Hybrid 3D printer, and hybrid 3D printing method

Abstract

The invention relates to a hybrid 3D printer and to a hybrid 3D printing method. The aim of the invention is therefore to eliminate the disadvantages of the prior art and provide a hybrid 3D printer and a hybrid 3D printing method, the hybrid 3D printer and the hybrid 3D printing method allowing for the bilateral building of biological and technical structures using a wide variety of additive manufacturing technologies and materials. This aim is achieved by means of the features specified in the claims.

Description

Hybrid 3D printer and hybrid 3D printing process description

[0001] The invention relates to a hybrid 3D printer and a hybrid 3D printing method.

[0002] Light-based 3D printing enables the computer-aided production of 3D structures, point-by-point, layer-by-layer, or volumetrically, using build spaces that are at least partially filled with a light-curing fluid. A variety of technologies exist, which, depending on their mode of operation, are categorized into vector-based (stereolithography), mask-based (digital light processing), and volumetric additive manufacturing processes, and have evolved extensively over the past decades.

[0003] Levato, R., Dudaryeva, O., Garciamendez-Mijares, CE et al. Light-based vat-polymerization bioprinting. Nat Rev Methods Primers 3, 47 (2023). https: / / doi.org / 10.1038 / s43586-023-00231-0 provides a comprehensive overview of these technologies.

[0004] Nowadays, such technologies are used in an interdisciplinary manner, particularly in biomedicine and bioelectronics, and especially in sensor technology and microfluidics.

[0005] Bioprinting, the additive processing of cell-laden biomaterials, as a subfield of tissue engineering and regenerative medicine, is still in its early stages of development. Despite impressive results, it remains a major technical challenge, especially to mimic complex tissues, including their material, multicellular, and functional architecture. One of the greatest challenges remains processing high cell densities in a vital manner, as well as processing cells or structural components and multiple materials in a single process. April 14, 2025

[0006] Roland Yingjie Tay, Yu Song, Dickson R. Yao, Wei Gao, Direct-ink-writing 3D-printed bioelectronics, Materials Today, Volume 71, 2023, Pages 135-151, ISSN 1369-7021, https: / / doi.org / 10.1016 / j.mattod.2023.09.006 provides a comprehensive overview of the use of additive processes in the field of bioelectronics.

[0007] US 2018 / 0 243 982 A1 discloses a system for the simultaneous deposition of thermoplastic and thermoset plastic, comprising a substrate holder, an extruder for thermoplastic molten material, a photopolymerizing light source, a prepolymer container, and a controller. Structures are built from above on a build platform.

[0008] JP 2017 056 591 A discloses a device for three-dimensional molding capable of improving the properties of a three-dimensional molded object and increasing the process speed. Structures are built up from below on a build platform (holding member).

[0009] US 4,575,330 A relates generally to improvements in devices for forming three-dimensional objects from a liquid medium, and more particularly to stereolithography, which uses lithographic techniques to produce three-dimensional objects, allowing such objects to be formed quickly, reliably, accurately, and economically. Structures are built up either from above, from below, or from the side of a build platform (lifting platform).

[0010] A disadvantage of the cited prior art is that known devices and methods have a build platform that hinders or prevents bilateral additive manufacturing, both during a bottom-up and a top-down approach. Description of the invention

[0011] It is the object of the invention to overcome the disadvantages of the prior art 14.04.2025 and to provide a hybrid 3D printer and a hybrid 3D printing process, whereby the hybrid 3D printer and the hybrid 3D printing process enable bilateral construction of biological and technical constructs using a wide variety of additive manufacturing technologies and materials.

[0012] This problem is solved by the features listed in the claims.

[0013] The problem is solved by a hybrid 3D printer, wherein the hybrid 3D printer has a build space, a pump system, at least one first additive manufacturing technology, and at least one second additive manufacturing technology. The build space has a build surface and a first optical access. The first optical access is arranged on an underside of the build space and is the build surface of the build space. The at least one first additive manufacturing technology is light-based and optically connected to the build space via the first optical access of the build space. The pump system is configured to fill and / or empty the build space with at least one fluid. The at least one second additive manufacturing technology is arranged above the build space. Preferably, the first additive manufacturing technology is different from the second additive manufacturing technology.

[0014] The build envelope is the space available for a 3D printing process. The build envelope is therefore an area defined by length, width, and height within which the hybrid 3D printer can produce constructs using additive manufacturing technologies. The build envelope thus defines the maximum dimensions of a finished construct. April 14, 2025

[0015] The build area of ​​the build space is the area on which a first layer of a construct to be manufactured is built up using the at least one first and / or at least one second additive manufacturing technology. The construct to be manufactured is then further built up on this first layer. A layer is defined here by a material composition and material arrangement rather than by a layer thickness. A layer can have one material or one material composition. However, a layer can also have multiple materials or material compositions that are arranged in a construct-specific manner. The person skilled in the art will recognize that there are any number of possible arrangements on a build area. For example, multiple materials or material compositions can be arranged next to one another. Inclusions, for example in the form of capsules, can also be created.By using specific materials, so-called sacrificial materials, cavities can be created in the finished construct.

[0016] The build surface of the build chamber is simultaneously the first optical access of the hybrid 3D printer. The optical access is therefore a flat component that is at least partially permeable to electromagnetic waves. Transmission can be limited to one or more wavelength ranges, in particular to wavelengths in the visible range. Furthermore, the first optical access can be designed such that it can change its transparency with respect to one or more wavelength ranges. This is the case, for example, for intelligent glass, also called switchable or smart glass. A change in transparency can occur abruptly, gradually, or continuously. For example, a transmission can be limited to a 14.04.2025 increasing construction height of a construct to be manufactured can be increased serially (graduated or continuously) in order to increase a light penetration depth into the construction space, or a radiation energy at a given point in the construction space, of at least one first additive manufacturing technology which is optically connected to the construction space.

[0017] The first additive manufacturing technology comprises a radiation source or light source. An arrangement of the first additive manufacturing technology below the build space is preferred so that irradiation of the first additive manufacturing technology by means of the light source can directly irradiate the build space from below via the optical access. Indirect coupling of the electromagnetic waves or light into the build space, for example, via a mirror system, whereby the light or radiation source of the first additive manufacturing process can also be arranged elsewhere than below the build space, is conceivable.

[0018] The pumping system can comprise any type of machine for transporting fluids, especially liquids. These can be flow pumps or positive displacement pumps, which are collectively referred to as pumps below. In a particularly advantageous embodiment, the pumping system comprises a syringe pump. In this case, the pumping system can comprise one or more pumps. Multiple pumps enable the serial transport of multiple fluids, eliminating any necessary flushing processes to clear lines and / or machine rooms of residual fluid. Furthermore, multiple pumps enable the simultaneous transport of multiple fluids that are only intended to come into contact with each other shortly after a 3D printing process, for example, to create a 14.04.2025 to maintain otherwise negatively affected functionality, which may be due, for example, to thermal, pH and / or chemical incompatibility.

[0019] The pumping system may comprise one or more storage tanks and / or residue tanks for corresponding fluids.

[0020] Emptying the build space using the pump system can be achieved with one or more pumps. These can be the same pumps used to fill the build space, for example, to return fluid to an original reservoir. However, it is also conceivable for the pump system to have dedicated pumps for emptying. Furthermore, it is conceivable for the build space to have a drain exclusively or additionally for this purpose. The drain can be exposed manually or automatically. The pump system can have a vacuum pump, which removes residual fluid from the build space when the drain is exposed. The pump system can also have a combination of the described devices.

[0021] Arranging the at least one first additive manufacturing technology, which is light-based, below the build space enables the arrangement of the at least one second additive manufacturing technology above the build space. Bilateral manufacturing is ensured in particular by eliminating the need for a separate build platform, unlike prior art devices. In generic 3D printers, this build platform hinders bilateral manufacturing.

[0022] According to various embodiments, the at least one fluid is a photosensitive building material or a cleaning agent.

[0023] For an additive manufacturing process, the at least one fluid can be a photosensitive building material which can be produced by means of the at least one 14.04.2025 first additive manufacturing technology. For this purpose, the at least one first additive manufacturing technology emits light through the first optical access into the build space. As already mentioned, the at least one fluid can comprise a plurality of fluids, in particular a plurality of photosensitive build materials, which can be processed in parallel, for example in the form of a blend of a plurality of photosensitive build materials, or serially. Any build material that can be at least partially cured by photopolymerization can be considered as a photosensitive build material. The at least one fluid can likewise comprise one or more cleaning agents, which can be used, for example, to dilute, rinse out, and remove residues from a process step of a 3D printing process.

[0024] However, at least one fluid can also be any other form of fluid.

[0025] For example, the at least one fluid can comprise biologically active substances, in particular pharmaceutically active ingredients. These can be enclosed in a construct, for example, by a pre-finished printed layer having recesses that are flooded with the at least one fluid comprising biologically active substances before a further layer is applied and cured. If this further layer is formed from a construction material with a lower density than the at least one fluid comprising biologically active substances, there is no mixing of the construction material and the at least one fluid comprising biologically active substances, and liquid inclusions of the at least one fluid comprising biologically active substances can be formed. April 14, 2025

[0026] However, the at least one fluid can also be selected such that it effects a surface modification of an already completed print layer. For example, the at least one fluid can cause a chemical reaction on the already completed print layer, for example, by means of oxidation. It is also conceivable for the at least one fluid to contain a coating agent that forms a coating on the already completed print layer, for example, after the at least one fluid containing a coating agent has evaporated. For this purpose, it is conceivable for the hybrid 3D printer to have means for temperature control of the build space.

[0027] According to various embodiments, the first optical access to the installation space is uneven and / or flexible.

[0028] The first optical access point of the build space is simultaneously the build surface of the build space. The first optical access point, i.e., the build surface, can be uneven, i.e., have a complex structure, which enables the production of a three-dimensional structure in a single exposure process. For example, the optical access point can have a convex or concave curvature. A convex curvature can, for example, mimic the convexity of a human cornea during a biomimetic 3D printing process in tissue engineering. However, the first optical access point can also have angular and / or round and / or grooved or other types of recesses or elevations. Elevations on the first optical access point result in corresponding recesses on the manufactured construct.These recesses can be used, for example, to place technical elements, such as microchips and / or electrical wires. Recesses in the first 14.04.2025. The optical access results in corresponding elevations on the manufactured construct. These elevations can be used, for example, to couple the construct to another component, for example, by creating an exposed hook-shaped recess that results in an exposed, hook-shaped elevation on the construct. The skilled person will understand that various complex forms of the first optical access result in a multitude of possible uses.

[0029] The first optical access can additionally or exclusively be flexibly shaped. A flexible design of the first optical access makes it possible, for example, to create the complex shapes mentioned above without having to replace the first optical access. For this purpose, corresponding transparent molded bodies are produced which are inserted into the flexibly designed optical access and give it a corresponding shape. A transparent design of such a pressure body is necessary to ensure transmission through the at least one first additive manufacturing technology. A flexible design of the first optical access also makes it possible to influence the external shape of the construct before, during or after production by having the construct shaped by a molded body which presses against the flexibly designed first optical access.This offers the possibility, for example, of curving two or more, possibly differently designed, printing layers equally.

[0030] According to various embodiments, the at least one first additive manufacturing technology comprises a device for real-time beam shaping and guidance. April 14, 2025

[0031] The device for real-time beam shaping and guidance can, for example, comprise a digital mirror device and / or a spatial light modulator, but also any other suitable system.

[0032] According to various embodiments, the at least one second additive manufacturing technology comprises an inkjet technology, an extrusion technology, a lithographic system and / or a laser-induced forward transfer system. Other systems for additive manufacturing are conceivable. Furthermore, the use of a single technology is conceivable, but also the combination of two or more additive manufacturing technologies. Technologies can be used here which require photopolymerization by means of the at least one first additive manufacturing technology. However, technologies can also be used for which photopolymerization is not necessary. All building materials that can be processed by the at least one second additive manufacturing technology are suitable here. The building materials can be technically and / or biologically active.For example, bioinks can be used as building materials for the production of artificial living tissue. These inks consist largely of the cells used, but are often used in conjunction with additional materials that encapsulate the cells. The building materials can also contain conductive components for the production of electronic circuits, for example.

[0033] According to various embodiments, the photosensitive building material is a photopolymerizable fluid, for example, methacrylated gelatin, methacrylated collagen, or a synthetic hydrogel. Other types of photosensitive building material are conceivable, as already described. April 14, 2025

[0034] According to various embodiments, the hybrid 3D printer further comprises at least two electrodes which are configured to generate at least one electromagnetic field in the build space.

[0035] The additional integration of electrodes makes it possible, by controlling the at least one electromagnetic field within the build space, to align electrically active components of the build materials of the at least one second additive manufacturing technology and / or electrically active components of the at least one fluid along this at least one electromagnetic field and subsequently fix them in their aligned position in the material using the at least one first additive manufacturing technology. Electrically active components can be, for example, molecules, cells, or corresponding filler materials.

[0036] According to various embodiments, the hybrid 3D printer further comprises at least one sensor unit.

[0037] The at least one sensor unit can, for example, include a fill level monitor. The at least one sensor unit can also include a pH and / or temperature monitor. It is also conceivable for the at least one sensor unit to include a radiation energy monitor, for example, that of the at least one first additive manufacturing technology. The use of multiple sensor units is conceivable.

[0038] According to various embodiments, the at least one sensor unit is an optical sensor unit. The optical sensor unit is optically connected to the installation space via the first optical access and / or a second optical access. April 14, 2025

[0039] According to various embodiments, the optical sensor unit comprises a microscope and / or an optical coherence tomography system.

[0040] An optical sensor unit, for example a microscope and / or an optical coherence tomography system, requires optical access to the build space. This can, for example, be the first optical access arranged on the underside of the build space. Accordingly, the optical sensor unit would be arranged next to or within the at least one first additive manufacturing technology. However, the hybrid 3D printer can also have a second optical access, which can, for example, be arranged above the build space. Accordingly, the optical sensor unit would be arranged next to or within the at least one second additive manufacturing technology. However, the second optical access can also be arranged on a side surface of the build space to ensure lateral process monitoring. The use of multiple optical sensors at multiple optical accesses is conceivable.

[0041] According to various embodiments, the hybrid 3D printer further comprises a control and / or regulation unit which monitors, controls and / or regulates all components of the device.

[0042] According to various embodiments, the first optical access to the installation space is vertically movable.

[0043] The task is further solved by a hybrid 3D printing process. The hybrid 3D printing process comprises the following process steps, whereby the process steps are carried out in a different order. 14.04.2025 sequence and wherein individual method steps can be repeated: a. applying at least one printing layer by means of a second additive manufacturing technology from above onto a construction surface of a build space or onto an at least partially cured printing layer and / or onto at least partially cured photosensitive fluid, b. at least partially filling the build space with at least one photosensitive fluid by means of a pumping system, c. polymerizing the at least one photosensitive fluid by means of a first additive manufacturing technology, wherein the first additive manufacturing technology is light-based and illuminates the at least one photosensitive fluid from below via a first optical access to the build space by means of a light source.

[0044] According to various embodiments, the hybrid 3D printing method further comprises the following method step: d. at least partially filling the construction space (1) with at least one fluid by means of a pump system (2).

[0045] The individual process steps can be performed in different sequences and / or repeatedly. For example, the build space can first be filled with at least one fluid (process step b)) before it is polymerized (process step c)) and a print layer is applied (process step a)). However, two print layers with different materials can also be applied initially, so that process step a) is performed twice. Between individual process steps, the build space can be rinsed with at least one fluid, for example, a cleaning agent. April 14, 2025 (Process step d)). The skilled person will understand that a multitude of combinations of the process steps are possible, which are carried out specifically for each construct to be manufactured.

[0046] According to various embodiments, the at least one printing layer from process step a) is polymerized by means of the light source of the first additive manufacturing technology.

[0047] The construction material of the at least one printing layer from process step a) can be a photosensitive construction material which can be polymerized, i.e. cured, by means of the first additive manufacturing technology.

[0048] According to various embodiments, the at least one printing layer from process step a) and / or the at least one photosensitive fluid from process step b) is polymerized using a second first additive manufacturing technology. The second first additive manufacturing technology is light-based and, using a second light source, illuminates the at least one printing layer and / or the at least one photosensitive fluid from above via a second optical access to the build space.

[0049] The hybrid 3D printer can have a second optical access, which can be arranged above the build space. Accordingly, the second first additive manufacturing technology would be arranged next to or within the at least one second additive manufacturing technology. This enables polymerization not only by means of the at least one first additive manufacturing technology from below, but also by means of the second first additive manufacturing technology from above. This is particularly beneficial for fine structures or for the targeted influencing of cross-linking at defined positions. The second first additive 14.04.2025 Manufacturing technology can correspond to at least one first additive manufacturing technology, or can be designed differently.

[0050] According to various embodiments, the curing of the at least one printing layer and / or the at least one photosensitive fluid is carried out by the at least one first additive manufacturing technology by means of continuous frontal photopolymerization.

[0051] The continuous polymerization step allows significantly better optical properties to be achieved, since there is no layered structure as known from conventional processes and therefore no optical impairments due to the typical layered construction (staircase effect) occur.

[0052] According to various embodiments, the at least one printing layer and / or the at least one photosensitive fluid comprises functionalized molecules, functionalized materials and / or cells.

[0053] According to various embodiments, an electromagnetic field is generated in the build space, at least temporarily, using at least two electrodes, such that the functionalized molecules, functionalized materials, and / or cells align along the electromagnetic field. The aligned functionalized molecules / materials and / or cells are fixed by method step c).

[0054] According to various embodiments, the at least one photosensitive fluid and / or the at least one fluid is removed from the build space once or repeatedly during the process by means of the pumping system. April 14, 2025

[0055] Removal of the at least one photosensitive fluid may be necessary to subsequently fill the build space with another photosensitive fluid. Removal of the at least one photosensitive fluid may also be necessary to subsequently fill the build space with at least one fluid. The at least one fluid may comprise one or more cleaning agents or be any other form of fluid.

[0056] According to various embodiments, the 3D printing process is monitored by means of at least one sensor unit.

[0057] According to various embodiments, the at least one sensor unit is an optical sensor unit. The optical sensor unit is optically connected to the installation space via the first optical access and / or a second optical access. The optical sensor unit provides data for higher-level process and quality monitoring.

[0058] According to various embodiments, the optical sensor unit comprises a microscope and / or an optical coherence tomography system.

[0059] A sensor unit designed in this way provides meaningful data about both the construction process and the resulting object. The data can be used directly to create a digital twin and represents an important step toward digitalization and standardization (GMP, GLP). A link to a comprehensive, decentralized concept for quality assurance and traceability of the process chain (from raw material to product) can then be established using blockchain technology.

[0060] The device and the method according to the invention provide a combination of a controlled frontal 14.04.2025 Polymerization reaction in a build space via exposure from below and the application of functional layers from above using different application principles.

[0061] This double-sided manufacturing method makes it possible to place various materials, cells, pharmaceuticals, proteins, etc., even in thin layers, site-specifically, and to replicate the architectural structure of tissues using a biomimetic approach. Many biological tissues are characterized by a specific structural arrangement, for example, lamellar or fibrillar structures (e.g., collagen fibrils).

[0062] In addition to bioprinting and the application of hybrid 3D printers and hybrid 3D printing processes for regenerative medicine and tissue engineering, other technical fields of application also arise. The described hybrid 3D printing process is predestined for the production of sensors. By exploiting the high local precision of the hybrid 3D printing process and the possibility of combining processes using different materials, electrically conductive paths can be integrated into a matrix, thus implementing various sensor principles (biophysical, biochemical, electrophysiological). The conductive paths made of conductive polymer systems such as PEDOT:PSS or in the form of highly loaded conductive nanoparticle inks (graphene oxide, MXene) can be integrated into the matrix of the at least one fluid (main material) using at least one second additive manufacturing technology (top-down, e.g., extrusion-based, inkjet).The variety of materials and the possibility of locally incorporating 3D structures (e.g., coils) into the matrix allow for the implementation of a variety of systems. This flexibility in terms of materials and manufacturing technologies enables the development of microfluidic systems (such as 14.04.2025). Lab-on-a-chip) in a single process. Combining the system with bioprinting elements (cells, biocompatible materials) makes the direct production of an organ-on-a-chip conceivable. Embodiment of the invention

[0063] The invention is explained in more detail using several exemplary embodiments. Figure 1 shows a hybrid 3D printer with a flat build surface, Figure 2 shows a hybrid 3D printer with a convexly curved build surface, and Figure 3 shows a hybrid 3D printer with a concavely curved build surface.

[0064] In the description, reference is made to the accompanying drawings, which show, by way of illustration, specific embodiments in which the arrangement according to the invention may be practiced. In this regard, directional terminology such as "top," "bottom," etc., is used with reference to the orientation of the described drawings. The directional terminology is for illustrative purposes and is in no way limiting.

[0065] It is understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. It is understood that the features of the various exemplary embodiments described herein may be combined with one another unless specifically stated otherwise. The following detailed description is therefore not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. April 14, 2025

[0066] In the figures, identical or similar elements are provided with identical reference numerals where appropriate.

[0067] The hybrid 3D printer according to the invention is shown in Figure 1. The hybrid 3D printer has a build space 1, a pumping system 2, at least one first additive manufacturing technology 3, and at least one second additive manufacturing technology 4a,b. The build space 1 has a build surface 5 and a first optical access 6. The first optical access 6 is arranged on an underside of the build space 1. The first optical access 6 is the build surface 5 of the build space 1. The at least one first additive manufacturing technology 3 is light-based and is optically connected to the build space 1 via the first optical access 6 of the build space 1. The pumping system 2 is configured to fill and / or empty the build space 1 with at least one fluid 7. The at least one second additive manufacturing technology 4a,b is arranged above the build space 1.

[0068] The hybrid 3D printer according to the invention according to Figure 1 has two second additive manufacturing technologies 4a and 4b. From Figure 1, it can be seen that the two second additive manufacturing technologies 4a and 4b work with different build materials, which are found in the build space 1. The first optical access 6 corresponds to the build surface 5 of the build space 1. A first print layer 11a is arranged on the build surface 5, which was applied by means of the at least one second additive manufacturing technology 4a,b. Fluid 7, which was photopolymerized by the at least one first additive manufacturing technology 3, in that the at least one first additive manufacturing technology 3 emits light through the first optical access 6, is located above the polymerized fluid 7. April 14, 2025 Printing layer 11b, which in turn was applied by means of the at least one second additive manufacturing technology 4a,b.

[0069] The hybrid 3D printer according to Figure 1 has two electrodes 8, which generate an electric field along which functionalized molecules, functionalized materials, and / or cells 12, which were introduced here using the two second additive manufacturing technologies 4a and 4b, align. The now aligned functionalized molecules, functionalized materials, and / or cells are fixed within the polymerized fluid 7.

[0070] The hybrid 3D printer according to Figure 1 has a sensor unit 9. In this case, the sensor unit 9 is an optical sensor unit, which is optically connected to the build space 1 via a second optical access 10. The second optical access 10 is arranged above the build space.

[0071] Figure 2 shows the hybrid 3D printer according to Figure 1 with convex curved build surface 5.

[0072] Figure 3 shows the hybrid 3D printer according to Figure 1 with a concavely curved build surface 5.

[0073] The method according to the invention will now be described using a biometric example (construction of a biomimetic cornea) in the context of tissue engineering, whereby neither the hybrid 3D printer nor the hybrid 3D printing method are limited to one application.

[0074] The human cornea has a highly hierarchical structure and essentially consists of five layers, each with a different structural / molecular makeup and containing different cells. Essential 14.04.2025 The challenges here lie in constructing a corneal substitute that mimics the geometry (convexity) of the human cornea, along with its mechanical and refractory properties, and combines several structurally distinct layers. With the hybrid 3D printer and hybrid 3D printing process described here, it is possible to produce an artificial biomimetic cornea in a single process.

[0075] The process begins with the application of a first print layer 11a,b (the first corneal layer, the endothelium). A bioink adapted to the endothelium is used for production. This bioink is applied from above onto a smooth or pre-formed, convex build surface 5 by the first additive manufacturing technology 4a, for example, an inkjet module. This layer is cured from below using light by the first additive manufacturing technology 3, for example, a digital mirror device (DMD). Subsequently, an acellular layer simulating the Descemet's layer is built (from above) using a second additive manufacturing technology 4a, for example, a second inkjet module, and cured via DMD. In the third step, the largest layer, the stroma, is built in a single pass.For this purpose, the fluid level 7 in the build chamber 1 is raised by pump system 2, and through continuous exposure and targeted control of the DMD (fading of mirrors and modulation of intensity), the stromal matrix material (e.g., methacrylated collagen, keratocytes, and proteoglycans) is cured through continuous frontal polymerization until the physiological thickness is reached. Electrodes 8 can be used to align functionalized molecules, functionalized materials, and / or cells 12 along an electromagnetic field. The changes occurring during the build process are described in detail in the following sections. By means of a moving polymerization front, aligned functionalized molecules, functionalized materials, and / or cells 13 can be fixed in the fluid 7. This allows microstructurally hierarchical structures to be realized that mimic the structure of biological tissues (aligned collagen fibers, etc.). Once the polymerization front reaches the desired height (thickness of the stroma), the exposure stops, and the acellular Bowman's layer and the epithelium can be built using a second additive manufacturing technology 4a,b (or another one), as in steps 1 & 2. Specially adapted bioinks are also used here.The structure of the artificial cornea can be monitored via a first optical access 6 or second optical access 10 using a sensor unit 9. For example, imaging can be performed using optical coherence tomography (OCT), and data can be provided for the creation of a digital twin and for implemented (GMP-compliant) process and quality monitoring. April 14, 2025. Reference numerals 1 build space 2 pump system 3 first additive manufacturing technology 4a first second additive manufacturing technology 4b second second additive manufacturing technology 5 build area 6 first optical access 7 fluid 8 electrode 9 sensor unit 10 second optical access 11a first print layer 11b second print layer 12 functionalized molecules, functionalized materials and / or cells 13 aligned functionalized molecules, functionalized materials and / or cells 14.04.2025

Claims

AMENDED CLAIMS received by the International Bureau on 9 September 2025 (09.09.2025) 1. Hybrid 3D printer, comprising a build space (1), a pump system (2), at least one first additive manufacturing technology (3), and at least one second additive manufacturing technology (4a, b), wherein the build space (1) has a build surface (5) and a first optical Access (6), wherein the first optical access (6) is arranged on an underside of the construction space (1) and wherein the first optical access (6) is the construction surface (5) of the construction space (1), wherein the at least one first additive manufacturing technology (3) is light-based and is optically connected to the construction space (1) via the first optical access (6) of the construction space (1), wherein the pump system (2) is designed to fill and / or empty the construction space (1) with at least one fluid (7), and wherein the at least one second additive manufacturing technology (4a, b) is arranged above the construction space (1).

2. Hybrid 3D printer according to claim 1, characterized in that the at least one fluid (7) is a photosensitive building material or a cleaning agent.

3. Hybrid 3D printer according to claim 1 or 2, characterized in that the first optical access (6) of the build space (1) is uneven and / or flexible.

4. Hybrid 3D printer according to one of the preceding claims, characterized in that the at least one first additive Manufacturing technology (3) comprises a device for real-time beam shaping and guidance.

5. Hybrid 3D printer according to one of the preceding claims, characterized in that the at least one second additive manufacturing technology (4a, b) comprises an inkjet technology, an extrusion technology, a lithographic system and / or a laser-induced forward transfer system.

6. Hybrid 3D printer according to claim 2, characterized in that the photosensitive build material is a photopolymerizable fluid.

7. Hybrid 3D printer according to one of the preceding claims, further comprising at least two electrodes (8) which are configured to generate at least one electromagnetic field in the build space (1).

8. Hybrid 3D printer according to one of the preceding claims, further comprising at least one sensor unit (9).

9. Hybrid 3D printer according to claim 8, characterized in that the at least one sensor unit (9) is an optical sensor unit, wherein the optical sensor unit is optically connected to the construction space (1) via the first optical access (6) and / or a second optical access (10).

10. Hybrid 3D printer according to claim 9, characterized in that the optical sensor unit comprises a microscope and / or an optical coherence tomography system.

11. Hybrid 3D printer according to one of the preceding claims, further comprising a control and / or regulation unit.

12. Hybrid 3D printer according to one of the preceding claims, characterized in that the first optical access (6) of the build space (1) is vertically movable.

13. Hybrid 3D printing process, comprising the following process steps, wherein the process steps can be carried out in a different order and wherein individual process steps can be carried out repeatedly: a. applying at least one printing layer (11a, b) by means of a second additive manufacturing technology (4a, b) from above onto a construction surface (5) of a build space (1) or onto an at least partially cured printing layer (11a, b) and / or onto at least partially cured photosensitive fluid, b. at least partially filling the build space (1) with at least one photosensitive fluid by means of a pump system (2), c. polymerizing the at least one photosensitive fluid by means of a first additive manufacturing technology (3), wherein the first additive manufacturing technology (3) is light-based and illuminates the at least one photosensitive fluid from below via a first optical access (6) to the build space (1) by means of a light source.

14. Hybrid 3D printing method according to claim 13, further comprising method step: d. at least partially filling the construction space (1) with at least one fluid by means of the pump system (2), 15. Hybrid 3D printing process according to claim 13 or 14, characterized in that the at least one printing layer (11a, b) from process step a) is polymerized by means of the light source of the first additive manufacturing technology (3).

16. Hybrid 3D printing method according to one of claims 13 to 15, characterized in that the at least one printing layer (11a, b) from method step a) and / or the at least one photosensitive fluid from method step b) is polymerized by means of a second first additive manufacturing technology (3), wherein the second first additive manufacturing technology (3) is light-based and by means of a second light source illuminates the at least one printing layer (11a, b) and / or the at least one photosensitive fluid from above via a second optical access (10) to the construction space (1).

17. Hybrid 3D printing method according to one of claims 13 to 16, characterized in that the curing of the at least one printing layer (11a, b) and / or the at least one photosensitive fluid by the at least one first additive manufacturing technology (3) takes place by means of continuous frontal photopolymerization.

18. Hybrid 3D printing method according to one of claims 13 to 17, characterized in that the at least one printing layer (11a, b) and / or the at least one photosensitive fluid comprises / comprising functionalized molecules, functionalized MMaatteerriiaalliieenn and / or cells (12).

19. Hybrid 3D printing method according to claim 18, characterized in that an electromagnetic field is generated in the construction space (1) at least briefly by means of at least two electrodes (8) in such a way that the functionalized molecules, functionalized materials and / or the cells (12) align themselves along the electromagnetic field, wherein the aligned functionalized molecules / materials and / or cells (13) are fixed by method step c).

20. Hybrid 3D printing method according to one of claims 13 to 19, characterized in that the at least one photosensitive fluid and / or the at least one fluid is removed from the construction space (1) once or repeatedly by means of the pump system (2) during the method.

21. Hybrid 3D printing process according to one of the claims according to one of claims 13 to 20, characterized in that the 3D printing process is monitored by means of at least one sensor unit (9).

22. Hybrid 3D printing method according to one of claims 13 to 21, characterized in that the at least one sensor unit (9) is an optical sensor unit, wherein the optical sensor unit is optically connected to the construction space (1) via the first optical access (6) and / or a second optical access (10), wherein the optical sensor unit provides data for a überrggeooorrddnneettee process and quality monitoring.

23. Hybrid 3D printing method according to claim 22, characterized in that the optical sensor unit comprises a microscope and / or an optical coherence tomography system.

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