Device and method for additive manufacturing of a component

Abstract

A device for additive manufacturing of a component includes a material dispensing unit for depositing a building material and an actuator assembly which is designed to move the material dispensing unit over a work surface in order to deposit the building material layer by layer in predetermined print paths. The device has at least one first guide leg which is designed to shape a first surface of the one or more layers of building material deposited by the material dispensing unit. The at least one first guide leg is displaceable and driven by a first actuator, in at least one translational degree of freedom (x, y, z) relative to the material dispensing unit. The at least one first guide leg is driven by a second actuator so as to be pivotable relative to the material dispensing unit in at least one rotational degree of freedom (dx, dy, dz).

Claims

1. A device for additive manufacturing of a component, having a material dispensing unit for depositing a building material and an actuator assembly which is designed to move the material dispensing unit over a work surface in order to deposit the building material layer by layer in predetermined print paths, as well as at least one first guide leg which is designed to shape a first surface of the one or more layers of building material deposited by the material dispensing unit, wherein the at least one first guide leg is displaceable, driven by a first actuator, in at least one translational degree of freedom (x, y, z) relative to the material dispensing unit, wherein the at least one first guide leg, driven by a second actuator, is pivotable relative to the material dispensing unit in at least one rotational degree of freedom (dx, dy, dz).

2. The device according to claim 1, wherein the at least first and second actuators are configured to drive the at least one first guide leg independently of one another in such a way that the at least one first guide leg can be moved simultaneously in at least one translational degree of freedom (x, y, z) relative to the material dispensing unit and in at least one rotational degree of freedom (dx, dy, dz) relative to the material dispensing unit.

3. The device according to claim 1, wherein the device has at least one second guide leg for shaping a second surface of the one or more layers of building material deposited by the material dispensing unit, which leg, driven by an actuator, is displaceable at least in one translational degree of freedom (x, y, z) relative to the material dispensing unit and, driven by a further actuator, is pivotable relative to the material dispensing unit at least in one rotational degree of freedom (dx, dy, dz), wherein the actuator for the driven displacement of the at least one second guide leg at least in one translational degree of freedom (x, y, z) relative to the material dispensing unit has the first actuator for the driven displacement of the at least one first guide leg and/or a third actuator, and wherein the further actuator for the driven pivoting of the at least one second guide leg at least in one rotational degree of freedom (dx, dy, dz) relative to the material dispensing unit has the second actuator for the driven pivoting of the at least one first guide leg and/or a fourth actuator.

4. The device according to claim 3, wherein the at least one first guide leg and the at least one second guide leg can be displaced together, driven by the first actuator, at least in one translational degree of freedom (x, y, z) relative to the material dispensing unit, wherein at least one of the at least one first guide leg and the at least one second guide leg is connected to the first actuator by means of a first coupling assembly.

5. The device according to claim 3, wherein wherein the at least one first guide leg and the at least one second guide leg can be pivoted together, driven by the second actuator, at least in one rotational degree of freedom (dx, dy, dz) relative to the material dispensing unit, wherein at least one of the at least one first guide leg and the at least one second guide leg is connected to the second actuator by means of a second coupling assembly.

6. The device according to claim 3, wherein the at least one first guide leg and the at least one second guide leg can be displaced and/or pivoted independently of one another, in particular driven by the corresponding first and second or third and fourth actuators.

7. The device according to claim 1, wherein the displacement, driven by the first actuator, of the at least one first guide leg relative to the material dispensing unit in at least one translational degree of freedom (x, y, z) comprises a movement of the at least one first guide leg in the vertical direction or in the horizontal direction (x, y).

8. The device according to claim 1, wherein the pivoting, driven by the second actuator, of the at least one first guide leg relative to the material dispensing unit in at least one rotational degree of freedom (dx, dy, dz) comprises a pivoting movement of the at least one first guide leg about an axis of rotation which extends in the horizontal direction and in particular parallel to the print path (dx, dy) or which extends in the vertical direction.

9. The device according to claim 1, wherein the at least one first guide leg and/or the at least one second guide leg can be displaced, driven by a further actuator, at least in one further translational degree of freedom relative to the material dispensing unit and/or can be pivoted in a further rotational degree of freedom relative to the material dispensing unit.

10. The device according to claim 1, wherein the device has at least one control unit which is configured to control at least one of the actuators for moving the at least one first guide leg and/or the at least one second guide leg.

11. The device according to claim 10, wherein the device further comprises at least one control device which is configured to control the actuator assembly for moving the material dispensing unit over the work surface, wherein the at least one control device can comprise the at least one control unit for controlling the actuators for moving the at least one first guide leg and/or the at least one second guide leg and/or can be in communicative connection with the at least one control unit.

12. The device according to claim 11, wherein the control device, which is configured to control the actuator assembly for moving the material dispensing unit over the work surface, has an interface in order to obtain, via the interface, 3D data of a component to be produced, and a computing unit in order to convert the obtained 3D data into printer data for additive manufacturing of the component, based on which both the actuator assembly for moving the material dispensing unit can be controlled by the control device and also at least one of the actuators for moving the at least one first guide leg and/or the at least one second guide leg can be controlled by the control device and/or the control unit communicatively connected thereto.

13. The device according to claim 1, wherein the material dispensing unit has a housing, wherein the housing has at least one receiving opening, wherein in particular the at least one first guide leg and/or the at least one second guide leg, in a working position, is/are capable of projecting, at least in portions, from the interior of the housing through the at least one receiving opening, and/or wherein in particular the at least one first guide leg and/or the at least one second guide leg, in a rest position, can be accommodated at least in portions, preferably predominantly, for example almost completely, in the housing.

14. The device according to claim 13, wherein at least one of the actuators for moving the at least one first guide leg and/or the at least one second guide leg is accommodated in the housing at least in portions.

15. The device according to claim 1, wherein at least one of the actuators for moving the at least one first guide leg and/or the at least one second guide leg has at least one motorized drive, in particular a servomotor, a closed-loop motor, a stepper motor or the like, which is suitable for returning its current position to a control unit or control device.

16. The device according to claim 1, wherein the device has a cleaning assembly with at least one cleaning portion associated with the at least one first guide leg and/or the at least one second guide leg, wherein in at least one relative position of the at least one first guide leg and/or the at least one second guide leg relative to the material dispensing unit, the cleaning portion is arranged at least in portions in cleaning contact with the associated guide leg, in such a way that during a displacement and/or rotation relative to the material dispensing unit, the at least one first guide leg and/or the at least one second guide leg is capable of stripping off building material residues on the cleaning portion, which is in cleaning contact at least in portions.

17. The device according to claim 16, wherein the cleaning portion associated with the at least one first guide leg and/or the at least one second guide leg is arranged on the material dispensing unit, for example on the housing, in particular in the region of the at least one receiving opening of the housing.

18. The device according to claim 16, wherein the cleaning assembly has an elastic element which is capable of pre-tensioning the at least one first guide leg and/or the at least one second guide leg against the associated cleaning portion.

19. The device according to claim 18, wherein in at least one relative position of the associated guide leg relative to the material dispensing unit, the elastic element of the cleaning assembly is arranged at least in portions in cleaning contact with the associated guide leg in such a way that during a displacement and/or rotation relative to the material dispensing unit, the associated guide leg is capable of stripping off building material residues on the elastic element of the cleaning assembly, which is in cleaning contact at least in portions.

20. The device according to claim 1, wherein the device comprises a lubricating assembly which is designed to dispense a lubricating fluid to the at least one first guide leg and/or to the at least one second guide leg in order to wet this leg or legs with the lubricating fluid at least in portions.

21. The device according to claim 18, wherein the elastic element of the cleaning assembly is configured to wet the associated guide leg with a lubricating fluid dispensed by the lubricating assembly.

22. The device according to claim 1, wherein the at least one first guide leg and/or the at least one second guide leg has or have a longitudinal extension along a first or second central longitudinal axis, wherein the at least one first guide leg and/or the at least one second guide leg has or have a contour curved at least in portions in a cross section running perpendicular to the first or second central longitudinal axis.

23. The device according to claim 1, wherein the at least one first guide leg and/or the at least one second guide leg has or have a longitudinal extension along a first or second central longitudinal axis, wherein the at least one first guide leg and/or the at least one second guide leg has or have, in a longitudinal section running along the first or second central longitudinal axis, a contour curved at least in portions with a substantially straight guide portion.

24. The device according to claim 1, wherein the at least one first guide leg and/or the at least one second guide leg is designed substantially axially symmetrically with respect to the first or second central longitudinal axis.

25. A method for additive manufacturing of a component, wherein a material dispensing unit for depositing a building material is moved over a work surface by means of an actuator assembly in order to deposit the building material layer by layer in predetermined print paths, having at least the following method steps: a) feeding the building material to the material dispensing unit; b) displacing the at least one first guide leg with the aid of a first actuator in at least one translational degree of freedom (x, y, z) relative to the material dispensing unit; c) pivoting the at least one first guide leg with the aid of a second actuator in at least one rotational degree of freedom (dx, dy, dz) relative to the material dispensing unit; d) depositing the building material along the predetermined print path, and e) shaping the at least one surface with the aid of the at least one first guide leg.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Exemplary embodiments are described in more detail below with reference to the drawings.

(2) The figures each show preferred embodiments in which individual features of the present described embodiments are shown in combination with one another. Features of an embodiment can also be implemented separately from the other features of the same embodiment and can accordingly be easily combined with features of other embodiments by a person skilled in the art to form further useful combinations and subcombinations.

(3) In the figures, functionally identical elements are provided with the same reference signs.

(4) In the figures, schematically:

(5) FIG. 1 shows a simplified structure of a 3D printer in gantry design;

(6) FIG. 2 is an isometric representation of a device according to a first embodiment;

(7) FIGS. 3a, 3b, 3c show a cutaway view of the device shown in FIG. 2;

(8) FIG. 4 shows the sectional view G-G according to the sectional line G-G in FIG. 3a;

(9) FIGS. 5a, 5b show the sectional view A-A and B-B according to the sectional planes A-A and B-B in FIG. 2;

(10) FIG. 6 shows a cutaway view of the device shown in FIG. 2 according to a second embodiment;

(11) FIG. 7 shows a sectional view of the device according to a second embodiment, which corresponds to the sectional view A-A as shown in FIG. 2;

(12) FIG. 8 shows a sectional view C-C of the device according to the sectional plane C-C in FIG. 2;

(13) FIG. 9 shows the detail view D according to FIG. 8; and

(14) FIG. 10 shows an isometric detail view of the device according to FIGS. 8 and 9.

DETAILED DESCRIPTION

(15) FIG. 1 shows a highly simplified arrangement 1 for the additive manufacturing of a component 2. The arrangement 1 comprises a device 3 for additive manufacturing of the component 2, with a material dispensing unit 4, indicated only schematically, for depositing a building material, and an actuator assembly 5 which is designed to move the material dispensing unit 4 over a work surface 6 in order to deposit the building material layer by layer in predetermined print paths D.

(16) The embodiments are described below in particular in the context of 3D concrete printing, i.e. for the additive manufacture of a component 2 of a structure or of a complete structure from flowable mixed concrete. However, this is fundamentally not to be understood as limiting. The described embodiments are basically suitable for producing any additive components from any building material, in particular also for the manufacture of plastic components.

(17) In order to move the material dispensing unit 4, the actuator assembly 5 has at least one first horizontal guide 7, which in FIG. 1 and the following exemplary embodiments are each two horizontal supports 8 arranged in parallel and at a distance from one another. A second horizontal guide 9 is provided between these two horizontal supports 8, which guide is thus linearly movable along the first horizontal guide 7. The second horizontal guide 9 is designed as an individual cross-member 10 along which the material dispensing unit 4 can be moved in the manner of a trolley, i.e. transversely to the first horizontal guide 7. Finally, a two-dimensional movement of the material dispensing unit 4 over the work surface 6 can be allowed by the two horizontal guides 7, 9 (cf. arrows x and y).

(18) In addition, the actuator assembly 5 according to FIG. 1 has a vertical guide 11 along which the material dispensing unit 4 can be moved vertically relative to the work surface 6. Specifically, it can be provided that the vertical guide 11 has two groups of vertical struts 12, wherein the vertical struts 12 of each group are spaced apart from one another and are arranged in alignment with one another, and wherein both groups are spaced apart from one another. The first horizontal guide 7, or the horizontal supports 8 of the first horizontal guide 7, can thus be moved along the vertical struts 12 of the corresponding group (cf. arrow z).

(19) A traverse 14, which is mounted, for example, on two vertical struts 12 of the vertical guide, also carries a deflection roller 15 via which a conveying hose 13 for dry mortar is guided from a material preparation unit 16 (indicated as a black box) to the material dispensing unit 4.

(20) FIG. 1 and the exemplary embodiments thus show a 3D concrete printer in gantry design with linear axis guidance in each case. This allows the material dispensing unit 4 to move along all translational degrees of freedom x, y, z. Gantry printers, in particular for manufacturing concrete components 2 from concrete, are already known in principle, which is why additional details are not discussed further here.

(21) The aim of the described embodiments is to improve the shaping, in particular the surface treatment, of the lateral surfaces of a printed component with the aid of lateral guide legs. Furthermore, improved handling of such guide legs is provided.

(22) FIG. 2 shows an isometric view of a device 3 according to the described embodiments for additive manufacturing of a component 2 with improved shaping. FIGS. 3a to 3c, FIG. 4, and FIGS. 5a and 5b show a specific exemplary embodiment with further details, in an enlarged detail of the device 3; FIGS. 6 and 7 show a second exemplary embodiment, wherein the views substantially correspond to the representations of the first embodiment according to FIGS. 3a and 5a. Finally, FIGS. 8 to 10 show a further detail of the described embodiments, the cleaning assembly, in multiple views.

(23) FIG. 2 shows an isometric representation of a device according to the described embodiments, in particular a housing 20 having a plurality of housing parts or housing regions. It can be seen that the housing 20 has at least three housing parts or housing regions, namely a front housing cover 22a, a central housing region 22b, and a rear housing cover 22c.

(24) The front housing cover 22a and the central housing area 22b together form a material feed region 24 via which a building material can be fed from the guide hose 13 via an extruder (not shown) in a known manner. A building material duct 26, which opens into a discharge opening, is formed in the interior of the housing 20 in order to discharge the building material. The formed duct is indicated in the representation of FIG. 2 by the outer contour of the housing cover 22a (cf. reference sign 26).

(25) The guide legs 30, also seen in FIG. 2, are important to the described embodiments, wherein in the embodiment shown the device 3 has a first guide leg 30 and a second guide leg 30 which are substantially of identical design, so that reference is made below primarily to the first guide leg 30.

(26) In the described embodiments, the guide legs 30 are used to (subsequently) smooth the lateral surfaces of an applied building layer, for example to reduce the occurrence of grooves or edges in the not yet fully cured building material of a component 2 to be formed. The layers of building material dispensed by the material dispensing unit 4 are applied on top of one another in print paths D in the manner of tracks, wherein unevenness can form between the individual layers, for example. Other effects that can cause undesirable unevenness on the lateral surfaces of a component have been discussed above and can also be reduced by the guide legs 30 shown.

(27) A special feature of the described embodiments is that the guide legs 30 protrude at least in portions into the housing 20 of the device 3 through at least one, in the embodiment shown through two, receiving openings 28 (also see here in particular the further FIGS. 3a to 10). As can also be seen in the figures, the receiving openings can be formed in a plurality of adjoining housing parts, for example in the front housing cover 22a and the central housing region 22b, in such a way that the guide legs 30 can project into a part of the housing 20 that forms the material duct 26.

(28) Finally, FIG. 2 shows three sectional planes A-A, B-B, and C-C, wherein the sections formed thereby illustrate the features of the described embodiments in more detail.

(29) FIGS. 3a to 3c show the device 3 according to the described embodiments according to FIG. 2 in a front view, omitting the front housing cover 22a. FIG. 4 is a sectional view of the section along the bent sectional line G-G of FIG. 3a.

(30) It can be seen in FIGS. 3b and 3c that the guide legs 30 can both be translationally displaced in a vertical direction, i.e. upward or downward in the figures (indicated by the arrow z), and can also be set at an angle of incidence a and B relative to a longitudinal axis L of the housing 20. For this purpose, the guide legs 30 can be pivoted about an axis of rotation in a rotational degree of freedom dx.

(31) In the embodiment shown, the longitudinal axis L (cf. FIGS. 3b, 3c) of the housing 20 coincides with a perpendicular to the work surface 6 and thus with the vertical direction, wherein, when the device 3 is tilted relative to a perpendicular to the work surface 6, these may no longer coincide. In the present case, for a simplified description of the described embodiments, it is assumed that the device 3 is oriented precisely vertically in such a way that the longitudinal axis L of the housing 20 coincides with a perpendicular to the work surface 6.

(32) In the simplified representation of the described embodiments discussed below, the component 2 also has a substantially vertical extension without overhangs in the horizontal direction, whereby two lateral surfaces that delimit the wall thickness are formed, which surfaces are substantially perpendicular to the work surface 6 and can be smoothed by the guide legs 30. In principle, a vertical displaceability of the guide legs 30, as shown, for example, in the exemplary embodiment of FIGS. 6 and 7, is also sufficient for such a comparatively simple geometry and smoothing task.

(33) FIGS. 6 and 7 also show a representation without the front housing cover 22a (FIG. 6) and a sectional representation according to the sectional plane A-A of FIG. 2 (FIG. 7), wherein FIGS. 6 and 7 relate to a second embodiment, for which reason the section in FIG. 7 is designated A-A.

(34) FIG. 7 also makes it easy to understand the structure of the device, while FIG. 6 shows the guide leg 30 in a rest position almost completely retracted into the housing 20.

(35) In FIG. 7, on the left it can be seen that the first guide leg (in the representation the guide legs have been omitted in the representation for simplification) can be moved up and down in the vertical direction z with the aid of an actuator 40 (also indicated by the driven output shaft 40a).

(36) In the present case, the actuator 40 can comprise a servomotor which is accommodated in the rear housing cover 22c and is configured to drive a toothed wheel 42 (omitted on the right-hand side), which in turn is in meshing engagement with a toothed rack 44 (omitted on the right-hand side), whereby a driver 46 (omitted on the right-hand side) can be moved up and down with the guide leg (not shown).

(37) In FIGS. 6 and 7, the two actuators for moving the guide legs are both designated by the reference sign 40. Theoretically, this can be an actuator that is suitable for moving both guide legs, for example via a coupling assembly. However, it can in particular also be two actuators 40 which can be operated independently of one another and are each associated with one of the guide legs 30 and adjust the two guide legs individually and independently of one another.

(38) Furthermore, a guide contour 48 can be seen in particular at the right in FIG. 7, which can be formed directly on the housing 20 or on a separate component which can be arranged on the housing 20, in particular the central housing region 22b.

(39) In the simplified embodiment of FIGS. 6 and 7, in which the guide legs 30 are moved up and down only in a substantially vertical direction z, the guide contour 48 can be fixedly connected to the housing 20.

(40) This guide contour 48 serves, in particular with the curved region formed at an end region 48a, to introduce a slight pivoting movement of the free end of the associated guide leg 30 into this leg when the guide leg 30 is almost completely retracted into the housing 20 (cf. FIG. 6).

(41) It can be seen that the guide leg 30 is connected to the driver 46 by a pin (indicated in FIG. 7 by the reference sign 32), wherein the pin 32 can execute a slight horizontal movement relative to the driver 46 within a horizontally running groove 46a. As a result, the slight pivoting movement of the free end of the associated guide leg 30 can take place when it is retracted almost completely into the housing 20.

(42) This slight pivoting movement is also allowed by the specific design of the guide legs 30, which have an elongated contour with a flat guide portion 34a and a curved end portion 34b when viewed in longitudinal section (along their central longitudinal axis) (see also FIG. 5b). By means of the guide contour 48 and the horizontal relative movement of the guide leg pin 32 relative to the driver 46, this curved end portion 34b can also be retracted or pivoted into the housing 20.

(43) The curved end region 34b (curved away from the surface to be shaped when viewed in a central longitudinal section) forms a run-in or run-out zone in relation to a vertical movement of the guide legs relative to the component 2, in particular relative to the surface to be shaped, which is particularly advantageous for smoothing the transitions. Furthermore, this can reduce or completely avoid the constriction of the lower layers of building material known from practice with flat smoothing spatulas, as described above, which in turn can reduce or avoid the known and undesirable effect of edge formation.

(44) A further special feature of the design of the guide legs 30 can also be clearly seen in FIGS. 4 and 9. Viewed in cross section, these are not straight (and thus flat, at least at the guide portion 34a), as is known from the prior art, but have a curvature. This curvature can be continuous, as in the embodiment shown, but it is also possible to provide a curvature only at the end portions (viewed in cross section), while a central region (viewed in cross section) can be flat. This specific design allows a run-in zone and run-out zone to be created in relation to the direction of movement x when printing the print paths B, which is particularly favorable for the shaping process, especially for smoothing.

(45) In contrast to the comparatively simpler embodiment of FIGS. 6 and 7, which provides a substantially only vertical relative displacement of the guide legs 30 relative to the material dispensing unit 4 from a working position, in which the guide legs 30 are capable of shaping, in particular smoothing, the lateral surfaces (first surface and second surface) of a component 2, into a rest position in which the guide legs 30 are almost completely retracted into the housing 20, in the embodiments of FIGS. 3a to 3c, 4 and 5a to 5b the guide legs 30 can additionally be pivoted relative to the material dispensing unit 4 in at least one rotational degree of freedom dx.

(46) Alternatively or in addition to the solution shown, it can of course be provided that a pivoting takes place in a further rotational degree of freedom, indicated by the rotational degrees of freedom (in FIG. 3a) dy and dz.

(47) In particular, FIGS. 3b and 3c show how at least one of the guide legs 30 can be pivoted in an angle of incidence a or B relative to the material dispensing unit 4 (shown here symbolically by the axis L). Both a pivoting of the end portion 34b of the guide leg 30 away from the material dispensing unit 4 (angle ) and toward the material dispensing unit 4 (angle ) are possible. In this way, for example overhangs and inclined walls of a component 2, but also tapered end portions of a component 2, can be smoothed.

(48) It can also be seen in FIGS. 3b and 3c that the guide legs 30 are individually adjustable, both with respect to their vertical relative position (as also in the embodiment of FIGS. 6 and 7) and with respect to their rotational position relative to the material dispensing unit 4.

(49) For this purpose, a first or third actuator 40 is provided in a manner comparable to the first embodiment, which actuator serves to displace the guide legs 30 in the vertical direction z. In the present case, the actuator 40 can comprise a servomotor which is accommodated in the rear housing cover 22c or, as shown, in the central housing region 22b, and is configured to drive a toothed wheel 42, which in turn is in meshing engagement with a toothed rack 44, whereby a driver 46 can be moved up and down with the connected guide leg 30 (in FIG. 5a, these have been omitted for simplification).

(50) In FIGS. 5a, 5b, the two actuators for vertically moving the guide legs are both designated by the reference sign 40. Theoretically, this can be an actuator that is suitable for moving both guide legs, for example via a coupling assembly. However, it can in particular also be two actuators 40 which can be operated independently of one another and are each associated with one of the guide legs 30 and adjust the two guide legs individually and independently of one another.

(51) Furthermore, a second mechanism for pivoting the guide legs 30 is provided. This mechanism also comprises an actuator 50, i.e. a second actuator 50 and a fourth actuator 50, which, analogous to the first and third actuators, can comprise a common actuator or, as shown, two actuators 50 that can be operated independently of one another. Each of the actuators 50 is designed to rotationally drive a toothed wheel (spur gear) 52 with its output shaft 50a. A further toothed wheel 54, which is connected to a spindle 56 in a non-rotatable manner, is in meshing engagement with the toothed wheel 52. In the embodiment shown, a further driver 58, which is displaced into horizontal movement in the y-direction when the spindle 56 is driven (cf. FIG. 5a), is seated on the spindle 56.

(52) In the embodiment shown, the second driver 58 is formed in one piece with a guide contour 48. Within the guide contour 48, a pin (indicated in FIG. 5a by the reference sign 32) is connected to the second driver 58, wherein the pin 32 can execute a substantially vertical movement relative to the second driver 58 within a substantially vertically running guide groove of the guide contour 48.

(53) As in the simplified embodiment of FIGS. 6 and 7, in which the guide legs 30 are moved up and down only in a substantially vertical direction, the guide contour 48 also serves, in particular with the curved region formed at an end region 48a, to introduce a slight pivoting movement of the free end of the associated guide leg 30 into this leg when the guide leg 30 is almost completely retracted into the housing 20.

(54) It can be seen that the guide leg 30, as in the embodiment of FIGS. 6 and 7, is additionally connected to the driver 46 (and also to the driver 48) with its pin (indicated in FIG. 5a by the reference sign 32), wherein the pin 32 can execute a horizontal movement relative to the driver 46 in the direction y within a horizontally running groove 46a. On the one hand, this allows the slight pivoting movement of the free end of the associated guide leg 30 (with the curved end portion 34b), as described above, to take place when this leg is almost completely retracted or pivoted into the housing 20. On the other hand, this also allows the pivoting movement to be achieved in order to implement the angle of incidence shown in FIGS. 3b and 3c.

(55) In this embodiment as well, the slight pivoting movement allows the guide legs 30, which have an elongated contour with a flat guide portion 34a and a curved end portion 34b when viewed in a longitudinal section (cf. FIG. 5b also), to be retracted or pivoted into the housing 20 with the curved end portion 34b.

(56) Furthermore, the second driver 58 is mounted at a bearing point on the housing 20 so as to be pivotable relative thereto about an axis of rotation Dx (indicated in FIG. 3b). The axis of rotation Dx extends substantially parallel to the print path D or moves with it, whereby components with curved print paths can also be smoothed laterally.

(57) As a result of a pivoting movement of the second driver 58, the guide contour 48 is also pivoted along with it, such that the guide groove of the guide contour 48 no longer extends substantially vertically in the direction z but at an angle to it (in accordance with the angle of incidence; cf. FIGS. 3b and 3c). Accordingly, when there is a vertical movement of the associated guide leg 30 initiated by the actuator 40, the connecting pin 32 of the guide leg 30 executes a translational movement along the guide contour 48 at the selected angle of incidence.

(58) Furthermore, the contact surfaces of the receiving openings 28 form a support for the corresponding guide leg 30, so that this leg, seated thereon, is pivoted accordingly in a degree of freedom dx by the pivoting movement of the second driver 58 and the guided entrainment of its pin 32 in the guide contour 48 of the second driver 58

(59) The actuators 50 and the transmission and connection structures provided in the form of the described components thus provide a pivoting movement of the guide legs 30 relative to the material dispensing unit 4 in addition to a vertical displacement movement relative to the material dispensing unit 4.

(60) The actuators 40 and 50 can be actuated individually and can thus implement a completely individual adjustment of the guide legs 30.

(61) Furthermore, the actuators can be operated simultaneously, wherein the transmission and connection structures are designed in such a way that they do not interfere with each other when the actuators are operated simultaneously, so that a simultaneous movement is made possible both in a translational degree of freedom z and in a rotational degree of freedom dx.

(62) In this embodiment as well, the actuators 40, 50 can in particular be designed as servomotors and can in particular be accommodated in the rear housing cover 22c or the central housing region 22b.

(63) A further special feature of the described embodiments is shown in FIGS. 8 to 10.

(64) The multi-part device 3 (see FIG. 2) with its front housing cover 22a comprises a cleaning assembly 60, which in the embodiment shown is arranged in the region of the housing opening (receiving opening) 28. This opening serves both to protect against building material residues drying out on the guide legs 30, in particular in a rest position, and to protect the transmission and connection structures in the interior of the housing 20 from contamination.

(65) This comprises a cleaning portion 62 in the form of an edge which, when in contact with the associated guide leg 30 (in particular on its shaping side), is capable of stripping off building material residues from the contacted surface (the shaping side) of the guide leg during a translational relative movement.

(66) As already explained in connection with FIGS. 3a to 7, in each of the two embodiments the guide legs 30 can be moved by means of the actuators 40 at least in a vertical movement in the direction z relative to the housing 20 of the material dispensing unit 4. The cleaning assembly 60 with the cleaning portion 62 is attached to the housing 20, in particular in the embodiment shown in FIGS. 8 to 10 in the region of the receiving openings 28. Thus, each receiving opening 28 has an edge 62a on its side facing the discharge opening 26a of the material dispensing unit 4, which edge rests against the associated guide leg 30 on a shaping side 30a of the guide leg.

(67) The term shaping side here refers to the side of the guide leg 30 that also faces the discharge opening 26a of the material dispensing unit 4. The substantial smoothing effect of the guide leg is achieved with the shaping side 30a of the guide leg 30, because this side comes into contact with the surface to be smoothed. Accordingly, the shaping sides 30a of the guide legs 30 are situated quasi-opposite one another, and in the shown arrangement they laterally delimit the space into which the building material is discharged as a building material layer through the discharge opening 26a.

(68) In the arrangement shown in FIG. 8, the guide legs 30 can be in a working position in which their shaping sides 30a can be in shaping contact with a building material layer (not shown). If the guide legs 30 are now retracted upwards in the vertical direction z into the interior of the housing 20 (only the front housing cover 22a is shown in FIG. 8), each of the guide legs 30 strips off any building material residues that may still adhere to the shaping surface 30a on the associated edge 62a of the cleaning portion 62. The shaping side 30a of the guide legs 30 is cleaned in this way.

(69) Furthermore, an elastic cleaning element 64 can be seen which is arranged on the opposite side of the receiving opening 28 and has, for example, a rubber lip. The elastic cleaning element 64 pre-tensions the abutting guide leg 30 at least slightly and holds it in contact with the cleaning portion 62. In this way, it is ensured that the shaping surface 30a of the guide leg remains in contact with the cleaning portion 62 over the entire width (i.e. in the horizontal direction) and that building material residues can be reliably stripped off.

(70) In addition, the elastic cleaning element 64 is also suitable for stripping off any building material residues on the abutting surface (on the side 30b opposite the shaping side 30a of the guide leg) of the associated guide leg 30, if necessary. For this purpose, the elastic cleaning element 64 also has an edge 64a. In the same way as the edge 62a of the cleaning portion 62, this edge acts as a stripper for any building material residues on the side 30b of the guide leg 30 when the guide leg 30 is moved vertically upwards in direction z (i.e. into the interior of the housing).

(71) The elastic cleaning element 64 of the shown embodiment, which is designed as a rubber lip in the embodiment shown, also seals the receiving opening 28 of the housing 20, which is particularly favorable for protecting the components accommodated therein.

(72) It can be seen in FIG. 10 that both the cleaning portion 62 and the elastic element 64 have a contact contour which in each case has a negative contour relative to the contour of the associated guide leg 30 in the region of contact with the guide leg 30. In the embodiment shown, this means that the cleaning portion 62, i.e. the edge 62a, as well as the elastic element 64, have a curvature when viewed in cross section which allows contact with the corresponding curvature of the shaping side 30a or the opposite side 30b of the guide leg 30. A particularly efficient and full-surface cleaning of the guide leg on the shaping side 30a and the opposite side 30b is thereby made possible.

(73) Finally, FIG. 10 shows that the cleaning assembly 60 can have a closed contact contour when viewed in cross section, which represents a negative shape of the entire cross section of the guide leg 30, and the cleaning assembly 60 thus completely encloses the guide leg 30. Here the cleaning portion 62 and the elastic element 64 can merge into one another or further cleaning portions can be provided in order to connect them to form a closed contact contour spanning the guide leg 30. Any further cleaning portions can accordingly also have a cleaning edge in the manner of the edge 62a, which projects inwards toward the guide leg and allows building material residues to be stripped off.

(74) It is also possible for only one elastic cleaning element in the form of a rubber ring to be inserted into the receiving opening 28 and, in a comparable manner, to span the entire guide leg with a contact contour that has a negative contour relative to the contour of the guide leg (viewed in cross section). In such a solution, the elastic cleaning element assumes the partial function of cleaning the cleaning portion 62.

(75) Finally, the elastic cleaning element 64 can also serve as a lubricating element in a manner which is not shown, in which this lubricating element is capable of applying a lubricating fluid, for example water, to the associated guide leg 30. For this purpose, the elastic cleaning element 64 can also be inserted as a circumferential element, for example as a rubber ring into the receiving recess 28 of the housing 20.

(76) It can be seen in FIG. 10 that both the cleaning portion 62 and the elastic element 64 have a contact contour which in each case has a negative contour relative to the contour of the associated guide leg 30 in the region of contact with the guide leg. A particularly efficient and full-surface cleaning of the guide leg on the shaping side and the opposite side is thereby made possible. Of course, this can also be advantageous for an optional lubrication.

(77) It is also not shown that the controlling of the actuators 40, 50 can take place via an additional control unit and/or via the control device for controlling the actuator assembly 5. On this, see the statements in the introduction to the description.