Method and device for removing resin adhering to additively manufactured components

Abstract

: A method for at least partially removing at least partially unreacted resin (10) adhering to components (1) produced by means of a lithographic generative manufacturing process, comprising a) loading at least one optionally closable container (3) with at least one component (1), b) arranging the container (3) at one of a number of receiving positions of a centrifuge device (7, 8) that are eccentric with respect to an axis of rotation (6), c) centrifuging the at least one container (3) by means of the heatable centrifuge device (7, 8), whereby the adhering, at least partially unreacted resin (10) is detached from the component (1), d) collecting the detached resin in an optionally removable collecting portion (12) of the at least one container (3). Figure 1

Description

[0001] Method and device for removing resin adhering to additively manufactured components

[0002] The invention relates to a method and a device for at least partially removing at least partially unreacted resin adhering to components produced by means of a lithographic generative manufacturing process.

[0003] In radiation-curing additive manufacturing processes, liquid or viscous reactive resins are usually exposed to radiation locally and with high resolution at process temperature and are thereby cured. The first layer is cured on a build platform or a substrate, to which the three-dimensional molded bodies, which are then cured layer by layer, can adhere. The layer-by-layer construction of the molded bodies can take place in a bottom-up or top-down process. Examples of radiation-curing additive manufacturing processes are stereolithography, digital light processing (DLP), two-photon lithography, inkjet, volumetric 3D printing and various process combinations. In addition, the technologies and process combinations mentioned can also be combined with additional technologies (e.g.with other generative manufacturing processes, such as fused deposition modeling, subtractive processes, fiber placement systems, fiber coating devices, drilling devices, soldering devices, dye coating systems, die bonding devices, cold and hot plasma treatment devices, wire bonding devices, spray coating and micro-droplet systems, casting devices, for example to fill components, cutting and milling devices, pick-and-place units such as robot arms and many other object manipulators). Another process is the hot lithography technology developed by the applicant. Here, viscous, highly viscous, solid and / or highly filled resins at room temperature are heated non-selectively or selectively and the viscosity is thereby reduced until the resins can be processed for layering processes.

[0004] After the 3D geometries have been successfully printed, they are still contaminated with reactive resin residues. There may be residual resin present at least on the surface of printed objects and / or in cavities, undercuts, and object details with capillary action. The unwanted residual resin is usually removed in immersion baths containing organic solvents. The solvent partially or completely dissolves the residual resin adhering to the 3D printed structures and thus removes it more or less effectively from the crosslinked photopolymer component. These solvents can only absorb small amounts of resin, and the cleaning performance can vary greatly depending on the loading of the solvent with resin residues.

[0005] Newer approaches to cleaning resin-coated components are based on the use of centrifuge technology (US 10004578 B1, WO 2019209732 A1, US 2021237358 A1). This can make it possible to subsequently reuse the separated resin, thereby reducing the chemical waste generated and the amount of resin required per component for the manufacturing process, and thus cutting production and waste costs. This also indirectly contributes to resource and environmental protection. Approaches for heating and evacuating centrifuges have also been described; however, in these cases the entire centrifuge chamber is always heated or evacuated, which inevitably leads to increased energy costs and longer process times due to the larger volume.An additional problem concerns load distribution in rotation processes: since the most homogeneous load distribution possible in the rotating drum or along the rotating circumference is essential for non-destructive operation of centrifuges, the centrifuge loading must be well planned. The design freedom of generative processes and the high degree of customization of additively manufactured components inevitably lead to a large variety of geometries, which is reflected in different masses and loads. Consequently, a homogeneous load distribution in a centrifuge is de facto never achieved and can lead to significant problems in use.

[0006] This problem is further exacerbated when spinning different printed components, especially when print batches made of highly viscous and / or highly filled resins made from different materials are to be cleaned at the same time. Since standard lithography resins usually have comparatively low viscosities below 2 Pa . s at room temperature, a uniform cleaning result can be expected with centrifuge cleaning. In the case of highly viscous and / or highly filled resins, however, an elevated temperature must usually be used for successful cleaning in order to force a reduction in the viscosity of the resin and as a result improve the cleaning performance. It is often not possible to find a common temperature for components made from different resins that delivers a satisfactory cleaning result for all possible resins.Furthermore, the strength of the components to be cleaned also plays a key role. It is well known that strength decreases with increasing temperature, and this can lead to irreversible component deformation or even damage when cleaning using rotational motion. This complicates the simultaneous cleaning of components constructed from different resins and the simultaneous cleaning of different 3D printing batches.

[0007] This situation occurs frequently in additive manufacturing companies and is logistically difficult to avoid, as order intake and printing times per component or component batch can fluctuate by several orders of magnitude in additive processes, and, especially in lithographic processes, component cleaning must be carried out quickly after the printing process. Mixing several printing materials is particularly fatal when recycling spun-off resin residues and consequently completely prevents the reuse of such residual resin quantities.

[0008] The invention therefore aims to improve centrifuge processes and consequently to reduce energy costs, increase throughput times and guarantee the efficient separation and improved preparation for recycling of residual resin.

[0009] To achieve this object, the invention provides, according to a first aspect, a method for at least partially removing at least partially unreacted resin adhering to components produced by means of a lithographic generative manufacturing process, comprising: loading at least one optionally sealable container with at least one component, arranging the container at one of several receiving positions of a centrifuge and / or rotation device that are eccentric with respect to a rotation axis, centrifuging the at least one container by means of the centrifuge device, whereby the adhering, at least partially unreacted resin is detached from the component, collecting the detached resin in an optionally removable collecting section of the at least one container.

[0010] The invention is therefore based on the idea of ​​providing at least one container into which at least one resin-contaminated, 3D-printed component is introduced via an opening and, if necessary, fastened, and which can optionally be closed. The component can be introduced into the container as an individual part, fastened in special holders, or adhered to a component carrier, in particular a construction platform. If the component is fastened in a special holder, existing holes in the printed component geometry can be used, for example, to fix the component with screws. If the component is arranged on a component carrier, a printed plate, a printed layer, or an existing component onto which at least one lithographically generatively manufactured structure is placed and / or printed can be used as the component carrier.Ideally, a build platform is attached to one of the container walls. The wall facing away from the axis of rotation is designed so that it can ideally accommodate spun-off resin and direct it into the collection section, which is preferably located at the bottom, such as a resin collection basin. After loading and optionally closing the at least one container, it can be heated and / or placed under vacuum if required. Alternatively or additionally, according to a preferred embodiment of the present invention, the centrifuge chamber of the centrifuge device can be heated, wherein the centrifuge chamber is preferably heated with a heating device comprising a compressor and / or fan unit and a heating element, and the heated air is circulated. This is particularly effective when working with open containers. The introduction of various gases, liquids or liquid vapor is also possible.The centrifuge chamber is understood to be a space enclosed by a housing of the centrifuge device which contains the containers.

[0011] The container preferably has holes to ensure better flow of fluid through the container.

[0012] One or more containers can then be attached to the rotor or a rotor platform in the centrifuge, whereby the temperature, vacuum, etc. in the centrifuge chamber or inside the container can optionally be controlled. The containers then move in a circle around the axis of rotation of the centrifuge device, which separates the resin from the component surface into the container. Typical rotation speeds are in the range from 50 to 5000 and preferably between 300 and 2000 revolutions per minute. Optionally, there are additional rotating and / or pivoting movements of the container around one or more axes of rotation, which can be inside and / or outside the container or a combination of such axis conditions. The remaining residual resin is caught by the container wall or container lining facing away from the axis of rotation and in the collection section, i.e.a volume portion of the container designated for collection. Particularly suitable container linings include fluorinated polymers such as PTFE or FEP, as well as metals such as aluminum or aluminum alloys.

[0013] Another major advantage of the invention is that the components to be cleaned can be placed directly into the container while still on the build platform. These containers can be separated from the rotor quickly and easily. This ensures rapid loading and unloading of the centrifuges and avoids the more laborious and time-consuming removal of the components directly from the rotor. This leads to significant savings in process time and improved centrifuge utilization in everyday production.

[0014] The invention is further based on the idea of ​​dividing the available total volume of the centrifuge device into smaller areas which are separated from one another in the circumferential direction and which are arranged around the axis of rotation. Accordingly, the invention provides that the container or containers are each arranged at one of a plurality of receiving positions of a centrifuge device which are eccentric with respect to a rotation axis. The total volume of the centrifuge device available for receiving components is thus formed by the sum of the container volumes, with a receiving position being provided for each container. The containers can preferably be fastened to the rotor of the centrifuge device at the respective receiving position in a form-fitting manner.The provision of a plurality of containers instead of a single centrifuge volume increases flexibility and enables individual adjustment of the process parameters, as will be explained in more detail below.

[0015] With highly viscous resins, separation is particularly supported and generally considerably improved by the application of heat. As already mentioned, increased temperature reduces the viscosity of the adhering residual resin, which makes separation from the component easier. This can be achieved, among other things, by applying heat throughout the centrifuge chamber. The heat can be introduced into the centrifuge chamber by convection or radiation. Since increased temperatures also reduce the mechanical strength of the components, which can lead to irreversible deformation or component damage during centrifugation, a compromise regarding the temperature between viscosity and strength must be found individually for each material / resin system. This makes simultaneous cleaning of, for example, two, three or four resin systems in one centrifuge at the same time very difficult.Heatable containers offer the optimal solution here if, as is the case with a preferred embodiment of the invention, the temperatures for each container can be individually adjusted. Furthermore, the small containers compared to the total centrifuge volume are a great advantage because the heating times and the energy costs incurred are significantly lower due to the small volume of the containers. Appropriate optional thermal insulation of the heated containers is advantageous. In addition, the spun-off residual resin is collected in the container, which prevents resin contamination in the centrifuge and consequently increases throughput times. This also means that containers containing different components and resins can be spun at the same time. A sieve or filter built into such containers prevents any broken support structures from getting into the collection section.An optionally installed vacuum connection helps to degas the collected resin in the collection section during centrifugation, or at least to prevent the introduction of air or gases into the resin and resin foaming. Particularly in the manufacture of medical or medical-technical components, such contamination-free use of a centrifuge unit is essential, and only by collecting the spun-off residual resin in such a defined manner, for example, in disinfectable containers, is there a chance of reusing such resin quantities for production.

[0016] A further major advantage is that quick material changes are possible without contamination with other resins. For example, four different containers with four different materials at four different temperatures and / or pressures can be cleaned at the same time in the same centrifuge, provided that four containers can be fixed in place. In an alternative design, the centrifuge can actively support the active heating and / or degassing and / or flooding of the containers. For this purpose, either electrical and / or pneumatic and / or mechanical connections can be provided, or the container atmosphere can be indirectly controlled by placing it in or introducing it into a heated and / or degassed receiving zone. Alternatively, such a container can also be filled and / or flooded with a defined gas, e.g. a protective or reaction gas.

[0017] If a homogeneous mass distribution in the centrifuge is not possible due to the quantity of components or build plates to be cleaned—which, as mentioned above, is the rule rather than the exception in additive manufacturing—such a homogeneous mass distribution can be achieved by inserting counterweights into the centrifuge. The entrainment of counterweights represents "dead mass" in terms of the energy efficiency of the process. In special cases, the insertion of counterweights is necessary to ensure the smooth operation of the centrifuge. The homogeneous distribution can be determined using scales, which can also be integrated into the centrifuge.

[0018] In a special embodiment of the invention, the containers have closable openings (holes) at different heights (in the z-axis) through which spun-off resin can escape from the containers or is pushed out by centrifugal forces (usually radially). By opening the appropriate hole for a container, the height at which the resin escapes from this container in the centrifuge can be controlled. Resin chutes running around the centrifuge are arranged at different heights (in the direction of the rotation axis). This means that resin can be separated indirectly via the centrifuge itself, even from containers with different fillings. An additional advantage of this embodiment is that although the resin containers can be individually preheated or heated, degassing can take place centrally via the centrifuge and is therefore very practical.

[0019] In a simpler embodiment of the invention, the at least one container can also be designed without a lid and / or without the resin collection section being removable. Furthermore, it can be expedient to insert holes or openings in certain areas of the container to ensure better flow. This can lead to faster fluid circulation when hot air or gases are introduced, which reduces the process time. It is advantageous to conduct the hot air or hot gas in a closed circuit in order to reduce the spinning time, keep energy costs low, and also increase operational reliability with regard to the escape of chemically contaminated gases.

[0020] In an alternative embodiment, the at least one container is designed such that it is rotatably mounted about one or more defined additional axes of rotation, which can be located both inside the container and outside the container or in any combination thereof. In addition to the rotary movement of the centrifuge rotor in the centrifuge, the container can therefore perform additional rotary and pivoting movements. Alternatively, the at least one component or the component carrier can be rotatably mounted inside the container, with the container itself remaining fixed in place on the rotor. In both cases, a wide variety of load change profiles and, above all, load change speeds occur.This is particularly relevant given that additively manufactured components can withstand widely varying G-forces, that these tolerated G-forces can be direction-dependent depending on the material and geometry, and that additively manufactured components can also contain cavities and undercuts, which make multiple load changes for the discharge of resin residues appear advantageous. In this case, it is advantageous if the containers, depending on their design, can perform purely passive rotating and swiveling movements. These movements depend on the rotation profile and load or mass distribution of the containers themselves, or if such additional axial movements (rotating, swiveling) are implemented by active drive mechanisms of the container supports in the centrifuge or by special interfaces between the container and the centrifuge.

[0021] In a special embodiment of the invention, the resin collected in the collection section can be closed with a lid after centrifugation has ended and homogenized in an intermediate step. Alternatively, the resin can also be emptied from the container and optionally homogenized. The homogenization step is particularly advantageous for resins filled with fillers, since the centrifugal force can lead to settling of the fillers. This can already be the case for lightly filled photoresins of 0.1 to 1 wt. % filler; in any case, however, for photoresins with filler levels of 1 to 10 wt. % and particularly pronounced for photoresins with fillers of 10 to 95 wt.-%, whereby the difference between the resin density and the filler density, the morphology of the fillers added, the general particle size and particle size distribution of the fillers in the resin, and surface-chemical effects between the resin and filler can be decisive factors for the demixing. If necessary, the separated resin can be homogenized using various mixing methods, with one or more mixing methods being able to be carried out simultaneously or sequentially. Alternatively, it is possible to combine several batches of separated residual resin and optionally homogenize them afterwards, or to mix them with fresh resin and optionally homogenize them. The newly obtained photoresins can then be reused for the 3D printing process.It should be noted that unfilled resin systems in particular tend to show no or only negligible separation in the centrifuge process and consequently a homogenization step is usually unnecessary.

[0022] Whether the resin that has been spun off and subsequently collected in the container can be reused can be determined by various analyses to control and ensure resin quality. Some classic methods for quality control and quality assurance of photoreactive resins are measuring the resin viscosity, measuring the degree of curing of the resin, determining the particle distribution in the resin, opacity measurements, spectrometric methods and / or spectroscopic methods. Typical methods for measuring resin viscosity include flow cups, rotational viscometers, capillary viscometers, falling body viscometers or Melt Flow Index (MFI) measuring devices. Viscosity is a particularly good indicator of resin quality. For example, partial crosslinking of the resin usually leads to an increase in viscosity, and the settling of filler particles leads to a viscosity gradient in the resin.One way to measure curing is to expose the photoreactive resin to a defined radiation dose or intensity for a certain period of time, which should lead to the curing of a thin film. This film, usually a few to several hundred microns thick, can then be measured (e.g., with an outside micrometer, optically, or electronically).

[0023] Particle distributions can be easily determined using a grindometer, for example. Quality control is successful when the measurement results of the respective method are as close as possible to the results of the starting resin. The maximum possible deviation of the measurement results from the starting resin / fresh resin depends heavily on the specific resin. Reasonable tolerance ranges are ±5%, ±10%, ±15%, ±20%, ±25%, or higher, based on the respective measured value of the starting resin / fresh resin.

[0024] The at least partially unreacted resin to be removed from the component is preferably a photoresin. Photoresins typically consist of (end-group-modified, reactive) oligomers, low-molecular-weight mono- and / or multifunctional reactive diluents, fillers, additives, and / or at least one photoinitiator. Examples of (end-group-modified, reactive) oligomers are, in principle, all polymers, polyaddition products, and polycondensation products, for example, polyethers, polyesters, polyurethanes, polycarbonates, polyamides, polythioethers, polythioesters, silicones, etc. In most cases, the reactive components have at least one or more reactive end groups, which cure upon exposure to radiation of a suitable wavelength, decomposing at least one photoinitiator and forming a solid, cross-linked polymer.Examples of reactive end groups include unsaturated double bonds, vinyl, acrylates, methacrylates, acrylamides, allyl compounds, norbornenes, vinyl ethers, epoxides, oxetanes, maleimides, and thiols, to name a few. Typical photoinitiators, upon decomposition or activation, form radicals, cations, anions, or other active species (e.g., Grubbs catalysts), which trigger polymerization upon irradiation at specific wavelengths and usually result in a cross-linked photopolymer.

[0025] Photoresins can also contain a high proportion of organic, inorganic, ceramic, and / or metallic fillers, resulting in hybrid materials after polymerization. Fillers can also be oligomers, prepolymers, and / or polymers. Typical filler contents range from 1 to 95 wt%. After purification, photopolymers filled with inorganic, ceramic, or metallic fillers can be further processed into ceramics or metals in debinding and sintering processes. Furthermore, these photopolymers can also consist of dual-cure systems, with a first crosslinking process for shaping occurring during the 3D printing process, and a second crosslinking process triggered, for example, thermally, in downstream processes.

[0026] Preferably, the at least partially unreacted resin to be removed from the component is a resin that is still medium-viscous at room temperature (20°C) with a viscosity of 5 to 30 Pa.s, a high-viscosity resin with a viscosity of 30 to several hundred Pascal seconds or a resin with a very high viscosity of 1,000 Pa.s and higher.

[0027] The method according to the invention is preferably embedded in a process chain of a manufacturing process. In general, the process chain comprises, as an initial step, digital preparation, in which the three-dimensional components to be manufactured are digitally prepared, after which the components are printed using a lithography-based additive manufacturing process. This can then be followed by one or more optional pre-cleaning steps for the components. The components are then cleaned according to the cleaning method according to the invention, and finally, the final three-dimensional component is obtained in one or more downstream processes.

[0028] In the digital preparation step, existing 3D data for a component is optimized and prepared for the printing process according to the specifics of the subsequent generative manufacturing process. These processing steps on the 3D model can include, among other things, data error analysis and possible data repair, scaling, positioning of the 3D models on the digital build platform, geometric compensation, for example for over-polymerization that occurs in radiation-curing processes, creation of support geometries, and the generation of layer information. All sub-steps can be carried out manually, semi-automatically, or fully automatically. Alternatively, the print data can also be created directly in CAD software according to process-dependent design guidelines, including all sub-steps.

[0029] In photopolymerization-based printing processes, the photo resins are irradiated locally with radiation in high resolution using a lithography-based method, whereby the irradiated areas harden into a solid. The process takes place step by step or continuously, and the previously prepared three-dimensional structures are built up. The components are usually located on a build platform. Build platforms can come in a wide variety of designs. They can be made from various materials, such as metals, ceramics, plastics, hybrid materials, composites, or blends. They usually have a smooth, flat surface, but roughened surfaces, recesses, and / or holes can also be advantageous.Recesses and holes in the build platform can be useful for centrifuge cleaning because the resin can be thrown off by centrifugal forces through the holes and recesses from the component to the build platform and through the recesses and holes in the build platform.

[0030] The build platforms and / or components can be made uniquely identifiable and distinguishable using unique identifiers (UIDs) (e.g., using chips, barcodes, QR codes, RFID, numbering, NFC, etc.). This also facilitates identification throughout the entire process chain, from digital preparation of the parts through 3D printing, post-processing, to quality control of the final component or even integration into the final product.

[0031] After a successful 3D printing process, the components can be finalized or refined. These processes are referred to as post-processing and comprise a multitude of downstream processes in order to achieve the final component properties. Typical post-processing steps are cleaning using centrifugal forces, cleaning with solvents using turbulent flows, directed jets, ultrasound, steam, aerosols and / or pressure swing processes, cleaning using gases and / or directed gas flows (e.g. compressed air, heated compressed air), drying of components, post-curing, which can be carried out in various ways (e.g. thermally, radiation-induced, microwaves), removal of support structures as well as coloring, coating (e.g. metal or plastic coating), painting, and assembly of 3D printed components (e.g. with microchips, pins, cables, electrical contacts).Furthermore, other generative manufacturing processes can be used, such as fused deposition modeling, subtractive processes, fiber placement systems, fiber coating devices, drilling devices, soldering devices, dye coating systems, die bonding devices, cold and hot plasma treatment devices, wire bonding devices, spray coating and micro-droplet systems, casting devices for filling components, cutting and milling devices, pick-and-place units such as robot arms, and many other object manipulators. All of the post-processing methods mentioned can, where appropriate, be performed in any order, not at all, simultaneously, sequentially, and as often as desired, as well as manually and / or semi-automatically and / or fully automatically. It should also be mentioned at this point that post-processing steps can optionally also take place before centrifuge cleaning.For example, solvent cleaning can be carried out beforehand and the centrifuge step can be used to separate the residual solvent on the components.

[0032] After post-processing, a final 3D component is obtained.

[0033] Examples of such 3D components are medical, dental and orthodontic applications such as intraoral applications such as regulations, aligners, splints or attachments, medical technology products, the food industry, electronic components such as plug connectors, connectors, plugs or housings, 3D printed shoe soles, parts for the aerospace industry, applications in the military sector, applications in the consumer goods sector, applications in the mobility, automotive and electromobility sector, 3D printed parts for use in the energy sector, applications in the sports sector such as shoe soles or cushioning elements, applications in the printed electronics sector, applications in the tool manufacturing sector, to name just a few.

[0034] According to a second aspect, the invention relates to a device for at least partially removing at least partially unreacted resin adhering to components produced by means of a lithographic generative manufacturing process, in particular for carrying out the method according to the invention, comprising a centrifuge device with a rotor which can be driven to rotate about a rotation axis and a plurality of containers, each with a container opening provided for loading with at least one component and fastening means for fastening the at least one component in the container interior, wherein the rotor has a plurality of receptacles which are eccentric with respect to the rotation axis for the eccentric arrangement of one of the plurality of containers, wherein the containers optionally have a closure part for closing the container opening and an optional collecting section for collecting detached resin.Preferred embodiments of the invention.

[0035] Device are specified in the subclaims.

[0036] The invention is explained in more detail below with reference to exemplary embodiments shown in the drawing. In these, Fig. 1a-e show various designs of a centrifuge device with rigidly arranged containers, Fig. 2 shows an alternative design of a centrifuge device with components mounted so as to be rotatable relative to the centrifuge platform, Fig. 3a-e show several designs of a container for arrangement in the centrifuge device, Fig. 4a-d show various geometric options for the container walls, Fig. 5 shows an example sequence of the centrifuging process, Fig. 6 shows an example reuse cycle, Figs. 7a, 7b and 7c show alternative options for a centrifuge design, Fig. 8 shows an embodiment of a container with a specially designed wall and Fig. 9 shows a view of a container from above.

[0037] The illustrations shown and described below serve only to facilitate a better understanding of the invention and do not represent a limitation of the invention. The dimensions of the components shown can vary as desired. To facilitate understanding of the invention, only the essential assemblies and parts of the invention are shown. For example, fastenings, connections, and / or transmissions can be implemented in a wide variety of ways.

[0038] Fig. 1a shows a centrifuge device comprising a static outer wall 5, a rotor rotation axis 6 and a rotor 7 driven to rotate about the rotor rotation axis. At opposite ends of the rotor 7, at a respective receiving position, a fastening device 4 for fastening the container 3 to the rotor 7 is arranged. In the container 3, at least one component 1 adhering to a construction platform 2 is arranged or fastened, which component was produced by means of a lithographic generative manufacturing process and to which at least partially unreacted resin adheres, which is detached by centrifugation. The construction platform 2 together with the component 1 are arranged in the container 3 such that the side of the construction platform 2 facing the component 1 is directed radially outwards.

[0039] Fig. 1b shows a similar centrifuge structure to Fig. 1a, wherein the construction platform 2 together with the associated component(s) 1 are arranged in the container 3 such that the side of the construction platform 2 facing away from the component 1 is directed radially outwards.

[0040] Fig. 1c and 1d show a modified embodiment of the centrifuge device with a rotor platform 8 driven to rotate about a central axis of rotation. The rotor platform 8 has a plurality (here: two) of eccentric receiving positions for receiving a container 3, each of which is provided with a fastening device 4 for mounting the container 3 on the rotor platform 8. The term rotor platform does not represent a geometric limitation of the rotating device.

[0041] While the containers 3 are mounted on the outer wall of the rotor platform 8 in the embodiment according to Fig. 1c, they are mounted on the inner wall of the rotor platform in the embodiment according to Fig. 1d. Accordingly, the construction platform 2 including component 1 is arranged in the container 3 such that either the side facing the component 1 (Fig. 1c) or the side facing the

[0042] Component 1 facing away from the side (Fig. Id) of the construction platform 2 is directed radially outwards

[0043] Fig. 1e shows an alternative embodiment of the centrifuge device with a rotor platform 8 on which one or more, in this special case four, containers 3 are fastened.

[0044] The components 1 shown in Fig. 1a-e, which are optionally printed on construction platforms 2, can be attached facing the axis of rotation, facing away from it or in any other way.

[0045] Fig. 2 shows a centrifuge device with a rotor platform 8, wherein the basic rotation about the axis of rotation 6 can be superimposed with a further rotation about a further axis of rotation 6a arranged eccentrically to the axis of rotation 6. For this purpose, according to a first embodiment, the respective container 3 is arranged statically relative to the rotating rotor platform 8 and the associated construction platform 2 is mounted so as to be rotatable about the further rotor axis 6a relative to the container 3. According to a second embodiment, the container 3 is mounted so as to be rotatable about the further rotor axis 6b and the associated construction platform 2 is fixedly fastened to the container 3. In all of the examples given in Fig. 1, 2 and 8, the movably mounted assemblies can rotate as desired both clockwise and counterclockwise about the axis of rotation and / or axes of rotation.

[0046] Fig. 3a-e each shows a side view of a container 3, wherein the construction platform 2 with the component 1 is fastened in the container 3 via a fastening device 9. Due to the centrifugal forces (F Z f) the resin 10 can be detached from the component 1 and collected in a collection section or resin reservoir 12 at the bottom of the container 3. Ideally, the wall or walls optionally opposite the component 1 are slightly inclined downwards so that the resin can more easily reach the resin reservoir due to the centrifugal forces. The build platform 2 can be attached to the fastening device 9 at different angles. In Fig. 3a the build platform 2 is arranged at a right angle to the centrifugal force. In Fig. 3b the build platform 2 is tilted slightly upwards compared to the orientation according to Fig. 3a and in Fig. 3c the build platform 2 is tilted slightly downwards compared to the orientation according to Fig. 3a.

[0047] In Fig. 3c, the container 3 is also equipped with a lid 11 to close the container 3. Furthermore, the resin reservoir 12 is designed to be removable and can thus be emptied more easily.

[0048] Fig. 3d shows a container 3 in which two construction platforms 2 are mounted rotatably about a further rotation axis 6a, and which additionally has a permeable filter or a permeable sieve 13 which is arranged between the component 1 and the resin reservoir 12.

[0049] Fig. 3e shows the case of a resin-permeable build platform 2a, where the resin permeability can be achieved through recesses or holes in the build platform 2a. Here, the resin residues are separated from the component 1 by centrifugal forces toward the build platform 2a and then pass through the recesses or holes into the optionally removable resin reservoir 12. Figs. 4a-d show various geometries for the container wall and the container rear wall from above. These can be rectangular, oval, trapezoidal, or polygonal geometries, for example.

[0050] Fig. 5a-c describe an exemplary structure of a container 3 and an exemplary process sequence. Fig. 4a shows a container 3 which is attached to the rotor 7 via a fastening device 4. The rotor 7 contains a power supply and / or cable 15, which can, for example, operate a heater or ensure data transfer, as well as a vacuum line or a gas and / or liquid inlet 16, via which the container 3 can be flooded. This rotor 7 could also be a rotor platform 8. In Fig. 4a, the container 3, closed with a lid 11, with resin-coated components 1 is subjected to centrifugal forces (F Zf). In this case, resin residues 10 are spun off the component 1, pressed through a sieve or filter structure 13 and collected in the resin reservoir 12. The sieve 13 primarily prevents any components or support structures that may have become detached from the resin reservoir 12. After the centrifugation process is finished (Fig. 4b), the parts 14 that have largely been freed of resin can be ejected from the centrifuge together with the build platform 2 by opening the container lid 11. Analogously, the resin reservoir 12 filled with resin 10 can be removed from the container 3. In step (c), the cleaned components 14 are fed to the further post-processing process and the separated resin reservoir 12 is fed to the recycling cycle after optionally being closed with a closure cap 17.Subsequently, the container 3 can be loaded with a new construction platform 2 with resin-coated components 1 and a new, cleaned resin reservoir 12 can be attached to the container 3.

[0051] Fig. 6 shows possible recycling cycles for the separated residual resin. This allows the separated residual resin to be mixed directly with fresh resin and then reprocessed in the 3D printer. It is also possible to homogenize one or more separated residual resin batches and then feed them into the 3D printing process, or to mix the homogenized residual resin with fresh resin before returning it to the 3D printer.

[0052] Fig. 7a shows the cross-sectional view of a preferred centrifuge construction with containers. Here, the containers 3 are fastened by means of a fastening device 4 on a rotor platform 8 which rotates about a rotor axis 6. The outer of the two fastening devices 4 preferably corresponds to a solid ring construction which is fastened along the outer edge of the rotor platform 8 and holds the containers 3 on the rotor plate. The fastening devices 4 can also be designed such that the container is fixed obliquely to the rotor axis 6. The outer housing 5 of the centrifuge can be closed with a lid 11a. Optionally, the centrifuge chamber can also be heated, for example with hot air, infrared radiators and / or heating sleeves.

[0053] In an alternative embodiment ( Fig . 7b ) of the

[0054] In a centrifuge construction, the containers 3 are mounted such that the centrifugal forces acting on the components 1 point towards the printed surface, for example a build platform 2, i.e. the components 1 are mounted pointing in the direction of the rotation axis 6 or in an upright position. This is particularly preferred when the components 1 are sensitive to tensile stress or when special component geometries can thereby ensure preferential resin drainage. Optionally, the centrifuge chamber enclosed by the outer housing 5 and the lid 11a can also be heated (e.g. hot air, infrared radiators and / or heating sleeves), evacuated and / or purged with steam or gases.

[0055] Fig. 7c shows another embodiment of the centrifuge, in which the centrifuge chamber is connected to a heating device consisting of a compressor and / or fan unit and / or pump unit 16 (e.g., a radial or axial compressor) and a heating element 17 (e.g., a heating cartridge or heating coil). A possible movement of the air streams 15 is shown.

[0056] In Fig. 7c, the containers 3 are designed without lids and are provided with holes at preferred locations to allow for better circulation of preheated air. As shown in Fig. 7c, the preheated air 15 is preferably circulated during the centrifugation process to minimize energy consumption.

[0057] An example of holes or recesses 18 in the container wall 3 is shown in Fig. 8. These holes or recesses are designed to ensure better flow of fluids (e.g., air). These are preferably located on the side facing away from the resin collection wall.

[0058] Fig. 9 shows a view of a container 3 from above. The

[0059] The container is designed so that the build platform 2 with the resin-coated components 1 can be easily moved into and out of the container via a form-fitting rail. The form-fitting rail also has the advantage of ensuring user safety and eliminating the need for additional securing measures. Alternatively, the build platforms could also be provided with a lateral groove, which can then be pushed into a designated guide with a form-fitting fit and thus locked in place for the spinning process.

Claims

Patent claims:

1. Method for at least partially removing at least partially unreacted resin (10) adhering to components (1) produced by means of a lithographic additive manufacturing process, comprising: Loading at least one preferably sealable container (3) with at least one component (1), arranging the container (3) at one of several eccentric receiving positions of a centrifuge device (7, 8) with respect to an axis of rotation (6), centrifuging the at least one container (3) by means of the centrifuge device (7, 8) whereby the adhering, at least partially unreacted resin is detached from the component (1), collecting the detached resin in an optionally removable collection section (12) of the at least one container (3).

2. Method according to claim 1, characterized in that the at least one component (1) is arranged adhering to a component carrier (2), in particular a building platform, in the container (3).

3. Method according to claim 1 or 2, characterized in that the at least one component (1) or the component carrier (2) is located in the container (3), preferably on a side or wall of the container facing towards or away from the axis of rotation (6) of the centrifuge device (7, 8). (3) is attached.

4. Method according to claim 1, 2 or 3, characterized in that a centrifuge chamber of the centrifuge device (7,8) is heated, preferably the centrifuge chamber is heated by a heating device comprising a compressor and / or fan unit (16) and a heating element (17) and the heated air is circulated.

5. Method according to one of claims 1 to 4, characterized in that the container (3) has holes (18) to ensure better flow through the container (3) with fluid.

6. Method according to one of claims 1 to 5, characterized in that the at least one container (3) is closed before centrifugation.

7. Method according to one of claims 1 to 6, characterized in that at least one component (1) arranged in the container (3) is heated by means of a heating device before and / or during centrifugation.

8. Method according to one of claims 1 to 7, characterized in that the loading step comprises arranging at least one component (1) in a first container (3) and arranging at least one further component (1) in a second container (3), wherein the heating of the first and second containers (3) is controlled such that a different temperature prevails in the first container (3) during centrifugation than in the second container (3).

9. Method according to one of claims 1 to 8, characterized in that the interior of the container (3) is placed under reduced pressure after closing.

10. Method according to one of claims 1 to 9, characterized in that the at least one container (3) is rotated relative to a rotor (7, 8) of the centrifuge device carrying the at least one container (3) during centrifugation and may be driven to rotate.

11. Method according to one of claims 1 to 10, characterized in that the collecting section (12) together with the detached resin (10) arranged therein is separated from the container (3).

12. Method according to one of claims 1 to 11, characterized in that the resin (10) collected in the collection section (12) is recycled to a method for the lithographic additive manufacturing of components and is preferably subjected to quality control before recycling, wherein the quality control preferably includes a viscosity measurement and / or a measurement of the through-curing.

13. Device for at least partially removing at least partially unreacted resin (10) adhering to components (1) produced by means of a lithographic additive manufacturing process, in particular for carrying out a method according to one of claims 1 to 12, comprising a centrifuge device (7, 8) with a rotor (7, 8) driveable to rotate about an axis of rotation (6) and a plurality of containers (3) each with a container opening provided for loading with at least one component (1) and fastening means (9) for fastening the at least one component (3) inside the container, wherein the rotor (7, 8) has a plurality of eccentric receptacles with respect to the axis of rotation (6) for the eccentric arrangement comprising one of the plurality of containers (3), wherein the containers (3) optionally have a closure part (11) for closing the container opening and an optionally removable collection section (12) for collecting detached resin (10).

14. Device according to claim 13, characterized in that the centrifuge device (7, 8) has heating devices, each of which is assigned to a respective container (3), and that means for individual control of the heating devices are provided so that the temperature of each container (3) can be set separately.

15. Device according to claim 13 or 14, characterized in that the centrifuge device (7, 8) has at least one vacuum source which is fluidically connected to the interior of the containers (3) via a controllable closure part.

16. Device according to claim 13, 14 or 15, characterized in that the containers (3) are rotatably mounted on the rotor (7,8) relative to the rotor (7,8).

17. Device according to one of claims 13 to 16, characterized in that the containers (3) each have a fastening device (9) for fastening the at least one component (1) or component carrier on one side or wall of the container (3) facing towards or away from the axis of rotation (6) of the centrifuge device (7, 8). ( 2 ) exhibit .

18. Device according to one of claims 13 to 17, characterized in that the containers (3) each have a Collection section (12) shall have an upstream retention device (13), such as a sieve or a filter.

19. Device according to one of claims 13 to 18, characterized in that the collecting section (12) is detachably connected to the container (3) and is preferably designed as a collection tray.

20. Device according to one of claims 13 to 19, characterized in that the collecting section (12) is fluidically connected to a side or wall of the container (3) facing away from the axis of rotation (6) of the centrifuge device (7, 8), in particular is arranged below it.

21. Device according to one of claims 13 to 20, characterized in that the collecting section (12) is designed as a collection tray, on the wall of which facing away from the axis of rotation (6) at least one closable opening is formed, and that the centrifuge device (7, 8) has at least one annular, in particular stationary, collecting channel which surrounds the circular path of the opening.

22. Device according to one of claims 13 to 21, characterized in that a centrifuge chamber of the centrifuge device (7, 8) is connected to a compressor and / or fan unit (16) and a heating element (17).

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