3D printing system

Abstract

The invention relates to a 3D printing system (1). The 3D printing system has a first cartridge container (2) for reversibly accommodating a first cartridge in which a printing fluid for 3D printing is stored, and a print head (10) having an outflow opening. Furthermore, the 3D printing system (1) has a first fluid line (14) connecting the first cartridge container (2) to the printhead (10) for conveying a printing fluid to the printhead (10). Furthermore, the 3D printing system (1) has a first temperature control channel (20) which covers the first cartridge container (2) and the first fluid line (14) on the outside and through which a temperature control medium flows in the defined use state.

Description

Technical Field

[0001] The present invention relates to a 3D printing system. Background Art

[0002] 3D printing systems have their origins in the field of so-called "rapid prototyping", i.e. the creation of prototypes in a short period of time. 3D printing was and is often associated with a method also originally known as "fused deposition modeling", in which a thermoplastic material, usually in the form of a "filament", is melted and applied in the form of threads and layers through a nozzle onto a substrate.

[0003] However, rapid prototyping methods in general and therefore also 3D printing have the potential for single-piece production and small batches, because (especially in the field of plastic processing) the complex and cost-intensive tool production can be omitted. In addition, relatively complex geometries can also be reproduced using this method, even those with cavities and various undercuts.

[0004] However, 3D printing is also of particular interest for medical applications, such as implants and similar applications. Usually, thermoplastic materials are not used for this purpose (or only a few specific thermoplastic materials are used), but rather solidified materials are often used, for example, initially biologically inert materials such as silicone, but also water-based hydrogels such as alginates and similar materials. Commonly used bioactive "bioinks" (printing fluids) are based on gelatin and its derivatives (such as methacrylated gelatin) and represent an inexpensive compromise between biocompatibility, printability achieved by thermal gelation, and crosslinkability achieved, for example, by chemical modification. Recently, the focus has shifted from synthetic materials (such as liquid silicones and hydrogels) to natural biomaterials. In particular, components of the extracellular matrix (such as collagen) are increasingly being used, because they are highly bioactive and can, for example, be caused to gel by temperature changes. Here, the timing of the gelation and thus the temperature control is important and decisive for obtaining a good printing result, so as to be able to achieve the best possible printability, bonding of the printed layers and thus shape stability. Summary of the invention

[0005] The object of the present invention is to improve 3D printing with temperature-sensitive materials.

[0006] According to the invention, this object is achieved by a 3D printing system having the features of claim 1. Advantageous and partially inventive embodiments and developments of the invention are listed in the dependent claims and the following description.

[0007] The 3D printing system according to the present invention comprises: a first cartridge container for reversibly accommodating a first cartridge storing a printing fluid for 3D printing, a print head having an outflow opening, and a first fluid line connecting the first cartridge container and the print head for conveying the printing fluid to the print head. In addition, the 3D printing system further comprises a first temperature control channel, which covers the first cartridge container on the outside and guides at least along the first fluid line, and the temperature control medium flows through the first temperature control channel in a prescribed use state.

[0008] The cartridge container is preferably designed in such a way that it surrounds the cartridge on the outside in the intended state of use, at least around the section containing the printing fluid.

[0009] Here and below, a printing fluid is understood to be a material which, in the state during processing, preferably at least temporarily has a sufficiently low viscosity for transport and application (here in particular for printing), but which can also undergo a significant increase in viscosity (or solidification) (by means of an external "trigger" or by itself). Due to the latter, the printing fluid can be used to form three-dimensional objects. In this case, the printing fluid can be cross-linked, partially cross-linked or cross-linked in the transportable state. The viscosity increase can be achieved here by solidification and / or cross-linking (gelling). Single-phase and / or single-component materials as well as multi-component and / or multi-phase materials (which, for example, are also only mixed during printing) are conceivable.

[0010] Preferably, the first temperature control channel also covers the first fluid circuit on the outside, that is, it is especially arranged coaxially with the first fluid circuit. This advantageously results in a particularly good heat exchange. Alternatively, however, the temperature control channel can also extend "only" next to the first fluid circuit, especially at a spacing as small as possible, for example, less than 1 mm. But optionally, the temperature control channel can also be divided into a plurality of sub-channels in the area of ​​the fluid circuit, which extend along the first fluid circuit next to the first fluid circuit (and at a small spacing of, for example, less than 1 mm). For example, these sub-channels can also be coiled around the first fluid circuit. The latter is suitable, for example, when using pipes or hoses, when the first fluid circuit and the first temperature control channel are freely laid, or when the first fluid circuit and the first temperature control channel are guided in a "connection block" or connection module between the first cartridge container and the print head.

[0011] Due to the arrangement and construction of the above-mentioned temperature control channel, it is advantageously possible to achieve (at least almost) continuous temperature control of the printing fluid from the "tank" (i.e., the cartridge) to the print head and then at least almost to the outlet. Here and below, "at least almost" is understood to be at least 70 percent of the total length of the corresponding channel or line, preferably at least 80 percent. Suitably, the first temperature control channel is designed so that the first temperature control channel at least covers the first cartridge container and extends at least to the print head along the first fluid line over its entire length, or in particular also covers the print head. Therefore, the solidification behavior of the printing fluid can be influenced in an advantageous manner, in particular controlled. For example, premature cooling and thus premature gelation can be prevented (in the corresponding fluid line) (at least to prevent the viscosity from increasing beyond the transport capacity limit).

[0012] In a preferred embodiment, the first temperature control channel continues into the print head. In this case, the first temperature control channel advantageously at least partially surrounds the first fluid channel for the printing fluid in the print head on the outside. As a result, the "temperature control length" (i.e. the length of the printing fluid over which the temperature is controlled) is proportional to the length of the first fluid line and the first fluid channel, and thus a temperature control that is as continuous as possible can be achieved. In principle, it is also conceivable here that the first temperature control channel extends in the print head next to the first fluid channel there, i.e. is guided along the first fluid channel.

[0013] In a suitable embodiment, the first temperature control channel merges into the first return line on the print head side, i.e. in the print head or at the end of the first fluid line before the print head (or as described below, optionally only in the region of the print nozzles that can be reversibly coupled to the print head indirectly or directly). In particular, the first return line is guided coaxially with the first temperature control channel at least in the region of the first fluid line (in particular on the outside of the first fluid line). This is preferably the case when the first temperature control channel surrounds the first fluid line and possibly also the first fluid channel on the outside. In this way, thermal insulation of the first temperature control channel can be achieved.

[0014] In an alternative embodiment, the first temperature control channel transitions into a return portion on the print head side. Here, the return portion is guided separately from the first fluid line at least in the region of the first fluid line. In particular, the return portion is an independent hose line.

[0015] In a preferred embodiment, the 3D printing system has a temperature control device for adjusting the temperature of the temperature control medium. In particular, the temperature control device is set up to adjust the target temperature value in the temperature control medium at least on the supply side and / or in the area of ​​the first cartridge container. Since the 3D printing system itself has the temperature control device, the 3D printing system is advantageously self-sufficient in this respect. In addition, in this way, the control of the temperature control is relatively simple. Preferably, the 3D printing system also has a controller, which is set up to drive the temperature control device to adjust the temperature value predetermined on the controller side (optionally in an interactive manner with an operator).

[0016] In an alternative embodiment, the temperature control device has a first heating and / or cooling element, in particular in the form of a Peltier element, in the region of the first cartridge container. The Peltier element thus has the advantage that it can both heat and cool. The temperature control device is thus relatively flexible, in particular in the case of relatively small installation spaces. In this case, the Peltier element is preferably arranged in a section of the first temperature control channel surrounding the first cartridge container and is suitably coupled to this section in a heat-conducting manner.

[0017] In an optional variant, the temperature control device has a plurality of heating and / or cooling elements, by means of which the temperature profile within and along the temperature control channel can be predetermined. For example, Peltier elements are used here, since they can be used locally and can perform both heating and cooling functions. Alternatively, a "conventional" heating cartridge can also be used.

[0018] In another suitable embodiment, the 3D printing system has a second cartridge container, a second fluid circuit and a second temperature control channel. These are preferably implemented similarly to the above-mentioned first cartridge container, the first fluid circuit and the first temperature control channel. In particular, the second cartridge container is therefore used to reversibly accommodate a second cartridge that stores printing fluid for 3D printing. The second fluid circuit connects the second cartridge container to the print head to transport the printing fluid to the print head. The second temperature control channel covers the second cartridge container, and preferably also covers the second fluid circuit on the outside, and is flowed through by the temperature control medium in the prescribed use state. Optionally, the 3D printing system also has a third cartridge container, a third fluid circuit, a third temperature control channel, etc. (or has many, i.e., four or more).

[0019] The presence of a second (and possibly a third or further) cartridge container or the like advantageously enables multi-component printing, i.e. printing with different "inks" (i.e. printing fluids), which are optionally used alternately or in sequence, without having to change the system. In addition, different printing fluids can also be used simultaneously, i.e., first mixed in the print head in particular. In addition, however, a plurality of cartridge containers can also enable a certain degree of continuous operation in that the same printing fluid is considered for at least two cartridge containers, but the cartridges are used alternately, so that an empty cartridge can be replaced during the use of another cartridge. It is also possible to use a multi-component system for the printing fluid, whereupon the individual components of the multi-component system are, for example, respectively filled into the assigned cartridges and, for example, mixed in the print head.

[0020] In a preferred embodiment, the first fluid line and the second fluid line merge into an outflow opening in the print head (especially with their respective fluid channels). In other words, the respective fluid channels lead via the outflow opening to the surrounding environment or to an optional downstream and especially reversibly coupled print nozzle.

[0021] Optionally, the 3D printing system has more than two (for example, at least three) cartridge containers and associated fluid circuits and temperature control channels, which are preferably constructed in the same manner as described above. Preferably, these multiple fluid circuits also merge into the outflow opening in the print head (especially using their respective fluid channels).

[0022] In an advantageous embodiment, the print head has an additional supply for the temperature control medium, for example a separate temperature control line (i.e., in particular, additional to the above-mentioned respective temperature control channel), by means of which the temperature control medium is preferably supplied at a different temperature value than the cartridge container during the intended operation, and / or an additional heating and / or cooling element (in particular, in the form of a Peltier element). As a result, the temperature value can be predetermined relatively flexibly and independently of the first or second temperature control channel locally at the print head. Preferably, the additional supply for the temperature control medium (i.e., the separate temperature control line) is connected locally at the print head to the corresponding (in particular, the other temperature control channel) for this purpose.

[0023] In an optional embodiment, a possible plurality of (two or more) temperature control channels merge in the print head to form a mixed temperature and, in particular, surround the merged fluid line. Subsequently, the merged temperature control channels transition into a common return portion (or the above-mentioned coaxial return line). Alternatively, however, each individual temperature control channel may also have a separately assigned return portion or coaxial return line in order to specifically prohibit the formation of such a mixed temperature. However, even in the case of more than two temperature control channels, multiple temperature control channels may be guided to a common return portion (or return line).

[0024] In a suitable embodiment, the 3D printing system has the aforementioned printing nozzle, which is reversibly and optionally indirectly or directly connected to the outflow opening at least in the intended use state. The printing nozzle is passed through a nozzle channel for the printing fluid, through which the printing fluid flows in the intended use.

[0025] Optionally, the 3D printing system has a plurality of printing nozzles, which have different nozzle channel cross sections and can therefore be used for different printing tasks. Preferably, the nozzle channel is at least partially coaxially surrounded by a channel for a temperature control medium. In addition, preferably, the printing nozzle is constructed in a triaxial manner, and therefore has two channels that are respectively hood-shaped or coaxially surround the (especially central) nozzle channel, which can realize the conveying and returning of the temperature control medium. In an optional embodiment, these channels are preferably connected to the temperature control channel, preferably to the section of the temperature control channel constructed in the print head, especially in the state of being connected as specified, and thus the temperature control medium is supplied from the print head (supply and return).

[0026] In order to reversibly couple the print nozzle with the print head, the two preferably have coupling mechanisms corresponding to each other. These coupling mechanisms can, for example, cause magnetic coupling, preferably electromagnetic coupling. However, preferably, the coupling mechanisms, for example, jointly form a bayonet-type connection in the following manner, that is, a groove with an undercut is arranged on the print head or the print nozzle, or a corresponding pin (for example, with a mushroom head) is arranged on the print nozzle or the print head. For example, the groove has a circular arc segment-type direction (for example, a quarter circle). In this case, the print nozzle is placed on the print head (pins, preferably two pins, are respectively sunk into the corresponding openings of the associated grooves), and is fixed on the print head in a corresponding rotation relative to the print head.

[0027] In a further suitable embodiment, the printing nozzle has a shut-off valve for the nozzle channel. This allows particularly precise printing, since the entire fluid flow through the 3D printing system does not need to be stopped, but only interrupted at the outlet side.

[0028] Optionally, a mixing channel or "homogenizing channel" is formed in the print head or in the print nozzle, for example in the form of a static mixer. Alternatively, such a "mixing unit" (i.e. such a channel) can also be formed in a separate component, which can be connected, for example, between the print head and the print nozzle. In this way, in particular when mixing a plurality of fluids which were previously stored in separate cartridges, the (entire) printing fluid can be homogenized before it overflows.

[0029] In an optional suitable embodiment, the 3D printing system has at least one additional module (or also referred to as: intermediate module), which is connected or can be connected between the above-mentioned printing nozzle and the print head (i.e., it is connected in the middle in a specific use state of the task-specific use configuration of the 3D printing system). For example, the additional module forms the above-mentioned separate component. The additional module or the corresponding additional module has coupling mechanisms on the side facing the print head and the side facing the printing nozzle (i.e., on both sides), and these coupling mechanisms are suitably complementary to the coupling devices arranged on the printing nozzle or the print head. The additional module also has a fluid channel, which can realize the printing fluid from the print head to the nozzle channel of the printing nozzle in the prescribed use state. In the case where the printing nozzle also has a temperature control channel, this temperature control channel is also formed in the additional module so as to realize the temperature control medium to be guided to and from the printing nozzle. Optionally, the additional module also has electrical contact elements, which can realize an electronic connection between the print head and the print nozzle and / or between the print head and the electronic components of the additional module (for example for power supply and / or data exchange). The print head expediently has corresponding (corresponding) contact elements. For example, the additional module can have a sensor (such as a temperature sensor or a pressure sensor or a sensor for measuring resistance), which can be connected to the controller of the 3D printing system by means of such an electronic connection.

[0030] Furthermore, the additional module optionally has one or more "insertion channels" (e.g. sensor holes, milled recesses or similar insertion channels), into which sensors, heating elements, cooling elements or similar sensors can be inserted as required in order to detect process variables of the printing fluid and / or the temperature-control medium and / or to be able to additionally influence the printing fluid and / or the temperature-control medium (e.g. temperature control). Furthermore, sensor means for detecting the surroundings and / or the substrate, such as cameras, lidar sensors, confocal lasers, ultrasonic sensors or similar sensor means, can also be accommodated in such insertion channels.

[0031] Optionally, the entry shaft can also penetrate into the fluid channel so that the elements placed therein are flowed around and / or through by the printing fluid. In this variant, the (respective) temperature control channel is preferably guided around the entry shaft. For example, the entry shaft can accommodate at least one sensor (e.g. for measuring pressure, measuring temperature, measuring pH value or measuring impedance), a "lab-on-a-chip", a mixing unit (e.g. a static mixer or similar unit) or an additional material entry for other components of the printing fluid.

[0032] Optionally, the print nozzle also has the above-mentioned type of displacement shaft.For example, a (especially unilateral) force sensor can be placed in such a (not intruding into the fluid channel) displacement shaft, and the force acting on the print nozzle (laterally and axially) can be detected by means of the force sensor.The detected force is suitably evaluated in the controller to identify the collision of the print nozzle, such as the collision with the substrate or the like, in order to measure the surface by contact (especially in the form of a three-coordinate measuring machine or the like) or to know the degree (especially angle) of the deflection of the print nozzle, especially the needle nozzle tip.Knowing the deflection of the print nozzle (also referred to as: nozzle flexure) can be advantageously used for the use of the print nozzle sinking into the viscous medium during the printing process and printing in the medium, and is considered for positioning the print nozzle as accurately as possible on the target coordinates regardless of the possible deflection of the print nozzle.For example, deflection can be regarded as a kind of offset here.In principle, different nozzle heads (i.e., with different lengths and / or diameters) can also be used for different printing processes here, so that different bending behaviors are respectively present. Furthermore, separately controllable temperature control elements (such as heating elements, Peltier elements, etc.) with associated temperature sensors can also be introduced into such an insertion shaft of the printing nozzle in order to be able to realize additional temperature zones in the 3D printing system.

[0033] In a suitable improvement, the respective additional modules and / or print nozzles also have an identification element for automated identification. The identification element can be, for example, a microchip, an RFID or NFC tag or an optical identification unit (such as a barcode or QR code). The information stored in this identification element includes in particular the type of print nozzle or additional module, preferably the structural type, and optionally may also include a sensor configuration, provided that this aspect is implemented, for example, in a fixed predetermined additional module or print nozzle. The 3D printing system preferably also has a mechanism for reading the corresponding identification element (for example, an interface or code scanner for wireless communication). Based on the information of the additional module or print nozzle read in, a predetermined software function can be enabled in the controller of the 3D printing system, for example. Optionally, RFID or NFC tags are also used to locate the print nozzle in three-dimensional space.

[0034] Preferably, in particular before the fluid circuit enters the printhead or in the printhead itself, each fluid circuit is also assigned a (preferably controllable) valve. Thus, for example, it is possible to avoid that printing fluid from other fluid circuits enters an "empty" fluid circuit when replacing a cartridge.

[0035] In a suitable embodiment, the 3D printing system has a controller as described above and at least one temperature sensor interconnected with the controller. In this case, the controller is particularly configured to control the temperature control device in dependence on a temperature value detected by means of the temperature sensor or the respective temperature sensor. For example, the controller is configured to adjust the temperature control medium to a predetermined temperature value (target value) based on the detected temperature value (actual value).

[0036] Preferably, the 3D printing system also has a pump which is designed to convey the temperature control medium.

[0037] In a suitable embodiment, the first or second (or each additional) cartridge container is set up to accommodate a common syringe on the market as a cartridge and couple it to the first or second fluid circuit. Preferably, a volumetric capacity between 3 ml and 55 ml is used as a common syringe volume. For special applications, for example, for relatively large "printing tasks" (printing larger tissue models, organs (such as liver) and / or for supporting structures, when the cartridge container is matched accordingly, a correspondingly larger syringe with a volumetric capacity between 180 ml and 960 ml can be used, for example. Alternatively, the cartridge can also be a special tank for printing fluid, for example, similar to a "tank module" of an inkjet printer.

[0038] At least in the case of a syringe as a cartridge, the 3D printing system also has a pump device, which is used to operate the cartridge container, i.e., in particular the syringe, in continuous operation to deliver the fluid. In the case of a syringe, this can be achieved by a syringe pump. Hydraulically or pneumatically actuated pump devices can also be used here.

[0039] In a further suitable embodiment, the 3D printing system (in particular, respectively) has a valve which is designed to change the flow rate between the section of the first or second temperature control channel surrounding the first or second cartridge container and the section surrounding the first or second fluid line. In particular, the flow rate of the temperature control medium and / or the residence time of the temperature control medium in the respective section can thus be controlled.

[0040] In a preferred embodiment, the first or second fluid circuit and the corresponding section of the first or second temperature control channel are flexibly configured ("hose circuit"). Since many of the above-mentioned "bio-inks" have photosensitive components, the corresponding fluid circuit and / or the associated temperature control channel are suitably designed to be opaque. Alternatively, for the use of a printing fluid that is not sensitive to light, the corresponding fluid circuit or temperature control channel can also be configured to be transparent.

[0041] In an alternative embodiment, at least one optical window (i.e. a radiation-transmissive region) is arranged in front of the outflow opening (e.g. in the print head or in the corresponding fluid line itself) or in the print nozzle, through which the printing fluid can be loaded with radiation. Preferably, the optical window (or the respective optical window) is designed for connecting an optical fiber for transmitting radiation. For example, so-called photocrosslinking, i.e. photoinduced crosslinking, can be achieved by means of infrared or ultraviolet radiation, so that pregelatinization can be achieved in a targeted manner, in particular for increasing the viscosity. The latter can contribute to the shape stability of the printed pattern (i.e. the object to be printed).

[0042] Optionally, the optical window (or at least one of a possible plurality of optical windows) is arranged at the smallest possible distance from the nozzle opening (on the outflow side). This is particularly suitable when a rapid reaction of the printing fluid to the radiation is to be expected.

[0043] In another alternative embodiment, complementary coupling means are arranged on two opposite sides of the print head, preferably on flat sides with a small spacing, so that a plurality of print heads can be coupled to each other in a row. This makes it possible to carry out surface printing with a plurality of print heads, which is particularly advantageous in the case of fast-reacting printing fluids and / or large-area "printing patterns" (having a relatively large cross-sectional area, for example, objects exceeding 5 cm to 10 cm).

[0044] Therefore, the 3D printing system also has a plurality of the above-mentioned print heads, which are respectively connected to at least one first (and possibly second) cartridge container and a correspondingly assigned temperature control channel by means of fluid lines. In other words, there are a plurality of 3D printing systems in the above-mentioned 3D printing system and they respectively form "subsystems", which are in turn coupled to each other closely by means of print heads, thereby forming a "print head strip", so that fast surface printing can be achieved.

[0045] Preferably, the 3D printing system also has a wide-slot nozzle, which, in the intended use state, is connected downstream of a plurality of print nozzles coupled to form a print head strip. As a result, not only a plurality of relatively thin strands (filaments; in the absence of the wide-slot nozzle) can be printed, but also relatively wide strips (e.g., several centimeters, e.g., 3 to 15 centimeters) can be printed.

[0046] In another suitable embodiment, the 3D printing system has a (preferably above-mentioned) controller and at least one pressure sensor interconnected with the controller. The pressure sensor is arranged so that the pressure sensor is in contact with the printing fluid in a prescribed operating state. Suitably, the pressure sensor is arranged in the print head or in the printing nozzle. Here, in addition to the above-mentioned control of the temperature control device, or alternatively, the controller is particularly set up and arranged to control the above-mentioned pump device depending on the pressure value detected by the pressure sensor for conveying the printing fluid, especially to regulate it (especially in the sense of "closed loop"). Suitably, the 3D printing system has a plurality of pressure sensors, for example, in order to detect the pressure difference between the respective cartridge and the printing nozzle (and / or the pressure difference before mixing different printing fluids or components of the printing fluid), and preferably can also be used for regulation.

[0047] Advantageously, the invention described above, in particular in the case of the additional presence of Peltier elements (which can be used both for heating and for cooling), can also achieve a temperature profile along the length of the temperature control channel, at least in sections. For example, in this way, a "pre-gelatinization" of the printing fluid (for example by locally increasing or decreasing the temperature) can be achieved before the printing fluid escapes from the print head or the nozzle opening.

[0048] The conjunction “and / or” is to be understood here and below in particular to mean that the features connected by means of this conjunction can be constituted both jointly and as alternatives to one another. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The following is a detailed explanation of the embodiments of the present invention with reference to the accompanying drawings.

[0050] Figure 1 A 3D printing system is schematically shown in a fragmentary perspective view;

[0051] Figure 2 The 3D printing system is shown in side view;

[0052] Figure 3 The 3D printing system is schematically shown in perspective from below;

[0053] Figure 4A 3D printing system is schematically shown in a perspective view in a partially disassembled state;

[0054] Figure 5 A 3D printing system is shown in a schematic cross-sectional view;

[0055] Figure 6 Based on Figure 5 The 3D printing system is schematically shown in detail view VI;

[0056] Figure 7 Based on Figure 6 The cross-sectional view VII-VII schematically shows the 3D printing system;

[0057] Figures 8 to 12 Different embodiments of the channel paths inside the print head of the 3D printing system are shown in schematic cross-sectional views respectively;

[0058] Figure 13 A further embodiment of a 3D printing system is schematically shown in a perspective view from below;

[0059] Figure 14 Based on Figure 13 A further embodiment of the 3D printing system is again schematically shown by way of a view of FIG.

[0060] Figure 15 The top view schematically shows the Figure 14 3D printing system;

[0061] Figure 16 A further embodiment of a 3D printing system is schematically shown in a perspective view from below in a partially assembled state;

[0062] Figure 17 Based on Figure 1 The diagram schematically shows the Figure 16 3D printing system;

[0063] Figure 18 The side view schematically shows the Figure 16 Detailed view of a printing nozzle of a 3D printing system;

[0064] Figure 19 Based on Figure 18 The cross-sectional view IX-IX schematically shows the printing nozzle;

[0065] Figure 20 The schematic cross-sectional view shows Figure 16 3D printing systems; and

[0066] Figure 21 Based on Figure 20 A further embodiment of a 3D printing system is shown by way of illustration.

[0067] Parts that correspond to one another are always provided with the same reference symbols in all the figures. DETAILED DESCRIPTION

[0068] Figure 1 A section of a 3D printing system 1 is shown in . In the embodiment shown, the 3D printing system 1 is set up for processing so-called "bio-ink" as a printing fluid. The bio-ink is a biologically active material, such as cells in an extracellular matrix or similar materials, which is used for so-called "tissue engineering", that is, for artificially creating human tissue or human-like tissue. For example, the bio-ink of the present embodiment is based on collagen. However, despite this, other materials, such as silicone or similar materials can also be processed (printed) with the help of the 3D printing system 1 described in detail here and below. The processing of bio-ink in 3D printing requires temperature control in order to prevent the bio-ink from gelling prematurely (i.e. before printing) on ​​the one hand, but on the other hand, it can also achieve gelling as quickly as possible after printing so as to achieve the desired dimensional accuracy of the object to be printed.

[0069] For this purpose, the 3D printing system 1 in the present embodiment has a first cartridge container 2 and a second cartridge container 4, which are respectively configured to reversibly accommodate a first cartridge 6 or a second cartridge 8. The cartridges 6, 8 are configured in the form of syringes and are stored with bio-ink for 3D printing. The 3D printing system 1 has a print head 10 for printing bio-ink, which has an outflow opening 12 (see Figure 3 ). Each cartridge container 2, 4 is assigned a corresponding first fluid circuit or fluid circuit 14, 16, which connects the respective cartridge container 2, 4 to the print head 10 to transport the bio-ink to the print head 10. In order to control the temperature of the bio-ink, the 3D printing system 1 has a first temperature control channel 20, which surrounds the first cartridge container 2 on the outside (with a "container section 20a") and the first fluid circuit 14 (with a circuit section 20b), and the first temperature control channel is flowed through by a temperature control medium when used in accordance with the regulations. Similarly, the 3D printing system 1 has a second temperature control channel 22, which surrounds the second cartridge container 4 in a similar manner (with a container section 22a) and surrounds the second fluid circuit 16 (with a circuit section 22b). In Figure 4 and Figure 5 The arrangement of the two temperature control channels 20 and 22 can be seen in the sectional view in FIG. Therefore, the fluid lines 14 and 16 together with the temperature control channels 20 and 22 respectively surrounding them form a coaxial line.

[0070] In the case of multi-component printing, the two cartridges 6 and 8 are stocked with different bio-inks. Optionally, the two cartridges 6 and 8 are also stocked with components for the actual bio-ink, which are first mixed in the print head 10 (however, in this case, the respectively stocked printing fluids are also referred to here and below as bio-inks).

[0071] Especially from Figure 5 and Figure 6 It can be seen that the first and second temperature control channels 20, 22 are continued into the print head 10 as a "head section" 20c or 22c, respectively. The first and second fluid lines 14 and 16 are continued in the print head 10 in the form of first and second fluid channels 30 and 32 for biological ink, and are at least partially covered on the outside by the correspondingly assigned head sections 20c and 22c. The two fluid channels 30 and 32 merge in the print head 10 and lead together to the outlet opening 12. The two head sections 20c and 22c also merge ("merge") in the print head 10 and form a sheath line 34, which surrounds the merged fluid lines 20, 22 until close to the outlet opening 12 (see Figure 5 , Figure 6 ) (ie except for the remaining wall thickness of the print head 10 which is required for production technology). This makes it possible to achieve a continuous temperature control of the bioink (except for a negligible remaining distance, ie the remaining wall thickness).

[0072] In order to allow the temperature control medium to not only surround the cartridges 6, 8, the fluid lines 14, 16 and the fluid channels 30, 32, but also to flush them around, the jacket line 34 transitions via a U-shaped reversing channel 36 in cross section into a return 38 connected to the print head 10. The return 38 is in turn connected to a pumping reservoir (e.g., a tank) not shown in detail. The temperature control medium is supplied from the pumping reservoir via an inlet 40 to the two temperature control channels 20 and 22 in the upper region of the cartridge containers 2, 4 by means of a pump (not shown).

[0073] Figures 8 to 12 Schematically shows another embodiment of the guiding method of the temperature control channels 20, 22 inside the print head 10. Figure 8(This figure shows a slight modification of the above-described embodiment) The reversing channel 36 extends coaxially with the head section 22c of the second temperature control channel 22 (and thus also with the fluid channel 32). In this case, the return section 38 also extends coaxially with the line section 22b outside the print head 10 as a return line. In this case, a mixed temperature formed by the two temperatures selected for the first and second temperature control channels 20 and 22 will appear in the jacket line 34 in a known manner. In addition, the coaxial guidance of the return section 38 relative to one of the temperature control channels 20 or 22, in particular here relative to the line section 22b, can also facilitate the thermal insulation of the corresponding temperature control channel 20 or 22 and the corresponding fluid line 14 or 16.

[0074] according to Figure 9 , the two temperature control channels 20 and 22 are not merged into the sheath line 34. Instead, the first temperature control channel 20, specifically its head section 20c, transitions into the reversing channel 36a, which is coaxially led back as a return line. In contrast, the second temperature control channel 22 uses its head section 22c to form the sheath line 34 and the reversing channel 36, which is as shown in FIG. Figure 8 The advantage here is that two printing fluids to be temperature-controlled independently of one another can be temperature-controlled even in a mixed state by means of only one of the temperature control channels 20 or 22 (here by means of the second temperature control channel 22 ).

[0075] Figure 10 Shown according to Figure 5 and Figure 6 A further geometric modification of the embodiment of . The return 38 is guided laterally out of the print head 10 .

[0076] Figure 11 Show according to Figure 9 and Figure 10 In this case, however, the first temperature control line 20 does not transition into the reversing channel 36a, but rather into a non-coaxially guided, laterally branched return portion 38a.

[0077] Figure 12 . Here, the "supply" in the form of the second temperature control channel 22 transitions into the first temperature control channel 20 via the reversing channel 36, so that the first temperature control channel 20 is formed by a return for the second temperature control channel 22. This is advantageous, for example, when the printing fluid (corresponding bio-ink) flowing through the first fluid line 14 needs to be at a lower temperature than the printing fluid flowing through the second fluid line 16.

[0078] The temperature control of the temperature control medium, i.e. the adjustment of the temperature value of the temperature control medium, is achieved in the illustrated embodiment by means of a temperature control device (not shown) of the 3D printing system 1. The temperature control device has a first or second heating and / or cooling element in the region of the first and second cartridge containers 2, 4, respectively, in particular a Peltier element 41 (in Figure 13 By way of example, it comprises a housing 41 a in which a fan 41 b is arranged. The respective Peltier element 41 is arranged on the section of the respective temperature control channel 20 , 22 surrounding the respective cartridge container 2 , 4 (and advantageously projects into this section in a fluid-tight manner).

[0079] exist Figure 13 In the embodiment shown in , two further Peltier elements 42 are arranged on the print head 10. A fan which may be present is not shown here. These Peltier elements 42 are used to carry out local temperature control inside the print head 10, for example, in the area of ​​the mixed printing fluid.

[0080] Alternatively (or additionally), the temperature control medium is controlled in the aforementioned pump reservoir. In the case of temperature control only inside the pump reservoir or only in the region of the cartridge container 2, 4, a temperature drop will occur along the fluid lines 14, 16. Additional temperature control by means of Peltier elements 41 and / or 42 can have the advantage that only local energy supply by means of the corresponding Peltier element 41 or 42 is required. Furthermore, the corresponding Peltier element 41 or 42 can also be used for (local) cooling.

[0081] Figure 5 The structure of the cartridge containers 2 and 4 and the respective surrounding temperature control channels 20 or 22 can be seen in the sectional view there. Thus, the respective cartridge container 2 or 4 forms a receiving shaft for the respective cartridge 6 or 8 (here, the respective syringe). In the cartridge containers 2 and 4, a flange 43 is respectively formed on the bottom side, which is used to accommodate and couple a nozzle 44 of a cartridge (syringe, in particular according to the Luer lock principle). Opposite to this flange 43, a hose sleeve 46 is formed on the outside of the respective cartridge container 2 or 4 (and thus inside the respective temperature control channel 20 or 22), which in the specified assembled state (see Figure 4 ), a hose forming the respective fluid line 14 or 16 is put onto the hose sleeve.

[0082] The container section 20a or 22a is formed by the outer wall 48 surrounding the respective cartridge container 2 or 4 as a double wall, and is further formed by the intermediate space between the cartridge container 2 or 4 and the outer wall 48. A connection opening 50 is machined into the outer wall 48 in alignment with the hose sleeve 46. The fluid line 14 or 16 is guided through the connection opening. The line sections 20b and 22b are formed by a hose 52 coaxially surrounding the fluid line 14 or 16. The hose 52 (that is, in the prescribed use state) is fastened in the connection opening 50 and ends in the connection opening. As a result, the temperature control medium can flow from the respective inlet 40 into the container section 20a or 22a, and from there through the connection opening 50 into the corresponding line section 20b or 22b, without the temperature control medium coming into contact with the respective bio-ink (or printing fluid).

[0083] Furthermore, an opening 54 is introduced into the outer wall 48. This opening can be used to drain the respective temperature control channel 20 or 22, to supply a further temperature control medium or to introduce sensors, such as temperature sensors or pressure sensors.

[0084] Figure 14 and Figure 15 Another embodiment of the 3D printing system 1 is shown in FIG. Figure 1 The embodiment of the present invention is similar to that of the embodiment of the present invention, and a plurality of (four are shown here) print heads 10 are constructed similarly, and each of them has two (not shown in detail) cartridge containers 2 or 4 coupled thereto. The print heads 10 are coupled to each other in a row. For this purpose, the print heads 10 have coupling mechanisms on the respective opposite flat sides 56, which are exemplarily formed in the form of positioning joints 58a and complementary positioning recesses 58b, concave and convex flanks 58c or 58d and retaining magnets 58e. In this way, a "print head strip" can be formed, which enables relatively fast large-area printing.

[0085] In an embodiment not shown, the 3D printing system also has a wide-slit nozzle that is connected to the print head 10 coupled into a print head strip and thus enables printing of a wide band instead of just printing a single filament.

[0086] Figure 16 and 17 . The print head has three interfaces for the first and second fluid lines 14, 16, which have respectively associated temperature control channels 20, 22 (line sections 20b, 22b), and an associated temperature control channel 62 (line section 62b) for the third fluid line 60. A total of three fluid lines 14, 16 and 60 and three temperature control channels 20, 22 and 62 are combined in a manner similar to that described above (see Figure 20 sectional view in ).

[0087] Furthermore, in this embodiment, the 3D printing system 1 further comprises a printing nozzle 70 that can be reversibly coupled to the printing head 10. In this case, the sheath line 34 and the reversing channel 36 are not connected to each other inside the printing head 10, but are open at the bottom side and thus lead to the corresponding channel of the printing nozzle 70 (at Figure 20 The sheath line 34 and the reversing channel 36 surround the nozzle channel 72, through which the bio-ink is applied. The print nozzle 70 has a plurality of electrical contacts 74 (contact pins in this case) on the connection surface 73 facing the print head 10 for coupling with the print head 10 in terms of signal transmission technology, and by means of these electrical contacts, for example, sensors (such as temperature sensors and / or pressure sensors, which are not shown) or heating elements 76 of the print nozzle 70 can be connected.

[0088] The print nozzle 70 is designed to be connected to the print head 10 by means of a bayonet connection. For this purpose, the print nozzle 70 has two pins 78, which are inserted into corresponding holes 80 and are locked in a form-fitting manner by turning approximately a quarter turn in a groove 82 in a manner not shown in detail. The counter-contact corresponding to the contact 74 is thus formed by a metallic circumferential line section 84 (see Figure 16 ).

[0089] In addition to the heating element 76 , the print nozzle 70 also has a sensor opening 86 , into which a temperature sensor or a pressure sensor can optionally be introduced and which can be connected to an evaluation unit via contacts 74 .

[0090] The print nozzle also has an optical window 88. The optical window is used to connect a light-conducting element, such as an optical fiber, by means of which the bioink flowing through the nozzle channel 72 can be optically manipulated, in particular pre-gelled ("photo-cross-linked"), for example by means of UV radiation.

[0091] The 3D printing system 1 also has a controller (not shown), which is configured to drive a temperature control device for temperature control of the temperature control medium. The one or more temperature sensors mentioned above (and possibly also the heating element 76 of the printing nozzle 70) are connected to the controller in order to enable precise control, in particular regulation, of the temperature control. Optionally, the controller is also configured to control or regulate the delivery amount of the respective printing fluid and is interconnected to this end with at least one corresponding pressure sensor (see above description).

[0092] Figure 21 Another embodiment of the 3D printing system 1 is shown in FIG. Figures 16 to 20In addition to the print nozzle 70, there are a plurality of intermediate modules 90 and 92 which can optionally be coupled between the print nozzle 70 and the print head 10. In the embodiment shown, the reversing channel 36 already opens into the return 38 in the print nozzle 70, which is guided outside the intermediate modules 90, 92 and the print head 10 in this case in conjunction with a hose.

[0093] The print nozzle 70 has a heating element 76 and a temperature sensor 94 which is inserted into the (later introduced here) sensor opening 86. As an alternative to the above-described bayonet connection, the print nozzle 70 has a plurality of magnetic pins 96 as coupling elements which, in the specified assembled state, are locked into likewise magnetic magnetic recesses 98.

[0094] The intermediate modules 90 and 92 (for intermediate coupling) have magnetic recesses 98 on one side and magnetic pins 96 on the other side on their two coupling surfaces.

[0095] In the present exemplary embodiment, the intermediate module 92 serves as a sensor carrier and comprises a pressure sensor 100 . The associated sensor opening here reaches into the fluid channel 30 .

[0096] In the present exemplary embodiment, the intermediate module 90 forms an insertion module for the static mixer 102 and has an insertion shaft 104 for this purpose. The fluid channel 30 opens into the insertion shaft 104 and emerges from the insertion shaft 104 again. The jacket line 34 is guided around the insertion shaft 104 in this case.

[0097] The subject matter of the present invention is not limited to the above-mentioned embodiments. On the contrary, other embodiments of the present invention can be derived from the above description by those skilled in the art. In particular, the individual features of the present invention described in conjunction with different embodiments and their implementation variants can also be combined with each other in other ways.

[0098] Reference numerals list

[0099] 1 3D printing system

[0100] 2 Barrel container

[0101] 4 Barrel container

[0102] 6 Barrel

[0103] 8 Barrel

[0104] 10 Print head

[0105] 12 Outflow opening

[0106] 14 Fluid lines

[0107] 16 Fluid lines

[0108] 20 Temperature control channels

[0109] 20a Container section

[0110] 20b Line Section

[0111] 20c Head section

[0112] 22 Temperature control channels

[0113] 22a Container section

[0114] 22b Line Section

[0115] 22c Header section

[0116] 30 Fluid Channels

[0117] 32 Fluid Channels

[0118] 34 Sheathed Line

[0119] 36 Reversing Channels

[0120] 36a Reversing channel

[0121] 38 Return

[0122] 38a Return

[0123] 40 Enter the Ministry

[0124] 41 Peltier element

[0125] 41a Housing

[0126] 41b fan

[0127] 42 Peltier element

[0128] 43 Flange

[0129] 44 Nozzle

[0130] 46 Hose socket

[0131] 48 outer wall

[0132] 50 Connection opening

[0133] 52 Hose

[0134] 54 Opening

[0135] 56 Flat side

[0136] 58a positioning connector

[0137] 58b positioning notch

[0138] 58c flank

[0139] 58d Flanker

[0140] 58e holding magnet

[0141] 60 Fluid lines

[0142] 62 Temperature control channels

[0143] Line section 62b

[0144] 70 Print Nozzle

[0145] 72 Nozzle channel

[0146] 73 Connection surface

[0147] 74 Contact Department

[0148] 76 Heating element

[0149] 78 Pin

[0150] 80 holes

[0151] 82 slots

[0152] 84 Circumference line segment

[0153] 86 Sensor hole

[0154] 88 Optical Window

[0155] 90 Intermediate Module

[0156] 92 Intermediate Module

[0157] 94 Temperature Sensor

[0158] 96 Magnetic Pin

[0159] 98 Magnetic Notch

[0160] 100 Pressure Sensor

[0161] 102 Static mixer

[0162] 104 Move into the shaft

Claims

1. A 3D printing system (1), the 3D printing system comprising: - a first cartridge container (2) for reversibly accommodating a first cartridge, the first cartridge being stored with a printing fluid for 3D printing, - a print head (10) having an outflow opening (12), and - a first fluid circuit (14) connecting the first cartridge container (2) to the print head (10) for delivering printing fluid to the print head (10), and a first temperature control channel (20), which surrounds the first cartridge container (2) on the outside and is guided at least along the first fluid line (14), and through which a temperature control medium flows in a specified state of use.

2. The 3D printing system (1) according to claim 1, in, The first temperature adjustment channel (20) covers the first fluid circuit (14) on the outside.

3. The 3D printing system (1) according to claim 1 or 2, in, The first temperature control channel (20) continues into the print head (10) and is guided along a first fluid channel (30) for printing fluid in the print head (10), preferably at least partially enveloping the first fluid channel on the outside.

4. The 3D printing system (1) according to any one of claims 1 to 3, in, The first temperature control channel (20) transitions into a first return line on the print head side, and the first return line is guided coaxially with the first temperature control channel (20) at least in the region of the first fluid line (14).

5. The 3D printing system (1) according to any one of claims 1 to 3, in, The first temperature control channel (20) transitions on the print head side into a return portion (38), which is guided separately from the first fluid line at least in the region of the first fluid line (14).

6. The 3D printing system (1) according to any one of claims 1 to 5, The 3D printing system comprises a temperature control device for adjusting the temperature of a temperature control medium.

7. The 3D printing system (1) according to claim 6, in, The temperature control device has a first heating and / or cooling element, in particular a Peltier element (41), in the region of the first cartridge container (2).

8. The 3D printing system (1) according to any one of claims 1 to 7, The 3D printing system comprises a second cartridge container (4), a second fluid circuit (16) and a second temperature control channel (22).

9. The 3D printing system (1) according to claim 8, in, The first fluid line and the second fluid line (14, 16) merge into the outflow opening (12) in the print head (10).

10. The 3D printing system (1) according to claim 8, The 3D printing system comprises more than two cartridge containers (2, 4), more than two fluid circuits (14, 16, 60) and more than two temperature adjustment channels (20, 22, 62). in, The fluid lines (14, 16, 60) merge into the outflow opening (12) in the print head (10).

11. The 3D printing system (1) according to any one of claims 1 to 10, in, The print head (10) has an additional supply for a temperature-control medium and / or additional heating and / or cooling elements.

12. The 3D printing system (1) according to any one of claims 1 to 11, The 3D printing system comprises a printing nozzle (70) which is reversibly coupled to the outflow opening (12), in particular in, The nozzle channel (72) for the printing fluid is coaxially surrounded at least in sections by a channel for the temperature control medium.

13. The 3D printing system (1) according to claim 12, in, The printing nozzle (70) has a shut-off valve for the nozzle channel (72).

14. The 3D printing system (1) according to claim 12 or 13, The 3D printing system has at least one additional module (90, 92), which is connected or can be connected between the printing nozzle (70) and the printing head (10) and forms a carrier for at least one sensor (94, 100), a heating and / or cooling element, a mixing unit (102) and / or a microfluidic chip.

15. The 3D printing system (1) according to any one of claims 1 to 14, The 3D printing system has a controller and at least one temperature sensor interconnected with the controller, in, The control device is designed to control the temperature control device as a function of the temperature value detected by means of the temperature sensor or the respective temperature sensor.

16. The 3D printing system (1) according to any one of claims 1 to 15, in, The first or second cartridge container (2) is designed to receive a commercially available syringe as a cartridge and couple it to the first or second fluid line.

17. The 3D printing system (1) according to any one of claims 1 to 16, The 3D printing system comprises a valve which is designed to change a flow rate between a section of a first or second temperature control channel (20, 22) surrounding a first or second cartridge container (2, 4) and a section surrounding a first or second fluid line (14, 16).

18. The 3D printing system (1) according to any one of claims 1 to 17, in, The first or second fluid line (14, 16) and the section of the first or second temperature control channel (20, 22) respectively associated with the first or second fluid line are flexibly designed.

19. The 3D printing system (1) according to any one of claims 1 to 18, in, At least one optical window (88) is arranged upstream of the outflow opening (12) or in the printing nozzle (70), through which the printing fluid can be acted upon by radiation.

20. The 3D printing system (1) according to any one of claims 1 to 19, comprising: - a plurality of first cartridge containers (2), - a number of print heads (10) corresponding to the number of the first cartridge containers (2), each of which is connected to one of the first cartridge containers (2) via a respective first fluid line (14), and - respectively assigned first temperature control channels (20), in, Complementary coupling means (58a, 58b, 58c, 58d, 58e) are arranged on two opposite sides (56) of the print head (10), so that a plurality of print heads (10) can be coupled to one another in a row.

21. The 3D printing system (1) according to any one of claims 1 to 20, comprising: A controller and at least one pressure sensor interconnected with the controller, the pressure sensor being in contact with the printing fluid in a specified operating state.

Images