air to a specific vacuum level. The volume remains under vacuum for a predetermined time. The vacuum cap 151 is a box with a sealant in the area of ​​attachment to the flat plate 109a.

[0071] Vacuum pump 170 is connected to main valve 153 by hose 152. Vacuum pump 170 may be, for example, a single or two stage rotary pump.

[0072] The vacuum process can be monitored by a vacuum sensor 154. The vent valve 155 is, for example, a normally closed pneumatic valve connected to the vacuum cap 151. A pneumatic actuator 156 moves the cap 151 up and down between open and closed positions illustrated by Figures 11A and 11B, respectively.

[0073] Once the process tray is locked into position under the vacuum station 26, the pneumatic actuator 156 moves the cap 151. The cap is attached to the flat plate 109a, and the main valve 153 is set to the open position for the volume to be pumped. The vacuum level, indicated by the vacuum sensor 154, is monitored electronically, for example, using an on-board computer. After the vacuum drying process is complete, the main vacuum valve 153 is closed. In one embodiment, the vacuum pump may continue to operate to prepare for the next tray. At this point, the vent valve 155 is turned on, allowing ambient air to flow into the evacuated volume. Gradually, the pressure within the volume reaches atmospheric or ambient pressure. Once ambient pressure is reached, the pneumatic actuator 156 lifts the cap, releasing the tray and parts and allowing the tray to move to the next position under the control of the indexer. In one embodiment, pressurized air is supplied to the volume through the vent valve 155 to accelerate the venting process.

[0074] Returning again to Figures 8 and 9, inspection station 28 is the next station the tray reaches along the periphery of the table. Station 28 is shown in more detail in Figure 12 and includes a camera 161, typically a digital camera, that compares the layer image with the layer after it has cured. Any defined deviations detected by the camera and associated image processing are analyzed and acted upon according to predefined rules. If a layer is damaged, corrections may be made by moving to a cutter position, removing the last layer, and remaking it.

[0075] Referring to Figure 13, an alternative embodiment of the additive manufacturing machine of the present invention is shown. The additive manufacturing machine 200 is a linear additive manufacturing machine. The machine 200 is based on a plate 201 that moves precisely back and forth on rails 202. The plate can be attached to a linear motor, a ball screw, or any other known transport method.

[0076] A vertical linear Z-stage 108 allows parts to be raised and lowered above the plate 201 so that the layers being fabricated are always at the same height. Mounted on top of the Z-stage 108 is a process table assembly 109, conveniently similar to that shown in Figure 4 and described above, which provides the build tray.

[0077] As shown in FIG. 4, the table assembly 109 includes a flat plate having a sealing surface 109a, slotted rails 109b, and a process tray 109c that is movable on the rails and on which products or parts are assembled.

[0078] Tray 109c may be pulled out of assembly 109, for example, to remove the parts for post-processing after production is complete. As noted above, after printing, the parts are preferably only moved along with the tray.

[0079] The process stations are arranged along rail 202. Printing station 210 consists of an array of printheads that move perpendicular to the direction of tray movement. Pasting station 212, drying station 214, and vacuum station 216 are as described above, and additional drying and inspection stations can be added as desired. Numeral 218 denotes an optical inspection system.

[0080] Reference is now made to Figure 14, which is a variation of the linear embodiment of Figure 13. Note that parts that are the same as those in Figure 13 are numbered the same and will not be explicitly referenced except as necessary to understand this embodiment. In the embodiment of Figure 14, multiple build trays 180, 182 move independently on rails 184, 186, thus allowing for parallel processing of multiple build trays simultaneously. The build trays are described in more detail above with respect to Figure 13.

[0081] It is expected that during the life of the patent from this application to its expiration, many related die slots, pastes, sintering techniques, vacuum techniques, 3D printing techniques and drying techniques will have been developed, and the scope of corresponding and other terms is intended a priori to include all such new technologies.

[0082] The terms "comprises," "comprising," "includes," "including," "having," and combinations thereof, mean "including but not limited to."

[0083] As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0084] It is understood that certain features of the invention, which are for clarity described in the context of separate embodiments, may also be provided in combination in a single embodiment, and the text should be construed as if such single embodiment were explicitly recited. Conversely, various features of the invention that are, for brevity, described in the context of a single embodiment, may also be provided separately, or in any suitable subcombination, or as appropriate in any other described embodiment of the invention, and the text should be construed as if such separate embodiments or subcombinations were explicitly recited herein.

[0085] Certain features described in the context of various embodiments should not be considered essential features of those embodiments, unless the embodiment is inoperable without those elements.

[0086] While the present invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, the present invention is intended to embrace all such alternatives, modifications, and variations that fall within the spirit and broad scope of the appended claims.

[0087] All publications, patents, and patent applications mentioned in this specification are incorporated by reference herein in their entirety as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference herein. Furthermore, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent section headings are used, they should not be construed as necessarily limiting. Additionally, any priority documents of this application are incorporated herein by reference in their entirety.

Claims

1. 1. An additive manufacturing machine for building a part layer by firstly using additive manufacturing to create a mold to define spaces for the layers and secondly filling the spaces with paste to build the layers of the part; The additive manufacturing machine comprises: The frame and a first mold forming station having a nozzle configured to form the mold, the first mold forming station being attached to the frame; a second station spaced from the first mold forming station on the frame, the second station being a paste dispensing station and including a dispensing die slot for dispensing paste into the space; Equipped with the additive manufacturing machine is configured to operate on multiple parts simultaneously, the first station and the second station are each arranged around a rotary table, the rotary table is rotatably mounted on the frame, the periphery of the rotary table is supported by the frame so that it rests on supports around its periphery for rotation relative to the frame, and each part is transported on a production tray on the rotary table along a path through each of the stations.

2. The additive manufacturing machine of claim 1 , wherein the first station and the second station are fixed on the frame.

3. 3. The additive manufacturing machine of claim 2, wherein the first station and the second station each form a bridge on the path between an inside of the path and an outside of the path, and the fixation is on the inside and the outside, respectively.

4. 4. The additive manufacturing machine of claim 1, wherein the paste dispensing station comprises a roller preceding the dispensing die slot and a cutter following the dispensing die slot, the roller configured to level the mould to a predetermined level and the cutter configured to level the paste, and the roller and the cutter are mounted at the same level.

5. The additive manufacturing machine of any one of claims 1 to 4, wherein the first station and the second station are arranged around a circumference.

6. 6. The additive manufacturing machine of claim 5, wherein the first station and the second station are arranged such that rotation of a part around the stations provides a total number of completed layers for the part.

7. 7. The additive manufacturing machine of claim 5 or 6, wherein the rotary table is configured to transport production trays between at least the first station and the second station.

8. 8. The additive manufacturing machine of claim 7, wherein the rotary table is connected to the frame via a central axle, the central axle providing rotation to the rotary table.

9. 9. The additive manufacturing machine of claim 8, wherein the rotation is controlled by an indexer to stop the rotary table when the parts are aligned at their respective stations.

10. An additive manufacturing machine according to any one of claims 7 to 9, wherein the periphery of the rotary table is supported vertically from the frame, thereby providing vertical support.

11. 11. The additive manufacturing machine of claim 10, wherein the periphery of the rotary table includes rails and the frame includes cam followers extending upwardly toward the rails, thereby providing the vertical support.

12. 12. The additive manufacturing machine of claim 11, wherein the cam followers are aligned with the first station and the second station, respectively, thereby holding the rotary table vertically and securely at each station.

13. 13. An additive manufacturing machine according to any preceding claim, comprising at least one additional paste dispensing station.

14. An additive manufacturing machine according to any preceding claim, comprising a drying station.

15. An additive manufacturing machine according to any preceding claim, comprising a vacuum station.

16. An additive manufacturing machine according to any preceding claim, comprising a viewing station.

17. 17. The additive manufacturing machine of claim 16, wherein the observation station is configured to control the additive manufacturing machine to remove a layer found to be damaged in order to reconstruct the layer.

18. An additive manufacturing machine according to any preceding claim, configured to vary the height of the mould so that different layers have different thicknesses.

19. The additive manufacturing machine of claim 6 , wherein the total number is greater than one.

20. 14. The additive manufacturing machine of claim 13, wherein the at least one additional paste dispensing station is configured to dispense pastes of different compositions or to form parts made of composite materials.

21. 1. A method of additive manufacturing, the method comprising: Providing a frame; providing a rotary table and a path around the rotary table, the rotary table being rotatably mounted on the frame; supporting the rotary table from a periphery of the rotary table on peripheral supports so that the rotary table rests on the peripheral supports, thereby rotating the rotary table relative to the peripheral supports; providing a plurality of stations along the path, the stations being mounted on the frame; providing a build tray on said rotary table; moving the build tray across the turntable, pausing at each station; performing different stages of additive manufacturing in parallel at each of the stations during the pause so that a part traversing the path is built up layer by layer; and A method comprising:

22. 22. The method of claim 21, including constructing a mold to enclose a space at one of the stations.

23. 23. The method of claim 22, including filling the space with a paste.

24. 24. The method of claim 23, including smoothing the paste to the level at which the mold is smoothed.

25. 25. The method of claim 24, including drying the paste.

26. 26. The method of claim 25, wherein the drying comprises air drying and forced heat drying performed at two successive stations.

27. 27. The method according to any one of claims 23 to 26, wherein the step of filling the spaces with paste is performed with different paste materials at different stations or at the same station using two different die slots.

28. The method of any one of claims 22 to 26, wherein the path is a circular path.

29. A method according to any one of claims 22 to 28, wherein each layer is of variable thickness, the method comprising setting the mould build to a variable height.

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