WO2019034526A1

WO2019034526A1 - 3D PRINTING DEVICE AND 3D PRINTING METHOD

Info

Publication number: WO2019034526A1
Application number: PCT/EP2018/071636
Authority: WO
Inventors: Christoph Mayer
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2017-08-18
Filing date: 2018-08-09
Publication date: 2019-02-21
Anticipated expiration: 2020-02-18

Abstract

L'invention concerne un dispositif d'impression 3D, en particulier pour l'impression de structures longues et/ou pliées, telles que des pales de rotor d'éolienne, comprenant au moins un applicateur de matériau d'impression et au moins un moyen de support pour le matériau à imprimer, le moyen de support pouvant tourner par rapport à une ouverture de l'applicateur de matériau d'impression et comprenant au moins une surface de support incurvée et/ou bordée.The invention relates to a 3D printing device, in particular for printing long and / or folded structures, such as wind turbine rotor blades, comprising at least one printing material applicator and at least one means for supporting the material to be printed, the support means being rotatable relative to an opening of the printing material applicator and comprising at least one curved and / or lined support surface.

Description

3D P INTING DEVICE AND 3D PRINTING METHOD

Technical Field

The present invention relates to a device and a method for 3D printing.

Technical Background

3D printing devices and corresponding method are generally known. A standard configuration applies the 3D printing on a flat bed, using a Cartesian coordinate system and X/Y/Z-positions. Moreover, it is known to use filaments ("hot melts") which pass a heated extrusion nozzle and are placed as a melt on an X-Y printing bed in subsequent layers in Z-direction. This principle is not only limited to hot melts in general but can be also used for cementitious systems and 1C- and 2C- reactive materials, where instead of a simple heated extruder nozzle, a feed of one or more components (e.g. via an integrate mixing head) can be used.

Other printing devices use cylindrical coordinates in direction of a vertical Z-axis. Moreover, there exists solutions where the printer bed can be tilted and/or rotated (along the Z-axis direction) in order to avoid two large overhangs. Also these known solutions work with a flat bed.

In any event, the known solutions are restricted to certain structures, in particular to structures with relatively low overhangs and/or a relatively small size.

Summary

It is an object of the present invention to propose a device and method for 3D printing, wherein restrictions of the 3D printing process should be reduced and, in particular, wherein it should be possible to print long and/or bent structures, such as wind rotor blades.

According to a first aspect of the invention, a 3D printing device, in particular for long and/or bent structures, such as wind rotor blades, is proposed, comprising at least one printing material applicator and at least one supporting means for the material to be printed, wherein the supporting means is rotatabie (via at least one rotating device of the 3D printing device) in relation to an opening (in particular nozzle) of the printing material applicator and comprises at least one curved and/or edged supporting surface.

A core idea of the present invention is to provide a print material supporting means being rotatabie in relation to an opening (nozzle) of a printing material applicator.

The supporting surface is, in particular, the surface onto which the material is printed. That is, the first layer of printed material may come into (direct) contact with the supporting surface. The supporting means comprises the supporting surface. The supporting means is preferably an integral part of the 3D printing device (so that the 3D printing device is not complete, i.e. does not work without the supporting means). The supporting means may be fixed to the 3D printing device in such a way that it cannot be removed (without breaking the supporting means or other parts of the 3D printing device or at least without complex de- installation). Alternatively, the supporting means may be removable.

There may be one or more opening(s)/nozzle(s) from which printing material can be applied (immerged) onto the supporting surface. In general, the supporting means is rotatabie with respect to an opening (nozzle) of the printing material applicator. This includes the alternatives that the supporting means rotates and the opening stands still or that supporting means stands still and the opening rotates (in particular together with the printing material applicator) or both, that the supporting means and the opening (nozzle) rotate. A reference surface for determining whether a component stands still or moves may be the ground or any ground contacting surface of the 3D printing device (in use) . In general, there may be (exactly) one opening (nozzle) or more than one, preferably more than two openings (nozzles). The relative rotation is in such a case performable with respect to at least one opening (nozzle) . The supporting surface may be curved and/or edged. This means, in particular that at least one cross-section through the supporting surface has a curved and/or edged shape (e.g. a rectangular cross-section with rounded edges) .

Only portions of the surface of the supporting means onto which the material is applied may be regarded as supporting surface (or part thereof). For example, side surfaces (such as a peripheral edge surface of a disk-like structure) should not be regarded as supporting surface (or part thereof) because such peripheral edge surfaces are not configured to receive material to be printed (or in other words, such a 3D printing device would not be configured, in particular with respect to the printing material applicator, to apply material onto such a surface). Preferably, at least 20%, further preferably at least 30% of the supporting surface is curved. Alternatively or in addition, the supporting surface may be edged over at least 10%, preferably at least 30% of its length (being generally defined by the dimension in a direction of a connecting line of two points which have the longest distance towards each other of all possible pairs of points of the supporting means; if the supporting means has at least one axis of rotational symmetry, the length of the supporting means is preferably defined by the maximum length of the supporting means along the one or more rotational axes ; for example, for a circular cylinder, such length may be defined by the central axis of symmetry). If not stated otherwise, the supporting surface is to be regarded as the total supporting surface meaning in particular the total surface which can be covered by the printing material applicator. In general, the printing material applicator may restrict (or define) the supporting surface due to its restriction with respect to positioning and (optionally) movement. In addition, also positioning and (potential) movement of the supporting means may restrict the supporting surface. The (total) supporting surface is, hence, in particular defined by position and (optional) movement of the parts printing material applicator and supporting means as such . The supporting means may be rotatable (via one or more corresponding rotating devices(s) of the 3D printing device) about (exactly) one axis or about (exactly) two or (exactly) three or more different axes. If the supporting means is rotatable about two or three different axes, these axes may be perpendicular with respect to each other. For each rotation axis, there may be a separate rotating device. However, it is alternatively possible that one rotating device allows rotation with respect to two different or three different (or more) axes. A rotating device may comprise a driving means (such as one or more motors) and holding and/or supporting means which hold the supporting means and/or printing material applicator (or the opening thereof) such that it has rotational freedom. The holding means may comprise one or more bearings (such as one or more ball bearings and/or needle roller bearings). Moreover, the holding means may comprise a shaft driven by the driving means (e.g. motor).

A radium of curvature of at least one cross-section (in particular a radial cross- section) of at least one portion of the supporting surface may be less than 5 m, preferably less than 1 m, further preferably less than 30 cm. The radius of curvature may be more than 1 mm, preferably more than 1 cm. If the radius of curvature is varying over the length of the supporting means (or supporting surface, respectively), the above values are fulfilled for at least 20%, further preferably at least 50% of the length. A contour line of at least one cross-section of the supporting means may be (at least in parts) polygonal, in particular quadrilateral, preferably rectangular, further preferably square. Alternatively or in addition, at least one cross-section may be oval (but not elliptical) or elliptical (but not circular) or circular. The supporting means may have a parallelepiped, preferably a cuboid, further preferably a rectangular cuboid shape. Alternatively, the supporting means may have a cylindrical, preferably circular or elliptic cylindrical shape. A length of the supporting means may be at least lm, preferably at least 3m, further preferably at least 10m, even further preferably at least 30m, even further preferably at least 50m. Alternatively or in addition, a length of the supporting means may be not more than 200m, preferably not more than 150m, further preferably not more than 100m. The supporting surface is provided preferably over at least 20%, further preferably at least 50% of the length of the supporting means.

A width (in particular diameter) of the supporting means may be at least 1 cm, preferably at least 10 cm and/or not more than 100 cm, preferably not more than 50 cm.

A freedom of rotation of the rotatable supporting means may be at least 30°, preferably at least 90°, further preferably at least 180°, even further preferably at least 270°, even further preferably at least 360°.

Prefera ly, the supporting means is elongated such that a ratio of the length (as defined above) to the width (as dimension of the supporting means perpendicular to the length, if varying, in particular the maximum of such dimension) is preferably at least 5, further preferably at least 10, even further preferably at least 30, even further preferably at least 50. An upper limit for such ratio may be 500 or 200. In particular, such elongated supporting means allows efficient and reliable printing of comparatively long structures such as wind rotor blades. The (total) supporting surface may be provided over at least 50%, further preferably at least 80% of the length of the supporting means.

Optionally, the supporting means is translationally moveable (by at least one corresponding moving device) in relation to an applicator opening (in particular nozzle) in at least one direction. The at least one direction is preferably a direction perpendicular to at least one rotational axis. A freedom of a

translational movement may be at least 50 cm, further preferably at least 3m, even further preferably at least 5m and/or less than 20m, preferably less than 12m. The translational movement of the supporting means in relation to an applicator opening may comprise moving of the supporting means (where the applicator opening stands still) or moving of the applicator opening (where the supporting means stands still) or both moving the supporting means and the applicator opening with respect to a reference point outside of the supporting means and the applicator opening of the 3D printing device. The supporting means may be translationally moveable in more than one or more than two (different) directions in relation to the applicator opening. If it is moveable in more than one direction in relation to the applicator opening, these (different) directions are preferably perpendicular with respect to each other.

In embodiments, the applicator is pivotally and/or translationally moveably mounted or held. Alternatively, or in addition the supporting means is pivotally and/or translationally moveably mounted or held. A corresponding mounting structure or holding means may be provided (such as a bearing structure).

In other embodiments, the applicator comprises more than one applicator head, preferably two or three.

The supporting means may comprise (or consist of) a protruded and/or pultruded and/or filament winded and/or a fibre reinforced and/or a composite and/or a tubular body (or portion). Alternatively or in addition, the supporting means may comprise a reinforcement structure (in particular within an outer structure outside of the reinforcement structure), in particular a cable, preferably made of metal (such as steel). For such embodiments, the supporting means (even if relatively long) is not (or not to a great extent) bent under its own weight (due to its integral stability).

According to another aspect of the invention, a 3D printing method is proposed, in particular for long and/or bent structures, such as wind rotor blades, in particular with utilisation of the above 3D printing device, comprising: - providing at least one printing material applicator and at least one supporting means for the material to be printed, wherein the supporting means comprises at least one curved and/or edged supporting surface

- rotating the supporting means in relation to an opening (nozzle) of the printing material applicator and

- applying material onto the supporting surface of the supporting means.

Preferably, the material being applied contains reinforcing particles, in particular fibres. Further preferably, the fibres are aligned with respect to each other when applied onto the surface (meaning at least when leaving the opening, in particular nozzle of the applicator and, preferably, also when attached to the supporting surface). In general, when working with printing materials containing non-spherical particles, in particular fibres, these may not be distributed in a random direction in the beads. Due to the liquid state of the applied printed material and an induced flow, these particles (fibres) may be aligned (at least to a certain degree) parallel to a main flow and thus be aligned in a printing direction (being defined by a direction of the bead, for example). Therefore, an additional reinforcement by aligned fibres may be possible in printing direction. Due to the provided rotation axis, these reinforcements may be designed for different (every) designated print directions, which would not be possible using a conventional 3D printer, where such reinforcements could not be placed, correspondingly. Hence, a design with strengthening of the structure along main load forces may be integrated into the printing design. This means, it is possible to improve the structure, in particular strength of the printed product.

The supporting means may be rotated with respect to the opening about (exactly) one axis or about (exactly) two or (exactly) three or more different axes.

Moreover, the supporting means may be translationally moved with respect to the opening in one direction or two or three or more different directions.

A printing bead may have a thickness of at least 0.2 mm, preferably 0.8 mm and/or a width of at least 1 cm, preferably at least 2 cm. Further method features of the present invention are defined in the context of the explanation of the 3D printing device. In particular, any functional feature mention there may correspond to a method step of the method according to the invention.

According to another aspect of the invention, a use of a 3D printing method, in particular according to the above 3D printing method or the use of a 3D printing device, in particular according to the above 3D printing device, for printing a wind rotor blade and/or for printing an (integral or monolithic) object of at least 20m, preferably at least 50m, is proposed. In this regard, a (further) core aspect of the invention is, also, to consider the option of 3D printing of structures which have been, so far, not 3D printed.

In particular, rotor blades may have a length of up to 60 to 80 m and are usually produced by a lot of manual work. Usually, these blades are manufactured by creating two composite half-shells which are subsequently glued together. In general, three concepts are known:

- a comparatively heavy, monolithic approach, which does not use two half- shells;

- a structural spar design, wherein a maximum length is limited by weight and wherein a high number of necessary process steps is to be performed.

In this context, a structural spar absorbs all loads of the blade; and

- Shear web design with a self-supporting, integral body using I- or C-shear webs, where all parts are supported supporting the structural stability of the design under load.

A typical rotor blade may have a weight of 10-15 tons, in some embodiments up to 30 tons. Moreover, wind rotor blades may have an (entirely) pre-bent structure so that it is at least difficult to print them on a flat bed (since only two points would be in the first layer). A heavy amount of support structure (printed or in form of a mold) would be necessary in order to support the blades lower part on a flat bet. These support structures must necessarily be removed afterwards to release the blade. In general, using conventional techniques: a heavy support is necessary which supports the blade (or a mold); a high length of the blade requires a large printing in X-axis; the desired light-weight structure requires a high stability; mechanics of composites in X-direction would be superior to pure printing material thus a heavier infill (shear webs) may be needed presumably resulting in a higher weight of the blade; and overhangs and flat top parts are comparatively difficult (if possible at all) to print.

The present invention deals with these problems and provides a solution for 3D printing also of large structures such as wind rotor blades. To a certain extent, the present invention may be compared to a turning lathe. A difference is that on a turning lathe material is taken away from a turning axis, resulting in rotational symmetric shapes. The inverted set-up of the present invention, namely building up a structure from a turning axis results in either symmetric or non-symmetric shapes (or both, symmetric or non-symmetric shapes). The technologies of the prior art have a flat bed which is difficult for structures, containing one long, preferential axis which are in addition relatively (but not exactly) flat. Normally, overhangs, as well as flat top parts are difficult to print in a reproducible and good quality, independently on the printing material used (at least without support). The present invention allows in particular to print these (so far "difficult" structures), containing a long, preferential axis and provides additional benefits in combining a certain printing set-up with special properties of the printing material, including but not limited to adhesives only.

Preferably, an axis can be used as a rotation axis and the entire structure (such as wind rotor blade) may be built along this axis from an inside to an outside. This has the advantages that no (or less) support is needed, less overhang printing is to be performed and no (or less) flat top parts have to be printed. Moreover, the movement of Y and Z-direction for asymmetric structures is minimalised - the movement of X and Z does not necessarily need to both reach on outermost point in every possible rotational position. Printing in any direction by rotation of the additional axis is possible. A self-supporting structure from inside to outside can be printed in a simple and reliable manner. In the direction of the rotation axis, a cylindrical coordinate's base may be defined.

For an X-axis, a (light) structural spar (such as a protruded, uniaxial fibre reinforced hollow tube or filament winded composite spar), a protruded +-shaped structure with several, e.g. four, fins or another beneficial shape (such as a structure with less than or more than four fins may be provided) which is fixed in a pivot mount in X-direction with for example at least 270°, preferably at least 360° rotational freedom may be provided. Due to a high length of the X-axis (e.g. 60 to 80 m), such fixation may be corrected against the curvature of the earth.

The supporting means (spar) should advantageously not bend along the X-axis under its own weight. This may be achieved (at least to a certain degree) due to an integral stability and/or by mechanical support, e.g. a pre-stressed steel cable running inside the supporting means (e.g. hollow spar). On the other hand, such bending may be taken into account in the design of the printing process.

For the Y- and/or Z-axis, only small displacements in the range of less than 10 m might be sufficient to reach every point of the structure to be printed (in particular wind rotor blade) with a printing head (applicator).

The printing material is preferably a printing material of high mechanics and/or highly toughened. A fibre filling may be provided in particular for better stress distribution and strengthening of the structure. A lightweight structure is possible. Temperature resistance above 65°C or preferably higher is preferred.

In case of reactive printing material, additional requirements concerning viscosity and curing activity may be necessary. Optional reactive materials may be 2C reactive material such as 2C EP (i.e. two component material based on epoxy resin) as well as 2C PU (i.e. two component materials based on polyurethane) or based on other technologies. In general, the materials may have a comparatively high yield point (preferentially in-situ thix for faster pumping). The materials may be pumpable with high extrusion rates. The materials may cure comparatively fast at room temperature (due to a large structure feasible with common 2C technologies, such as 2C EP or 2C PU, or other materials). A low shrinkage is preferred. In an exemplary embodiment, the method includes the use of un re active

(hotmelts, thermoplastic materials) and/or reactive 1C or 2C materials as printing material. These include polymeric or cementitious systems or hybrids of different technologies, especially reactive 2C materials or any kind of water/humidity curing, irradiation activation/curing (e.g. heat, IR, UV, microwave) or induction curing materials, with activation possible during application of the printing head or after application with a dedicated activation device.

According to an exemplary embodiment, primer is applied on the supporting means before the material is applied onto the supporting means.

This leads to better adhesion of the material on the supporting means.

In an exemplary embodiment, the method includes the incorporation of prefabricated parts for local reinforcement, incorporated in the structure by use of adhesive or by fixation using extrusion material by the application heads.

In a preferred embodiment, the prefabricated parts comprise composite plates, such as fiber reinforced composite plates, casted or injection molded reinforcing elements. The composite plates may comprise glass fibers, carbon fibers or plastic fibers, or contain a uni- or multiaxial layup.

In an exemplary embodiment, the method includes the use of a wet layup of a composite on top of the entire or of parts of the printed structure by using fiber fabric and a liquid resin, e.g. glass or carbon or polymer fiber fabric for (local) reinforcement of critical modes, e.g. wet layup with a liquid or thixotropic 2C resin. In an exemplary embodiment, the method includes filament winding techniques of fibers around the structure as an intermediate step or final step using the rotational axis of the printer for further reinforcement. In an exemplary embodiment, the method includes deposition of a continuous fiber or fiber bundle together with the reactive (2-component) printing component by the printing head.

In an exemplary embodiment, the method includes a spraying application using the application head, e.g. for surface finishing after final print.

Standard 3D printer can only print layer by layer, usually in Z-direction. This means, usually, the material bead cannot be laid in the direction of the Z-axis. By introducing the Z-axis as rotational axis, it is possible to lay beads of the print material along every axis and combinations thereof. This leads to a major performance advantage compared to conventional 3D print techniques.

To sum up, the present invention reduces the necessity for a support structure; allows printing with less overhang and flat top parts; minimises movement in Y and Z-direction; allows printing preferably in any direction by rotation of the Z- axis; allows to reintroduce reinforcements preferably in any direction (which may be necessary for example for a certain rotor blade design) when using fibres in the printing material; allows to form a self-supporting structure from inside to outside.

Preferably, a cylindrical coordinate's base can be defined, facilitating

programming.

The 3D printing device (for complex shapes, in particular with one preferred, long axis) may contain at least one rotational axis on which a support structure is fixed which acts as a printing bed. The support structure may have a round, rectangular or any other suitable shape of cross-section, facilitating printing the desired structure. Preferably, there are two or more additional axes. The printing head (applicator) may be mounted movable so that it may cover the length of the printed object (such as rotational blade). All other axes may be performed by moving the printing head (applicator) adequately and/or by moving the rotation axis in the direction of the two or more additional axes and/or by a combination of such options.

Printing may be performed on the support means (support structure) with a minimum of 270°, preferably at least 360° rotation so that printing from inside to outside is possible. Bending may be minimised by printing a self-supporting structure from the inside to the outside.

The printing may (not necessarily though) have a rotational symmetry with respect to the axis. Optionally, fibres in the printing materials may be used (allowing designing strengthening in several or all dimensions, which is not possible with current printing technologies).

According to an exemplary embodiment, the fibres comprise at least partially inorganic or polymeric or organic fillers.

According to a further exemplary embodiment, the fibres have an aspect ratio of greater than 1, preferably greater than 2, more preferably greater than 3. Preferably, the printing applicator (head) is movable in X, Y and Z direction

(being directions perpendicular to each other). The rotational X-axis may be fixed and no further movement in Y/Z direction of this axis may be possible. Fibres containing printed material for reinforcing the printed structure in every direction are provided . Further preferably, the inventive 3D printing device, a

reinforcement direction and the lay-up of different fibre directions for best stress distribution, stiffness and maximum loading of the structure are provided .

As generally known filaments ("hot melts") may be provided which pass a heated extrusion nozzle and are placed as a melt on the printing bed (supporting surface) in subsequent layers in Z-direction . Brief Description of the Drawings In the following, a preferred embodiment of the present invention is described with reference to the drawings. Thereby shows:

Fig. 1 A schematic drawing of a 3D printing device of the present

invention.

Detailed Description of the Embodiment

Fig. 1 shows a schematic drawing of a 3D printing device according to the present invention. The device comprises a printing material applicator 10 (print head) with a nozzle 11 at a (in Fig. 1) lower end of the applicator. In Fig. 1, the nozzle cannot be directly seen due to the (optional) adjusting means 12, to be described later. Moreover, the device of Fig. 1 comprises a support frame 13 (which may be replaced by any other suitable support structure) supporting a supporting means 14 comprising a spar or rod-shaped member. The supporting means 14 is rotatably held on the supporting frame 13 via a bearing 15 so that it may rotate around the X-axis (as illustrated in Fig. 1). Onto the supporting means or the outer surface thereof, material can be applied (printed). In addition to the rotation about the X-axis, a rotation about the Y and/or Z-axis may be provided (not shown in Fig. 1).

The printing material applicator 10 is movable in the X-direction. Preferably, this is performed by moving the adjusting means 12 in the X-direction. Moreover, optionally, a translational movement in the Y- and/or Z-direction may be performed. A movement in the Y-direction may be, for example, performed by moving of the printing material applicator 10 within the adjusting means 12 (in particular within a gliding structure such as a slot therein).

Reference signs:

10 Printing material applicator

11 Opening (nozzle)

12 Adjusting means

13 Support frame

14 Support means

15 Bearing

Claims

A 3D printing device, in particular for printing of long and/or bent structures, such as wind rotor blades comprising at least one printing material applicator (10) and at least one supporting means (14) for the material to be printed, wherein the supporting means (14) is rotatable in relation to an opening (11) of the printing material applicator (10) and comprises at least one curved and/or edged supporting surface.

The 3D printing device of claim 1, characterised in that the supporting means (14) is rotatable about one axis or about two or three or more different axes.

The 3D printing device of claim 1 or 2, characterised in that the supporting means (14) is elongated.

The 3D printing device of one of the preceding claims, characterised in that a radius of curvature of at least one cross-section, in particular a radial cross-section, of at least one portion of the supporting surface is less than 5 m, preferably less than 1 m, further preferably less than 30 cm.

The 3D printing device of one of the preceding claims, characterised in that a contour line of at least one cross-section of the supporting means and/or supporting surface (14) is polygonal, in particular quadrilateral, preferably rectangular, further preferable square or round, in particular oval or elliptical or circular and/or

in that the supporting means (14) has a parallelepiped, preferably a cuboid, further preferably a rectangular cuboid shape or a cylindrical, preferably circular or elliptic cylindrical shape.

The 3D printing device of one of the preceding claims, characterised in that a length of the supporting means (14) is at least 1 m, preferably at least 3 m, further preferably at least 10 m, even further preferably at least 30 m and/or not more than 150 m, preferably not more than 100 m and/or a width, in particular diameter of the supporting means, is at least 1 cm, preferably at least 10 cm and/or not more than 100 cm, preferably not more than 50 cm and/or the freedom of rotation of the rotatable supporting means (14) is at least 30 °, preferably at least 180 °, further preferably at least 270 °, even further preferably at least 360 ° and/or a ratio of the length to the width of the supporting means (14) is at least 10, preferably at least 50.

The 3D printing device of one of the preceding claims, characterised in that the supporting means (14) is translationally movable in relation to an applicator opening, in particular nozzle, in at least one direction, in particular a direction perpendicular to at least one rotational axis, wherein a freedom of the translational movement is preferably at least 50 cm, further preferably at least 3 m, further preferably at least 5 m.

The 3D printing device of one of the preceding claims, characterised in that the applicator (10) is pivotally and/or translationally movably mounted or held and/or in that the supporting means (14) is pivotally and/or translationally movably mounted or held.

9. The 3D printing device of one of the preceding claims, characterised in that the supporting means (14) comprises a pultruded and/or a fibre- reinforced and/or a composite and/or a tubular body and/or comprises a reinforcement structure, in particular a cable, preferably made of metal such as steel.

A 3D printing method, in particular for long and/or bent structures such as a wind rotor blade, in particular with utilization of the 3D printing device of one of the preceding claims, comprising

providing at least one printing material applicator (10) and at least one supporting means (14) for the material to be printed, wherein the supporting means (14) comprises at least one curved and/or edged supporting surface

rotating the supporting means (14) in relation to an opening (11) of the printing material applicator (10), and

applying material onto the supporting means (14).

The 3D printing method of claim 10, characterised in that the material being applied contains reinforcing particles, in particular fibres, wherein the fibres are preferably aligned when applied onto the surface.

The 3D printing method of claim 10 or 11, characterised in that the supporting means (14) is rotated with respect to the opening (11) about one axis or about two or three or more different axes and/or

in that the supporting means (14) is translationally moved with respect to the opening in one direction or two or three or more different directions.

The 3D printing method of claim 10, 11 or 12, characterised in that a printing bead has a thickness of at least 0.2 mm, preferably 0.8 mm and/or a width of at least 1 cm, preferably at least 2 cm.

Use of a 3D printing method, in particular according to any of the claims 11 to 13 or a 3D printing device, in particular according to one of the claims 1 to 11 for printing a wind rotor blade and/or for printing an object of at least 20 m, preferably at least 50 m.