3D PRINTER FOR THE ADDITIVE MANUFACTURE OF A COMPONENT, AND PRINTING METHOD

Abstract

The invention comprises a 3D printer for additively manufacturing a multilayer component. The 3D printer comprises at least two separate dispensers (2) coating a conveyor belt (3) with respectively different raw material, a manufacturing unit in which at least part of the raw material is added to the component (8) as a new layer, at least two separate recovery devices (12) for selectively recovering the respectively different raw material, which is not consumed when a layer is added to the component (8), and returning the raw material to the respective associated dispenser (2) and conveyor belt (3) which transports the raw material from the dispenser (2) to the manufacturing unit and further to the recovery device (12) in the lateral direction.

Claims

1. 3D printer for additive manufacturing of a multilayer component, comprising at least two separate dispensers which each coat a conveyor belt with different raw materials, a manufacturing unit in which at least part of the raw material is added to the component as a new layer at least two separate recovery devices for selectively recovering the respectively different raw material which is not consumed when a layer is added to the component and for returning the raw material to the respectively associated dispenser, the conveyor belt that transports the raw material from the dispenser to the manufacturing unit and further to the recovery device in a lateral direction.

2. 3D printer according to claim 1, wherein the conveyor belt comprises a radiation permeable foil moved by rotating rollers.

3. 3D printer according to claim 2, in which the foil can be circulated in a circuit and can thus be coated again.

4. 3D printer according to claim 1, wherein each of the raw materials comprises a paste comprising either a ceramic, or a metallic, or an organic powder and a photopolymerizable organic binder.

5. 3D printer according to claim 1, wherein each dispenser comprises a device for storing the raw material and a coating device for coating the conveyor belt with the raw material.

6. 3D printer according to claim 1, wherein the manufacturing unit comprises: a work surface over which the conveyor belt is guided and which comprises a window which is radiation permeable, a radiation source arranged below the window so that the raw material on the conveyor belt can be radiated and cured through the window and the conveyor belt, a building plate, to the underside of which the component adheres, which is arranged above the work surface parallel thereto, and a positioning system that can raise and lower the building plate normal to the work surface and is configured to adjust the distance between the component and the conveyor belt.

7. 3D printer according to claim 1, wherein the manufacturing unit comprises at least two cleaning devices for cleaning the component from the respective associated raw material.

8. 3D printer according to claim 7, wherein the cleaning devices can be moved laterally along the surface of the component by a drive system.

9. 3D printer according to claim 7, wherein a return device is provided for each of the cleaning devices, and wherein each return device comprises a conveying device for returning the recovered raw material to the respective associated dispenser.

10. Method for additively manufacturing a three-dimensional, multilayer component and for recovering unused raw material, comprising the following steps: applying a layer of a raw material to a conveyor belt by a dispenser, wherein the applied layer thickness of raw material corresponds at least to the desired layer thickness of a layer to be added to the component, transporting the conveyor belt with the layer of raw material onto a work surface, bringing the layer of raw material on the work surface into contact with a surface of the component to be coated, and structurally hardening a portion of the raw material to form a new structured layer of the component, lifting the component comprising the new layer off the work surface, transporting the remaining raw material on the conveyor belt to a recovery device, removing the remaining raw material from the conveyor belt by means of the recovery device, and returning the raw material to a dispenser, repeating the aforementioned process steps with a second raw material and a second dispenser, wherein a second recovery device is provided so that the first and second raw material can each be selectively returned to the corresponding dispenser.

11. Method according to claim 10, wherein the work surface has a window which is radiation permeable and wherein the window has at least the dimensions of the layer to be added, a building plate with the component is positioned above the window, the building plate is lowered normal to the window until the distance between the surface of the component and the upper side of the conveyor belt corresponds to the desired layer thickness of the new structured layer to be added to the component, the raw material is structured and hardened by irradiation of the multilayer component through the window to form a new layer, and the building plate with the component and the new layer adhering thereto is lifted off the conveyor belt.

12. Method according to claim 11, comprising the following subsequent steps: providing a cleaning device for cleaning the component from raw material, removing the excess raw material from the surface of the component by laterally moving the cleaning device along the surface of the component, returning the raw material to the dispenser corresponding to the raw material by an associated return device.

13. Component, which comprises a plurality of layers, which are delimited from each other along a planar surface, comprise different materials, and are chemically directly bonded to each other.

14. Method according to claim 10, wherein the conveyor belt transports the raw material from the dispenser to the manufacturing unit and further to the recovery device in a lateral direction.

Description

[0064] The drawings show:

[0065] FIG. 1: Schematic representation of a first embodiment of the 3D printer. Shown is the manufacturing step.

[0066] FIGS. 2A, 2B, 2C, 2D, 2E and 2F: Schematic illustration of a printing process using the first embodiment of the 3D printer.

[0067] FIG. 3: Schematic illustration of a second embodiment of the 3D printer in which the foil is circulated.

[0068] FIG. 4: Schematic representation of a printed multilayer component.

[0069] The figures are schematic representations. The figures do not represent true-to-scale images of the 3D printer. Dimensions and proportions may differ from those shown in the drawings.

[0070] FIG. 1 shows a first embodiment example of the 3D printer 1. The 3D printer 1 comprises three separate dispensers 2 arranged side by side. The dispensers 2 are arranged above a conveyor belt 3, and are each configured to apply different raw materials to the conveyor belt. The dispensers 2 are designed here as die coaters.

[0071] The conveyor belt 3 comprises a foil guided over a plurality of rollers 4. The foil is made of a polymer such as polyethylene terephthalate (PET). In the present example, the four rollers 4 shown rotate counterclockwise at the same speed, thus moving the conveyor belt 3. Prior to printing, the foil is rolled up on the roller 4a shown on the far right and is unwound from it during the process before being deflected in a desired direction by a first deflection roller 4b and passing through the 3D printer 1.

[0072] After passing through the 3D printer 1, the foil is deflected by a second deflection roller 4c in the direction of a roller 4d shown on the far left in FIG. 1, where it is rolled up again. It is possible to return the foil for recycling if the left and right rollers, 4a and 4d are changed after the process.

[0073] To support the foil, a carrier plate 5 is placed under the foil at the point of raw material application, on the side opposite to the dispensers 2. The carrier plate 5 and the foil are not connected to each other. The foil lies loosely on the carrier plate 5. The conveyor belt is used to transport the raw material applied by the dispensers to a work surface 6 arranged laterally next to the carrier plate 5. The foil also lies loosely on the work surface 6.

[0074] The work surface 6 includes a radiation permeable window which occupies most of the surface area. A projector 7 is arranged below the window, which irradiates the raw material between the foil and the components 8, which is to be added to the components 8 as a new layer, in a predetermined pattern, thereby structuring and hardening it. Exemplary light beams 10b are shown in the figure. The pattern may be defined, for example, in the form of a mask applied to the projector 7. Alternatively, the pattern may be digitally pre-programmed, for example.

[0075] The pattern may be such that the new layer covers only an area of the underside of the previous component 8 after printing on the component. Thus, in a later printing process, another layer can also be printed laterally next to an existing layer.

[0076] Several components 8 are attached to a building plate 9. The number of possible attached components 8 depends on the geometry of the components 8 and the building plate 9. In the present example, four components 8 are attached to the building plate 9. The building plate 9 includes an underside with high surface roughness to which the components 8 adhere well. The building plate 9 is arranged parallel to the work surface 6 above it. By means of a positioning system 10, the building plate 9 with the components 8 can be raised and lowered normal to the work surface 6. For this purpose, the positioning system 10 is positioned centrally above the work surface 6 and vertically with respect thereto.

[0077] Furthermore, the 3D printer 1 comprises a cleaning device 11 that can be moved along the undersides of the components 8 by means of a drive system. Said drive system is therefore positioned parallel to the building plate 9 at a sufficiently large distance above the work surface 6 and in front of or behind the positioning system 10. In this case, the cleaning device 11 is designed as a blade that can scrape unused raw material from the components 8.

[0078] Furthermore, in the first embodiment, the 3D printer 1 comprises three recovery devices 12. The recovery devices 12 are designed as blades that scrape the excess raw material from the moving conveyor belt 3. A separate recovery device 12 is provided for each raw material. The recovery devices 12 are located over a portion of the conveyor belt 3 that is laterally adjacent to the work surface 6, but on a different side than the carrier plate 5.

[0079] Further, the recovery devices 12 each comprise a hose 13, for returning the raw material to the associated dispensers 2. A pump is provided in the hose 13, which sucks the raw material from the recovery device 12 and delivers it through the hose 13. The hoses 13 connect the recovery devices 12 to the respective associated dispensers 2.

[0080] An exemplary method is illustrated in FIGS. 2A, 2B, 2C, 2D, 2E and 2F with reference to the first embodiment. In a first step A, a first dispenser 2a applies a first raw material to the conveyor belt 3. The conveyor belt 3 transports the raw material onto the work surface 6.

[0081] Subsequently, in a step B, the positioning system 10 lowers the building plate 9 to such an extent that the building plate comes into contact with the raw material applied to the conveyor belt and the distance between the building plate 9 and the conveyor belt 3 corresponds to the desired thickness of the new layer. Excess raw material is displaced here to the edges of the building plate 9 as the first layer is printed.

[0082] Then, in step C, the raw material under the building plate 9 is irradiated by a projector 7 according to a desired pattern or structure. Incident radiation hardens the material by photopolymerizing the organic binder and forms a first layer of components 8 that adheres to the building plate 9. The building plate 9 can now be lifted using the positioning system 10, leaving the majority of the remaining uncured raw material on the conveyor belt 3.

[0083] The remaining raw material left on the conveyor belt 3 and not transferred to the building plate or component is further transported by it in step D and removed from the conveyor belt 3 by a first recovery device 12a, which is designed as a blade. The hose 13a then conveys the raw material back to the first dispenser 2a driven by a pump integrated in the hose 13a.

[0084] Parallel to the recovery, new raw material can already be applied to the conveyor belt 3, analogous to step A. This can be the same dispenser as in step A, applying the same raw material, or a different dispenser applying a different raw material. The conveyor then simultaneously transports old, unused raw material away from the work surface 6 to the first recovery device 12a and new raw material from one of the dispensers 2 to the work surface 6.

[0085] In parallel, in step E, after lifting the building plate 9 with the components 8 adhered thereto, the underside of the newly printed layer is cleaned by running the surface of the component 8 with the cleaning device 11.

[0086] The raw material is also returned to the associated first dispenser 2a.

[0087] Once the first layer has been printed and cleaned and the first raw material has been completely removed from the conveyor belt 3, a second and then further layers can be applied to the component 8 by repeating the aforementioned process steps with a different hardened structure, if necessary. If a different raw material is provided for the second or a further layer, the first dispenser 2a and the first recovery device 12a are raised and instead a second or alternatively a third dispenser and a second or correspondingly third recovery device are lowered to the conveyor belt 3 and the entire process is repeated with a further raw material.

[0088] Since at least one layer of the component 8 is then already adhering to the building plate 9, in a step F corresponding to step B, the component 8 is lowered to such an extent that the distance between component 8 and conveyor belt 3 corresponds to the thickness of a desired new layer. Excess raw material is now displaced to the edges of the existing layers of component 8.

[0089] The first raw material is, for example, a ceramic raw material containing an organic binder. The second raw material, shown hatched in FIG. 2F, is for example a polymer paste which also contains the organic binder. Further layers may again contain the same or further different raw materials. Each layer can be applied with a different structure or as a different pattern, so that the production of a component with any external spatial shape and any internal structure can be generated.

[0090] FIG. 3 shows a second embodiment of the 3D printer 1, which is substantially the same as the first embodiment. However, unlike the first embodiment, in the second embodiment the conveyor belt 3 is circulated so that the foil used for the conveyor belt 3 can be reused in a circulating manner without interruption or intervention in the process. For this purpose, the conveyor belt 3 is guided over four rollers 4 which, in the present example, rotate counterclockwise at a suitable speed. The rollers may also rotate clockwise in other embodiment examples. The arrangement of the rollers 4 corresponds to the arrangement of the four rollers of the first embodiment example. In contrast, all rollers now serve as deflection rollers. The foil is not unwound or wound on any roller.

[0091] In a preferred embodiment, a cleaning device is provided along the circulated conveyor belt 3 downstream of the recovery device, which removes the last remnants of raw material from the conveyor belt 3, so that it is ensured that there is no mixing of the various raw materials.

[0092] FIG. 4 shows schematically an example of a printed, multilayer component 8. Here, the component comprises six layers 14a to 14f in four vertically stacked levels 15a to 15d. The first and third layers (15a, 15c) from the bottom each comprise two layers (14a, 14b, 14d, 14e). The top layer 14f corresponds to the layer produced first in the printing process. The lowest layers 14a and 14b were manufactured last in the printing process.

[0093] The component 8 comprises layers of three different materials, which are represented by different hatchings. One of the three materials is a metal, the others are two different polymers or ceramics.

[0094] The boundary between each of the layers is along a planar interface parallel to the outer sides 16 of the component 8. The individual layers may fully encompass a horizontal plane of the component 8, as in the second and fourth layers (14c, 14f) from the bottom in the present component 8, but the layers may also be laterally adjacent to each other as in the first and third planes (15a, 15c) of the component 8.

[0095] The layer thicknesses of the component 8 may vary. The uppermost layer 14f in the depicted component 8 is thinner, and the lowermost two layers 14a and 14b are thicker than the other layers of the component 8.

[0096] No further intermediate layers or bonding layers, such as adhesive layers, exist between the layers described.

REFERENCE SYMBOLS

[0097] 1 3D printer [0098] 2 dispenser [0099] 2a first dispenser [0100] 3 conveyor belt [0101] 4 rollers of conveyor belt 3 [0102] 4a right roller [0103] 4b first deflection roller [0104] 4c second deflection roller [0105] 4d left roller [0106] 5 carrier plate [0107] 6 work surface [0108] 7 projector [0109] 8 component [0110] 9 building plate [0111] 10 positioning system [0112] 10b light beam [0113] 11 cleaning device [0114] 12 recovery device [0115] 12a first recovery device [0116] 13 hose [0117] 13a first hose [0118] 14a-14f layers of component 8 [0119] 15a-15d layers of component 8 [0120] 16 outer surface of component 8