Method for producing a test specimen

Abstract

A method for producing a test specimen for diffusion-weighted magnetic resonance tomography, the test specimen comprising a plurality of liquid-filled channels embedded in a connecting material (3), the test specimen being formed from a plurality of capillaries (2) by additive manufacturing, the method comprising providing a virtual model of the test specimen defining the course of the capillaries (2) in three-dimensional space, supplying a capillary (2) to a discharging head (12), and repeatedly performing the following sequence of steps: - discharging the capillary (2) from the discharging head (12), - depositing the capillary (2) together with or into the connecting material (3) in accordance with the course defined in the virtual model, the capillary (2) being at least partially embedded in the connecting material (3), and - as and when required, severing and sealing the capillary (2).

Description

[0001] Method for producing a test specimen

[0002] The invention relates to a method for producing a test body, such as a nerve tissue phantom, for diffusion-weighted magnetic resonance imaging, which has a plurality of liquid-filled channels embedded in a connecting material.

[0003] A nerve tissue phantom represents a replica of a portion of human nerve tissue. Using nerve tissue phantoms, magnetic resonance imaging (MRI) scanners can be calibrated more efficiently, and algorithms for better differentiation of axon pathways can be developed, validated, and implemented. Reliable differentiation of axon pathways is essential because incorrect differentiation of crossing, tangent, and bypassing axons poses a significant risk, for example, in surgical planning in neurosurgery.

[0004] The invention generally relates to the reproduction of any region of human neural tissue or other fibrous tissue, such as muscle fibers. Preferably, the invention relates to the reproduction of a portion of the human brain, referred to here as a brain phantom.

[0005] Diffusion-weighted magnetic resonance imaging (DW-MRI) is an imaging technique that uses magnetic resonance imaging to measure the diffusion movement of water molecules in body tissue and visualizes it with spatial resolution. Diffusion tensor imaging (DTI) also records the directional dependence of diffusion. Within a sample, the microstructure of the material determines the mobility of the water molecules and makes them directionally dependent. This directional dependence provides information about the anisotropy and microstructure of the sample.

[0006] An interesting application of DTI is the study of white matter in the brain, which contains a network of bundles of parallel axon fibers. In this environment, orientation-dependent diffusion occurs because diffusion along the axon direction is significantly stronger than across the fiber direction. This preferred direction of diffusion provides information about the orientation of the fibers. However, the reliability and quality of the results obtained from DTI depend on the acquired data, which can be affected by, for example, a low signal-to-noise ratio, patient movement during the scan, chemical shift or inhomogeneities in the magnetic field, or low resolution. Furthermore, the spatial resolution of DTI is several orders of magnitude lower than the dimensions of the fibers, and entangled or crossing fibers provide very similar signals.The acquired data must be digitally processed and analyzed in a subsequent step. Given the uncertainties, it is desirable to quantitatively verify the accuracy of the results and the measured and calculated diffusion parameters and fiber directions to avoid misinterpretations. This can be achieved by direct measurements on nerve tissue phantoms.

[0007] Nerve tissue phantoms comprise a large number of channels in a structural material, with the individual channels simulating the axon fibers. In order to simulate the bundles of parallel axon fibers, a nerve tissue phantom must comprise corresponding bundles of parallel channels, whereby these can be realized as crossing, tangent, or past each other channel bundles. In order to carry out successful tractography of diffusion tensor imaging data acquired from a nerve tissue phantom, very small channel diameters are essential. Based on the mean diffusion length of water molecules at body temperature of around 25 pm, this results in a maximum channel diameter of around 20 pm. At the same time, the channel walls must be as thin as possible in order to maximize the total proportion of water molecules and thus the achievable MR signal strength. In addition, the high-resolution measurement of very small samples orNerve tissue phantoms cannot be created using conventional magnetic resonance imaging systems for human use. The problem is essentially due to the limited strength of the magnetic field gradients required for spatial encoding.

[0008] The production of nerve tissue phantoms with a closely arranged, open-pore channel system therefore requires a manufacturing process that has high-resolution microstructuring properties. The phantom structure should exhibit both material stability and a clear diffusion difference between the structural material and the channels. Furthermore, it must be ensured that sharply defined channels are produced, since only clearly defined edges at the transition to the channels enable the precise detection of directed diffusion. Furthermore, the phantoms should achieve a total size of at least several cubic centimeters to enable use in human scanners. Finally, the process should be economical and production should therefore be possible with sufficient throughput.

[0009] WO 2020 / 124106 A1 has already proposed producing nerve tissue phantoms using a 3D printing process. Conventional 3D printing processes used to create large constructs with volumes in the milliliter and liter range are limited in their resolution. High-resolution processes, in turn, have limitations in terms of throughput and the resulting restrictions on the possible overall structure size.

[0010] For applications based on the detection of directed diffusion signals, bundles of solid fibers are currently used instead of microchannels, in which water diffuses along the fiber surface. The fibers are either packed, wound, or spun. This approach limits control over diffusion directions, design complexity and precision, fiber arrangement, and the signal-to-noise ratio. Furthermore, diffusion along a fiber represents a less authentic imitation of biological tissue than diffusion in channels.

[0011] The present invention therefore aims to create a method which allows the realization of relatively large structures with a volume in the range of milliliters or even liters, and which at the same time ensures a high structural resolution for the creation of very long, thin channels with an aspect ratio of approximately 1000 or more.

[0012] To achieve this object, the invention provides a method for producing a test body for diffusion-weighted magnetic resonance imaging, which has a plurality of liquid-filled channels embedded in a connecting material, wherein the test body is constructed from a plurality of capillaries by means of additive manufacturing, comprising the provision of a virtual model of the test body, which defines the course of the capillaries in three-dimensional space, the feeding of a capillary to a delivery head and the repeated execution of the following sequence of steps:

[0013] Detaching and dispensing the capillary into and out of the dispensing head, placing the capillary according to the course defined in the virtual model together with or in the connecting material, whereby the capillary is at least partially embedded in the connecting material, if necessary detaching and sealing the capillary.

[0014] The invention is therefore based on the idea of ​​using prefabricated capillary structures for the additive construction of a test specimen, instead of forming the channels in a polymer material by solidifying individual voxels, as is the case with conventional 3D printing processes. This allows test specimens on the order of liters to be produced in a relatively short time. Capillaries are available in various materials in dimensions suitable for forming a test specimen. In particular, capillaries with an inner diameter of < 20 pm, preferably < 10 pm, can be used. This means that the additively manufactured test specimens can be designed and produced in such a way that they contain many thousands of channels with diameters of less than 10 micrometers, despite their relatively large overall size.The invention thus achieves a combination of high throughput and high resolution, which resolves the conflict in existing technologies between resolution, design, and construction size. Compared to prior art high-resolution processes, the overall size of the test specimen produced and the number and length of the microchannels can be increased considerably. Compared to high-throughput processes, the channel diameters provided are smaller and lie in the range of the channels that can be achieved with high-resolution processes. The additive manufacturing process offers freedom in design and a high degree of control over the channel arrangement. Furthermore, capillaries allow a more realistic imitation of diffusion in tissue than solid fibers without a void.

[0015] According to an advantageous development of the invention, a further increase in efficiency can be achieved by using a capillary or hollow fiber bundle as the capillary. This allows the application head to deposit a large number of capillaries in a single step.

[0016] In one embodiment of the present invention, capillaries with different inner diameters are used to fabricate the test specimen. This enables the creation of channels with different liquid volumes and flow properties, thus simulating a range of biological situations. For example, capillaries with a larger cross-section can represent regions of higher diffusion, while capillaries with a smaller cross-section can mimic areas of restricted diffusion. The use of capillaries with different diameters to construct the test specimen therefore offers the opportunity to evaluate the performance and accuracy of diffusion-weighted magnetic resonance imaging systems for a variety of tissue types and physiological conditions.

[0017] In another embodiment of the present invention, the use of capillaries with different cross-sectional shapes to fabricate the test specimen is contemplated. The capillaries can have circular, elliptical, square, rectangular, or other cross-sectional shapes. The different shapes allow for the simulation of a wider range of biological microenvironments, since the cross-sectional shape can influence the diffusion patterns of water molecules.

[0018] In a further preferred embodiment of the present invention, a hollow-core glass fiber or a hollow-core glass fiber bundle is used as the capillary. Such fibers, which are typically used in telecommunications, can be advantageously used within the scope of the invention because they have precise dimensions on a microscale, are geometrically uniform, and can be bundled to simulate more complex structures. The use of hollow-core glass fibers as the capillary structure offers the advantage of exact dimensional control, which enables the accurate simulation of various diffusion scenarios. Furthermore, the spectrum of simulable diffusion environments can be expanded.

[0019] Preferably, the capillary is filled with a liquid, particularly water, before being fed to the dispensing head. This eliminates the need for subsequent liquid introduction into the fully assembled test specimen, thus simplifying the manufacturing process. By introducing the liquid, particularly water, before the capillary is deposited, a more precise, uniform, and controlled diffusion environment is created.

[0020] In a preferred embodiment of the present invention, the capillary is fed to the dispensing head as a continuous capillary and is preferably unwound from a roll. This procedure ensures a uniform, uninterrupted feed of the capillary material and facilitates a consistent and efficient manufacturing process. The use of a roll for the storage and feeding of capillaries minimizes the risk of kinks or deformations in the capillary, which could impair the diffusion properties within the test specimen. This also enables longer production runs, permitting the manufacture of larger and more complex test specimens.

[0021] In a further preferred embodiment of the present invention, the capillaries are cut and sealed before being fed to the dispensing head and are fed to the dispensing head via a magazine. This procedure makes it possible to check the capillaries for defects and air inclusions before feeding.

[0022] As already mentioned, an essential step of the method according to the invention consists in depositing the capillary together with or into the connecting material, so that the capillary is at least partially embedded in the connecting material. The connecting material is responsible for fixing the individual capillaries in their relative positions within the test specimen and thus imparting inherent stability to the test specimen.

[0023] The bonding material used is preferably a flowable material that is allowed to solidify or harden during or after the capillaries have been embedded. A material that hardens thermally or through irradiation, particularly IR radiation or UV light, or a self-crosslinking two-component system is particularly suitable as the bonding material.

[0024] With regard to embedding the capillary(s) in the bonding material, a wide variety of process variants are possible. In one of these variants, the capillary can be coated with the bonding material before it is fed to the dispensing head, or can already be coated when it is fed to the dispensing head. Pre-coating ensures a homogeneous coating of the capillary and reduces the handling required for introducing the bonding material into the test specimen structure.

[0025] Alternatively, the capillary can also be coated with the bonding material directly in the dispensing head, which enables better process control and adjustment options, for example with regard to setting the required coating thickness.

[0026] In another alternative, it can be provided that the connecting material and the capillary are dispensed separately from the dispensing head or from the dispensing head and a further dispensing head, and the capillary is embedded in the connecting material when it is deposited. The connecting material and the capillary can be dispensed simultaneously or one after the other. For example, the connecting material can be deposited first to create a bed of the connecting material, after which the capillary is deposited in the bed thus created. For this purpose, it can be provided that the dispensing of the connecting material from the dispensing head precedes the dispensing of the capillary, as seen in the direction of travel.When using separate application heads for the connecting material and the capillary, it can be provided that the application head for the connecting material is positioned upstream of the application head for the capillary in the direction of travel.

[0027] According to a further preferred embodiment of the invention, the interconnect material may contain a component such as hydrogel capsules, which generates additional diffusion patterns. These hydrogel capsules or similar structures can be distributed throughout the interconnect material and filled with liquids with different diffusion properties, thereby creating different diffusion microenvironments. This enables a more nuanced and comprehensive representation of complex diffusion patterns observed in biological tissues. The integration of hydrogel capsules or other diffusion-modifying elements into the interconnect material therefore allows for a refinement of the calibration and validation process.

[0028] Preferably, it can further be provided that a thermoplastic is used as the connecting material, which is brought into the flowable state in the dispensing head by the application of heat, wherein the thermoplastic is allowed to solidify after the coated capillary has been laid down. The connecting material can be applied to the capillary as a coating during production of the capillary, so that the capillary is fed to the dispensing head in the coated state. In the dispensing head, the thermoplastic is brought into the plastic or flowable state by the application of heat and solidifies again after the coated capillary has been laid down to build up the test specimen. As a result of the solidification, the capillary is fixed in its intended position within the structure of the test specimen.This approach takes advantage of the favorable properties of thermoplastics, including their ability to be repeatedly melted and solidified without significant deterioration.

[0029] Alternatively, the capillary can be coated with the flowable thermoplastic directly in the dispensing head.

[0030] In a further preferred embodiment of the invention, the thermoplastic can be brought into a flowable state in the dispensing head under negative pressure, preferably a vacuum. This is intended to prevent the formation of bubbles in the thermoplastic material during the heating and coating process. Bubbles could impair the diffusion characteristics within the capillary and lead to discrepancies in the structure of the test specimen. By melting the thermoplastic under negative pressure or vacuum conditions, a homogeneous and consistent bonding material can be ensured.

[0031] Instead of a thermoplastic material, the bonding material can be a material that hardens thermally or through radiation, particularly IR radiation or UV light. When exposed to certain environmental conditions or stimuli, such materials change from a flowable state to a solidified state, effectively encapsulating and securing the capillaries within the structure of the test specimen. This process can be precisely controlled to ensure accurate positioning and stability of the capillaries. Preferably, a radiation-curing material is dispensed in a flowable state and, after embedding the capillary, is solidified by irradiation.

[0032] Alternatively, the bonding material can be a self-crosslinking two-component system. In such systems, two separate components react with each other to form a solidified, crosslinked structure. These systems offer the advantage of curing at room temperature.

[0033] In a further preferred embodiment of the present invention, the bonding material can be extruded from the dispensing head through a nozzle. This method enables the controlled and precise deposition of the bonding material around the capillary or onto the structure of the test specimen under construction. The nozzle, which can be designed with different diameters and shapes, allows precise control of the flow rate, pattern, and direction of the bonding material. The extrusion process can be tuned to ensure a homogeneous and uniform application of the bonding material. Furthermore, this approach is compatible with both thermoplastic materials and self-crosslinking two-component systems. In a further preferred embodiment of the present invention, the capillary is separated using a separating device arranged in or on the dispensing head.This device can be designed to cleanly and precisely cut or sever the capillary after it has been deposited and embedded in the bonding material, ensuring that each segment of the capillary is correctly positioned within the test specimen. Integrating the severing device into the dispensing head enables a seamless and efficient manufacturing process, eliminating the need for subsequent manual intervention to sever the capillary.

[0034] In this case, it can advantageously be provided that the channel of the capillary is closed during separation. This ensures that the liquid is effectively contained in the capillary and the integrity of the diffusion properties in the capillary is maintained for diffusion-weighted magnetic resonance testing. Sealing can take place simultaneously with the cutting process using heat or pressure or by a special sealing unit within the separation device. By integrating the closure mechanism into the cutting process, liquid loss or contamination is reduced to a minimum, thereby increasing the reliability and accuracy of the resulting test specimen.

[0035] According to the method according to the invention, the capillary is deposited by the dispensing head according to the path defined in the virtual model. The virtual 3D model of the test specimen defines the position and path of the capillaries within the test specimen and specifies how the liquid-filled capillaries should be arranged in three-dimensional space.

[0036] During the deposition of the individual capillaries, it must therefore be possible to adjust the orientation and / or position of the capillary relative to a construction platform or the test specimen at least partially built on the construction platform.

[0037] According to an advantageous development of the invention, this can be done in such a way that the capillary is deposited by at least one-axis, preferably at least two-axis, displacement of a construction platform relative to the dispensing head during the dispensing of the capillary.

[0038] Alternatively, or in combination with the displacement of the build platform, the capillary can be deposited by at least uniaxial, preferably at least biaxial, displacement of the dispensing head relative to a build platform during the capillary dispensing process. The dispensing head can be pivotally mounted to adjust the orientation of the dispensed capillary relative to the build platform.

[0039] If the capillary is made of a fragile material, such as a hollow-core glass fiber or a hollow-core glass fiber bundle, precise control of the maximum curvature of the capillary as it passes through the dispensing head and is deposited is required to prevent breakage. From a design perspective, this can be achieved, for example, by orienting the dispensing head with its dispensing axis as parallel as possible to the build platform or to the surface of the partially built test specimen on which the capillary is to be deposited, or by minimizing the angle between the dispensing axis and said surface of the test specimen.

[0040] An alternative approach to prevent excessive capillary bending is to incorporate a feedback control system into the dispensing mechanism. This system could monitor the capillary curvature in real time during deposition and adjust the movement of the dispensing head or build platform accordingly to ensure the capillary does not exceed a predetermined maximum curvature. This real-time adjustment could be facilitated by sensors and actuators integrated into the dispensing mechanism.

[0041] With regard to the control of the application head and / or the construction platform to achieve the desired course of the capillaries, it is preferably provided that the virtual model is fed to a control unit which generates control signals for controlling at least one drive of the application head and / or the construction platform in order to deposit the capillary in accordance with the course defined in the virtual model.

[0042] The invention is explained in more detail below with reference to exemplary embodiments shown in the drawing. In these, Fig. 1 shows a cross section of a capillary bundle for use in the method according to the invention, Fig. 2 shows a cross section of a test specimen made up of capillary bundles, Fig. 3 is a plan view of a test specimen made up of capillary bundles, Fig. 4 shows a first embodiment of a device for carrying out the method according to the invention in a front view, Fig. 5 is a side view of the device according to Fig. 4, Fig. 6 is a second embodiment of a device for carrying out the method according to the invention in a front view, Fig. 7 is a side view of the device according to Fig. 6 and Figs. 8 to 12 show different variants of print head designs for use in the invention.

[0043] Fig. 1 shows a capillary bundle 1, which can also be referred to as a hollow fiber bundle, comprising a plurality of capillaries 2.

[0044] Fig. 2 shows a test specimen 4 with an exemplary course of capillary bundles 1 embedded in a connecting material 3 in cross section.

[0045] In the plan view according to Fig. 3, capillary bundles with different courses are shown using a further example of a test specimen 4. Parallel capillary bundles 5 are shown, which cross parallel capillary bundles 6 running perpendicularly thereto. Furthermore, parallel capillary bundles 7 and 8, which have a curved course and cross one another, are visible.

[0046] Fig. 4 and 5 show a device comprising a supply of a capillary bundle wound on a roll 9 and a supply of a connecting material wound on a roll 10 in the form of a strand of material or filament. The capillary bundle 1 unwound from the roll 9 and the strand of material 11 of the connecting material 3 unwound from the roll 10 are fed to a print head or dispensing head 12 in which the capillary bundle 1 is coated with the connecting material 3. A capillary bundle 14 coated with connecting material 3 is thus dispensed from the nozzle 13 of the dispensing head 12 and deposited in accordance with the predetermined course to build up the test specimen 4. In order to coat the capillary bundle 1 with the thermoplastic connecting material 3, the material strand 11 is melted in the dispensing head 12, so that the capillary bundle 14 leaving the dispensing head 12 via the nozzle 13 contains the connecting material 3 in a flowable or meltable state.plastic state. During or after the deposition of the capillary bundle 14, the connecting material 3 solidifies, so that a test specimen 4 is formed in which a large number of capillaries are embedded.

[0047] In order to deposit the capillary bundle 14 according to the course defined in the virtual model, the dispensing head 12 and the construction platform 15 are arranged so as to be displaceable relative to one another in three spatial directions. In the example shown here, the dispensing head 12 is displaceably mounted on a guide 16 in order to achieve a displacement of the dispensing head in an x-direction. The construction platform 15 is also arranged so as to be movable, specifically in at least a y- and a z-direction. Furthermore, the dispensing head 12 is pivotally mounted about a joint 17 in order to be able to adjust its orientation relative to the construction platform 15 or the test specimen 4 at least partially built thereon.

[0048] 6 and 7 show a modified device, wherein the components which are the same as in the embodiment according to FIGS. 4 and 5 are provided with the same reference numerals as in FIGS. 4 and 5. In contrast to the embodiment according to FIGS. 4 and 5, no thermoplastic connecting material 3 is used, but rather a radiation-curing connecting material 3, such as a UV-light-curing connecting material 3. The connecting material is fed from a storage container 18 in flowable form via a line 19 to the dispensing head 12, where the capillary bundle 1 is filled with the connecting material 3. The nozzle 13 of the dispensing head 12 is equipped with a UV lamp 20, so that the connecting material 3 which is dispensed as a coating of the capillary bundle and laid down to build up the test specimen 4 can be solidified.

[0049] Figs. 8 and 9 show embodiments of a discharge head 12 equipped with a separating device 21 for separating the capillary bundle 1 or the coated capillary bundle 14 (as the case may be). The separating device 21 comprises at least two cutting blades 22 movable relative to one another. As a possible alternative, the cutting blades can also be replaced by a melting device.

[0050] In the embodiment according to Fig. 8, the separating device 21 is arranged on the nozzle 13 of the application head 12, so that the capillary bundle 1 or 14 can be separated directly at the outlet from the nozzle 13. In the embodiment according to Fig. 9, the separating device 21 is arranged inside the application head 12.

[0051] Fig. 10, 11 and 12 show embodiments of the dispensing head 12 with different possibilities for introducing and removing the capillary bundle 1 and the connecting material 2. In the embodiment according to Fig. 10, the capillary bundle 1 and the strand 11 of the connecting material 3 are fed separately to the dispensing beater 12 and removed separately from it after the connecting material 3 has been heated and liquefied in the dispensing beater 12.

[0052] In the embodiment according to Fig. 11, the material strand 11 of the connecting material 1 is brought into the flowable state in the dispensing head 12 by means of a heating device 23, so that the capillary bundle 1 is coated with the connecting material 1. A coated capillary bundle 14 is dispensed from the dispensing head, as in the embodiment according to Figs. 4 and 5.

[0053] In the embodiment according to Fig. 12, the bonding material, as in the embodiment according to Figs. 6 and 7, is a radiation-curing material, such as a UV-light-curing material, which is introduced into a chamber 24 of the dispensing head 12. The capillary bundle 1 is guided through the chamber 24 and thereby coated with the bonding material 3. A coated capillary bundle 14 is therefore dispensed from the dispensing head.

Claims

Patent claims:

1. A method for producing a test body for diffusion-weighted magnetic resonance imaging, which test body has a plurality of liquid-filled channels embedded in a connecting material (3), wherein the test body is constructed from a plurality of capillaries (2) by means of additive manufacturing, comprising providing a virtual model of the test body (4) which defines the course of the capillaries (2) in three-dimensional space, feeding a capillary (2) to a delivery head (12) and repeatedly carrying out the following sequence of steps: Ejecting the capillary (2) from the dispensing head (12) , Placing the capillary (2) according to the course defined in the virtual model together with or in the connecting material (3), wherein the capillary (2) is at least partially embedded in the connecting material (3), if necessary separating and sealing the capillary (2).

2. Method according to claim 1, characterized in that a capillary or hollow fiber bundle (1) is used as the capillary (2).

3. Method according to claim 1 or 2, characterized in that a hollow-core glass fiber or a hollow-core glass fiber bundle is used as the capillary (2).

4. Method according to claim 1, 2 or 3, characterized in that the capillary (2) is filled with a liquid, in particular water, before it is fed to the application head (12).

5. Method according to one of claims 1 to 4, characterized in that the capillary (2) is fed to the application head (12) as an endless capillary and is preferably unwound from a roll (9).

6. Method according to one of claims 1 to 5, characterized in that the capillary (2) is coated with the connecting material (83) before or during the application, preferably in the application head (12).

7. Method according to one of claims 1 to 5, characterized in that the connecting material (3) and the capillary (2) are dispensed separately from one another from the dispensing head (12) or from the dispensing head and a further dispensing head and the capillary (2) is embedded in the connecting material (3) when deposited.

8. Method according to one of claims 1 to 7, characterized in that the connecting material (3) contains a component, such as hydrogel capsules, which creates additional diffusion patterns.

9. Method according to one of claims 1 to 8, characterized in that a thermoplastic is used as the connecting material (3), which is brought into the flowable state in the dispensing head (12) by the action of heat, the thermoplastic being allowed to solidify after the coated capillary (14) has been laid down.

10. Method according to claim 9, characterized in that the thermoplastic in the application head (12) under a under pressure, preferably a vacuum, into the flowable state.

11. Method according to one of claims 1 to 8, characterized in that the connecting material (3) is a material which hardens thermally or by irradiation, in particular IR radiation or UV light, or a self-crosslinking two-component system.

12. Method according to one of claims 1 to 11, characterized in that the connecting material (3) is extruded from the application head (12) through a nozzle (13).

13. Method according to one of claims 1 to 12, characterized in that the separation of the capillary (2) is carried out with a separation device (21) arranged in or on the application head (12).

14. Method according to one of claims 1 to 13, characterized in that the channel of the capillary (2) is closed during separation.

15. Method according to one of claims 1 to 14, characterized in that the deposition of the capillary (2) is carried out by at least one-axis, preferably at least two-axis, displacement of a construction platform (15) relative to the application head (12) during the deployment of the capillary (2).

16. Method according to one of claims 1 to 15, characterized in that the deposition of the capillary (2) is carried out by at least uniaxial, preferably at least biaxial, displacement of the application head (12) relative to a Construction platform (15) during the deployment of the capillary (2).

17. Method according to one of claims 1 to 16, characterized in that the dispensing head (12) is pivotally mounted in order to adjust the orientation of the dispensed capillary (2) relative to the construction platform (15).

18. Method according to one of claims 1 to 17, characterized in that the virtual model is fed to a control unit which generates control signals for controlling at least one drive of the application head (12) and / or the construction platform (15) in order to deposit the capillary (2) according to the course defined in the virtual model.

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