3D printing equipment

Abstract

The invention relates to a device for forming a molded article from granular material layer by layer, comprising at least one processing unit (1.5, 5.2, 6.2), which can preferably be automatically introduced and installed in the device and comprises a printing unit (2.6, 3.6, 7.6) and a coating system (2.2, 3.2, 7.2) with a dynamic filling system; and / or a receiving device for a building container; a preferably automatic feeder for the building container (1.3); and an adjustment device for an offline production process unit.

Description

Technical Field

[0001] The present invention relates to an apparatus and method for producing 3D molded articles using at least one processing unit, which is particularly suitable for large-scale batch production of 3D molded articles, such as casting cores, molds and other articles that are in high demand. Background Art

[0002] European Patent EP 0 431 924 B1 describes a process for producing three-dimensional objects based on computer data. In this process, a thin layer of granular material is deposited onto a platform by a coater. The granular material has a binder material selectively printed onto it by a print head. The granular areas with the binder printed on them bond and cure under the influence of the binder and, optionally, an additional hardener. Next, the build platform is lowered by one layer or the coater / print head is raised, and a new layer of granular material is applied, also printed as described above. These steps are repeated until the desired height of the object is reached. Thus, the printed and cured areas form a three-dimensional object (molded part).

[0003] Once completed, the object made of the solidified granular material is embedded in the loose granular material and subsequently released from the loose granular material. This can be done, for example, using a suction device. This leaves the desired object, which must then be freed of any residual powder, for example by brushing it off.

[0004] Other powder-based rapid prototyping processes such as selective laser sintering or electron beam sintering work in a similar way, also applying loose particulate material layer by layer and selectively solidifying it using a controlled physical radiation source.

[0005] In the following, all these processes will be summarized by the term "three-dimensional printing method" or "3D printing method".

[0006] Some of these methods utilize different coating options. In some methods, the entire layer of granular material is placed in front of a thin blade. The blade then moves over the build area, spreading the material placed in front of it and smoothing it out. Another type of layer application involves continuously placing small amounts of granular material in front of the blade as it moves. To achieve this, the blade is typically mounted on the underside of a movable silo. Directly above or next to the blade, an adjustable gap is provided through which the granular material can flow out of the silo. The flow is stimulated by introducing oscillations into the silo / blade system.

[0007] Subsequently or during the layer application, selective curing is performed by liquid application and / or exposure to radiation.In many cases, in order to ensure print quality, the distance of the mobile printing device to the current layer plane must be as constant as possible.

[0008] After printing, the part typically resides in a build container. In most cases, this container forms a cuboid volume. This volume can have a variety of geometries to efficiently utilize the machine.

[0009] Some prior art printers have a build container that is removable from the machine and is also known as a work box or build container. These containers act as a boundary for the powder, thereby stabilizing the build process. Replacing the build container allows process steps to be performed in parallel, thus effectively utilizing the machine. Other machines print on a platform that can be removed from the machine, similar to the build container. Methods are also known that print on a continuous conveyor belt at an angle. These machine features make the build process more economical and help reduce downtime. However, a drawback of well-known 3D printers is that significant downtime means low utilization.

[0010] 3D printing based on powdered materials and the introduction of liquid binders is the fastest method of layer-building technology. This method allows the processing of different granular materials, including - as a non-exhaustive example - natural biomaterials, polymeric plastic materials, metals, ceramics and sand.

[0011] On the other hand, the build site plane is determined by the coating blade in contact with the powder and the traverse axis of the coating blade.

[0012] Now, if one or more components (coating blade, print head or radiation source) are replaced, either the spare part and its receiver must be precisely manufactured to restore the required parallel alignment, or one of the two elements must have a device that allows them to be adjusted to each other.

[0013] Often, machine components or spare parts are not manufactured with sufficient precision to meet these requirements. Therefore, replacing one of these components requires shutting down the machine for the duration of the replacement and readjustment. Depending on the machine type, this can require several hours of downtime. Furthermore, this work must be performed directly at the machine by experienced technicians.

[0014] The aforementioned downtime of a 3D printer is a clear economic disadvantage, especially for 3D printers or production lines designed to achieve high production volumes, where the aforementioned downtime is problematic and even inconsistent with the desired production targets.

[0015] Furthermore, in many cases, 3D printers cannot be integrated into series production because they require excessive downtime for maintenance work, which slows down other production steps.

[0016] It is therefore an object of the present invention to provide an apparatus with which a maximum output of printed parts can be achieved with a high degree of automation while minimizing downtime.

[0017] Another object of the present application is to provide a device that enables a high degree of automation and preferably online quality control. Summary of the Invention

[0018] The present disclosure relates to an apparatus for forming a molded article layer by layer from a granular material, comprising

[0019] At least one processing unit, which can preferably be automatically guided to and installed in the device and comprises a printing unit and a coater with a dynamic filling system; and / or an automatic feeder for building containers; and an adjustment device for an offline preparation process unit.

[0020] On the one hand, the present disclosure relates to an apparatus for forming a molded article layer by layer from a granular material, and the apparatus comprises at least one processing unit that can be directed to and installed in the apparatus, the processing unit comprising a printing unit and a coating system, and an adjustment device for an offline preparation process unit.

[0021] In one aspect, the present disclosure relates to an apparatus for forming a molded article layer by layer from a particulate material, and the apparatus includes at least one processing unit that can be guided to and installed in the apparatus, the processing unit including a printing unit and a coating system, and a digital camera, a line scan camera, or an infrared camera that can be moved with the processing unit for measuring the temperature of a build site and / or printing an image.

[0022] Preferably, the device according to the invention comprises a thermal sensor for measuring the temperature of the building site, such as an infrared camera, and optionally an air conditioner. According to a preferred embodiment, the thermal sensor may be connected to the air conditioner, preferably via a control and processing unit.

[0023] According to a particularly preferred embodiment, a line sensor is arranged in the region between the coater unit and the printing unit.

[0024] Preferably, the line sensor is connected to a further process and control unit so that process factors can be corrected directly based on the measurements of the line sensor, preferably in closed loop mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic front view of an apparatus according to a preferred embodiment of the present invention is shown.

[0026] Figure 2 A cross section of a processing unit according to another preferred embodiment of the present invention is shown.

[0027] Figure 3 Shown according to Figure 2 A top view of a processing unit;

[0028] Figure 4A front view of an adjusting device according to another preferred embodiment of the present invention is shown.

[0029] Figure 5 A front view of a transport box according to another preferred embodiment of the present invention is shown.

[0030] Figure 6 shows a schematic diagram of a removal aid according to a preferred embodiment;

[0031] Figure 7 A coating machine and a feed container according to a preferred embodiment of the present invention are shown, and

[0032] Figure 8 A top view (a) and a front view (b) of a build container feeder (job box feeder) according to a preferred embodiment are shown.

[0033] Reference Signs List

[0034] Figure 1

[0035] 1.1 Rack (1)

[0036] 1.2 Z axis (2)

[0037] 1.3 Building a container / job box (3)

[0038] 1.4 Traverse axis (4)

[0039] 1.5 Processing Unit (5)

[0040] 1.6 Housing (6)

[0041] 1.7 Air Conditioning (7)

[0042] 1.8 Infrared Camera (8)

[0043] 1.9 Building the Site (9)

[0044] 1.10 Suction device

[0045] 1.11 Feed container (11)

[0046] Figure 2

[0047] 2.1 Mounting plate (1)

[0048] 2.2 Coating machine unit (2)

[0049] 2.3 Vacuum closure (3)

[0050] 2.4 Infrared radiators (4)

[0051] 2.5 Water-cooled IR (5)

[0052] 2.6 Print Head (6)

[0053] 2.7 Line Scan Camera (7)

[0054] Figure 3

[0055] 3.1 Mounting plate (1)

[0056] 3.2 Coating machine unit (2)

[0057] 3.3 Vacuum closure (3)

[0058] 3.4 Infrared radiators (4)

[0059] 3.5 Water-cooled IR (5)

[0060] 3.6 Print Head (6)

[0061] 3.7 Line Scan Camera (7)

[0062] 3.8 Horizontal offset (8)

[0063] 3.9 Horizontal offset actuator (9)

[0064] 3.10 Quick clamping system (10)

[0065] 4.1 Base frame (1)

[0066] 4.2 Processing Unit (2)

[0067] 4.2 Quick release closure (3)

[0068] 4.4 XY guide system (4)

[0069] 4.5 Measuring equipment (5)

[0070] 4.6 Printhead closure (6)

[0071] 4.7 Control panel with display of measurement data (7)

[0072] Figure 5

[0073] 5.1 Base frame (1)

[0074] 5.2 Processing Unit (2)

[0075] 5.3 Quick release closure (3)

[0076] 5.4 Cover (4)

[0077] 5.5 Lock (5)

[0078] 5.6 Print head closure (6)

[0079] Figure 6

[0080] 6.1 Base frame (1)

[0081] 6.2 Processing Unit (2)

[0082] 6.3 Quick release closures (3)

[0083] 6.4 Cover (4)

[0084] 6.5 Removing auxiliary parts

[0085] 6.6 Guide elements (6)

[0086] 6.7 Transport lock (7)

[0087] Figure 7

[0088] 7.1 Coating machine hopper (1)

[0089] 7.2 Coating machine (2)

[0090] 7.3 Vacuum closures (3)

[0091] 7.4 Infrared radiators (4)

[0092] 7.5 Water-cooled IR (5)

[0093] 7.6 Print Head (6)

[0094] 7.7 Line Scan Camera (7)

[0095] 7.8 Granular material feeding (8)

[0096] 7.9 Suction opening (9)

[0097] 7.10 Suction device (10)

[0098] 7.11 Feed container (11)

[0099] 7.12 Feed container fasteners (12)

[0100] 7.13 Suction device closure (13)

[0101] Figure 8

[0102] 8.1 Rack (1)

[0103] 8.2 Z axis (2)

[0104] 8.3 Building a container (3)

[0105] 8.4 Support rollers (4)

[0106] 8.5 Traction device (5)

[0107] 8.6 Feed drive

[0108] 8.7 Traction device bracket (7)

[0109] 8.8 Building a container scaffold (8)

[0110] 8.9 Roller conveyor section (9). DETAILED DESCRIPTION

[0111] In the following, several terms will be defined more precisely. Otherwise, the terms used shall have the meanings known to those skilled in the art.

[0112] In the sense of the present disclosure, “layer building methods” or “3D printing methods”, respectively, are all methods known from the prior art which are able to build three-dimensionally shaped parts and are compatible with the process components and devices described further herein.

[0113] As used in this disclosure, "binder jetting" refers to applying a powder layer to a build platform, printing one or more liquids across a cross-section of a part on this powder layer, changing the position of the build platform by one layer thickness relative to its previous position, and repeating these steps until the part is complete. In this context, binder jetting also refers to layer build methods that require further processing of the component, such as layer-by-layer exposure using infrared or ultraviolet radiation, and a process also known as high-speed sintering.

[0114] In the sense of the present disclosure, “molding” or “part” or “3D molding” or “3D part” refers to all three-dimensional objects that are produced by a 3D printing method and exhibit dimensional stability.

[0115] As used herein, a "3D printer" or "printer" refers to a device capable of performing a 3D printing process. A 3D printer, as defined herein, includes a device for applying a build material, such as a fluid containing particulate material, and a curing unit, such as a print head or an energy input device, such as a laser or a heating lamp. Depending on the specific requirements, other machine components known to those skilled in the art and components known in 3D printing may be combined with the aforementioned machine components in individual cases.

[0116] A "build field" is a plane or, more broadly, a geometric location on or in which a bed of particulate material thickens during a build process of repeated coating with particulate material. The build field is frequently bounded by a bottom, the "build platform," walls, and an open overhead space, the build plane.

[0117] As used in this disclosure, a "process unit" or "functional unit" refers to a device or component that can achieve the coating and selective curing process results; this may include a coater, a print head, a nozzle, a laser unit, a heat source, a UV light source or / and further layer processing devices.

[0118] The process of "printing" or "3D printing" in the sense of the present disclosure summarizes the operations of material application, selective curing or imprinting, and working height adjustment, and is performed in an open or closed processing chamber.

[0119] A "receiving surface" in the sense of the present invention is a surface onto which the building material is applied. According to the present disclosure, the receiving surface is always freely accessible in one spatial direction by a linear movement.

[0120] For the purposes of this invention, a "traverse axis" is an axis that carries a processing unit or allows production along a processing unit, is located above the build site tool, and has a long travel distance compared to other axes in the system. The "traverse axis" can also indicate, for example, the direction in which the build site tool is synchronized and can be coordinated with other system components. The print head can also move on the "traverse axis."

[0121] In the sense of the present disclosure, a "build site tool" or "functional unit" is any device or device component used for fluid application, such as granular materials, and selective curing in the production of molded articles. Therefore, all material application devices and layer handling devices are also build site tools or functional units.

[0122] According to the present disclosure, "distribution" refers to any manner in which particulate material is distributed. For example, a larger amount of powder can be placed at the beginning of a coating pass and can be distributed or spread into the layer volume by blades or rotating rollers.

[0123] As "building material" or "granular material" or "powder" in the sense of the present disclosure, all flowable materials known for 3D printing can be used, in particular flowable materials in the form of powders, slurries or liquids. These flowable materials may include, for example, sand, ceramic powder, glass powder and other inorganic or organic material powders, such as metal powders, plastic materials, wood particles, fiber materials, cellulose and / or lactose powders, as well as other types of organic, powdery materials. The granular material is preferably a free-flowing powder when dry, but sticky, cut-resistant powders can also be used. This cohesiveness can also be due to the addition of an adhesive material or an auxiliary material, such as a liquid. The addition of a liquid can cause the granular material to flow freely in the form of a slurry. Synthetic resins such as epoxides or acrylates can also be regarded as building materials in the sense of the present disclosure. In general, granular materials can also be referred to as fluids in the sense of the present disclosure.

[0124] "Overfeed" or "overfeed" is the amount of particulate material that is pushed along the front of the coater during the coating pass at the end of the build site.

[0125] As used in this disclosure, a "coater" or "material application device" refers to a device for applying a fluid to a build site. The unit may consist of a fluid reservoir and a fluid application unit. According to the invention, the fluid application unit comprises a fluid outlet and a "coating knife device". The coating knife device may be a coating blade. However, any other conceivable, suitable coating knife device may be used. For example, a rotating roller or a nozzle is also conceivable. The material can be fed in a free-flowing manner from a reservoir or by an extruder screw, pressurization or other material conveying device. Coating machines with one material outlet or two material outlets in opposite directions can be used. Blades can be attached to the material outlets to apply the material. These can be controlled by generating oscillations, so that the outlet can be controlled by bridges or material cone formation in the powder material, or the bridges or material cone formation can be broken and controlled by blowing in gas, such as circulating air. The coater can be combined with a print head arranged transversely thereto, so that coating can be carried out in both directions and then adhesive application can be carried out in both directions during the pass. Such a device may also be combined with cameras, preferably digital cameras, line scan cameras or IR cameras arranged on both sides for measuring the temperature of the build site and / or printing images. The coater may be part of the processing unit.

[0126] A "print head" or device for selective curing within the meaning of this disclosure generally consists of various components. These components can include a print module. The print module has a large number of nozzles from which the "adhesive" is ejected in a controlled manner as droplets onto the build surface. The print module is aligned with the print head. The print head is aligned with the machine. This allows the positions of the nozzles to be assigned to the machine coordinate system. The plane on which the nozzles reside is often called the nozzle plate. Another means of selective curing can also be one or more lasers or other radiation sources or heat lamps. Arrays of such radiation sources, such as laser diode arrays, are also conceivable. Within the meaning of this disclosure, it is possible to implement selectivity separately from the curing reaction. Thus, a print head or one or more lasers can be used to selectively process a layer, while other layer processing devices can be used to initiate the curing process. An example of this is printing on a layer with a UV-reactive resin, followed by curing with a UV light source. In another embodiment, an IR absorber is printed on a particulate material and then cured with an IR source. The print head can be part of the processing unit.

[0127] A "layer manipulation device," within the meaning of this disclosure, refers to any device suitable for achieving a certain effect in a layer. This can be the aforementioned units, such as print heads or lasers, but also IR emitters or other forms of heat sources, or other radiation sources, such as UV emitters. Means for deionizing or ionizing the layer are also conceivable. All layer manipulation devices have in common that their area of action is linearly distributed over the layer, and like other layering units, such as print heads or coaters, they must be guided through the build site to reach the entire layer.

[0128] “Actuators” in the sense of the present disclosure are all technical devices which are suitable for triggering a movement of layer handling devices relative to one another within an exchangeable functional unit or for carrying out a movement of individual components or assemblies within a layer handling device.

[0129] As used in the disclosed apparatus, a "receptacle" refers to an area on a 3D printer where a replaceable functional unit is inserted into or removed from the 3D printer for replacement. The receptacle may be open or closed by a suitable means (e.g., a closure or a reclosable flap). Opening and closing may be achieved by separate controls; alternatively, the closure may be automatically opened and reclosed by retracting and extending the replaceable functional unit. The receptacle may also have a barrier, such as a slit film or bristles, through which the replaceable functional unit can be pushed.

[0130] A "suitable receiving device" within the meaning of the present disclosure is a device arranged at a target location that facilitates the positioning and proper functioning of the replaceable functional unit at the target location. Therefore, the positional tolerances of the replaceable functional unit within the 3D printer are defined by the suitable receiving device, and thus the positional tolerances of the layer processing device are also defined by the build site.

[0131] A "connection device" within the meaning of the present disclosure may be a guide rail, a frame, or other component by which the functional units of the replaceable functional unit are interconnected and arranged in their three dimensions, and may optionally also be used to support the retraction and extension of the replaceable functional unit into the 3D printer. In a specific embodiment, the functional units may also be directly connected to each other, and furthermore, the device for retracting and extending the replaceable functional unit may be attached to the replaceable functional unit. Preferably, the connection device is designed to allow easy access to the individual functional units for adjusting their position or replacing them.

[0132] A "closing device" within the meaning of the present disclosure is any device for closing a socket of an exchangeable functional unit, for example a flap, a door, a slide, a row of brushes or the like.

[0133] "Supply" within the meaning of this disclosure refers to the supply of energy, building materials, or other media, such as compressed air or cooling water, to the individual functional units. The supply is preferably configured for quick coupling by suitable means. Coupling preferably occurs at a common coupling point in the form of a coupling strip or coupling block. The supply can preferably be coupled without additional manual interaction, for example, simply by moving it in and out.

[0134] For the purposes of this disclosure, “presetting” means the positional alignment of the functional units contained in the replaceable functional units, so that simply moving them to the target position, using the fixtures and establishing the medium supply is sufficient to put the 3D printer back into operation immediately after such movement, without requiring any adjustment or readjustment of the replaceable functional units or any settings.

[0135] A “target position” in the sense of the present disclosure is the position in the 3D printer into which the replaceable functional unit is inserted and at which the replaceable functional unit is preferably fixed by a fixing device.

[0136] As used herein, the term "removal position" refers to the position in a 3D printer where a functional unit must be located in order for it to be extended from the machine. Therefore, the 3D printer's controls include instructions that, upon receipt of these instructions, cause the replaceable functional unit to approach the removal position with sufficient precision. Advantageously, this position is above the build site. More advantageously, the removal position is approximately midway above the build site. The two possible end positions for the replaceable functional unit are not suitable because the maintenance unit for the build site tool is typically located at these end positions and could be damaged when retracted or extended. When exchanging functional units, the build site tool should preferably not be engaged with the current layer. For example, this can be achieved by lowering the build platform an appropriate amount beforehand to ensure that the build site tool does not engage with the current layer. This procedure can also be stored in the control system so that lowering the build platform and moving to the removal position occur as a combined sequence to prepare for the replacement of the functional unit.

[0137] The term "processing unit" as used in this disclosure refers to a combination of several layer application devices, layer processing devices, and print heads. Preferably, the processing unit consists of a central print head that is as wide as the build area and has a print head traversing axis, flanked by two coaters or layer application devices and associated hoppers for feeding granular material. Subsequently, further layer processing devices, for example, in the form of infrared radiators, are installed. In addition, other inspection devices, such as line scan cameras, can be located on the processing unit. The processing unit has a self-supporting structure and can be separated from the machine by suitable coupling devices.

[0138] As used in this disclosure, a "coupling point" is a location in a machine where the processing unit is most easily removed from the machine. For example, this may be a central location where the processing unit can be removed sideways or upwards.

[0139] "Application unit" or "layer application unit" refers to the combination of a coater and a hopper.

[0140] A “zero-point clamp” in the sense of the present disclosure is a clamping device which reproducibly and precisely positions the respective material to be clamped.

[0141] For quality assurance purposes, it is important to record each processed layer optically, for example using a line scan camera, and to be able to evaluate it using special software. For example, if there is a corresponding contrast between the printed and unprinted granular material, it can be determined whether the printing process was carried out correctly. In prior art 3D printers, a digital camera with a suitable lens is usually sufficient for this purpose. For example, the camera is hung in a corner of the build volume, pointed at the build site. However, in an embodiment according to the present invention, the processing unit obscures each layer, making it impossible to clearly see the printed granular material. Instead, after each pass of the processing unit, a printed layer is covered with a new layer of granular material.

[0142] To still obtain evaluable images, a so-called line scan camera can be used. This is a digital camera whose pixels are arranged only in a thin, elongated pattern, that is, distributed across the entire width of the build site. A two-dimensional image is created only as the camera moves across the image to be recorded, and the recorded points are stored along with the corresponding position of the line scan camera. The advantage of this approach is that the camera requires very little space and can be easily integrated into the processing unit after the print head. Preferably, the processing unit then has two line scan cameras mounted to the left and right of the print head, enabling recording of each layer. However, without limiting its generality, other camera systems, for example with suitable optics for recording images between the print head and the coater, can also be used. In this case, the system also preferably has at least two camera systems, each recording its image to the left and right of the print head, or one camera recording images to the left and right of the print head with appropriate optics. When using a conventional camera with a two-dimensional image field, as with a line scan camera, the complete layer image is generated by combining multiple individual images, recorded as the processing unit moves across the build site.

[0143] The term "offset axis" as used in this disclosure refers to a device for moving the print head transversely to the printing direction. To prevent weak or malfunctioning nozzles on the print head from overlapping, it is advantageous to move the print head by a certain amount, preferably a different amount, before each print run. This is accomplished using an offset axis. To achieve high-quality printed images, the offset axis must be sufficiently precise and have a good resolution. Typically, the resolution of the transverse movement should be at least half the printing resolution. The positioning accuracy of the offset axis should be even higher. A combination of linear guides and ball screws with a servo motor is suitable for this task.

[0144] All application units, including the print head, require regular cleaning. This cleaning can be done passively, for example with a fixed brush. However, cleaning devices can also actively perform the cleaning process using their own motion mechanism.

[0145] In one aspect, the present disclosure relates to an apparatus for forming a molded article layer by layer from a particulate material, comprising

[0146] at least one processing unit, which can be preferably automatically guided to and installed in the device and which comprises a printing unit and a coating machine with a dynamic filling system;

[0147] an automatic feeder for building containers; and

[0148] An adjustment device is used to prepare the processing unit offline.

[0149] In another aspect, the present disclosure relates to an apparatus for forming a molded article layer by layer from a particulate material, comprising

[0150] At least one processing unit, which can be guided to and installed in the device, comprises a printing unit and a coating system, and a digital camera, a line camera or an infrared camera, which can be moved together with the processing unit, for measuring the temperature of the building site and / or printing an image.

[0151] Adjustment devices are also provided for offline preparation of the processing unit, particularly to minimize downtime of the device during production operation. Therefore, it is recommended to adjust the processing unit offline in a specially designed device. For example, such a device can be equipped with an integrated measuring device, which allows the processing unit to be set up, measured, and, if necessary, readjusted in a simulated machine installation. To this end, the adjustment device can, for example, be equipped with suitable guide elements, preferably with a flatness of + / - 0.02 mm over the entire traversing range, preferably approximately 1 m x 1.5 m, to move the measuring head in the X and Y directions along the processing unit. Ideally, the measuring head is an electronic device so that the measurement data can be automatically entered into a logbook.

[0152] Preferably, the device according to the invention comprises a thermal sensor for measuring the temperature of the construction site, such as an infrared camera, and optionally an air conditioner or a heat source, such as an infrared radiator. According to a preferred embodiment, the thermal sensor can be connected to the air conditioner and / or the heat source, preferably via a control and processing unit.

[0153] Since thermal management often plays a decisive role in part quality during 3D printing, a preferred embodiment recommends equipping the device according to the invention with an IR sensor, such as an IR camera system, to continuously monitor the build site temperature. If this sensor is then connected to an air conditioner via a processing unit and a control unit, online closed-loop thermal management is possible.

[0154] According to a particularly preferred embodiment, a line sensor is arranged in the region between the coater unit and the printing unit.

[0155] Preferably, the line sensor is connected to a further processing unit and a control unit so that process factors can be corrected directly based on the measurements of the line sensor, preferably in closed loop mode.

[0156] A major drawback of existing systems on the market is that the print result is only visible at the end of the printing operation, when the job box is opened. Since this can sometimes take several hours, a lot of valuable time is wasted. Newer systems already use common camera systems to check the printed image after each layer is completed.

[0157] This technology cannot be used, especially not in bidirectional operation. Therefore, it was recommended to install a sensor between the print head and the coater so that the printed image can be checked in situ even in bidirectional operation. To this end, a line scan camera was integrated between the print head and the left and right coaters, respectively. These cameras were then equipped with specially adapted software. This software then compares the actual printed image with the target image, thus indicating any faults to the operator at an early stage. The operator can then decide whether to abort the print or allow it to continue to the end. Furthermore, if multiple parts are being printed simultaneously, the machine operator can single out individual parts that may display a noticeable image.

[0158] According to the invention, downtimes etc. can now be reduced, since, for example, the use of a handling unit for replacement can also provide assistance which allows a rapid replacement of the device and can put the device back into operation within a short time.

[0159] The device according to the present invention advantageously reduces or avoids downtime of a 3D printer due to maintenance work or the necessary replacement of parts or functional components susceptible to wear. This increases machine operating time and makes it possible to integrate one or more 3D printers into other production systems, for example in mass production, such as automotive manufacturing.

[0160] The present invention thus enables for the first time the integration of a 3D printer into a substantially fully automated production process.

[0161] Previously, some 3D-printed parts had to be produced in advance, and under certain conditions, these parts could be a time-limiting factor in other production processes. In addition, storage and delivery involved organizational effort and costs.

[0162] The present invention can produce 3D molded parts directly on site and integrate them into other semi-automatic or fully automated manufacturing processes. This can simplify complex manufacturing processes.

[0163] Thus, the present invention advantageously facilitates further automation of the 3D printing process itself, as well as other manufacturing processes and types of mass production using 3D printing processes.

[0164] This 3D printer has the above advantages and also achieves the purpose of this application.

[0165] Furthermore, the 3D printing apparatus disclosed herein may include a receptacle having a closure device, wherein the closure device may be opened or closed or opened or passed through by the processing unit during retraction and extension.

[0166] On the other hand, the present disclosure relates to a method for retracting and / or extending (i.e., changing or replacing) a replaceable processing unit as described above into a 3D printing device, wherein the processing unit is optionally moved to the 3D printing device by a lifting device, optionally a crane, a lifting platform or a lifting trolley, the processing unit is inserted into a socket, positioned at a target position in the 3D printing device and fixed by one or more fixing devices.

[0167] This method makes it possible for the first time to replace multiple processing units simply and quickly, without requiring complex adjustment work on the machine itself during the replacement and without the associated disadvantages described. Advantageously, a replaceable processing unit comprising a plurality of pre-adjusted functional units is used, thereby eliminating the need for complex and time-consuming adjustment work on the machine itself.

[0168] Other aspects of the present disclosure will be described below.

[0169] In a well-known 3D printer, the print head and coating blade are essential wear parts. In addition, depending on the process, there is also an exposure unit and / or radiation unit.

[0170] To achieve good printing results, these units must be aligned with each other within a certain framework. The coater defines the spatial position of the layer plane, and the print head should maintain the most constant distance from the layer plane.

[0171] If individual components are replaced, they must be adjusted to the corresponding other components according to the individual configuration. Due to the different machine sizes, the manufacturing precision between the parts is often not sufficient to achieve the desired result without adjustments.

[0172] Adjusting a machine can also be a complex task, as it occurs in a confined space and is difficult to access. Furthermore, the machine may need to be placed in a special safety setup mode to allow operators to operate these units. After all, the machine may contain process media, and setup personnel must be protected from these media.

[0173] A coater is a device used to dispense a fluid medium, such as granular material, resin, slurry or paste, in a defined form onto a substrate so as to form a flat layer of such medium of a predetermined thickness. Coating machines can be used to apply powdered / granular materials.

[0174] For example, the coating machine can be configured as a roller that rotates in a direction opposite to the coating direction. A reservoir of particulate material can be added to the roller. For example, the reservoir can meter particulate material in front of the roller in a controlled manner via a rotary feeder.

[0175] Another embodiment relates to an oscillating coater having an oscillatingly suspended powder reservoir and a gap in the lower region of the side of the powder reservoir facing the coating direction, the gap being as wide as the build surface. The coater also includes a drive that oscillates the reservoir, causing powder to drip out of the gap.

[0176] On the one hand, an inkjet-type device can be used as the print head, but it is also conceivable to use a selective exposure unit, such as a laser, a projector, or a mirror, by which the selective radiation is projected onto the build field. Alternatively, other devices can be used to transfer the information, such as toners or transfer rollers known from laser printers or offset printing.

[0177] Furthermore, it is possible to attach other units, such as exposure units, which act similarly to a coater across the entire width of the unit. These exposure units can emit energy, for example in the UV range, but also in the thermal radiation range, onto the build site. It is also conceivable to attach drying units, which operate, for example, by supplying and removing hot air.

[0178] However, in addition to these components in the exchangeable process unit, it is also conceivable that the exchangeable process unit consists of a combination of a plurality of coaters, one or more print heads and a plurality of radiation units.

[0179] In the machine itself, the traverse axes are mounted so that they can easily pick up the replaceable process units and move them across the build site. Preferably, only one pair of axes is required for this, which are parallel to the coating direction and positioned transversely relative to the build site.

[0180] In one embodiment, the replaceable processing unit moves from one inverted position to another and produces a fully processed layer during this movement.

[0181] The machine may also have a maintenance unit that affects the replaceable process unit components and also requires access to the maintenance unit from time to time. This can be, for example, a print head cleaning station and / or a coater cleaning station. In an alternative embodiment, such a maintenance unit can also be mounted on and replaced with the replaceable process unit.

[0182] The machine also has a unit for supplying media, such as granular material, ink and energy, to the exchangeable process units.

[0183] The machine has a rectangular build field. It has been found that in the binder jet 3D printing process and apparatus employed herein, in accordance with the present disclosure and within the body of the present disclosure, a rectangular build field is advantageous over a square or other shaped build field. In this way, the output of the applicator can be advantageously optimized.

[0184] In one aspect, the build site has a short side and a long side. The application device moves across the build site along the short side. For example, the short side is between 0.3 and 2.5 m long, such as between 0.5 and 1.5 m long. For example, the long side is 1.2 to 4 times the length of the short side, more preferably 1.2 to 2.5 times the length of the short side.

[0185] Along the two short sides, there are devices that guide the application unit across the build site at a predetermined distance and speed. Linear axes are particularly suitable for this purpose. These can be driven by belts and servo motors to guide the application unit across the build site. However, linear axes with spindle drives or linear motors can also be used. The drives of the two axes can be synchronized via a connecting axis or through electrical coupling of individual electric drives on the two axes.

[0186] The drive must be able to move the application tool across the build site at a uniform travel speed of 0.2 - 2 m / s.

[0187] The linear axis has a coupling point on which the application unit, which is integrated in the so-called handling unit, is placed. The coupling point is designed to allow the handling unit to be quickly replaced and brought back to the appropriate position without further adjustment steps.

[0188] The coupling point can be designed using a combination of so-called zero-point fixtures.

[0189] The processing unit has an application unit for the granular material and one or more fluids. In addition, the processing unit also has other layer processing means, such as a radiation source or a fumigant, and an inspection unit, such as a line scan camera.

[0190] The processing unit is preferably symmetrical and has one or more printheads in the center. It preferably has one to two printheads. One printhead is designed to span the entire long side of the build site and print the fluid in a suitable pattern along the entire long side in a single pass. The printhead is a so-called drop-on-demand printing unit with a large number of individually controllable nozzles. The printhead resolution is typically 90-2000 dpi, advantageously 150-1200 dpi.

[0191] The printhead(s) have one or more fluid lines. They also have electrical contacts for transmitting data and control voltages, as well as lines for generating positive or negative pressure at the nozzles. All supply and drain lines on the printhead(s) are preferably designed to connect directly to or close to the printhead.

[0192] The print heads have a holder that allows the position of the print heads towards the build site in a suitable manner and the height of one or more print heads above the build site to be adjusted and fixed.

[0193] Furthermore, one or more print heads are mounted on a so-called offset axis, which allows the print head to be moved laterally in the direction of the long side of the build area. The axis is designed to move the print head by at least one nozzle width, preferably 50 to 200 nozzle widths.

[0194] Before each print run, the displacement of the print head is activated in a suitable manner to prevent individual nozzles from overlapping in the layer structure. This can be used to compensate for defective nozzles.

[0195] Spindle drives with servo motors are particularly suitable as offset axes. However, linear motors are also suitable.

[0196] Either side of the print head is provided an application device or coater for applying a layer of particulate material.

[0197] The granular material is preferably fed into the printer from above. The granular material can be stored in a silo or supplied continuously, with the granular material supply located essentially outside the machine. The granular material is transported from outside the machine to the printer via conveyor technology. Screw conveyors, screws, or systems based on positive or negative pressure are particularly suitable for this task. The material is then temporarily stored in a feed container. The feed container also serves to distribute the material across the entire width of the coater. Ultimately, the feed container is an elongated silo whose length roughly corresponds to the coater's width. The width of the feed container typically matches the width of the coater hopper. At least in the lower outlet area, the width of the feed container should be smaller than the width of the coater hopper. The height of the feed container must be designed to provide sufficient granular material for multiple coating passes, even at the edges. Even more advantageously, there should be enough granular material to completely fill the coater hopper. Distribution of the granular material in the feed container can be accomplished using a material cone, but this requires a higher container height. Alternatively, a distribution device located above the container, such as a screw or helical screw, can be used to distribute the granular material along its length. The feed container has a closable discharge opening in its lower part. This opening is designed to extend into the coater hopper and to convey the granular material to the coater hopper. Preferably, the closing mechanism on the feed container is designed so that the coater hopper is always filled to the same level, regardless of the filling state of the coater hopper before refilling. Different concepts can be considered for this purpose. One possible solution is a sliding mechanism with a series of openings and webs and a fixed counterpart of identical shape. If the moving part is moved relative to the fixed part so that the openings overlap, the granular material flows out. On the other hand, if the mechanism is moved so that the openings overlap the webs in each case, no granular material can flow out.

[0198] Another embodiment of a suitable closure element comprises a flap extending along the length of the feed container and suspended at each narrow side via a corresponding pivot point. A suitable flap is, for example, a pipe segment, wherein the pivot point advantageously coincides with the center of the pipe cross section. Such a flap can be easily operated, for example, by means of an operating lever or a pneumatic cylinder.

[0199] If the feed container is positioned above the hopper and the flap is open, granular material flows from the feed container into the hopper until a material cone forms at the transition from the feed container to the hopper and the flow of granular material stops. If the sand plate is subsequently actuated, it separates the material cone and closes the feed container. The hopper is then filled evenly across its entire width.

[0200] The granular material in the hopper is fed into the coater during the coating process. This is done passively by simply draining the water, or actively, for example, by a rotary feeder at the lower end of the hopper. There are various embodiments of the coater. One possible embodiment comprises rollers which extend in a rectangular manner transversely to the coating direction and which operate in a direction opposite to the coating direction. A more advantageous embodiment comprises a slot coater which in turn consists of an elongated container which can receive the granular material. The container is suspended in such a way that it can perform an oscillating movement about a longitudinal axis and the oscillations are caused by a drive. The lower part of the container has a slit-shaped discharge opening for the granular material which extends in the direction of the longitudinal axis. The opening can point downwards towards the building site or laterally towards the building site. The granular material then flows to the building site during the oscillating operation.

[0201] In addition to the closing mechanism for the feed container, there is also an advantageous device for extracting any dust that may form during the movement of the granular material into the hopper. Such a device can consist of a slotted tube to which negative pressure is applied, for example, by a suction device. This negative pressure serves to extract particles that are suspended or slowly sinking in the atmosphere of the build space. This tube is preferably guided along the width of each of the two feed containers.

[0202] The coater filling the hopper is preferably located above the discharge hopper. The discharge hopper is a container located below the build plane, to the side of the build area, and has an opening in the build plane that is at least as wide as the build area, but preferably slightly wider. The discharge hopper receives excess granular material, such as that located in front of the coater after a coating pass. Any granular material that overflows from the coater during the filling of the hopper or from the two containers, which may be scraped off at the end of the filling, also ends up in the discharge hopper.

[0203] In the apparatus according to the invention, two discharge hoppers can be provided on either side of the construction site in the longitudinal direction. These discharge hoppers can have a funnel-like shape to facilitate discharge. Thus, at the lowest point of the hopper, granular material can be collected in such a way that it can be easily transported away by a pneumatic conveyor or a feed screw or spiral conveyor.

[0204] In addition to the two openings for the discharge hopper, there are two more openings on the left and right sides of the build plane. These additional openings are designed to accommodate cleaning stations for the coater and the print head, respectively. Since particulate material can escape from the coater during the cleaning process, potentially negatively impacting the print head cleaning process, it's beneficial to spatially separate these two functions. This also facilitates the use of different cleaning media. For example, the coater can be cleaned dry using compressed air or a brush guided along or over the coater. Other cleaning mechanisms are also conceivable, such as a wiping unit or doctor blade with a moist carrier medium. In each case, the cleaning device can be passive or active. Passive means that the relative movement between the cleaning medium and coater is initiated by the active movement of the coater. Active means that the coater is stationary while the cleaning device moves relative to it. Combinations of passive and active cleaning, or different cleaning mechanisms, are also conceivable. Alternatively, the print head can be cleaned using a liquid cleaning medium guided along the metering side of the print head, for example, using a brush, a wiping lip, an absorbent wiping lip, or a sponge roller. In both cleaning situations, it makes sense to place the cleaning equipment outside so that it is easily accessible to the operator who needs access to check the function of the cleaning equipment or to perform regular maintenance and cleaning.

[0205] The printhead itself consists of multiple print modules, each with a limited number of nozzles. After applying an appropriate electrical signal, these print modules typically eject individual droplets of liquid binder from their nozzles with the help of piezoelectric actuators. The nozzle diameter is typically 10 µm to 100 µm. The print modules are inserted individually or in small groups into a so-called printhead holder. It is important to ensure that the print modules in the printhead holder are aligned with each other so that the nozzles of all modules are, if possible, the same distance apart transversely to the printing direction. In an embodiment according to the present invention, the printhead holder extends along the entire length of the build site and extends a short distance beyond. This distance is used to move the printhead a certain amount after each pass transversely to the printing direction. This displacement prevents malfunctioning nozzles from overlapping during multi-layer printing.

[0206] The print head holder has a suitable receptacle for the print module and is designed to support the weight of the module and at least its own weight so that the print head sags only a few tenths of a millimeter over its length.

[0207] Typically, the distance from the print head to the build site is 1-8 mm, more preferably 2-5 mm. To ensure that the printed image generated on the build site is as close as possible to the data model, this distance must be equal at every location on the build site if possible.

[0208] Above the print head carriage with the print module is a tank system that supplies liquid adhesive to the print module, as well as a circuit board that provides the necessary electrical signals to the print module.

[0209] In a preferred embodiment, the printhead carriage is designed to support all accessories and features means for positioning and securing them at both ends of the machine. The machine itself also features appropriate counterparts, as well as a mechanism for moving the printhead transversely to the printing direction. For example, this mechanism consists of a threaded spindle drive on one side of the printhead carriage and a plain bearing on the other. The spindle drive is operated by a servo motor with a flange-mounted speed sensor.

[0210] To accurately generate the print head signals, the machine features a linear scale, for example, parallel to one of the two guide systems used to move the processing unit. The probe of this linear scale is mounted at one of the coupling points on the linear axis and emits its signals as the processing unit moves. The modules that control the print heads respond to these signals. This ensures that the desired print image is correctly deposited across the entire build area, regardless of the processing unit's movement speed.

[0211] The machine or device comprises a build container, preferably a replaceable work box, containing a build platform. The work box is essentially a frame designed to prevent granular material from flowing off the build platform. Therefore, the build platform must be circumferentially sealed against the work box walls. The work box (including the build platform) must be designed to support the weight of the granular material after the entire job is completed. Depending on the build volume and the material, this can be several hundred kilograms. Another requirement is that even if the build platform moves downward during a build job, no, or at least minimal, granular material can flow downward between the work box walls and the build platform.

[0212] According to a preferred embodiment, the machine according to the invention has a system for converting work boxes to reduce the setup time between building jobs. This means that work boxes of the same type can be moved in and out of the machine alternately. To ensure that this happens without operator intervention, the work boxes are transported into the machine by a so-called feed system from a conveyor belt located in front of the machine. A suitable feed system that also allows the work boxes to be moved out is, for example, a chain conveyor system in the machine, which preferably engages with both sides of the work box and pulls the box into and out of the machine on pull-out tracks via transversely mounted guide rollers. Obviously, other principles such as cylinders, driven rollers, etc. are also suitable for achieving this purpose. For example, a conveyor system arranged in front of the machine and receiving the work boxes externally can have a driven roller conveyor on which the work boxes are located and allows the boxes to be moved in and out of the machine safely.

[0213] This conveyor system can be statically mounted in front of the machine or it can be a self-propelled transport system. The main advantage of a self-propelled transport system is that the space in front of the machine is only blocked during the unloading cycle.

[0214] The following paragraphs briefly describe the operation of the device according to the present invention.

[0215] In principle, the machine type described is suitable for all materials that can be processed using the binder jetting process. Examples include molding sand, plastics, ceramic powders, and metals. Furthermore, the machine can also be designed for so-called high-speed sintering. In this case, the system has suitable build-space heating and other equipment for sintering granular materials.

[0216] The device can be operated using various binder systems. These can be two-component or one-component systems. Without limiting their generality, suitable binders include furan resins, phenolic resins, acrylic resins, epoxides, and inorganic binders such as water glass. However, other solid binders can also be mixed into the powder and activated by a liquid. This includes, for example, hydraulic binders such as cement printed with an aqueous solution. However, other substances such as starch, sugar, etc. can also cause adhesion in the granular material. Other adhesion can be achieved at least by surface dissolution of the granular material. For example, certain alcohols or other solvents are suitable for this purpose.

[0217] In the preferred case, the machine uses molding sand and a binder commonly used in foundries, such as furan resin and water glass.

[0218] To this end, the machine is filled with granular material. The adhesive supply is filled with the appropriate adhesive, while the cleaning system is filled with the appropriate cleaning agent.

[0219] The processing unit first moves to the coater cleaning position, where it automatically cleans both coaters. It then moves to the printhead cleaning position, where it performs a printhead cleaning cycle. This may include several so-called purging or rinsing processes, a wiping process with cleaning fluid, and so-called spraying. Purging involves pressurizing the printhead adhesive reservoir to release adhesive into the nozzles. Spraying is understood as the process where all nozzles of the printhead are collectively controlled to generate a specific number of droplets.

[0220] An empty work box is then fed into the machine by pulling it into the machine. The Z axis automatically connects the build platform with the provided coupling and pushes it to the top position. The handling unit then moves to the filling position, where the feed container fills the corresponding hopper.

[0221] The processing unit then moves across the build site, discharging the granular material until it stops again at the opposite filling position. Here, another hopper is filled from the corresponding feed container, and the coating process is repeated. In this way, a so-called starting layer is created by passing through the build site multiple times without printing. This layer can consist of several layers and address different aspects. On the one hand, a build plane is created that is independent of the build platform position. On the other hand, the machine and build site must reach process temperature. Once this process is complete, the actual printing process can begin. This requires printing the data for the layers to be printed in the form of separate bitmaps. Typically, the 3D data of the part is broken down into its individual layers and converted into bitmaps before the print job is recorded on the preparation computer.

[0222] The processing unit then moves from one filling position to the next, depositing the fully processed layer. This means the build platform is lowered one layer at a time, and the processing unit then prints the previous layer with a binder, then applies a new layer of granular material and processes it, for example, with infrared radiation.

[0223] During the layer formation process, application units such as the coater and print head are cleaned regularly.

[0224] After the last layer is completed, the build platform can be lowered into the job box, which can then be transported out of the machine. In some cases, the completed print job can undergo further post-processing outside the machine, such as thermal curing.

[0225] Further embodiments of the present disclosure will be described below.

[0226] On the one hand, the present disclosure relates to a device for forming a molded article layer by layer from a granular material, comprising at least one processing unit that can be directed to and installed in the device, the processing unit comprising a printing unit and a coating system, and an adjustment device for an offline preparation process unit.

[0227] In another aspect, the present disclosure relates to an arrangement for forming a molded article layer by layer from a particulate material, comprising

[0228] At least one processing unit that can be guided to and installed in the device, the processing unit comprising a printing unit and a coating system, and a digital camera, a line camera or an infrared camera that can be moved together with the processing unit for measuring the temperature of the building site and / or measuring the printed image.

[0229] A preferred feature of the device according to the present disclosure is that it comprises a receiver for building the containers, the receiver comprising preferably an automatic feeder for building the containers.

[0230] A preferred feature of the device according to the present disclosure is that the coating system comprises a dynamic filling system.

[0231] A preferred feature of the device according to the present disclosure is that the device comprises an air conditioner, preferably wherein the control unit and / or the processing unit is connected to the air conditioner.

[0232] The device according to the invention is preferably characterized in that the line sensor is arranged in the area between the coater unit and the printing unit.

[0233] The device according to the invention is preferably characterized in that the line sensor is connected to a further process and / or control unit.

[0234] A preferred feature of the device according to the present disclosure is that the device comprises a bidirectional coater or two coaters, wherein a respective coater is provided for each coating direction.

[0235] A preferred feature of the device according to the invention is that the print head is arranged between the two coaters, or that the print heads are arranged or attached to both sides of a bidirectional coater, respectively.

[0236] A preferred feature of the apparatus according to the present invention is that the digital camera, the line scan camera or the infrared camera is arranged on the sides of the coater and the print head unit, respectively.

[0237] A preferred feature of the apparatus according to the present disclosure is that a digital camera, a line scan camera or an infrared camera is mounted in each of the forward and reverse directions of travel.

[0238] The present invention will be described below with reference to preferred exemplary embodiments shown in the accompanying drawings.

[0239] For example, in Figure 1 Examples of entire machines or entire systems according to the present disclosure are described in .

[0240] The basic components of the 3D printing system of the present disclosure are:

[0241] Rack (1.1)

[0242] Z axis (1.2)

[0243] Building a container (1.3)

[0244] Traverse axis (1.4)

[0245] Processing Unit (1.5)

[0246] Housing (1.6)

[0247] Air conditioning (1.7)

[0248] Suction device (1.10)

[0249] The following will refer to Figure 1-8Some example components and interactions of components according to the present disclosure are described in greater detail.

[0250] Examples of processing units, conditioning devices, coaters and feed containers according to the present disclosure are Figure 2 and Figure 7 Shown in.

[0251] For fully automated building operations, it is advantageous to equip the process unit (see FIG. 2 ) with a coater ( 2 . 2 , 7 . 7 ), which allows multi-layer building operations.

[0252] To fill the coating machines (2.7, 7.7), they are equipped with suitable feed containers (7.11). Suitable in this case means that during filling through the feed container (7.11), due to the distances involved and the cone-forming process, a hopper is provided to receive excess granular material that flows out of the feed container. In this case, the granular material (7.8) is fed via a horizontally arranged chain conveyor system. Since dust is typically generated during the filling process, the system is equipped with a preferably horizontal pipe machine directly at the filling point, which serves as a suction device (7.10). To this end, the pipe is provided with openings (7.9), such as holes or slots, at appropriate points. The suction flow can be adjusted accordingly using a suitable closure system (7.13).

[0253] An exemplary job box feeder (build container feeder) according to the present disclosure is Figure 8 Shown in.

[0254] To achieve the high degree of automation already described, a work container feeder must be designed that interacts with the system linkage (roller conveyor segment, 8.9). To this end, the printing system is equipped with a traction device (8.5) that pulls the build container into the machine via supports (8.7, 8.8). By changing the direction of rotation of the drive (8.6), the supports on the traction device stop on the other side of the corresponding build container support, allowing the container to be transported in the opposite direction. To facilitate the transition of the work container from the system linkage, i.e., the roller conveyor (8.9), to the 3D printing system, the machine is equipped with support rollers (8.4). These support rollers are preferably free-wheeling so that they can easily adapt to the speed of the traction device and the speed of the roller conveyor (8.9).

[0255] An exemplary infrared camera according to the present disclosure is as follows Figure 1 shown.

[0256] Since thermal management is an important factor affecting part quality in current processes, this system is equipped with an infrared camera system (1.8) that can continuously monitor the temperature of the build site (1.9).

[0257] Figure 4 Exemplary embodiments of a conditioning apparatus for offline preparation of a processing unit according to the present disclosure are described.

[0258] In order to minimize machine downtimes during production, it is therefore recommended to adjust the handling unit offline in a specially developed device. For this purpose, a device with an integrated measuring device was developed, which allows the handling unit with a quick-release closure (4.3) to be set up, measured and, if necessary, readjusted in a simulated machine installation. Figure 1 ). For this purpose, the device is equipped with suitable guide elements (4.4), which preferably have a flatness of + / - 0.02 mm over the entire travel range, preferably approximately 1 m x 1.5 m, in order to move the measuring head (4.5) along the processing unit in the X and Y directions. In order to be able to approach the measuring position reproducibly, the guide element (4.4) has an integrated displacement measuring system, which can be seen on the control panel (4.7). Preferably, a measuring head (4.5) with an electronic signal output is used, so that on the one hand the measurement data can be seen on the control panel and on the other hand the measurement data can be automatically entered into a logbook. In addition, the device has a parking position with a print head closure (4.6) that prevents the print head (2.6, 3.6) from drying out.

[0259] Figure 5 An exemplary shipping box with permanent printhead wetting according to the present disclosure is shown.

[0260] Because the processing unit (5.2) is a highly sensitive and cost-intensive component, a device has been developed that allows the processing unit (5.2) to be stored with the fully equipped print head in a ready-to-use form for the 3D printer. This means the print head is filled with printing medium and can be used by the printer for several days. The transport case consists of a base frame (5.1) with a print head closure (5.6) and a shockproof cover (5.4). To clearly position the processing unit (5.2), a quick-release closure (5.3) is used, just as in a 3D printer.

[0261] Figure 6 An exemplary embodiment of a removal aid for non-destructive removal / installation of a processing unit according to the present disclosure is shown.

[0262] Since current 3D printing systems are designed for a high degree of process automation, some of these systems will be combined with fully automated interconnections. Therefore, it may be useful to transport the processing unit to and from the machine and to lift it into and out of the machine using a universal lifting device (6.5). To ensure that the highly sensitive processing unit (6.2) is not damaged during processing, a device has been developed to ensure removal from the machine guide (6.6) and provide comprehensive protection after removal. In this case, a purely mechanical solution (6.7) was chosen, but a fully automated solution that can interact with the corresponding machine control system is also conceivable.

[0263] Figure 1-3 An exemplary processing unit according to the present disclosure is further described.

[0264] To meet high availability requirements and thus reduce maintenance time, a 3D printing system currently being developed for quick-change machines features a print head (2.6, 3.6), a horizontal offset (3.8), a coater (2.2, 3.2), an IR emitter (2.4, 3.4), and other associated components. To this end, these components are combined in a highly integrated and self-supporting handling unit. A quick-release clamping system (3.10) for mounting the handling unit on the traversing axis (1.4) and quick-release closures for all media (power, air, adhesive, etc.) create a compact unit that can be installed and removed from the 3D printing system as required in the shortest possible time. Another advantage of this solution is its multi-availability: as explained elsewhere, a network of 3D printing systems can be established, and the handling unit can be used in any of the 3D printing systems in the network. This can also be achieved by offline adjustment of the handling unit in the adjustment device described below (see also Figure 4). The processing unit essentially consists of a front mounting panel (3.1) with a quick-clamping system (3.10) attached thereto, and a combination of the following components: a full-width and intrinsically rigid printhead (2.6 and 3.6) with horizontal offset (3.8), a coater unit (2.2, 3.2), and an infrared emitter (2.4, 3.4) with water cooling (2.5, 3.5). The intrinsically rigid printhead configuration also allows for quick replacement of the printhead (2.6, 3.6). The system is supplemented by a line scan camera (2.7, 3.7) for in-situ print image acquisition and a coater closure (2.3, 3.3), which in this case is designed as a vacuum closure (2.3, 3.3) to ensure minimal wear and tear on the equipment over a large number of cycles and to maximize its service life.

[0265] Figure 2 and Figure 3An exemplary inspection device in the form of a line scan camera according to the present disclosure is shown in FIG.

[0266] A major drawback of existing systems on the market is that the print result can only be viewed at the end of the printing operation, when the build container is opened. This can sometimes take hours, wasting valuable time. Existing systems already use conventional camera systems to inspect the printed image after the respective layer is completed (e.g., VUT, Review of an Active Re-Coater Monitoring System for Powder Bed Fusion Systems).

[0267] Because this technology couldn't be used on this machine due to its bidirectional operating mode, it was necessary to develop an adapter system that could be installed between the print head and coater, allowing in-situ inspection of the printed image even in bidirectional operation. To achieve this, a line scan camera (2.7, 3.7) was integrated between the print head (2.6, 3.6) and the left and right coaters (2.2, 2.3). This was then equipped with specially adapted software that compares the actual printed image with the target image, thus indicating any process faults to the operator at an early stage. The operator could then decide whether to abort the print or allow it to continue to the end.

Claims

1. A device for forming a molded article layer by layer from a granular material, comprising at least one processing unit which can be introduced into and installed in the device, the processing unit comprising a printing unit and a coating system, and an adjustment device for offline preparation of the processing unit; in, The device also includes a quick clamping system for mounting the processing unit on the traversing axis; Wherein, the device further comprises a bidirectional coater or two coaters, with a corresponding coater provided in each coating direction; Wherein, the device further comprises a camera that moves together with the processing unit and is used to measure the printed image; wherein the device comprises a guide element having an integrated displacement measuring system; The device has a parking position, the parking position has a print head closure, the print head closure is used to prevent the print head from drying out, and the processing unit has the print head.

2. The device according to claim 1, characterized in that The invention also includes an infrared camera that can be moved together with the processing unit and is used to measure the temperature of the construction site.

3. The device according to claim 1 or 2, characterized in that Includes a receiver for building containers.

4. The device according to claim 1, characterized in that The coating system includes a dynamic filling system.

5. The device according to claim 1, characterized in that The device includes an air conditioner.

6. The device according to claim 1, characterized in that A line sensor is provided in a region between the coater unit and the printing unit.

7. The device according to claim 6, characterized in that The line sensor is connected to another process and control unit.

8. The device according to any one of the preceding claims, characterized in that The print head is arranged between the two coaters or in each case the print head is attached to both sides of a bidirectional coater.

9. The device according to claim 2, characterized in that Cameras or infrared cameras are installed in each direction of travel, forward and reverse.

Images