3D printers and printing methods for additive manufacturing of components

Abstract

To provide a three-dimensional (3D) printer for additive manufacturing of multilayer members.SOLUTION: A three-dimensional (3D) printer for additive manufacturing of multilayer members comprises: at least two dispensers (2) separated from each other, each for coating a conveyor belt (3) with different raw materials; a manufacturing unit in which at least a part of the raw materials are bonded to members (8) as a new layer; at least two collecting devices (12) separated from each other realized as blades scraping off the raw materials in excess from the conveyor belt (3) for selectively recovering unused different raw materials and returning the raw materials to the corresponding dispensers (2) when joining layers to the members (8); and the conveyor belt (3) transporting the raw materials from the dispenser (2) to the manufacturing unit along a lateral direction and then to the collecting devices (12).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a 3D printer for additive manufacturing of multi-layer parts, a method for additive manufacturing of three-dimensional multi-layer parts and to 3D printing multi-layer parts. [Background technology]

[0002] Printing installations for photopolymerization in a bath (see DIN EN ISO 17296) are characterized by the fact that the raw material is fed into the bath or applied to another work surface and then structured and hardened by contact with a multilayer component. There are also methods where the raw material is applied layer by layer to the work surface. The usual methods for structuring and hardening the raw material are stereolithography (SLA) or digital light processing (DLP). In these methods, the raw material is usually irradiated by a programmable digital radiation source. For this purpose, in SLA methods, usually a deflectable laser device is used, whereas in DLP methods, for example, a projector is used. The irradiation is carried out according to a defined pattern. The photosensitive raw material is then hardened by photopolymerization of the adhesive contained therein.

[0003] International patent application WO 2015 / 107066 A1 discloses a DLP-3D printer in which the raw material is applied to a conveyor belt and transported by this to the working surface. Usually only a portion of the provided raw material is used for structuring the new layer, so more raw material needs to be used than is needed to produce the part. This printing method is inefficient and expensive due to the excess raw material used.

[0004] Another 3D printer is disclosed in the international patent application WO 2017 / 009368 A1. In this printing method, the remaining raw material can be collected by a recovery device and then reused in the manufacturing process. In order to print with the second raw material, the entire printer, including the recovery device, needs to be cleaned to remove the residues of the first raw material. Therefore, it is not possible to print multiple layers of parts made of different materials in one printing process.

[0005] US Patent Application US 2017 / 0182708 A1 discloses a 3D printer with a laterally moving work surface. In this invention, different feedstocks can be applied by multiple feedstock dispensers. The work surface and parts must be cleaned before each material change. The disclosed device does not consider the recovery of excess feedstock.

[0006] When the number of elements is large, multiple layers of different materials are included. To achieve this, it is usually necessary to go through a complex manufacturing process, for example, printing each component separately and then assembling them. The prior art includes the first technical means of printing multi-layer elements of different materials, but these technical means are inefficient and expensive due to excessive raw material usage. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2015 / 107066 [Patent Document 2] International Publication No. 2017 / 009368 [Patent Document 3] US Patent Application Publication No. 2017 / 0182708 Summary of the Invention [Problem to be solved by the invention]

[0008] In view of this, the present invention aims to disclose a 3D printer and printing method capable of producing multi-layer parts made of different materials in a more efficient, more resource-saving and less costly manner. [Means for solving the problem]

[0009] The present invention as defined in claim 1 partially solves the above problem.

[0010] The present invention discloses a 3D printer for additive manufacturing of multi-layer parts.

[0011] The 3D printer comprises at least two dispensers, separate from each other, for coating a conveyor belt with different raw materials. The dispensers include a storage device in which the raw materials are stored and a coating device for applying a layer of the raw materials to the conveyor belt. The dispensers may include different technology embodiments. The dispensers may be realized, for example, as a nozzle coating device, a syringe pump, a verista pump, an inkjet head, a roller transfer device or a transfer film. As an example, an embodiment using a nozzle coating device will be described in detail.

[0012] The 3D printer further comprises a manufacturing unit in which at least a part of the raw material is bonded to the part as a new layer, where the manufacturing process is a photopolymerization additive process, and the first layer of the part can be bonded directly to a structural plate provided for the first layer of the part.

[0013] The 3D printer further comprises at least two separate collection devices for selectively collecting different unused feedstocks when bonding layers to the part, and returning the collected feedstocks to the corresponding dispensers, i.e., each feedstock corresponds to one dispenser that supplies only that feedstock, while corresponding to one collection device that collects only that feedstock and returns it to the corresponding dispenser.

[0014] In this way, it is ensured that different raw materials are not mixed with each other during both production and return, i.e. excess raw materials can be recovered without altering their quality and used again in the production process, allowing the printer to print multiple layers of components with different materials in one printing process in an efficient and resource-saving manner.

[0015] The printer further comprises a conveyor belt for laterally transporting the raw material from the dispenser to the production unit and then to the recovery device. The conveyor belt separates the material supply location from the production and material recovery location. In this way, the conveyor belt allows a flexible configuration of the printer.

[0016] In one embodiment, the dispenser storage device includes a mixer that thoroughly mixes the returned material and any new material that is added to ensure that the composition of each printed layer is uniform.

[0017] In one embodiment, the conveyor belt includes a radiation-transparent film that is moved by rotating rollers. The radiation transparency of the conveyor belt allows it to penetrate through the conveyor belt itself and harden the material by irradiation with a radiation source. In one embodiment, the film may be any polymeric film with high radiation transparency. Radiation, as used herein and in the following description, includes visible light, infrared (IR) and ultraviolet (UV) range light, and any other form of electromagnetic radiation.

[0018] Also, the conveyor belt can be circulated so that it can be recoated after one complete cycle, for example, when a thin film is used, the circulation of the conveyor belt can eliminate the need to continually transport new thin films, thereby allowing the process to be carried out in a resource-saving and low-cost manner.

[0019] The feedstock used in the printing process includes slurries that may contain ceramic or metallic or organic powders and photopolymerizable adhesives, i.e. organic adhesives that can be polymerized (photopolymerized) by radiation. Such feedstocks can be structured and hardened by radiation. The radiation forms a hardened structure in the feedstock, for example by activating and polymerizing the photopolymerizable organic adhesive.

[0020] Immediately after printing, debinding and sintering processes are carried out to remove the organic binder and to form the desired structure in the ceramic or metal element.

[0021] In one embodiment, the manufacturing unit of the 3D printer includes a unit for manufacturing parts according to the DLP or SLA method.

[0022] In this embodiment, the manufacturing unit comprises a working surface on which the conveyor belt is guided. The working surface comprises a window through which radiation is transparent. The manufacturing unit further comprises a radiation source arranged below the window. In this way, the radiation source can penetrate the window and the radiation transparent conveyor belt to expose and harden the raw material on the conveyor belt. The radiation source may be designed or programmed to irradiate and harden the raw material in a suitable pattern. The radiation source is for example a laser device (SLA process) or a projector (DLP process). It may be, for example, electromagnetic radiation in the visible light range, UV or IR range.

[0023] The manufacturing unit also comprises a construction plate, on the underside of which the components are manufactured and attached thereto, and which is arranged on a work surface parallel to said work surface. The positioning system can raise and lower the construction plate perpendicular to the work surface, thus setting the distance between the pre-printed layers of the components and the conveyor belt. The first layer is printed directly on the construction plate. In this case, the thickness of the layer bonded to the components is predetermined by the set distance.

[0024] A number of elements may be attached to the structural plate and new layers may be bonded in parallel to these elements. In this technical solution, all elements must be located within the working surface of the window through which radiation passes.

[0025] In one embodiment, the manufacturing unit includes a cleaning device for removing excess material from the workpiece. The cleaning device may include a drive system that allows the cleaning device to move laterally along a surface of the workpiece.

[0026] The cleaning device may be, for example, a suction nozzle, a blade or a roller. The cleaning device is preferably positioned laterally next to the member in the passive state and arranged to move laterally over the surface of the member in the active state.

[0027] There may be a separate cleaning apparatus for each material, with at least two cleaning apparatus included in the production unit.

[0028] There is one return device per cleaning device, each return device including a transport unit for returning the collected material to the respective dispenser. The transport devices are for example pumps and the return devices are for example hoses. The separate return devices ensure that the materials are not mixed together, so that they can be reused.

[0029] In one embodiment, the return device and the cleaning device may be integrated. For example, a roller having an adhesive surface may be used that runs over the surface of the member to remove the remaining material. The roller is then moved by a positioning system to a dispenser where the material is removed by the roller and deposited in the dispenser. Such a device is called a roller transfer device.

[0030] Similar technical measures can also be implemented by the adhesive surface of the transfer film. If the cleaning device is a suction nozzle, the return device can be realized as a hose, which for example contains a pump or a fan as a transport device. If the cleaning device is realized as a blade that scrapes the workpiece surface, the return device can be a tray that is arranged below the workpiece and can be moved to the dispenser by a positioning system.

[0031] The present invention further discloses a method for additive manufacturing of three-dimensional multi-layer parts and recovery of virgin raw materials, comprising the steps of:

[0032] The dispenser applies a layer of material to the conveyor belt, the layer thickness of the applied material corresponding at least to the desired layer thickness of the layer to be applied to the component.

[0033] Typically, excess material is required to produce a complete layer of the desired size.

[0034] The conveyor belt carrying the layer of raw material is transported to the working surface.

[0035] A conveyor belt separates the area where the raw material is applied from the area where it is produced, thereby making the process more flexible.

[0036] The layer of raw material and the surface of the component to be coated are brought into contact at the working surface and part of the raw material is hardened by structuring to form a new structured layer of the component.

[0037] The first layer of the component is fabricated so as to contact the surface of the structural plate provided for the first layer of the component.

[0038] The part containing the new layer is lifted off the work surface.

[0039] Lifting separates the hardened part from the unhardened material. There may be some excess material attached to the part.

[0040] The excess material on the conveyor belt is transported to a recovery device.

[0041] The withdrawal device may for example be realised as a suction nozzle, a blade or a roller and may further comprise a device for returning the material to the dispenser.

[0042] A reclaimer removes excess material from the conveyor belt and delivers the material back to the dispenser.

[0043] The device used for the return transport may be, for example, a hose or pipe system. The system may include a transport device, for example a pump or a fan.

[0044] If the collection device is a roller, this roller may be realized as a transfer roller device, which may absorb the material by its adhesive surface and then move to the dispenser, where it may release the material again into the corresponding dispenser.

[0045] The method steps are repeated with a second ingredient and a second dispenser. A second recovery device is provided for selectively returning the first ingredient and the second ingredient to their respective dispensers.

[0046] In another technical implementation of the method, the above method steps are repeated with a third or other raw material, a third or other dispenser, and a third or other recovery device. The third raw material is selectively returned to the corresponding dispenser. Similarly, the other raw materials are selectively returned to the corresponding other dispensers. Since the raw materials are not mixed, they can be reused in the printing method.

[0047] In one embodiment of the method, the working surface has a window through which radiation is transmitted. In terms of dimensions, the size of the window corresponds at least to the outer size of the layer to be added. The structural plate with the component attached is positioned above the window. The structural plate is lowered perpendicular to the window until the distance between the surface of the component and the top side of the conveyor belt is the desired layer thickness of the new structured layer to be added to the component. When printing the first layer of the component, the structural plate is lowered so that the distance between the surface of the structural plate and the conveyor belt is the desired thickness of the first layer.

[0048] In said method, radiation is directed through a window towards the multi-layer component, whereby a raw material is structured and hardened into a new layer, the raw material comprising a photosensitive adhesive, the radiation causing a photopolymerization of the adhesive.

[0049] In addition, in the method, the structural plate with the attached components and the new layer attached to the components are lifted off the conveyor belt. For this purpose, the adhesion between the components and the structural plate needs to be greater than the adhesion between the components and the conveyor belt. The large adhesion of the components to the structural plate is ensured by selecting the material of the structural plate and by increasing the surface roughness of the structural plate relative to the thin film. The higher the roughness, the easier it is for the components to adhere to the structural plate. When selecting the material of the structural plate, it is preferable to select a material with similar properties to the material of the components, or a metal plate with a rough surface.

[0050] In one method, the following steps are then performed.

[0051] A cleaning device is provided for removing material from the workpiece.

[0052] Preferably, the cleaning device is then positioned laterally next to the member.

[0053] The cleaning device is moved laterally along the surface of the component to remove excess material from the surface of the component.

[0054] The cleaning device may be, for example, a suction nozzle, a blade or a roller.

[0055] A corresponding return device returns the ingredient to the dispenser corresponding to the ingredient.

[0056] When using suction nozzles, the return device can be, for example, a hose system or a pipe system. When using rollers, the rollers can be transfer roller devices. If a cleaning device with a corresponding return device is assigned to each material, the raw materials are not mixed.

[0057] The present invention further includes a component comprising a plurality of layers, the layers comprising: Each is separated on a flat surface, Contains different materials, They are directly chemically connected.

[0058] The invention further includes a component having the above characteristics, the layers of which each have a thickness of up to 300 μm. Preferably, the component has a layer thickness of between 5 μm and 200 μm.

[0059] The layers may be arranged in parallel both horizontally and vertically. The interfaces between the different layers may be parallel to the outer surface of the part. The material of the part may include different metals, ceramics and plastics, or any one of them. There is no other adhesive, e.g. binder, between the layers. Flexible structuring of the part can be achieved by variably adjusting the layer thickness in the printing method.

[0060] In one embodiment, the component exists as a first structure after printing and includes the adhesive. For components made entirely of plastic, this first structure is the desired component structure. For metal or ceramic components, a sintering step may remove the adhesive and change the structure of the component. After sintering, the component exists as the desired second structure. [Brief description of the drawings]

[0061] The present invention will now be described in detail with reference to the drawings, in which: FIG. 1 is a schematic diagram of a method for manufacturing a semiconductor device according to the present invention;

[0062] [Figure 1] 1A-1D are schematic diagrams of a first embodiment of the 3D printer illustrating manufacturing steps. [Diagram 2] 3A to 3D printer according to a first embodiment of the printing method. [Diagram 3] FIG. 13 is a schematic diagram of a second embodiment of the 3D printer in which a thin film operates in a circulating manner. [Figure 4] FIG. 2 is a schematic diagram of a printed multi-layer member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0063] The drawings are schematic diagrams. The drawings are not based on the actual scale of the 3D printer. The actual size and size ratio may differ from those shown.

[0064] Fig. 1 shows a first embodiment of a 3D printer 1. The 3D printer 1 comprises three mutually separate dispensers 2 arranged in parallel. The dispensers 2 are arranged on a conveyor belt 3 and are each configured to apply a different feedstock to the conveyor belt. The dispensers 2 are realized here as nozzle coating devices.

[0065] The conveyor belt 3 includes a thin film guided by a number of rollers 4. The thin film is made of a polymer, for example polyethylene terephthalate (PET). In this example, the four rollers 4 shown rotate counterclockwise at the same speed, thereby moving the conveyor belt 3. The thin film is wrapped around the right-most roller 4a before printing, and unwound from this roller in the process before being deflected in the desired direction by the first deflection roller 4b and passing through the 3D printer 1.

[0066] After passing through the 3D printer 1, the film is deflected by the second deflection roller 4c towards the leftmost roller 4d shown in Figure 1, where it is wound again. After the process is complete, the right roller 4a is replaced by the left roller 4d, and the film can be returned for reuse.

[0067] To support the thin film, a support plate 5 is attached below the thin film and opposite the dispenser 2 at the application position of the material. The support plate 5 is not connected to the thin film. The thin film is movably placed horizontally on the support plate 5. A conveyor belt is used to transport the material applied by the dispenser to a working surface 6 arranged laterally next to the support plate 5. The thin film is likewise movably placed horizontally on the working surface 6.

[0068] The working surface 6 comprises a radiation-transmitting window, which occupies a large part of said surface. Below the window a projector 7 is arranged, which irradiates in a defined pattern the raw material which is added to the component 8 as a new layer between the thin film and the component 8, thereby structuring and hardening the raw material. In the drawing a beam 10b is exemplarily shown. The pattern may for example be defined as a mask arranged on the projector 7. Alternatively, the pattern may for example be digitally programmed beforehand.

[0069] The pattern may be designed to cover only some area under the feature 8 after a new layer has been printed onto it, so that in a subsequent printing process another layer may be printed laterally next to the existing layer.

[0070] A number of members 8 are attached to the structural plate 9. The number of members 8 that can be attached depends on the geometry of the members 8 and the structural plate 9. In this example, four members 8 are attached to the structural plate 9. The structural plate 9 includes an underside with a high surface roughness, to which the members 8 are preferably attached. The structural plate 9 is placed parallel to and on the work surface 6. The structural plate 9 with the members 8 attached can be raised and lowered perpendicular to the work surface 6 by means of a positioning system 10. For this purpose, the positioning system 10 is positioned in the center of the work surface 6 and perpendicular to the work surface.

[0071] The 3D printer 1 also comprises a cleaning device 11, which can be moved along the underside of the member 8 by means of a drive system, said drive system being therefore positioned parallel to the construction plate 9 and above the working surface 6, at a sufficient distance in front of or behind the positioning system 10. In this case, the cleaning device 11 is realised as a blade capable of scraping off unused raw material from the member 8.

[0072] In addition, in the first embodiment, the 3D printer 1 includes three collection devices 12. The collection devices 12 are realized as blades that scrape off excess material from the moving conveyor belt 3. A separate collection device 12 is provided for each material. The collection devices 12 are attached to the conveyor belt 3 at points that are arranged laterally next to the working surface 6 but on a different side from the placement plate 5.

[0073] Each of the recovery devices 12 further includes a hose 13 for returning the material to the corresponding dispenser 2. The hose 13 is provided with a pump for sucking the material from the recovery device 12 and transporting it through the hose 13. The hose 13 connects the recovery device 12 and the corresponding dispenser 2.

[0074] 2A, B, C, D, E and F show an exemplary method according to a first embodiment. In a first step A, a first dispenser 2a applies a first ingredient to a conveyor belt 3. The conveyor belt 3 transports the ingredient to a work surface 6.

[0075] The positioning system 10 then lowers the structural plate 9 in step B until it is in contact with the material applied to the conveyor belt and the gap between the structural plate 9 and the conveyor belt 3 is the desired thickness of the new layer. During printing of the first layer, excess material is now pressed against the edges of the structural plate 9.

[0076] Then, in step C, the raw material is irradiated according to a desired pattern or desired structure using a projector 7 below the structural plate 9. The incident radiation hardens the material by photopolymerization of the organic adhesive, forming a first layer of components 8 attached to the structural plate 9. The structural plate 9 can now be lifted by the positioning system 10, leaving most of the excess unhardened raw material on the conveyor belt 3.

[0077] In step D, the surplus raw material remaining on the conveyor belt 3, which has not been transferred to the structural board or component, is further transported by this conveyor belt and is removed from the conveyor belt 3 by a recovery device 12a realized as a blade. The hose 13a then returns the raw material to the first dispenser 2a by driving a pump integrated in the hose 13a.

[0078] Simultaneously with the recovery, fresh ingredient can be applied to the conveyor belt 3 as in step A. The dispenser utilized here can be the same dispenser that applies the same ingredient in step A or a different dispenser that applies a different ingredient. The conveyor belt then transports the fresh ingredient from one of the dispensers 2 to the work surface 6 while simultaneously transporting the previous, unused ingredient from the work surface 6 to the first recovery device 12a.

[0079] At the same time, in step E, the structural plate 9 with the member 8 attached thereto is lifted, and then a cleaning device 11 is run over the surface of the member 8 to clean the underside of the newly printed layer.

[0080] Similarly, the raw material is returned to the corresponding first dispenser 2a.

[0081] Once the printing and cleaning of the first layer is completed and the first feedstock has been completely removed from the conveyor belt 3, the above method steps can be repeated and, possibly, second and other layers can be applied as other hardened structures to the member 8. If other feedstocks are required for the second or other layers, the first dispenser 2a and the first collection device 12a are lifted and, alternatively, the second dispenser or an alternative third dispenser and the second collection device or a corresponding third collection device are lowered to the conveyor belt 3 and the entire method is repeated with the other feedstocks.

[0082] In this case, at least one layer of the elements 8 has already been attached to the structural plate 9, so that in step F, which corresponds to step B, the elements 8 are lowered so that the distance between the elements 8 and the conveyor belt 3 is the desired new layer thickness. The excess material is now pressed against the edge of the previous layer of the elements 8.

[0083] The first feedstock is, for example, a ceramic feedstock containing an organic adhesive. The second feedstock, shown shaded in FIG. 2F, is, for example, a polymer slurry also containing an organic adhesive. The other layers may contain the same or other different feedstocks. Each layer can be applied in a different structure or in a different pattern, and in this way, parts with any external spatial shape and any internal structure can be produced.

[0084] FIG. 3 shows a second embodiment of the 3D printer 1, which is almost similar to the first embodiment. However, the second embodiment differs from the first embodiment in that the conveyor belt 3 operates in a circular manner, making it possible to recycle and reuse the thin film used in the conveyor belt 3 without interrupting or interfering with the process. To that end, the conveyor belt 3 is guided by four rollers 4, which in this example rotate counterclockwise at an appropriate speed. In other embodiments, the rollers may also rotate clockwise. The arrangement of the rollers 4 is similar to the arrangement of the four rollers in the first embodiment. However, the difference is that in this case all the rollers are used as deflection rollers. The thin film is not wound on or unwound from the rollers.

[0085] In a preferred embodiment, a cleaning device is provided along the circulating conveyor belt 3 behind the recovery device, which removes the last raw material residues from the conveyor belt 3, thereby ensuring that different raw materials are not mixed together.

[0086] 4 exemplarily and diagrammatically illustrates a printed multi-layer member 8, which includes six layers 14a to 14f located in four vertically stacked planes 15a to 15d. The first and third planes from the bottom (15a, 15c) each include two layers (14a, 14b, 14d, 14e). The top layer 14f is the first layer produced in the printing process. The bottom layers 14a and 14b are the last layers produced in the printing process.

[0087] The member 8 includes layers of three different materials, which are shown with different shading, one of which is a metal and the remaining materials are two different polymers or ceramics.

[0088] The boundaries between the layers extend along planar interfaces parallel to the exterior 16 of the member 8. Each layer may comprise an entire horizontal surface of the member 8, such as the second and fourth layers (14c, 14f) from the bottom of the member 8, but may also be laterally juxtaposed, such as the first and third planes (15a, 15c) of the member 8.

[0089] The thickness of the layers of the member 8 can vary. The top layer 14f of the member 8 is shown to be thinner than the other layers of the member 8, and the bottom two layers 14a and 14b are thicker than the other layers of the member.

[0090] There are no other intermediate or connecting layers, such as adhesive layers, between the above-mentioned layers. [Explanation of symbols]

[0091] 1 3D printer 2 Dispenser 2a First Dispenser 3. Conveyor Belt 4 Conveyor belt 3 rollers 4a Right roller 4b First deflection roller 4c Second deflection roller 4d Left roller 5. Placement plate 6 Work Surface 7. Projector 8. Materials 9 Structural plate 10 Positioning System 10b Beam 11 Cleaning device 12 Recovery device 12a First recovery device 13. Hose 13a 1st Hose 14a to 14f Layers of member 8 15a to 15d Plane of member 8 16 Outside of member 8

Claims

1. At least two separate dispensers (2) for coating a conveyor belt (3) with different ingredients; a production unit in which at least a portion of said raw material is bonded as a new layer to an already formed part (8); at least two separate recovery devices (12) for selectively recovering unused different raw materials when joining layers to the member (8) and for returning said raw materials to the corresponding dispensers (2), said recovery devices (12) being realized as blades for scraping off excess raw materials from the moving conveyor belt (3) and each of said recovery devices (12) further comprises a hose (13) for returning the raw materials to the corresponding dispenser (2), said hose (13) being provided with a pump for sucking the excess raw materials from said recovery devices (12) and transporting them via said hose (13) to the corresponding dispenser (2); a conveyor belt (3) for transporting the raw material along a lateral direction from the dispenser (2) to the manufacturing unit and then to the recovery device (12); A 3D printer (1) for additive manufacturing of multi-layer parts, comprising:

2. 3D printer (1) according to claim 1, wherein the conveyor belt (3) comprises a radiolucent membrane, the membrane being moved by rotating rollers.

3. 3D printer (1) according to claim 2, wherein the thin film is cyclically operable, whereby the thin film can be recoated.

4. 4. The 3D printer (1) according to any one of claims 1 to 3, wherein the feedstocks each comprise a slurry, the slurry comprising a ceramic, metallic or organic powder and a photopolymerizable organic adhesive.

5. A 3D printer (1) described in any one of claims 1 to 4, wherein the dispensers (2) each include a container for storing the raw material and a coating device for coating the raw material onto the conveyor belt (3).

6. The manufacturing unit comprises: a working surface (6) on which the conveyor belt (3) is guided and which includes a window through which radiation is transmitted; a radiation source (7) arranged below the window and capable of exposing and curing the material on the conveyor belt (3) through the window and the conveyor belt (3); a structural plate (9) having the member (8) attached to its underside and disposed on the work surface (6) parallel to the work surface (6); a positioning system (10) configured to raise and lower the structural plate (9) perpendicular to the work surface (6) and to set a spacing between the member (8) and the conveyor belt (3); 3D printer (1) according to any one of claims 1 to 5, comprising:

7. 7. The 3D printer (1) according to any one of the preceding claims, wherein the manufacturing unit comprises at least two cleaning devices (11) for removing corresponding raw materials from the parts (8).

8. 8. The 3D printer (1) of claim 7, wherein the cleaning device (11) is movable laterally along the surface of the member (8) by a drive system.

9. One return device is provided for each cleaning device (11), 9. The 3D printer (1) according to claim 7 or 8, wherein each return device comprises a transport unit for returning the collected raw material to the respective corresponding dispenser (2).

10. 8. The 3D printer (1) according to claim 7, wherein the raw material removed by the cleaning device (11) is returned to the appropriate dispenser (2) by a corresponding return device.

11. A step of applying a layer of a first feedstock to a conveyor belt (3) by a first dispenser, the layer thickness of the applied first feedstock corresponding at least to a desired layer thickness of a layer to be added to an already formed component (8); conveying said conveyor belt (3) carrying said layer of said first material onto a working surface (6); - bringing the layer of said first feedstock into contact with the surface of said component (8) to be coated at said working surface (6) and hardening part of said first feedstock by structuring, thereby forming a new structured layer of said component (8); Lifting the part (8) including the new layer from the work surface (6); - conveying the excess first material on the conveyor belt (3) to a first recovery device, said first recovery device being realized as a blade; removing the excess first material from the conveyor belt (3) by means of the first recovery device, which is realized as a blade, and returning the removed first material to the first dispenser, by sucking the excess first material from the first recovery device using a hose (13) equipped with a pump of the first recovery device and transporting it via the hose (13) to the first dispenser; repeating the steps with a second ingredient, a second dispenser, and the second recovery device; A method for additive manufacturing of three-dimensional multi-layer parts and recovery of virgin materials, comprising:

12. the working surface (6) has a window through which radiation is transmitted, the size of the window corresponding in terms of dimensions to at least the outer size of the layer to be added; Positioning the structural plate (9) with the member (8) attached thereto above the window; lowering the structured plate (9) perpendicular to the window until the distance between the surface of the member (8) and the top side of the conveyor belt (3) is equal to the desired layer thickness of the new structured layer to be added to the member (8); structuring and solidifying the first and second feedstocks into a new layer by radiation transmitted through the window to the component (8); Lifting the structural plate (9) with the member (8) attached and the new layer attached to the member (8) from the conveyor belt (3); The method of claim 11.

13. The method further comprises: providing a cleaning device (11) for removing the first and second materials from the member (8); removing excess first and second raw materials from a surface of the member (8) by moving the cleaning device (11) laterally along the surface of the member (8); returning the removed first and second raw materials to the first and second dispensers corresponding to the first and second raw materials, respectively, by corresponding return devices; The method of claim 11 or 12, comprising:

14. 14. The method according to any one of claims 11 to 13, wherein the conveyor belt (3) transports the first and second raw materials along a lateral direction from the first or second dispenser, respectively, to the working surface (6) and further to the first or second collecting device.

15. 12. The method according to claim 11, wherein the step of removing excess first and second raw materials from the surface of the part (8) after the structuring and the curing is performed by moving a cleaning device (11) laterally along the surface of the part (8).

16. 16. The method according to claim 15, wherein the first ingredient and the second ingredient removed by the cleaning device (11) are returned by a corresponding return device to the corresponding appropriate first or second dispenser.

17. At least two separate dispensers (2) for coating a conveyor belt (3) with different ingredients; a production unit in which at least a portion of said raw material is bonded as a new layer to an already formed part (8); at least two recovery devices (12) separate from one another for selectively recovering unused different raw materials when bonding layers to said member (8) and returning said raw materials to the corresponding dispensers (2); a conveyor belt (3) for transporting the raw material from the dispenser (2) along a lateral direction to the manufacturing unit and then to the recovery device (12). 3D printer (1) for additive manufacturing of multi-layer parts, said manufacturing unit comprising at least two cleaning devices (11) for removing corresponding raw materials from said parts (8).

18. 18. The 3D printer (1) of claim 17, wherein the raw material removed by the cleaning device (11) is returned to the corresponding appropriate dispenser (2) by a corresponding return device.

19. One return device is provided for each cleaning device (11), 3D printer (1) according to claim 17 or 18, wherein each return device comprises a transport unit for returning the collected raw material to the respective corresponding dispenser (2).

20. A step of applying a layer of a first feedstock to a conveyor belt (3) by a first dispenser, the layer thickness of said applied first feedstock corresponding at least to the desired layer thickness of the layer to be added to an already formed component (8); conveying said conveyor belt (3) carrying said layer of said first material onto a working surface (6); - bringing the layer of said first feedstock into contact with the surface of said component (8) to be coated at said working surface (6) and hardening part of said first feedstock by structuring, thereby forming a new structured layer of said component (8); removing excess of the first feedstock from the surface of the member (8) by moving a cleaning device (11) laterally along the surface of the member (8); Lifting the part (8) including the new layer from the work surface (6); conveying the excess first material on the conveyor belt (3) to a first recovery device; removing the excess first ingredient from the conveyor belt (3) by the first recovery device and returning the removed first ingredient to the first dispenser; repeating the steps with a second ingredient, a second dispenser, and a second recovery device; A method for additive manufacturing of three-dimensional multi-layer parts and recovery of virgin materials, comprising:

21. 21. The method according to claim 20, wherein the first and second ingredients removed by the cleaning device (11) are returned by a corresponding return device to the appropriate corresponding first or second dispenser, respectively.

22. the working surface (6) has a window through which radiation is transmitted, the size of the window corresponding in terms of dimensions to at least the outer size of the layer to be added; Positioning the structural plate (9) with the member (8) attached thereto above the window; lowering the structured plate (9) perpendicular to the window until the distance between the surface of the member (8) and the top side of the conveyor belt (3) is equal to the desired layer thickness of the new structured layer to be added to the member (8); the radiation transmitted through the window to the component (8) structures and solidifies the first and second feedstocks, respectively, into a new layer; Lifting the structural plate (9) with the member (8) attached and the new layer attached to the member (8) from the conveyor belt (3); 22. The method of claim 20 or 21.

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