(19)
(11)EP 3 023 228 A1

(12)EUROPEAN PATENT APPLICATION

(43)Date of publication:
25.05.2016 Bulletin 2016/21

(21)Application number: 14194592.3

(22)Date of filing:  24.11.2014
(51)Int. Cl.: 
B29C 67/00  (2006.01)
B22F 3/105  (2006.01)
B33Y 30/00  (2015.01)
(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME

(71)Applicant: Trumpf Sisma S.r.l.
36013 Piovene Rocchette (VI) (IT)

(72)Inventors:
  • Riva, Fausto
    36010 Zanè (VI) (IT)
  • Canaglia, Sergio
    36030 Fara Vicentino (IT)

(74)Representative: Kramer Barske Schmidtchen Patentanwälte PartG mbB 
European Patent Attorneys Landsberger Strasse 300
80687 München
80687 München (DE)

  


(54)Gas flow within additive manufacturing device


(57) A device (1) for additive manufacturing of a three-dimensional object from powdered material comprises a main body (11) providing an object forming chamber (13) and, within a front wall (15), an opening (17) for accessing the object forming chamber (13). A work surface (21) delimites the object forming chamber (13) and comprises a build platform section (23A) for manufacturing thereon the three-dimensional object. The device (1) further comprises a door (31) provided at the front wall (15) and being positionable in a closed state to seal the opening (17) or in an opened state to provide access to the object forming chamber (13). The device (1) further comprises a gas flow system (41) for providing a gas flow (42) across the build platform section (23A), the gas flow system (41) comprising a first main body section (41A) extending within the main body (11) and a door section (41B) being part of the door (31), wherein the door section (41B) comprises a first opening structure (45A) arranged to release gas to or to receive gas from above the build platform section (23A) in the closed state of the door.




Description

Technical Field



[0001] The present disclosure relates generally to additive manufacturing devices and more particularly to controlling smoke during additive manufacturing using an inert gas flow.

Background



[0002] Additive manufacturing such as selective laser sintering or selective laser melting are usually performed in a gas-tight object forming chamber. In the chamber, a powdered material such as metal or ceramic powder is irradiated with electromagnetic radiation such as laser light. Therefore, a thin layer of powder is provided within the chamber on a build platform, which forms the bottom for the three-dimensional object. In a stepwise production, the three-dimensional object is manufactured, for example, layer by layer. A wiper structure will be used between steps to re-distribute powder on top of the partly manufactured material to form the next layer.

[0003] An exemplary device for additive manufacturing is disclosed in EP 2 732 890 A2.

[0004] The object forming chamber comprises usually a sequence of multiple sections including a processing section in-between a powder supply section and an unused powder section. The sequence is usually arranged within the chamber such that all sections can be easily accessed through an opening of the device. The direction of alignment of those sections is herein referred to as a lateral direction.

[0005] For manufacturing, a laser source may provide a laser beam that is directed onto the build platform and is absorbed by the powder to melt the same. Accordingly, optical elements are required for guiding the laser beam. Moreover, the laser beam will pass an output lens or an output window prior interaction before focusing down into the powder. During interaction of the laser beam with the powder, smoke is generated within the chamber. Particles from the smoke may deposit on the surfaces of the optical elements or the output lens or output window. The deposits may affect, for example, the laser performance. Also other internal elements provided within the chamber such as process sensors (e.g. video camera, pyrometer, thermometer, oxygen sensor) may be affected.

[0006] It is known to apply an inert gas flow within the chamber for protection of, for example, the optical elements from smoke deposit formation. Exemplary prior art configurations are disclosed, for example, in DE 10 2010 052 206 A1, DE 10 2006 014 835 A1, and WO 2010/007394 A1. The prior art configurations disclose, in particular, a gas flow in longitudinal direction.

[0007] The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior art systems and, in particular, to providing an efficient smoke removing flow of inert gas during manufacturing.

Summary of the Disclosure



[0008] Some of the objects may be achieved by a device for additive manufacturing of claim 1 and a method for removing smoke generated during operation of a device for additive manufacturing of claim 13. Further developments are given in the dependent claims.

[0009] According to a first aspect of the present disclosure, a device for additive manufacturing of a three-dimensional object for powdered material comprises a main body providing an object forming chamber and, within a front wall of the main body, an opening for accessing the object forming chamber, a work surface delimiting the object forming chamber and having a build platform section for manufacturing thereon the three-dimensional object, a door provided at the front wall and being positionable in a closed state to seal the opening and in an opened state to provide access to the object forming chamber, and a gas flow system for providing a gas flow across the build platform section. The gas flow system comprises a first main body section extending within the main body and a door section being part of the door. In particular, the language "being part of the door" comprises that the door section can be an integrated part of the door and/or an attached part of the door. The door section comprises a first opening structure arranged to release gas to or to receive gas from the build platform section in the closed state of the door.

[0010] In a further embodiment, a method is disclosed for removing smoke generated during operation of a device for additive manufacturing of a three-dimensional object from powdered material, wherein the smoke is generated in a processing region with an object forming chamber. The method comprises providing a gas flow that extends across the processing region between a door delimiting the object forming chamber at a front wall and a back side delimiting the object forming chamber at the side opposite to the door with respect to the processing region. For example, the gas flow originates from the door and ends at the back side, specifically gas is released/received at respective openings in the door and in the back side to form the gas flow.

[0011] Other features and aspects of this disclosure will be apparent from the following descriptions, the dependent claims, and the accompanying drawings.

Brief Description of the Drawings



[0012] 

Fig. 1 is a schematic perspective view of an exemplary additive manufacturing device;

Fig. 2 is a schematic cut view of the device of Fig. 1 parallel to the XY-plane and extending through the object forming chamber;

Fig. 3 is a schematic cut view of the device of Fig. 1 parallel to the XZ-plane as indicated in Fig. 2;

Fig. 4 is a schematic cut view of the device of Fig. 1 parallel to the YZ-plane as indicated in Fig. 2;

Fig. 5 is an enlarged schematic perspective view of a section of the door of the additive manufacturing device shown in Fig. 1 for illustrating a door section of a gas flow system integrated in the door;

Fig. 6 is a schematic cut view of the door shown in Fig. 5 parallel to the XY-plane and extending through the door section of the gas flow system;

Fig. 7 is a schematic perspective view of one half of the door shown in Fig. 5 for illustrating the structure of the door section of the gas flow system;

Fig. 8 and Fig. 9 are schematic views of further embodiments of a door-section of a gas flow system.


Detailed Description



[0013] The following is a detailed description of exemplary embodiments of the present disclosure. The exemplary embodiments described therein and illustrated in the drawings are intended to teach the principles of the present disclosure, enabling those of ordinary skill in the art to implement and use the present disclosure in many different environments and for many different applications. Therefore, the exemplary embodiments are not intended to be, and should not be considered as, a limiting description of the scope of patent protection. Rather, the scope of patent protection shall be defined by the appended claims.

[0014] The disclosure is based in part on the realization that by providing a gas flow across the build platform section from the front to the back (or vice versa), a localized and efficient removal of smoke can be achieved during the manufacturing process. In particular, it has been realized that, for generating such a flow, a respective gas flow system can at least partly be integrated into a door of an additive manufacturing device. Thereby, such a flow may be generated in particular for configurations, in which a powder supply region, a processing region, and an unused powder region are aligned laterally, i.e. along an access side which can be closed with the door.

[0015] In general, such manufacturing processes are performed in a gas-tight sealable chamber which can be flooded with inert gas. Such an environment of an inert gas will avoid or at least reduce that, for example, base metals react with oxygen present in the chamber. During the manufacturing, smoke may nevertheless be generated and distribute within the inert gas atmosphere. As mentioned above, smoke particles may affect, for example, optical elements. Specifically, deposits of the smoke may form on the optical elements and, thereby, may affect the beam quality and may even damage the optical elements by absorption.

[0016] Herein, a concept is disclosed which may allow using the flow of inert gas to reduce or even to avoid any deposits within the chamber. In particular, the concepts may be based on recirculation inert gas by using the door of the device. Moreover, the concepts may allow the formation of a flow that is at least partly independent from the movement of the powder distributor of the powder, in particular by forming a flow transvers to the movement of the powder distributor. Moreover, the concepts disclosed herein may allow a reduction in size and furthermore optimize any space needed for a respective gas flow system. Moreover, the configurations disclose herein may be implemented in a manner that allows for easy cleaning and maintenance.

[0017] Figs. 1 to 4 illustrate schematically a device 1 for additive manufacturing of a three-dimensional object 3 from a powdered material 5. Those devices are also referred to as 3D-printing systems or selective laser sintering machines or selective laser melting machines and the like. For the operation of such a device, it is referred to the above mentioned EP 2 732 890 A2.

[0018] Referring to Fig. 1, device 1 comprises a main body 11 which provides an object forming chamber 13. A front wall 15 delimits chamber 13 at a front side. Specifically, a front frame 15A forms an opening 17 through which chamber 13 within main body 11 can be accessed.

[0019] The processing is performed on a work surface 21, which delimits chamber 13 at a bottom side and provides inter alia a build platform section 23A. Build platform section 23A may be provided centrally with respect to opening 17. On build platform section 23A, the manufacturing process takes place, e.g. within a processing region defined on build platform section 23A.

[0020] Main body 11 further comprises a back side 18 and may further house at least parts of a gas flow system 41 such as a gas reservoir for, e.g. inert gas, and a pumping system (not shown). Furthermore, on top of main body 11, a laser system 51 such as a fiber or a disc laser and a scanner system may be mounted or light of a laser system may be guided to the top of main body 11 for being coupled into chamber 13, e.g. through an optical window. The laser beam of laser system 51 is directed on top of build platform section 23A, e.g., to sinter or to completely melt the powderd material 5 along a desired trajectory.

[0021] Furthermore, device 1 comprises a door 31 attached to front wall 15 for closing object forming chamber 13 during processing. In particular, door 31 can be locked in the closed state via a door handle 31A and a lock 31B. Fig. 2 shows such a closed state of door 31.

[0022] In an open state, as shown in Fig. 1, door 31 provides access through opening 17 to chamber 13. Accordingly, a user can take the necessary steps in preparation of the processing (clean the inside, refill powder) and take out any object 3 after completion of the processing. As further shown, for example, in Fig. 1, a depositing device 19 is provided within chamber 13 to distribute powdered material 5 within the processing region, e.g. onto build platform section 23A or any already created portion of object 3.

[0023] As shown in Fig. 2 and Fig. 3, build platform section 23A is arranged in a lateral direction (X-direction in the drawings) centrally in-between a powder supply region 23B and a powder collecting region 23C. Powder supply region 23B is connected to a powder reservoir, while powder collecting region 23C collects unused or no longer usable powder remains. In general, powder collecting region 23C may be optional.

[0024] As illustrated in Fig. 1, depositing device 19 extends in a transverse direction (Y-direction in the drawings) that is orthogonal with respect to lateral direction of the arrangement of regions 23A, 23B, and 23C.

[0025] The concept disclosed herein provides for a gas flow 42 across build platform section 23A in a direction from door 31 to back side 18 (or in the reverse direction) as indicated in Figs. 2 to 4 by an arrow.

[0026] To enforce gas flow 42, gas flow system 41 comprises a first main body section 41A, which extends within main body 11, and a door section 41B, which is part of door 31.

[0027] First main body section 41A may be fluidly connected to an inert gas supply chamber of gas flow system 41, e.g. via a gas pump, if it is used to supply gas to chamber 13. Alternatively, first main body section 41A may be fluidly connected to a gas reservoir, e.g. via a filter unit 71, if it is used to receive gas taken out of chamber 13.

[0028] Door section 41B comprises a first opening structure 45A. First opening structure 45A is arranged at a position with respect to door 31 such that - in the closed state of door 31 - gas can be released or received from the processing region, i.e. the region above build platform section 23A. Specifically, first opening structure 45A is located in Y-direction from build platform section 23A.

[0029] Gas flow system 41 further comprises a second main body section 52 with a second opening structure 55. Second opening structure 55 is positioned opposite to first opening structure 45A with respect to build platform section 23A. For example, second opening structure 55 may be integrated into back side 18 of main body 11.

[0030] In general, gas flow system 41 is configured to release gas from one of first opening structure 45A and second opening structure 55 into chamber 13 and to receive gas including smoke via the respective other opening. Due to the positioning of first opening structure 45A and/or second opening structure 55 in closeness to the processing region, smoke can be efficiently directed out of object forming chamber 13 and, thus, avoid or at least reduce any contamination of optical elements of laser system 51.

[0031] In general, gas flow system 41 may be configured as a closed loop system or be comprised of separate systems (e.g. one supply section and one receiving section) wherein the removed gas may be processed and cleaned prior reuse.

[0032] Referring again to Fig. 1, first main body section 41A comprises a main body port 43A, for example located at front frame 15A of front wall 15. Door 31 comprises a corresponding door port 43B, which is part of door section 41B and is fluidly connected to first opening structure 45A. In the closed state of door 31, main body port 43A and door port 43B are arranged to form a fluid connection between first main body section 41A and door section 41B of gas flow system 41.

[0033] Furthermore, as can be seen in Fig. 1, device 1 comprises a door sealing system for providing a tight sealing between door 31 and front wall 15 along a circumferential sealing path. Circumferential sealing path extends, for example, around an observation window 53 provided within door 31. For example, a main door gasket 61 may interact with a counter main body gasket 61B provided at front frame 15A. In particular, circumferential sealing path and similarly main door gasket 61A and main body gasket 61B extend around opening 17, thereby gas-tight sealing chamber 13 in the closed state of door 31.

[0034] As shown in Fig. 1, main body gasket 61B extends also around main body port 43A and main door gasket 61A extends similarly around door port 43B. Accordingly, the fluid connection between first main body section 41A and door section 41B is arranged within sealed chamber 13 such that any leakage from the fluid connection is released into sealed chamber 13 and does not flow into the surrounding environment.

[0035] As shown in Fig. 1, gaskets 63A and 63B provide gas-tight sealing for main body port 43A and door port 43B when forming the fluid connection.

[0036] As in particular shown in Figs. 3 and 4, first opening structure 45A and second opening structure 55 are positioned vertically above work surface 21, i.e., they are displaced in Z-direction. For example, the displacement in Z-direction is in the range from 0 cm to 5 cm such as 2 cm.

[0037] Furthermore, as can be seen in Figs. 2 and 3, the lateral extension of first opening structure 45A and/or second opening structure 55, i.e. the extension in X-direction, is comparable to the lateral extension of the processing region. For example, the lateral extension is in the range from 10 cm to 15 cm for a processing region with a diameter of about 10 cm, e.g. generally about the same size or broader. This allows providing a - at least to some extent - linear flow profile across the processing region. Alternative configurations for providing desired flow configurations are described below in connection with Figs. 8 and 9.

[0038] A first exemplary embodiment for door section 41B of gas flow system 41 is explained in the following in combination with Figs. 5 to 7.

[0039] Fig. 5 shows a section of door 31 which includes door port 43B and first opening structure 45A. Specifically, door 31 comprises a door plate 131 and a cover plate 133. Cover plate 133 is attached with screws 135 to door plate 131. A channel 137 is formed in between door plate 131 and cover plate 133. Channel 137 is sealed by a channel gasket 137A positioned between door plate 131 and cover plate 133 and surrounding channel 137. Door port 43B is partly shown and provides the fluid connection between first main body section 41A of gas flow system 41 and channel 137, when door 31 is closed.

[0040] Fig. 6 shows a cut view along channel 137 within door 31, while Fig. 7 shows a cut in Z-direction (vertical cut) through door 31 in the region of first opening structure 45A.

[0041] In particular, it is shown that first opening structure 45A is made of a separate unit that comprises a series of through holes 145A. Each through hole 145A extends in the closed state in Y-direction and the orientation of the series is in X-direction. As further shown in Fig. 6, first opening structure 45A is tapered along the series of through holes 145A such that - for the case of gas being released through first opening structure 45A - a pressure drop along X-direction due to gas exiting through the first couple of through holes 145A is compensated for the downstream located through holes. For example, the cross section of channel 137 narrows down to about 50 % along the extension of first opening structure 45A. However, it is noted that the pressure drop and its effects may generally depend on the pressure range, the dimensions of channel 137 and the size of through holes 145A.

[0042] Alternatively or additionally, for example, the shape and/or size of the through holes may be adjusted to vary the flow resistancy along the series of through holes.

[0043] The above is an exemplary embodiment of a channel formation based on some type of recess provided within the door and covered by some

[0044] structural element (i.e. as an integrated part). While channel 137 shown in Figs. 5 to 7 is provided within door plate 131, alternatively or additionally, channel 137 may be formed in cover plate 133 to form door section 41B as an integrated part of door 31.

[0045] Alternative configurations of door section 41B are shown in Figs. 8 and 9.

[0046] In the embodiment of Fig. 8, a separate channel unit 141B is attached to an inner face 47 of door 31 (as a separate part) that is delimited by main door gasket 61A. Accordingly, front wall 15 of main body 11 may need adaptation to provide an laid back position of main body port 43A. Separate channel unit 141B may extend into chamber 13, thereby providing even closer releasing/receiving of gas with respect to build platform section 23A. Moreover and in contrast to the door-integrated configuration, separate channel unit 141B provides the possibility to retrofit an existing gas flow system to existing door designs.

[0047] A further example of a separate channel configuration may be based on rigid or flexible pipes, which are attached at or guided through door 31. In some embodiments, those pipes may be fluidly connected to first main body section 41A via door port 43B and main body port 43A. In general, also combinations of integrated configurations and separate part configurations for door section 41 B may be provided.

[0048] Fig. 9 illustrates configurations in which door section 41B comprise more than one channel and/or more than one opening structure per channel. Channels extending to different positions at door 31 may allow releasing air into chamber 13 from different positions and, thus, forming a desired flow distribution within chamber 13.

[0049] For example, to provide a linear gas flow across build platform section 23A in a wider lateral range, two laterally displaced opening structures 245A and 245B are shown in Fig. 9. Laterally displaced opening structures 245A and 245B are fluidly connected with and, for example, supplied with gas via a common channel 237.

[0050] Fig. 9 further illustrates a vertically (in Z-direction) extending second channel 237A for providing inert gas in a region of chamber 13 that is at some height above work surface 21. Specifically, channel 237A is fluidly connected with an opening structure 245C that comprises a sequence of vertically arranged through holes for releasing/receiving gas.

[0051] Moreover, Fig. 9 illustrates schematically a two-way-valve 239 as an example for a valve-controlled gas supply/reception by different channels. Specifically, two-way-valve 239 is configured to selectively fluidly connect channel 237 and/or channel 237A with door port 43B. Thereby, depending on the type of processing or stage of processing, smoke removal and/or, for example, cooling/heating of chamber 13 may be activated.

[0052] As disclosed above, various configurations of a gas flow system (for example, partly integrated into a door or as separate parts mounted thereon) may simplify changing between different powder types and simplify required cleaning of the device from any unwanted powder (having, for example, particle sizes in the range from some to some tens of micrometers) when switching between powder types. In particular for integrated configurations, this may be caused essentially by no added surface structure such as edges, corners, narrow ridges or recesses between some added piping and the door's main structure.

[0053] Moreover, by providing a flow of gas from the back side to the door or vice versa, i.e. along or against a Y-axis direction indicated in the drawings, the disclosed configurations allow that inert gas can be provided to and taken away from the processing region, i.e. from above the build platform section. Thereby, after having caught any smoke from the processing region gas can be directly taken out of the object forming chamber. Thereby, a large portion of the smoke can be directly removed from the object forming chamber, without any (large amount of) smoke being distributed to other areas within the chamber.

[0054] Additionally, providing, for example, a filter at the gas receiving section of gas flow system, may simplify servicing of the gas flow system by replacement of that filter.

[0055] Moreover, the configuration disclosed herein may provide for a flow that is transverse, i.e. along Y-direction, and therefore is essentially independent of the movement of the depositing device, in particular if the same extends wiper-like in Y-direction. Moreover, by integration of the respective opening structures into the door - e.g. that a closed door guides and directs gas into the chamber at desired positions - the amount of space, which is needed for the gas flow system within object forming chamber, is reduced. Furthermore, providing the opening structure at the door provides more space to access the object forming chamber in the open state of the door.

[0056] Moreover, the gas flow system may include a control unit that interrupts any control of inert gas to door section 41B in case the door is opened and/or that controls any valve, e.g. within the door, for selecting channels.

[0057] Moreover, in some embodiments, an opening structure is designed as a specific removable insert (e.g. flow forming unit) as shown in Fig. 6. Its shape may be adapted to, e.g., a specific manufacturing process, thereby ensuring a uniform flow distribution within the desired range under varying conditions by simply exchange. For example, the extension in Z-direction of the required uniform flow may depend on the size of the manufactured object.

[0058] In general, the various sealings disclosed herein may be performed by form tight sealing and/or gasket or O-ring based sealings.

[0059] Finally, examples of additive manufacturing machines in which the herein disclosed concepts can be applied include selective laser sintering or selective laser melting machines such as the "mysint100" manufactured by TRUMPF SISMA und TRUMPF.

[0060] Although the preferred embodiments of this invention have been described herein, improvements and modifications may be incorporated without departing from the scope of the following claims.


Claims

1. A device (1) for additive manufacturing of a three-dimensional object (3) from powdered material (5), the device (1) comprising:

a main body (11) providing an object forming chamber (13) and, within a front wall (15) of the main body (11), an opening (17) for accessing the object forming chamber (13);

a work surface (21) delimiting the object forming chamber (13) and having a build platform section (23A) for manufacturing thereon the three-dimensional object (3);

a door (31) provided at the front wall (15) and being positionable in a closed state to seal the opening (17) and in an opened state to provide access to the object forming chamber (13); and

a gas flow system (41) for providing a gas flow (42) across the build platform section (23A), the gas flow system (41) comprising a first main body section (41A) extending within the main body (11) and a door section (41B) being an integrated or attached part of the door (31), wherein the door section (41B) comprises a first opening structure (45A) arranged to release gas to or to receive gas from the build platform section (23A) in the closed state of the door.


 
2. The device (1) of claim 1, wherein the gas flow system (41) further comprises a second main body section (52) with a second opening structure (55) opposite to the first opening structure (45A) with respect to the build platform section (23A), wherein the first main body section (41A), the door section (41B), and the second main body section (52) in particular provide for a recirculated flow path of gas through the object forming chamber (13).
 
3. The device (1) of claim 1 or claim 2, wherein the gas flow system (41) is configured to release gas from one of the first opening structure (45A) and the second opening structure (55) into the object forming chamber (13) and to receive gas including smoke from the respective other opening in the closed state of the door (31) during manufacturing of the three-dimensional object (3).
 
4. The device (1) of any one of the preceding claims, wherein the first main body section (41A) comprises a main body port (43A) and the door section (41B) comprises a door port (43B) that are arranged with respect to each other to provide a fluid connection between the first main body section (41A) and the door section (41B) in the closed state of the door (31).
 
5. The device (1) of claim 4, further comprising a door sealing system for providing a sealing between the door (31) and the front wall (15) along a circumferential sealing path around the opening (17), in particular to seal the object forming chamber (13) gas-tight, and
wherein the fluid connection between the first main body section (41A) and the door section (41B) is arranged to be within the sealed object forming chamber (13) such that in particular a leakage of the fluid connection is released into the sealed object forming chamber (13).
 
6. The device (1) of any one of the preceding claims, wherein the gas flow system (41) further comprises a filter unit (71) downstream the respective opening structure (45A, 55) or attached to the opening structure (45A, 55) at which gas is recieved.
 
7. The device (1) of any one of the preceding claims, wherein the door (31) comprises an inner surface (47) delimited by the sealing path, and wherein the door port (43B) is arranged on the inner surface (47); and/or
the door (31) comprises a door plate (131), and at least one channel (137) and/or at least one channel unit (141B), wherein the at least one channel (137) and/or at least one channel unit (141B) fluidly connect, as part of the door section (41B) of the gas flow system (41), at least one opening structure including the first opening structure (45A) with the door port (43B), and wherein the at least one channel (137) is integrated in the door plate (131) and the at least one channel unit (141B) is attached to the door (31) and in particular extends on the inner surface (47).
 
8. The device (1) of any one of the preceding claims, wherein the first opening structure (45A) and/or the second opening structure (55) are located at a height of 0 cm to 5 cm, for example approximately 2 cm, respectively to the build platform section (23A), and/or, in a lateral direction of the opening (17), face the build platform section (23A).
 
9. The device (1) of any one of the preceding claims, wherein the door section (41B) comprises a first flow forming unit forming the first opening structure (45A), which is in particular attached to and/or integrated into the door plate (131) and/or
wherein the second main body section (52) comprises a second flow forming unit forming the second opening structure (55), which is in particular attached to and/or integrated into a back side (18) delimiting the object forming chamber (13) at the side opposite to the door (31).
 
10. The device (1) of claim 9, wherein the first flow forming unit and/or the second flow forming unit are positioned and configured to direct gas, in particular uniformly, across the build platform section (23A) and/or to receive alternatively gas smoke originating on the build platform section (23A), respectively, thereby in particular enforcing the gas flow (42) across the build platform section (23A).
 
11. The device (1) of any one of the preceding claims, wherein the door (31) further comprises a second opening structure (245A, 245B) and/or a second channel (237A) and in particular a switching unit (239) for selectively controlling the fluid connection from the door port (43B) to the one or more channels (137, 137A) each having opening structures (245A, 245B, 245C) at respective positions of the door (31).
 
12. The device (1) of any one of the preceding claims, wherein the opening structure for releasing gas into the gas forming chamber (13) and/or the channel (137) are configured to compensate for pressure and flow variations along the opening structure.
 
13. A method for removing smoke generated during operation of a device (1) for additive manufacturing of a three-dimensional object (3) from powdered material (5) in a processing region with an object forming chamber (13), the method comprising:

providing a gas flow (42), that extends across the processing region between a door (31) delimiting the object forming chamber (13) at a front wall (15) and a back side (18) delimiting the object forming chamber (13) at the side opposite to the door (31) with respect to the processing region.


 
14. The method of claim 13, wherein, to form the gas flow (42), gas is released or received from an opening structure at the door (31) that is in particular fluidly connected to a first main body section (41A) of a gas flow system (41) of the device (1) for additive manufacturing and/or
wherein the device (1) for additive manufacturing is configured in accordance with any one of claims 1 to 11.
 




Drawing


























REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description