DE102017124352A1 - Plant, printhead and method for producing three-dimensional structures - Google Patents

Abstract

The invention relates to a system for producing three-dimensional structures comprising two or more different materials, comprising a 3D print head having a first material feed for feeding a quasi-fiber-less fiber material and at least a second material feed for feeding a thermoplastic matrix material in a common The mixing chamber of the print head open, wherein the mixing chamber of the 3D print head for tempering the mixing material supplied to the mixing chamber and for forming a material mixture of the fiber material and the matrix material is formed, wherein the mixing chamber communicates with an outlet of the 3D print head communicating, the Dispensing of the formed material mixture is adapted to produce the three-dimensional structure, wherein the first material supply has a feed channel, which opens into the mixing chamber and is arranged axially to the outlet such that a quasi-filament without and the plant has a control unit arranged to control the material supply of the quasi-non-fibrous material and / or the thermoplastic matrix material, the at least second material supply having three or more feed channels which are arranged around an axial course of the feed channel of the first material supply around and open in the mixing chamber.

Description

The invention relates to a plant for producing three-dimensional structures comprising two or more different materials. The invention also relates to a 3D printing head for this purpose and to a method for producing such a three-dimensional structure by means of the installation according to the invention.

Generative methods can be used to produce components of almost any shape using a suitable material. 3D printing using a 3D printer represents a very well-known representative of additive manufacturing processes. In this process, a fusible material, for example a thermoplastic material, is printed in layers by means of a 3D printer, whereby at the end of the process a three-dimensional component or gives a three-dimensional structure.

The rigidity and strength of a component produced on this basis depends significantly on the corresponding material properties of the fusible material used. Especially with regard to the lightweight construction, it is often desirable that the components are made of fiber composites in order to obtain a high weight-specific strength and rigidity. However, fiber composite materials have anisotropic material properties, so that strength and rigidity is direction-dependent and thus dependent on the fiber orientation. Therefore, multiple layers of fiber material are often arranged with different fiber orientations, so as to at least partially replicate the homogeneous material properties of metals.

Such, especially if necessary, integration of fiber material in 3D printing would have the decisive advantage that components and structures can be produced whose load paths are adapted exactly to the conditions without unnecessarily requiring fiber material.

From Hauke Prüß, Thomas Vietor: New design freedom through 3D-printed fiber-plastic composites "Forum for Rapid Technology" Issue 12/2015, a 3D printhead is known to which a quasi-free fiber material is fed. Furthermore, a plastic material is supplied to the 3D print head by means of two feed channels, with fiber material and plastic material opening in a common mixing chamber, whereby the fiber material passing through is wetted by the plastic material and output in this form. As a result, almost any structures with integrated load paths can be developed.

The disadvantage of this known 3D printing head lies in the fact that the supply of the plastic material into the mixing chamber by two feed channels, which are diametrically opposed to the fiber material for good and complete wetting always has to pass through the mixing chamber, that one side of the the first feed channel faces, while the other side faces the second feed channel. Upon rotation of the fiber material about its own axis by, for example, 90 ° would lead to the fact that the matrix material may no longer be reliably adhered to the fiber material.

Another disadvantage of this 3D print head with diametrically opposed feed channels lies in the lack of controllability of the material supply for the purpose of a corresponding adaptation of the material mixture to the predetermined structure to be produced. Because with a correct passage of the fiber material through the mixing head, the fiber material is uniformly wetted from all sides, but this is possibly undesirable depending on the shape and geometry of the structure to be produced. A finely graduated control of the course of the fiber material in cross section to the output material mixture of fiber material and matrix material is therefore not possible.

From the DE 20 2015 004 336 U1 Furthermore, a device for applying a material is known, which is made of a mixture of two printhead supplied materials. However, the printing of fiber-plastic composites is not possible with this head.

It is therefore an object of the present invention to provide an improved 3D printhead and an improved system and an improved method for producing three-dimensional structures, with which it is possible, the material mixture formed from the mixture of fiber material and matrix material to the shape and geometry of the three-dimensional To fine tune the structure and thus to optimize the structure to be produced.

The object is achieved with the system according to claim 1, the 3D print head according to claim 13 and the method according to claim 14 according to the invention.

According to claim 1, a plant for producing three-dimensional structures is proposed, which have two or more different materials. The system has a 3D print head having a first material feed for feeding a quasi-fiberless material and at least a second material feed for feeding a thermoplastic matrix material. Both the The first material feed and the second material feed open into a common mixing chamber, in which then the quasiendlose fiber material wets with the matrix material and thus the material mixture is formed. The mixing chamber also has an outlet through which the mixture of materials can be extruded from the mixing chamber of the 3D print head and thus the three-dimensional structure can be produced.

The mixing chamber is designed so that it is heatable (heatable), so as to melt the thermoplastic matrix material and make it deformable.

In this case, the first material supply has a feed channel which opens into the mixing chamber and is arranged axially relative to the outlet so that a quasi-free fiber material can be guided from the feed channel of the first material feed through the mixing chamber and the outlet, without being deflected in particular. In this way it is achieved, in particular, that the fiber material is not damaged during passage through the 3D printing head by corresponding contact points.

Furthermore, the system has a control unit which is set up to control the material supply of the quasi-non-volatile fiber material and / or the thermoplastic matrix material so as to be able to influence and manipulate the dispensing of the material mixture accordingly.

According to the invention, it is now provided that the at least second material supply has three or more feed channels, which are arranged around an axial course of the feed channel of the first material feed and open into the mixing chamber. The feed channels are arranged equidistant from one another about the axial course of the feed channel of the first material feed, through which the fiber material is guided into the mixing chamber, so that always two adjacent feed channels of the second material feed have the same distance from one another (within manufacturing tolerances).

As a result, it is now possible to vary and optimize the matrix material and the wetting of the fiber material in the mixing chamber in order to be able to adapt the material mixture to the given conditions or the given geometry of the structure to be produced in a finer graduated manner.

In this case, the inventors have recognized that the wetting of the fiber material can be improved by a separate material supply of the thermoplastic material by means of three or more feed channels, wherein by varying the feed rate of the thermoplastic matrix material of the individual feed channels using the control unit, the position and position of the matrix material within the cross section of the material mixture can be set almost arbitrarily. Thus, three-dimensional structures can be produced which are optimally adapted to the given conditions of use.

In an advantageous embodiment, the feed channels of the second material supply are not arranged axially to the outlet, but rather open at a certain angle to the outlet or to the axial course of the feed channel of the first material supply, so as to optimize the wetting of the fiber material during the passage ,

In one advantageous embodiment, the 3D printing head has in each case one feed unit for each feed channel of the second material feed, for advancing or pressing the thermoplastic matrix material into the mixing chamber through the respective feed channel of the second material feed. Each feed unit in this case is supplied in each case a separate material, which can be done for example by a material supply. The arranged on the 3D printhead feed unit now pulls the still usually solid material from the material supply and presses it into the respective feed, where it is heated due to the temperature of the mixing chamber and then enters the mixing chamber.

The feed units are arranged in particular releasably on the 3D print head, which significantly simplifies the cleaning of the system as a whole. In this case, it is conceivable that the respective feed unit is screwed or fastened directly to one of the feed channels, wherein a feed unit may have cooling fins between the feed channel and the feed unit in order to prevent premature melting of the still solid thermoplastic matrix material in the feed unit.

In a further advantageous embodiment, each of the feed units is connected to the control device, so that each of the feed units can be controlled separately by the control device. Each of the feed units can be controlled individually so that a corresponding feed rate or Materialzuführgeschwindigkeit for each of the feed units can be set separately and separately from the others. Due to the different material feed speeds of the individual feed units so the location and Position of the fiber material in the cross-section of the material mixture can be varied at the outlet and thus influenced depending on the desired position and position. So it is conceivable, for example, that for one or possibly more feed units of the feed is interrupted completely, so that a Materialzuführgeschwindigkeit is set by 0. As a result, the fiber material is wetted very unevenly, which is possibly desired for the structure of the structure.

In a further advantageous embodiment, the control unit is set up for setting and / or varying the material feed rate of the quasi-filamentary fiber material and / or of the thermoplastic matrix material. Thus, it is conceivable that, for example, the material supply of the quasi-fiber-free fiber material is temporarily interrupted so as to print areas without fiber material. It is also conceivable that different thermoplastic matrix materials are used, which are supplied as needed, the mixing chamber. In this case, a first thermoplastic matrix material is first fed into the mixing chamber, wherein, if necessary, then the feeding of the first thermoplastic matrix material is interrupted and the supply of the second thermoplastic matrix material is absorbed. This is particularly advantageous when the 3D printing has more than three feed channels of the second material supply device.

Moreover, it is particularly advantageous in this case if the control unit is designed to set and / or vary the material feed speed as a function of a printing speed and / or a printing speed change when printing the three-dimensional structure. Thus, it is conceivable that in the case of large-area components the material mixture is first output at a high printing speed, whereby a high material feed rate of both the quasi-filamentary fiber material and the thermoplastic matrix material is necessary. Slows down the printing speed, i. the relative speed of the 3D print head over the three-dimensional structure to be printed also reduces the material feed rate of both the quasi-non-fibrous material and the thermoplastic matrix material so as to accommodate the reduced print speed and thus output less material of the material mix per time. In this regard, it is also advantageous if the material feed rate is adjusted and / or varied in response to a given geometry and / or design of the three-dimensional structure to be fabricated so as to provide a material mixture adapted to the desired conditions at each time and place and location to spend the three-dimensional structure.

In a further advantageous embodiment, the installation has a first material supply device, which is designed to provide a quasi-filamentary material to the first material supply of the 3D print head, and has a second material supply device, which is for providing a thermoplastic matrix material to the second material supply of the 3D print head is trained. The first material feed has an entrance through which the quasi-filamentous fiber material is fed into the feed channel of the first material feed. Furthermore, a pressure source is provided which cooperates with the input of the first material supply such that at the entrance of the first material supply an overpressure can be generated, which prevents leakage of the thermoplastic matrix material at the entrance of the first material supply.

By pushing in the thermoplastic matrix material via the feed channels of the second material supply, a pressure is created in the mixing chamber, which is directed in the direction of the outlet and due to the system undesirably also in the direction of the first material feed. By generating the overpressure at the entrance of the first material supply, as mentioned above, an increase of the liquid thermoplastic matrix material from the mixing chamber to the entrance of the first material supply can be prevented, whereby the risk of contamination of the 3D print head and the curing of the thermoplastic matrix material is reduced in the feed of the first material supply.

The first material supply device preferably has a pressure vessel in which the quasi-filamentary fiber material is stored. In addition, the first material supply device has a pressure-tight fiber guide which is pressure-tightly connected to the pressure vessel on the one hand and pressure-tight on the first material supply of the 3D print head on the other hand and may be formed, for example, from a solid tube or a flexible hose. The pressure vessel and the pressure-tight fiber guide thereby form an interior or interior, which is delimited by the pressure vessel and the pressure-tight fiber guide of an outdoor area. This inner region is designed so that it can be printed by means of the pressure source with a printing medium, so that an internal pressure in the interior of the pressure vessel and the pressure-tight fiber guide can be generated such that the overpressure generated at the entrance of the first material supply and leakage of the thermoplastic matrix material at the first material supply, ie at the entrance of the first material feed on the 3D print head is prevented.

By printing on the inner region, an internal pressure is thus built up by the pressure source, which is intended to prevent the emergence of the thermoplastic matrix material from the first material supply, until the first material feed is received.

In a further advantageous embodiment, the control unit for controlling the pressure source is designed so that the generated overpressure at the entrance of the first material supply varies.

In a further advantageous embodiment, the control unit for controlling the pressure source is set up such that the generated overpressure is set as a function of a printing speed of the print head and / or as a function of a material feed rate of the quasi-filamentary fiber material and / or of the thermoplastic matrix material. Because with increasing printing speed or increasing Materialzuführgeschwindigkeit also increases the pressure generated in the mixing chamber, whereby the risk is increased that emerges thermoplastic matrix material at the inlet of the first material supply. This is compensated by adjusting the overpressure, for example by increasing the internal pressure at an increased printing speed or increased material feed rate.

In a further advantageous embodiment, the first material feed on the 3D print head has a sensor system which is designed to detect a filling level of the thermoplastic matrix material in the first material feed, wherein the control unit for controlling the pressure wave is set up such that the generated overpressure is dependent is set by the detected level. The higher the fill level within the first material supply, which can be detected via the sensor system, the greater the overpressure is set by the control unit.

In a further advantageous embodiment, the system, in particular the pressure source of the system, is designed for tempering the pressure medium used to generate the overpressure so as to prevent solidification or solidification of the liquid thermoplastic material from rising in the first material supply. For the higher the molten thermoplastic rises in the first material supply, the farther away it is from the tempered mixing chamber, which can cause it to cool down so far that it solidifies again. By tempering the pressure medium can be counteracted such solidification.

According to an advantageous embodiment, the 3D print head is arranged as an end effector on a motion machine and thus freely movable in space. It is also conceivable, however, for the 3D printing head to be arranged on a gantry installation or fixedly provided, with at least the deposition table then moving under the 3D printing head.

According to a further advantageous embodiment, the 3D print head has a head tip, which is detachably arranged on the 3D print head and within which the outlet, into which the mixing chamber opens for dispensing the material mixture, is provided. The outlet preferably has a diameter which is smaller than the diameter of the feed channels of the first and / or second material feed, so that access to the feed channels of the first and / or second material feed is made possible by the detachable head tip, for example to this clean or remove blockages.

Incidentally, the object is also achieved with a 3D print head as described above, wherein such a 3D print head then has three or more feed channels in the second material feed, all of which open in the common mixing chamber.

Incidentally, the object is also achieved with the method for producing a three-dimensional structure, wherein initially a system for producing a three-dimensional structure as described above is provided. Both a quasi-free fiber material and a thermoplastic matrix material is now supplied to the 3D print head of the system and mixed in the common mixing chamber to form a material mixture and then the material mixture is then printed to produce the three-dimensional structure.

In an advantageous embodiment for this purpose, it is conceivable that the Materialzuführgeschwindigkeit is varied in the material supply of the quasi-filamentary fiber material and / or the thermoplastic matrix material during printing, which may also mean that the Materialzuführgeschwindigkeit reduced to 0, and thus the material supply is interrupted.

• 1 - Perspektivische Darstellung eines 3D-Druckkopfes;
• 2 - Schnittdarstellung des 3D-Druckkopfes
• 3 - schematische Darstellung der erfindungsgemäßen Anlage.

The invention will be explained in more detail by way of example with reference to the attached figures. Show it:

• 1 - Perspective view of a 3D printhead;
• 2 - Sectional view of the 3D print head
• 3 - Schematic representation of the system according to the invention.

1 shows in a perspective view of the print head 10 , which is designed and intended to be arranged on an unillustrated motion machine. In the lower area is a mixing head 11 that has an outlet 12 from which finally the material mixture of fiber material and thermoplastic matrix material for printing the three-dimensional structure is output.

Inside the mixing head 11 This is the mixing chamber, not shown, in which both the first material supply 13 the fiber material as well as the second material supply 14 for the thermoplastic matrix material.

The first material feed 13 has a feed channel that is axial to the outlet 12 is provided, so that the fiber material through the first material supply 13 in the mixing head 11 and then from the outlet 12 can be led out.

The second material feed 14 has in the embodiment of 1 three feed channels 15 (please refer 2 ), which also on the mixing head 11 arranged and thus also in the inside of the mixing head 11 provided mixing chambers 20 (please refer 2 ). The feed channels 15 are about the axial course of the feed channel of the first material supply 13 arranged at a certain angle.

Each of the three feed channels 15 is a feed unit 16 assigned, which are formed, a first solid thermoplastic matrix material in their respective associated feed channel 15 the second material feed 14 to press, wherein the thermoplastic matrix material in the region of the mixing head 11 tempered and thereby melted. It may be provided that the feed unit 16 with cooling fins 17 in connection, so that the thermoplastic matrix material actually only in the region of the mixing head 11 reaches a temperature at which it is melted.

The arrangement of three feed channels (or possibly more) and each separate feed units, which can be controlled separately by means of a control unit, the material supply can be adjusted very fine graduated, whereby the position and position of the fiber material within the covering matrix material is defined adjustable.

So it is conceivable, for example, that the material supply of the fiber material is basically stopped, whereby only the thermoplastic matrix material at the outlet 12 is issued. It is also conceivable that in some of the feed channels and this supply channel 15 assigned feed unit 16 a control is carried out so that the material feed rate is reduced, whereby less thermoplastic matrix material in this area passes into the mixing chamber. Due to a resulting pressure gradient within the mixing chamber, the position and position of the fiber material with respect to the sheathing matrix material changes, whereby the material mixture can be adapted exactly to the predetermined conditions of the three-dimensional structure to be produced.

2 shows a sectional view through the 3D printhead, as well as he out 1 is known. There is a mixing chamber 21 provided in which the feed channels 15 the second material feed 14 lead. In addition, a feed channel opens 19 the first material feeder 13 also in the mixing chamber 21 so that there the fiber material can be mixed with the matrix material. The mixing chamber 21 then flows into an outlet 12 from which the material mixture is then output.

The outlet 12 is located in a head tip 18 that is detachable to the printhead 10 is arranged so as to remove the head tip 18 an access to the mixing chamber 21 and the feed channels 15 the second material feed 14 and the feed channel 19 to receive the first material feed. In this way, the 3D print head can be cleaned simply and reliably.

Because usually has the outlet 12 a smaller diameter than the feed channels 15 the second material supply or the supply channel 19 the first material feed, allowing cleaning without removing the head tip 18 only very difficult is possible.

The feed channels 15 the second material feed 13 for the thermoplastic matrix material are preferably straight and have no curvature within the head. In addition, the mixing chamber is so in the mixing head 11 arranged that the mixing chamber 21 right after removing the head tip 18 is accessible. The feed channels 15 the second material feed 13 then open into the mixing chamber 21 that after removing the head tip 18 in each feed channel a rod can be inserted, so as to be able to clean the feed channels accordingly. Preferably, the rod is thereby completely inserted into the respective feed channel.

3 shows a schematic representation of the plant according to the invention 100 , the first in a simplified representation of the printhead 10 , like out 1 known, has. For better illustration, the printhead is 10 here indicated only by way of example and has a total of three feed channels for thermoplastic matrix material and a central feed of fiber material.

The attachment 100 further comprises a control unit 20 on, first with the printhead 10 signal technology is connected, so as for example by controlling the feed units (not shown in FIG 2 ) to adjust the feed rate and thus the material feed speed.

Furthermore, the attachment points 100 a first material supply device 30 on, which is a fiber material 31 stores. The fiber material 31 is inside a pressure vessel 32 the first material supply device 30 arranged, wherein on the pressure vessel 32 a fiber feed 33 is arranged, on the one hand with the pressure vessel 32 and on the other hand, with the central fiber feed on the printhead 10 is arranged pressure-tight. The fiber material 31 can now from the first material delivery device 30 in the pressure vessel 32 through the fiber guide 33 to the print head 10 be transported.

Furthermore, an only schematically indicated second material supply device 40 provided to the printhead 10 the thermoplastic matrix material 41 to be supplied in solid form.

The control unit 20 stands with the first material supply device 30 Signaling in conjunction, so as to be able to stop the material supply if necessary. It is also conceivable that the printhead 10 a feed unit for the fiber material is provided, which is then controlled by the control unit 20 Accordingly, it can be controlled so that the material supply of the material 31 is stopped.

Furthermore, the pressure vessel points 32 a connection for a pressure source 34 on, with the inside of the pressure vessel 32 and the fiber feeder 33 can be printed with a print medium. This can prevent thermoplastic matrix material on the print head 10 rises in the central feed for the fiber material and escapes at the printhead opposite the outlet, as due to the pressure in the pressure vessel 32 in the fiber feeder 33 the pressure within the mixing head is counteracted.

It is conceivable that the pressure wave 34 through the control unit 20 is controlled so that, for example, the internal pressure can be variably adjusted. The adjustment of the internal pressure can take place, for example, as a function of a printing speed or a Materialzuführgeschwindigkeit, thereby correspondingly change the pressure conditions within the print head. It is also conceivable that the control device 20 for tempering the pressure medium, with which the internal pressure is to be built up, is formed so as to harden the thermoplastic matrix material in the region of the fiber feed for the fiber material 31 counteracted.

LIST OF REFERENCE NUMBERS

10

- Printhead

11

- mixing head

12

- outlet

13

- first material feed

14

- second material supply

15

- Feed channels of the second material supply

16

- Feed units

17

- cooling fins

18

- head tip

19

- Feeding channels of the first material supply

20

- Control unit

21

- mixing chamber

30

- First material supply device

31

- Fiber material

32

- Pressure vessel

33

- fiber feed

34

- Pressure source

40

- Second material supply device

41

- thermoplastic matrix material

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 202015004336 U1 [0008]

Claims (18)

A plant for producing three-dimensional structures comprising two or more different materials, comprising a 3D print head (10) having a first material feed (13) for feeding a quasi-fiberless material (31) and at least one second material feed (14) for feeding a thermoplastic matrix material (41), which open into a common mixing chamber (21) of the print head (10), wherein the mixing chamber (21) of the 3D print head (10) for tempering the mixing chamber (21) supplied matrix material (41) and the Forming a material mixture of the fiber material (31) and the matrix material (41) is formed, wherein the mixing chamber (21) communicating with an outlet (12) of the 3D print head (10) is in communication, which is adapted to output the material mixture formed to produce the three-dimensional structure, wherein the first material supply (13) has a feed channel (19) which opens into the mixing chamber (21) and axially to the outlet (12) is arranged such that a quasi-filamentous fiber material (31) from the supply channel (19) of the first material supply (13) through the mixing chamber (21) and the outlet (12) can be passed, and wherein the system is a control unit ( 20) arranged to control the material supply of the quasi-non-woven fiber material (31) and / or the thermoplastic matrix material (41), characterized in that the at least second material supply (14) has three or more feed channels (15) around a axial course of the feed channel (19) of the first material supply (13) are arranged around and in the mixing chamber (21) open. Plant after Claim 1 , characterized in that the supply channels of the second material supply (15) are not arranged axially relative to the outlet (12). Plant after Claim 1 or 2 , characterized in that the 3D print head (10) for each feed channel of the second material supply (15) each have a feed unit (16), the thermoplastic matrix material (41) through the respective feed channel of the second material supply (15) into the mixing chamber ( 21). Plant after Claim 3 , characterized in that the feed units (16) are arranged detachably on the print head (10). Plant after Claim 3 or 4 , characterized in that each feed unit (16) is controllable separately from the other by means of the control unit (20), wherein the control unit (20) for setting and / or varying the material feed rate of the thermoplastic matrix material (41) by appropriate control of the feed units ( 16) is arranged to adjust the feed rate of the feed units (16) separately. Installation according to one of the preceding claims, characterized in that the control unit (20) for adjusting and / or varying the material feed speed of the quasi-filamentous fiber material (31) and / or the thermoplastic matrix material (41) is arranged. Plant after Claim 6 characterized in that the control unit (20) is adapted to set and / or vary the material feed rate in response to a print speed and / or a print speed change and / or a predetermined geometry and / or a predetermined structure of the three-dimensional structure to be produced. Installation according to one of the preceding claims, characterized in that the system has a first material supply device (30) which is designed to provide a quasi-filamentary fiber material (31) to the first material supply (13) of the 3D printing head (10), and a second Material supply device (40), which is designed to provide a thermoplastic matrix material (41) to the second material supply (14) of the 3D print head (10), wherein the first material supply (13) has an input through which the quasi filamentary material (31 ) is supplied into the feed channel (19) of the first material supply (13), and wherein a pressure source (34) is provided which cooperates with the input of the first material supply (13) for generating an overpressure at the input of the first material supply (13) in that an escape of the thermoplastic matrix material (41) at the entrance of the first material feed (13) is prevented is. Plant after Claim 8 , characterized in that the first material supply device (30) has a pressure vessel (32) for supporting the quasi-filamentary fiber material (31) and has a pressure-tight fiber guide (33), the pressure-tight on the pressure vessel (32) on the one hand and pressure-tight at the first material feed ( 13) of the 3D printing head (10) is connected on the other hand, so that the quasi filthless fiber material (31) from the pressure vessel (32) through the pressure-tight fiber guide (33) to the first material supply (13) of the 3D print head (10) can be passed is, wherein the pressure source (34) for generating an internal pressure in the interior of the pressure vessel and the pressure-tight fiber guide (33) is formed such that the overpressure at the input of the first material supply (13) generates and a leakage of thermoplastic matrix material (41) on the first material supply (13) is prevented. Plant after Claim 8 or 9 , characterized in that the control unit (20) for controlling the pressure source (34) is arranged such that the generated overpressure varies. Plant according to one of the Claims 8 to 10 , characterized in that the control unit (20) for controlling the pressure source (34) is set up such that the overpressure generated as a function of a printing speed of the print head (10) and / or in dependence on a Materialzuführgeschwindigkeit of quasi filament material (31) and / or the thermoplastic matrix material (41) is adjusted. Plant one of the Claims 8 to 11 characterized in that the first material supply (13) has a sensor system adapted to detect a level of filling of the thermoplastic matrix material (41) in the first material supply (13), the control unit (20) for driving the pressure source (34) in such a way is set up that the generated overpressure is adjusted in dependence on the detected filling level. Plant according to one of the Claims 8 to 12 , characterized in that the system is designed for tempering the pressure medium used for generating the overpressure. Installation according to one of the preceding claims, characterized in that the system comprises a movement machine, on which is arranged as the end effector of the 3D print head (10). Installation according to one of the preceding claims, characterized in that the 3D print head (10) has a head tip (18) which is detachably arranged on the 3D print head (10) and in which the outlet (12) is provided. 3D print head (10) for producing three-dimensional structures having the features of one of the preceding claims. A method of manufacturing a three-dimensional structure comprising two or more different materials, comprising providing a plant for producing a three-dimensional structure according to any one of Claims 1 to 15 Feeding quasi-defensive fibrous material (31) and thermoplastic matrix material (41) to the 3D printing head (10) of the plant and printing the material mixture of the fibrous material (31) and the matrix material (41) to produce the three-dimensional structure. Method according to Claim 17 , characterized in that the Materialzuführgeschwindigkeit is varied in the material supply of the quasi-free fiber material (31) and / or thermoplastic matrix material (41) during printing.

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