WO2022096667A1

WO2022096667A1 - Coating device, central module, and process and apparatus for manufacturing three-dimensional objects by selectively solidifying a building material applied in layers

Info

Publication number: WO2022096667A1
Application number: PCT/EP2021/080815
Authority: WO
Inventors: Florian SCHAEDE; Kai Etzel; Lukas WITZ
Original assignee: Trumpf Laser- Und Systemtechnik Gmbh
Priority date: 2020-11-09
Filing date: 2021-11-05
Publication date: 2022-05-12
Also published as: DE102020129420A1

Abstract

The invention relates to a coating device (46) and a central module (33) for a process assisting device (21) in an apparatus for manufacturing three-dimensional objects (12) by selectively solidifying a building material, which is applied in layers, by means of a beam acting on the building material, the coating device (46) comprising two receptacles (83, 84) which run parallel to one another and extend perpendicularly to the moving direction, further comprising a partition (85) between the receptacles (83, 84), wherein a coating tool (87) is stationarily arranged on an underside of the partition (85) in the dispensing direction of the building material. The invention further relates to a process and an apparatus for manufacturing three-dimensional objects.

Description

Coating device, middle module and method and device for the production of three-dimensional objects by selective solidification of a layered applied construction material

The invention relates to a coating device, a central module of a process support and a method and a device for the production of three-dimensional objects by selective solidification of a layered applied construction material, in which the construction material is applied in layers in at least one process chamber on a construction platform and with a radiation source at least one Beam generated for solidification of the construction material and is fed via at least one beam guidance element to the construction material in the construction platform. A process support device, which has a central module and an outer module aligned with it, with the central module and/or the outer module being movable along the assembly platform, generates a primary gas flow along the assembly platform, so that between the central module and the at least one outer module there is an overflow path with primary gas is formed.

DE 10 2017 211 657 A1 discloses a device for the additive manufacturing of a component with protective gas flow and a method for this. This device comprises a process support device with a central module and an outer module aligned with the central module. The center module is above a mounting plate form movably controlled. The central module includes a coater, via which construction material is supplied from a powder reservoir so that it is discharged onto the construction platform during the movement of the central module. A protective gas outlet device is provided on both sides of the coater, in which case the protective gas outlets are directed in the direction of the outdoor module. During the hardening of the building material, a protective gas is emitted through a large number of the protective gas outlets and sucked off through the opposite outdoor module. This outer module, which is designed as a suction device, can be controlled so that it can be moved synchronously with the central module, while the building material is solidified in the area in between by means of a laser beam.

Furthermore, WO 2019/115140 A1 discloses a method and a device for producing three-dimensional objects by selectively solidifying a construction material applied in layers. This device comprises a receiving device, to which a central module and an outer module are fastened in a fixed manner adjacent to each other at the outer end. The center module includes a coater with two spaced-apart rollers for smoothing the applied build material. Two suction devices are provided on the central module, which are aligned with the outer module. While the laser beam is being fed onto a construction platform between an outer module and the middle module, a flow of process gas is generated from the outer module to the suction device on the middle module. The opposite outdoor module is switched off with regard to the supply of a process gas stream.

DE 10 2015 222 100 A1 discloses a coating device for dispensing a construction material in a device for producing three-dimensional objects by selective solidification of the construction material applied in layers by means of a jet acting on the construction material. This coating device has two mutually parallel aligned shots that extend transversely to the movement of the coating unit. A partition wall is provided between the two receptacles. A coating tool is provided on each outside of the receptacle to smooth the dispensed build material.

The invention is therefore based on the object of proposing a coating device, a central module for a process support device and a method and a device for producing three-dimensional objects by selectively solidifying a layered applied construction material, through which productivity is increased.

This object is achieved by a coating device which has two receptacles which extend parallel to one another, the direction of extension being aligned perpendicularly to the direction of travel and with a partition wall provided between the two receptacles, the partition wall pointing in the dispensing direction of the building material and a coating tool fixedly arranged on it having. This coating device has the advantage that the structure is simplified in that only one coating tool is provided. Provision is preferably made for the preceding receptacle to be filled with construction material, viewed in the direction of travel of the coating device, so that the coating tool that lags behind the filled receptacle can smooth the construction material dispensed onto the construction platform.

Advantageously, at least one, preferably both, of the receptacles has a dispensing opening that is free of closure elements. In other words, at least one, preferably both, of the receptacles has a dispensing opening for dispensing building material, a filling opening for receiving the building material and no movable closure elements. In other words, in at least one of the receptacles between its filling opening, through which the building material gets into the receptacle, and its discharge opening, through which the building material emerges from the receptacle, no movable closure element, such as a slider, flap or wheel, is provided. By omitting a movable, for example rotatable, foldable or displaceable closure element, direct communication between the filling and dispensing opening is provided at all times by means of the powdered building material. Due to the omission of a movable closure element, a structurally simple and therefore cost-effective solution is made possible, which is also less susceptible to wear and dirt and therefore ensures trouble-free operation of the coating device. This also has the advantage that when building material is applied, no moving parts have to be used, which could lead to vibrations in the coating tool and thus to an inhomogeneous application of building material, for example so-called chatter marks. Furthermore, a vibrating or stirring device can preferably be provided on or in the receptacle or receptacles, in order to improve the flowability of the building material from the receptacle or receptacles. This should preferably not be used during the build-up material application above the build platform.

Provision is preferably made for the at least one coating tool, which is preferably designed as a coating lip, to extend at least along the length of the receptacle. As a result, the applied construction material can be completely smoothed over the entire width of the construction platform. The coater lip is preferably arranged in an exchangeable manner on the partition wall between the two receptacles.

Advantageously, the receptacles of the coating device are shaft-shaped. This enables filling with construction material to be carried out in a simple manner above the receptacles and the construction material to be discharged and dosed downwards based on gravity during a displacement movement of the coating device. Provision is preferably made for the receptacles to have a discharge opening which is open at the bottom. This dispensing opening is dimensioned in cross-section for metered dispensing during a movement. This enables a particularly uniform application of the building material, despite the omission of a controllable opening, for example by a slide or a flap for dosing the building material.

The discharge opening of the receptacles of the coating device preferably has a rectangular or slit-shaped cross section. The receptacles preferably have wall sections which are aligned vertically, starting from the dispensing opening. Alternatively, it can also be provided that the wall sections aligned in the longitudinal direction of the coating device or the central module widen upwards. In both cases, the receptacles can be easily filled with the construction material from above by gravity.

The coating device preferably has a frame-shaped base body which accommodates and surrounds the at least two receptacles. Such a frame-shaped base body has the advantage that further components can be fastened to the frame-shaped base body, such as suction devices arranged on one or both sides of the receptacles. Furthermore, the at least two receptacles can alternatively be integrated into the frame-shaped base body. As a result, a compact structure can be formed. At the same time, a rigid arrangement of the receptacles relative to one another can also be achieved as a result.

In particular, it is provided that the shaft-shaped receptacles of the coating device include stiffening webs that extend between the wall sections. These stiffening webs are designed to be relatively thin in wall thickness in order not to form any interfering contours. Advantageously, these do not extend over the entire height, but are spaced apart from a dispensing opening, so that the building material can be applied evenly. The receptacles of the coating device preferably have a receptacle volume which corresponds to the release of the construction material for a single traversing of the construction platform. This makes it possible for the construction volume of the coating device to be of compact design and thus for low moving masses to be present.

The object on which the invention is based is also achieved by a central module for a process support device for the production of a three-dimensional object by selective solidification of a layered applied construction material, which comprises two suction devices that are arranged at a distance from one another and each have a suction opening that is aligned in opposite directions to one another and with a coating device, in particular according to one of the above-described embodiments, which is positioned between the two suction devices, the suction devices and the coating device being movable together, the coating device having at least two receptacles for the building material which are aligned with the suction devices and are separated by at least one partition and at least one coater tool is provided between the receptacles. This arrangement has the advantage that a structurally simple and weight-reduced configuration of a center module is created, which can be used for a parallel coating and exposure process. This configuration of the central module means that it can be controlled to be movable in two directions of movement within the process chamber and a layer of build-up material can be applied and smoothed in each direction of movement for the subsequent solidification process.

Provision is preferably made for the receptacles of the coating device to extend along, preferably parallel, to the suction directions over their length. Both the suction devices and the receptacles preferably extend at least over the width of the build platform, so that a full-surface layer can be applied by driving over the build platform once. Furthermore, it is preferably provided that the receptacles for the construction material and the suction devices are aligned as mirror images of the partition. As a result, a layer of the construction material to be solidified can be applied in each direction of travel of the central module. Furthermore, primary gas streams and possibly secondary gas streams, which are additionally fed into the process chamber above the process chamber, can be sucked off by the suction devices in order to enable a high degree of cleaning and flushing of the process chamber with process gas.

The object on which the invention is based is also achieved by a method for producing a three-dimensional object by selectively solidifying a construction material applied in layers, in which a process support device has a central module according to one of the embodiments described above with a coating device according to one of the embodiments described above, which along the structure platform for applying build-up material and for smoothing the applied build-up material. Such a central module enables the construction material to be applied when the construction platform is driven over and process gas flows to be maintained between the outer module or modules and possibly another feed device above the process chamber.

Advantageously, the central module is moved alternately into a left and right end position within the process chamber for filling with building material, and at least one receptacle is filled with building material in the end position. This enables the process time to be optimized, since the powdered construction material can continue to be solidified by a jet while the receptacle is being filled with the construction material.

In particular, it is provided that only one of the two recordings is filled by the middle module positioned in the end position, for which subsequent traversing movement, the preceding receptacle of the coating device is filled with building material. This makes it possible for the one coater tool provided between two receptacles to suffice, since this is always positioned following the receptacle with this filling strategy.

Furthermore, it is preferably provided that the receptacles of the coating device are filled with a dosing device. This dosing device can be positioned separately from the coating device or carried along by the coating device or the central module.

Provision is preferably made for the dosing device to have a dispensing head which is moved along the receptacle in order to dispense the building material. This dispensing head can transfer the building material into the receptacle by gravity. The degree of filling is preferably determined via the speed of travel along the recording.

Furthermore, it is advantageously provided that when the receptacle is passed over once, the required amount of construction material is transferred into the receptacle. This in turn enables a process time reduction.

For dispensing the building material through the dispensing head of the dosing device, an intermediate store is provided on the dispensing head, which is also moved to dispense the building material.

Furthermore, the dosing device can preferably have a shaking or stirring device. This shaking or stirring device can be provided on or in the buffer. As a result, the dispensing or the flowability of the building material from the temporary store into the dispensing head can be improved. Advantageously, the size or the volume of the buffer store is designed in such a way that the buffer store is filled after at least two travels along the receptacle of the coating device. Thus, the buffer can be moved from a first position for filling the receptacle to a second position transverse to the assembly platform or along the receptacle and rest there until the central module is back in the same end position after moving back and forth across the assembly platform then carry out a filling process again in order to be returned to the first position or the starting position. Only then is the intermediate memory filled again.

The object on which the invention is based is also achieved by a device for producing three-dimensional objects by selectively solidifying a build-up material applied in layers by means of a jet acting on the build-up material, which comprises a process support device which, in order to generate a primary gas flow along the build platform, has a central module and in each case to it aligned has an outer module, wherein the middle module is designed according to one of the embodiments described above. This has the advantage that the central module, which includes a coating device according to one of the embodiments described above, can be designed in a simple manner, especially since kinematics for a coating tool can be omitted.

Furthermore, it is preferably provided that a dosing device is provided in each case in a right and left end position in a travel position of the center module and adjacent to the assembly platform. The filling of the at least one receptacle of the central module with construction material can thus be carried out in parallel with an exposure strategy for solidifying the last applied layer of construction material in the construction platform.

The receptacles of the coating device are preferably filled via a dosing device. This dosing device can be separated be provided for the coating device or center module. This dosing device can also be carried along by the coating device or the central module.

The dosing device assigned to the process chamber preferably comprises a receiving head which can be moved along a longitudinal axis of the central module, in particular transversely to the direction of movement of the central module, above the central module's receptacle. This allows for a simple filling process.

The dispensing head of the dosing device preferably carries an intermediate store, which can be filled with building material via a conveyor device, in particular a conveyor device that is fixedly aligned with the process chamber. As a result, the mechanical complexity for filling and dosing the receptacle of the central module can be reduced, since the dispensing head is moved together with the intermediate store above the receptacle in order to transfer the building material by gravity into the receptacle of the central module below.

Furthermore, it is preferably provided that the dispensing head can be moved between two end positions transverse to the direction of travel along a guide and that the dispensing head has a dosing opening on its underside, which can be closed by a closure device arranged in the end position when it is moved into the respective end position. As a result, the dispensing head is designed without any mechanics. The dosing opening has a constant cross-section in order to fill the receptacle based on gravity.

According to a first embodiment of the dosing device, it is provided that the dispensing head can be moved along a stationary guide within the process chamber. Alternatively, it can be provided that the guide for the displacement movement of the dispensing head is attached to the coating device and/or to the suction device. In this case, the output head and the buffer at moved along with a movement of the central module or the coating device.

It is preferably provided that when the dosing device is moved along, the dispensing head above the receptacle of the coating device can be moved transversely to its longitudinal extension for filling the respective receptacle or that this dispensing head can be assigned to the respective receptacle by a pivoting movement to fill the respective receptacle of the coating device.

Provision is preferably made for the holding volume to include intermediate storage for the construction material, at least twice the filling quantity of the holding unit of the coating device. The dispensing head can thus be transferred from the first to the second end position without filling taking place in the second end position and being moved back to the first end position and the receptacle being filled along each movement.

The invention and other advantageous embodiments and developments thereof are described and explained in more detail below with reference to the examples shown in the drawings. The features to be found in the description and the drawings can be used according to the invention individually or collectively in any combination. Show it:

FIG. 1 shows a schematic side view of a device for producing three-dimensional objects by selectively solidifying a construction material applied in layers,

FIG. 2 shows a perspective sectional view of a process chamber according to FIG. 1,

FIG. 3 shows a perspective view of a feed device for a secondary gas flow, FIG. 4 shows a schematic view from below of the feed device for the secondary gas flow,

FIG. 5 shows a schematic side view of the process chamber with a primary gas flow and a secondary gas flow,

FIG. 6 shows a perspective view of a central module with a dosing device,

FIG. 7 shows a schematic side view of a process chamber according to an alternative embodiment to FIG. 5 during solidification of the building material by a jet,

FIG. 8 shows a schematic side view of the process chamber in a further work step to FIG. 7 for the production of a three-dimensional object,

FIG. 9 shows a schematic side view of the device according to FIG. 8 with an alternative embodiment of the dosing device, and

FIG. 10 shows a schematic side view of the device according to FIG. 8 with a further alternative embodiment of the dosing device.

FIG. 1 shows a schematic side view of a device 11 for producing three-dimensional objects 12 by selective solidification of a construction material applied in layers. These devices 11 are also referred to as 3D printing systems, selective laser sintering machines, selective laser melting machines or the like. The device 11 comprises a housing 14 in which a process chamber 16 is provided. The process chamber 16 is closed to the outside. This can be accessible via a door (not shown) or a safety lock. In the process chamber 16 a construction platform 17 is provided, on which at least one three-dimensional object 12 is produced in layers. The size of the construction platform 17 determines a construction field for the production of the three-dimensional objects 12. The construction platform 17 can be moved in height or in the Z direction. Overflow containers 19 or collecting containers are provided adjacent to the building platform 17, in which building material that is not required or has not solidified is collected. A process support device 21 is arranged in the process chamber 16 above the build platform 17 . This process support device 21 is controlled so that it can be moved at least partially in the X direction.

Associated with the process chamber 16 or attached to the process chamber 16 is a radiation source 26 which generates a beam 27, in particular a laser beam. This laser beam is guided along a beam guide 28 and deflected and directed via a controllable beam guiding element 29 onto the construction platform 17 . The jet 27 enters the process chamber 16 via a jet inlet opening 30 . The construction material applied to the construction platform 17 can be solidified at the impact point 31 of the beam 27 .

The process support device 21 comprises a central module 33 and an external module 34, 35 assigned to the central module 33.

In the embodiment of the process support device 21 according to FIG. The central module 33 can be moved between a left and right end position 34, 35. In the view according to FIG. 1, the central module 33 is positioned in the left end position 36. The outdoor modules 34 include an outlet nozzle 38 attached to a feed duct 39 . This outlet nozzle 38 preferably has vertically aligned guide surfaces. In addition, the outlet nozzle 38 is tapered in the exit direction. As a result, a primary gas flow fed into the process chamber 16 can be homogenized and stabilized. The central module 33 comprises two suction devices 41, each of which has a suction opening 42 aligned opposite to one another. A reservoir 44 for receiving building material is provided between the suction devices 41 . This reservoir 44 is formed by two receptacles 83, 84, which have at least one opening or dispensing slot directed toward the process chamber floor 18, so that when the central module 33 drives over the assembly platform 17, a layer of assembly material can be dispensed. A coating device 46 is preferably provided between the two receptacles 83, 84, which are arranged adjacent to the suction device 41. The receptacles 83, 84 that lead in the direction of travel of the central module 33 are preferably filled with construction material. The coating device 46 is trailing. In particular, the coating device 46 comprises at least one coater lip.

The middle module 33 is preferably filled with building material in the right and/or left end position 36, 37. In this regard, one or both end positions 36, 37 can be assigned a dosing device 48. This dosing device 48 can be moved along a guide 98, in particular in the Y direction (FIG. 2), so that the receptacles 83, 84 can be filled evenly over the width of the central module 33.

The overflow container 19 is also assigned to the right and left end position 36, 37 so that stripped building material can be discharged into the overflow container 19 by the coating device 46 of the central module 33 when the end position 36, 37 is assumed.

Each outdoor module 33 is connected to a supply line 52 . A primary gas is applied to this supply line 52 by a pump or primary gas source not shown in detail, so that a primary gas flow can be discharged into the process chamber 16 through the external modules 34 . A feed device 55 for a secondary gas flow into the process chamber 16 is provided above the process chamber 16 . This feed device 55 comprises two feed channels 56 lying opposite one another, which are positioned adjacent to the jet entry opening 30 . The secondary gas flows into the process chamber 16 via at least one feed opening 57, which is associated with the jet entry opening 30 or surrounds it, and is fed onto the build platform 17 from above.

The process chamber 16 has lateral wall sections 60 which delimit the length of the process chamber 16 . These wall sections 60 include flow surfaces 62 which extend in the direction of the build platform 17 and narrow a cross-sectional area of the process chamber 16 . A distance 61 is provided, which corresponds to the length of the assembly platform 17, which extends in the X-direction, or is preferably smaller, as is shown in FIG. Starting from the smallest distance 61, the flow area 62 widens. The wall section 60 transitions into a horizontal boundary surface 63 . This boundary surface 63 preferably runs parallel to the process chamber floor 18 and is provided at a distance from the process chamber floor 18 so that the process support device 21 can be positioned between the boundary surface 63 and the process chamber floor 18 . This configuration of the process chamber 16 achieves a tulip-shaped cross section or a tulip-shaped contour, which enables flow optimization when a secondary gas is fed into the process chamber 16 from above. Alternatively, the process chamber 16 can have a cone-shaped contour or the contour of a parabolic inlet funnel.

Each feed channel 56 of the feed device 55 is supplied with secondary gas via a supply line 52 via a secondary gas source not shown in detail. The supply device 55 for supplying a secondary gas and for forming a secondary gas flow within the process chamber 16 is described in more detail with reference to the following FIGS.

A perforated plate 71 extending over the cross section is preferably provided in the feed channel 56 . As a result, a first homogeneous flow distribution of the secondary gas supplied can already be achieved. The feed channel 56 opens into the feed opening 57. In the exemplary embodiment, the feed opening 57 is formed by a flow element 59, such as a flow sieve. This through-flow element 59 can also be designed, for example, as a perforated plate or as a gas-permeable knitted fabric or as a multi-layer metal fabric or the like. The feed opening 57 completely surrounds the jet entry opening 30. The feed opening 57 and the jet entry opening 30 therefore lie in a common plane.

Guide plates 72 extend between the perforated plate 71 in the feed channel 55 and the feed opening 57 and subdivide the cross section of the feed channel 55 into a core flow 74 and two external side flows 75 . These baffles 72 extend along the width of the jet entry opening 30, each over half the length of the jet entry opening 30. At the same time, the feed channel 56 has an upper curved surface 76 in order to feed the side streams 75 to the process chamber 16 via the lateral areas of the feed opening 57.

A blocking current fin 77 is provided on the feed opening 57 , assigned to the end face of the jet outlet opening 30 . This reverse current fin 77 is provided at a distance from the beam entry opening 30 on the inside of the process chamber 16 . These reverse current fins 77 are aligned almost horizontally. As a result, a horizontal blocking flow is supplied from both sides via the supply channels 56, which meet in the middle of the jet entrance opening 30 and subsequently produce a secondary gas flow directed downwards. A flow stabilizer 78 is provided in each case between an end face of the jet inlet opening 30 and the wall section 60 . This preferably has a Curvature corresponding to the flow surface 62 on. This flow stabilizer 78 extends over the entire width of the feed channel 56 or feed opening 57. These flow stabilizers 78 enable a turbulence-free secondary gas flow in the edge region of the process chamber 16, regardless of the position of the central module 33.

FIG. 5 shows a schematic side view of the process chamber 16 according to FIG. 1 during a work step for producing a three-dimensional object 12 . The beam 27 is directed onto the construction material in the construction platform 17 and solidifies the construction material at the impact point 31 . The center module 33 is positioned adjacent to the impact point 71 on the right, for example. This middle module 33 can follow the beam 27, which is moved towards the left end position 36, for example. At the same time, the process support device 21 is charged with a primary gas and the feed device 55 with a secondary gas. According to a first embodiment, a primary gas flow is generated between a left-hand outer module 34 and the central module 33 and a secondary gas flow is generated between the feed device 55 and the central module 33 . In this first embodiment, only the left suction device 41 of the center module 33 is controlled for the joint suction of the primary gas flow and the secondary gas flow. Alternatively, it can be provided that a primary gas flow is output through the left and right outer modules 34, 35, which is sucked off by the respective left and right suction device 41 of the middle module 33. In addition, at the same time, a secondary gas stream is fed to the center module 33 via the feed device 55 . Due to the position of the central module 33 shown in FIG. 5, an increased volume flow of the secondary gas is supplied to the left-hand suction device 41 and sucked off together with the primary gas flow. A lower volume flow of the secondary gas flow can be extracted via the right-hand extraction device 41 of the center module 33 together with the right-hand primary gas flow. In this embodiment takes place joint suction of the primary gas flow and secondary gas flow supplied to the process chamber 16 via both suction devices 41 of the central module 33 .

It is preferably provided that the outlet nozzle 38 of the external modules 34, 35 has an opening cross section in relation to the suction openings 42 of the suction device 41 of greater than 3.

Figure 6 shows a perspective view of the process support device 21 and of one of the dosing devices 48 assigned to the process chamber floor 18 or the assembly platform 17. The central module 33 extends across the entire assembly platform 17 at right angles to the direction of travel. The direction of movement of the central module 33 is in and opposite to the X-direction, as shown in FIG. The central module 33 comprises two suction devices 41 aligned opposite one another, the respective suction openings 42 of which are aligned in opposite directions. The suction openings 42 of the respective suction device 41 are assigned to the respectively opposite outer module 34, 35 and aligned therewith. A coating device 46 is provided between the suction devices 41 . This coating device 46 comprises two receptacles 83, 84 which are arranged separated from one another by a partition wall 85. A coater tool 87 is provided between the two receptacles 83 , 84 and the assembly platform 17 . This coater tool 87 can be designed as a coater lip, for example. This coating tool 87 is preferably arranged in a stationary manner on an underside of the partition wall 85 . This coater tool 87 can be provided on the partition wall 85 in an exchangeable manner.

The receptacles 83, 84 can be part of a frame-shaped base body or form this. A frame-shaped base body or another base body can also be provided, in which the receptacles 83, 84 are provided or fastened. The receptacles 83, 84 are preferably designed in the shape of a shaft. These preferably have a rectangular dispensing opening 89 . This discharge opening 89 is free of fasteners. Wall sections 91, 92 aligned parallel to one another preferably extend vertically upwards, starting from the dispensing opening 89, and form the receptacle 83, 84. The receptacle 83, 84 is also designed to be open at the top, ie it has a filling opening. In the embodiment described above, the receptacles 83, 84 are each designed as a so-called chute. Reinforcement webs 93 can preferably be provided between the wall sections 91, 92. As a result, the recordings 83, 84 can be stiffened. At the same time, a connection of the suction device 41 to the coating device 46 can thereby be provided. Furthermore, a vibrating or stirring device can preferably be provided on or in the receptacle 83, 84 or the receptacles 83, 84 in order to improve the flowability of the building material from the receptacle or receptacles 83, 84.

The dosing device 48 comprises a dispensing head 49 which has a dosing opening 50 pointing towards the construction platform 17 . This dosing opening 50 is preferably also designed without a closure element. The dispensing head 49 carries an intermediate store 51 that can be filled with building material from above via a conveyor device that is not shown in detail. It is preferably provided that the intermediate store 51 is only filled in a first end position 95 . In this first end position 95, the dispensing head 49 is seated on a closure device 97, so that the dispensing opening 15 is closed. In this first end position 95, the intermediate store 51 is filled with a volume of building material which corresponds to twice the filling quantity of the receptacle 83 or 84. A vibrating or stirring device can be provided on or in this intermediate store for improved emptying of the intermediate store 51 .

The filling process of the receptacle 83, 84 of the coating device 46 by the dosing device 48 takes place as follows: the central module 33 is positioned in the left end position 36, for example. The dispensing head 49 is positioned above the receptacle 83, i.e. the receptacle would take, which is positioned ahead of the next movement of the central module 33. In this case, the coater tool 87 is positioned after the receptacle 83 . The output head 49 is then moved from the first end position 95 to the second end position 96 . The building material is transferred via the dispensing head 49 into the receptacle 83 by gravity. The dispensing head 49 is then positioned stationary in the second end position 96 and the dosing opening 50 is closed by the closure device 97 . This is followed by activation of the movement of the central module 33 into the right end position 37. Due to gravity, the construction material is applied to the construction platform 17 during the movement of the central module 33 and smoothed by the coating tool 87 that follows. A dosing device 48 is also provided in the right-hand end position 97 . This is constructed in the same way as the dosing device 48 described above, which is assigned to the left end position 36 . In the right-hand end position 37, the receptacle 84 is filled by the metering device 48, which receptacle is in advance for the subsequent displacement movement. The central module 33 then travels over the assembly platform 17 again to the left end position 36. The dispensing head 49 is then moved from the second end position 96 to the first end position 95, with the preceding receptacle 83 being filled again for the subsequent movement of the central module 33. After the dispensing head 49 has reached the first end position 95, the intermediate store 51 is once again filled with building material by the conveying device.

FIG. 7 shows a schematic side view of a work step of the device 11 for the production of the three-dimensional object 12 with an alternative embodiment of the process support device 21 . Figure 8 shows another possible working position according to the embodiment in Figure 7.

In this embodiment, it is provided that the process support device 21 has two movably controlled external modules 34, 35 having. In this regard, the feed channels 56 are preferably designed telescopically, so that the outlet nozzles 38 can be moved relative to the construction platform 17 . The movable control of the outer modules 34, 35 relative to the movement of the central module 33 has the advantage that the overflow distance between the outlet nozzle 38 and the suction device 41 can be kept short. As a result, the homogeneity of the primary gas flow can be maintained along the overflow path, as a result of which improved suction can be achieved. In the illustration in FIG. 7 it is provided that the central module 33 is moved into an end position 36 . The right outer module 35 follows the center module 33, preferably at a constant distance. At the same time, the left outer module 34 is increasingly transferred to the left end position 36 . Complete flushing of the process chamber 16 can be achieved by the simultaneous supply of the primary gas streams and the secondary gas stream. During the displacement movement shown in FIG. 7, a primary gas flow is preferably output via both outlet modules 34, 35 and suction of the primary gas flow and secondary gas flow is controlled via both suction devices 41 of the central module 33.

The primary gas flow and/or the secondary gas flow is also maintained during the process of the central module 33 in an end position 36, 37 or in the end position 36, 37, such as the left end position 36. A constant flow of the entire process gas circuit is preferably provided.

FIG. 9 shows a schematic side view of the device 11 according to FIGS. 7 and 8. The embodiment according to FIG. 9 differs from the embodiment according to FIGS. 7 and 8 with regard to the dosing device 48 . In this respect, with the exception of the dosing device 48, reference can be made in full to the embodiment described above. In this embodiment it is provided that the dosing device 48 is attached to the coating device 46 or the central module 33 . The dosing device 48 is thus moved between the two end positions 36, 37 during a movement of the central module 33. The dispensing head 49 is provided on a traverse 101 . The traverse 101 can be moved along the receptacles 83, 84 on a guide 98. Two guides 98 are preferably provided on an upper side of the suction devices 41, so that the dispensing head 49 can be moved along the length of the receptacle 83, 84. In addition, the dispensing head 49 can be moved along the traverse 101 in and against the direction of travel of the central module 33 . This makes it possible for the respective leading receptacle 83, 84 to be filled for the subsequent coating process, depending on the end position 36, 37 of the central module 33 that is assumed.

FIG. 10 shows a schematic side view of the device 11 with an alternative embodiment of the dosing device 48 to FIG. Otherwise, reference can be made to the embodiment of the device 11 described above.

In this dosing device 48 according to FIG. 10, in contrast to the embodiment according to FIG. For the respective filling of the receptacle 83, 84, the dispensing head 89 has a dosing opening 50 which is mounted pivotably. As a result, the dosing opening 50 of the dispensing head 49 can be selectively aligned with the receptacle 83 or receptacle 84 in order in turn to fill the preceding receptacle 83, 84 for the subsequent movement of the central module 33.

Claims

23

Claims Coating device (46) for a process support device (21) in a device for producing three-dimensional objects (12) by selective solidification of a layered applied construction material by means of a jet acting on the construction material, with two receptacles (83, 84) which are parallel to one another extend, the extension direction of the receptacles (83, 84) being aligned perpendicularly to the direction of travel, with a partition wall (85) provided between the receptacles (83, 84), characterized in that on an underside of the partition wall (85) in the dispensing direction of the building material pointing a coater tool (87) is arranged fixed. Coating device according to Claim 1, characterized in that at least one, preferably both, of the receptacles (83, 84) has a dispensing opening (89) which is free of closure elements. Coating device according to Claim 1 or 2, characterized in that the at least one coater tool (87), which is preferably designed as a coater lip, extends at least along the length of the receptacles (83, 84). Coating device according to one of the preceding claims, characterized in that the receptacles (83, 84) are shaft-shaped and the receptacles (83, 84) are preferably open at the bottom. Coating device according to one of the preceding claims, characterized in that the construction material is discharged into the receptacles (83, 84) by the weight of the construction material downwards onto the construction platform (17) and the receptacles (83, 84) have discharge openings (89 ) having. Coating device according to Claim 5, characterized in that the delivery opening (89) has a rectangular or slot-shaped cross section and the receptacles (83, 84) are attached to the delivery opening (89) with vertical wall sections (91, 92) or in the longitudinal direction of the central module (33 ) seen with upwardly widening wall sections (91, 92) is formed. Coating device according to one of the preceding claims, characterized in that a frame-shaped base body is provided which surrounds the at least two receptacles (83, 84) or to which the at least two receptacles (83, 84) are attached or that the receptacles (83, 84 ) are integrated into the frame-shaped body. Coating device according to one of the preceding claims, characterized in that stiffening webs (93) are provided in the receptacles (83, 84). Coating device according to one of the preceding claims, characterized in that the receptacles (83, 84) have a receiving volume for the construction material which corresponds to a single movement of the central module (33) along the construction platform (17) for dispensing a layer of construction material. Central module for a process support device (21) in a device for producing three-dimensional objects (12) by selective solidification of a layered applied building material by means of a jet (27) acting on the building material, with two suction devices (41) which are aligned at a distance from one another and each have a suction opening (42) which are aligned in opposite directions to one another, with a coating device (46) which is positioned between the two suction devices (41), the suction devices (41) and the coating device (42) being movable together, characterized in that the coating device (46) is designed according to one of Claims 1 to 9. Central module according to Claim 10, characterized in that the receptacles (82, 83) extend along, preferably parallel to, the suction devices (41) over their length. Central module according to one of Claims 10 or 11, characterized in that the receptacles (83, 84) and the suction devices (41) are aligned as mirror images of the partition wall (85). Method for producing a three-dimensional object (12) by selectively solidifying a construction material applied in layers, in which the construction material is applied in layers in at least one process chamber (16) on a construction platform (17), 26 in which at least one beam (27) for solidifying the build material is generated with a radiation source (26) and is fed with at least one beam guiding element (29) onto the build material in the build platform (17), in which with a process support device (21) which has a central module (33) and an outer module (34, 35) aligned with it, a primary gas flow is generated along the assembly platform (17), so that between a central module (33) and the at least one outer module (34, 35) there is an overflow path with primary gas is formed, characterized in that the process support device (21) has a central module (33) according to one of the preceding claims 10 to 12 with a coating device (46) according to one of the preceding claims 1 to 9, which along the construction platform (17) to Applying building material and smoothing the applied building material. Method according to Claim 13, characterized in that the central module (33) is moved alternately into a left and right end position (36, 37) within the process chamber (16) for filling with construction material and in the respective end position (36, 37) the at least a receptacle (83, 84) is filled with construction material. Method according to Claim 13 or 14, characterized in that only the one receptacle (83, 84) of the central module (33) positioned in the end position (36, 37) is filled, which is used for the subsequent movement of the central module (33) over the assembly platform (17) is positioned in advance. 27 Method according to one of Claims 13 to 15, characterized in that the receptacles (83, 84) of the coating device (46) are filled with a dosing device (48) which is positioned separately from the coating device (46) or is controlled by the coating device (46) or the center module (33) are carried along. Method according to Claim 16, characterized in that the dosing device (48) has a dispensing head (49) which is moved along the receptacles (83, 84) to dispense the building material into the receptacles (83, 84). Method according to Claim 16 or 17, characterized in that when the receptacles (83, 84) of the central module (33) are passed over once, the quantity of construction material is transferred into the one receptacle (83, 84), so that a complete layer of construction material is applied when driving over the construction platform (17) with the central module (33) from one end position (36, 37) to the opposite end position (37, 36). Method according to one of Claims 17 or 18, characterized in that the dispensing head (49) of the dosing device (48) accommodates an intermediate store (51) which is also moved into the receptacles (83, 84) for dispensing the building material. Method according to Claim 19, characterized in that the intermediate store (51) is filled at least after a two-time movement along the receptacle (83, 84). Device for producing three-dimensional objects (12) by selective solidification of a building material applied in layers by means of a jet (27) acting on the building material, 28 with at least one process chamber (16) which has at least one construction platform (17) arranged in an X/Y plane, on which the three-dimensional object (12) is generated, with a radiation source (26) for generating the beam (27 ), with at least one beam guidance element (29) for guiding and directing the beam (27) onto the building material to be solidified, wherein the beam (27) can be coupled into the process chamber (16) via a beam inlet opening (30), with a process support device (21 ), which has a central module (33) and an outer module (34, 35) aligned with it in order to generate a primary gas flow along the assembly platform (17), so that between the at least one outer module (34, 35) and the central module (33) there is a Overflow path is formed with primary gas, characterized in that the process support device (21) is a central module according to one of claims 10 to 12 with a coating device (46) according to a em of claims 1 to 9. Device according to Claim 21, characterized in that a dosing device (48) is provided, by means of which the at least one receptacle (83, 84) of the coating device (46) can be filled with building material. 29 Device according to claim 22, characterized in that the dosing device (48) has a dispensing head (49) which is movable along a longitudinal direction of the central module (33) above the receptacle (83, 84) of the central module (33). Device according to Claim 23, characterized in that the dispensing head (49) carries an intermediate store (51) which can be filled with building material via a conveyor device. Device according to one of Claims 21 to 24, characterized in that a dosing device (48) is provided in a right and left end position (36, 37) of a travel position of the central module (33) and adjacent to the assembly platform (17). Device according to Claim 25, characterized in that the dispensing head (49) can be moved between two end positions (95, 96) transversely to the direction of movement of the central module (33) along a guide (98) and the dispensing head (49) has a dosing opening ( 50) which can be closed when moving into the end position (95, 96) by a closure device (97) arranged in the end position (95, 96). Device according to Claim 26, characterized in that the guide (98) for the displacement movement of the dispensing head (49) is aligned in a stationary manner with respect to the process chamber (16) or that the guide (98) for the displacement movement of the dispensing head (49) is on the coating device (46 ) and/or the suction device (41) is attached. Device according to Claim 27, characterized in that the dispensing head (49) carried along on the central module (33) is above the receptacle (83, 84) transversely to the longitudinal extension of the receptacle (83, 84) for the respective filling of the receptacle (83, 84). is designed to be movable or pivotable at the top. 30 Device according to claim 21 or 28, characterized in that a capacity of the temporary store (51) for the construction material corresponds to at least twice the filling quantity of the receptacle (83, 84).