Process chamber for an additive manufacturing apparatus

Abstract

The present disclosure is directed to a process chamber (1) for an additive manufacturing apparatus, wherein the process chamber (1) comprises: a front volume section (9) having a front opening (5) for manual access to the process chamber (1), a rear volume section (11) having a bottom opening (13) configured to receive a vertically movable building platform (15) on which a three-dimensional object (3) is additively manufacturable within an inert gas process atmosphere, and a process chamber door (7), wherein the process chamber door (7) comprises a first door panel (29) and a second door panel (31), wherein the first door panel (29) is configured to close the front opening (5) of the front volume section (9) when the process chamber door (7) is closed, wherein the second door panel (31) defines at least part of a separating wall (35) between the front volume section (9) and the rear volume section (11) when the process chamber door (7) is closed, wherein the process chamber door (7) defines a door volume (37) between the first door panel (29) and the second door panel (31), wherein the door volume (37) comprises a door atmosphere that is isolated from the inert gas process atmosphere, wherein the door volume (37) fills at least a part of the front volume section (9) when the process chamber door (7) is closed.

Description

[0001] Applicant: Nikon SLM Solutions AG

[0002] Title: Process chamber for an additive manufacturing apparatus

[0003] Our Ref.: SLMP 3808 WO

[0004] Description

[0005] TECHNICAL FIELD

[0006]

[0001] The present disclosure is directed to a process chamber for an additive manufacturing apparatus. In particular, the present disclosure re¬

[0007] 5 lates to a process chamber for additive manufacturing facilities for serial production at an industrial scale. More particularly, the additive manufacturing apparatus is preferably configured to apply laser powder bed fusion (LPBF) as the additive manufacturing technique for producing metallic objects.

[0008] BACKGROUND

[0009]

[0002] Additive manufacturing of three-dimensional objects is often referred to as 3D-printing. A specific form of additive manufacturing is laser

[0010] 15 powder bed fusion (LPBF), in which a layer of raw material powder is exposed to a high-energy beam of electromagnetic radiation, such as, for example, a laser beam or a particle beam, for selectively sintering and / or melting particles of the raw material powder. The three-dimensional objects are manufactured by sequentially sintering and / or melting layer-by-layer of raw material powder.

[0011]

[0003] Compared to conventional manufacturing techniques like moulding, additive manufacturing of a three-dimensional objects consumes considerably more time. Therefore, in the early days of 3D-printing,

[0012] 25 additive manufacturing was only applied for prototyping or for a small

[0013] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025 number of individual objects. However, as additive manufacturing offers the possibility to design and produce components than cannot be produced by other conventional manufacturing techniques, there is a high demand for using additive manufacturing for serial production at an in¬

[0014] 5 dustrial scale.

[0015]

[0004] One solution to speed up additive manufacturing is using several lasers in parallel. The largest additive manufacturing machines currently on the market use up to 12 lasers in parallel in a single process chamber.

[0016] 10 Using several lasers in parallel, however, implies a significant heat development within the process chamber during additive manufacturing. In particular, the process chamber door may become very hot and a safety issue may arise for the operating staff if there is a risk of touching a very hot process chamber door.

[0017]

[0005] EP 3 928 900 Al describes a process chamber housing with two doors. That solution, however, was found not to be effective enough to prevent the outer door from heating up to high temperatures.

[0018] 20

[0006] It is therefore an object of the present invention to provide a process chamber for an additive manufacturing apparatus ensuring more effectively that operating staff can use the process chamber safely.

[0019] SUMMARY

[0020]

[0007] This problem is solved by a process chamber according to the accompanying independent claim. Preferred embodiments can be deduced from the dependent subclaims, the description and the figures.

[0021] 30

[0008] According to the present disclosure, a process chamber for an additive manufacturing apparatus is provided, wherein the process chamber comprises:

[0022] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025 a front volume section having a front opening for manual access to the process chamber, a rear volume section having a bottom opening configured to receive a vertically movable building platform on which a three-di¬

[0023] 5 mensional object is additively manufacturable within an inert gas process atmosphere, and a process chamber door, wherein the process chamber door comprises a first door panel and a second door panel, wherein the first door panel is configured to close

[0024] 10 the front opening of the front volume section when the process chamber door is closed, wherein the second door panel defines at least a part of a separating wall between the front volume section and the rear volume section when the process chamber door is closed, wherein the process chamber door defines a door volume between the first door panel and the second door panel, wherein the door volume comprises a door atmosphere that it is isolated from the inert gas process atmosphere, wherein the door volume fills at least a part of the front volume section when the process chamber door is closed.

[0025] 20

[0009] The invention has at least two major advantageous technical effects compared to the prior art. The first advantageous technical effect is that the door atmosphere, which is isolated from the inert gas process atmosphere, is more effective in thermally decoupling the first door panel from the second door panel. The second advantageous technical effect is that the front volume section, which is normally fully filled with inert gas process atmosphere, is at least partly filled by the door volume, so that less inlet gas process atmosphere is needed. The less inert gas process atmosphere is needed, the quicker the additive manufacturing apparatus can be used again after the processed chamber door was

[0026] 30 opened. As will be described below, the present invention is particularly

[0027] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025 beneficial if a recoater garage is a bottom part of the front volume section and the door volume fills an upper part of the front volume section above the recoater garage.

[0028] 5

[0010] Optionally, the second door panel may be fixed relative to the first door panel. The second door panel is preferably an inner door panel and the first door panel is preferably an outer door panel.

[0029]

[0011] Optionally, the process chamber may further comprise

[0030] 10 a movable recoater configured to deposit layers of raw material powder into the rear volume section for layer-wise additive manufacturing of the three-dimensional object, and a recoater garage volume being a lower part of the front volume section, wherein the recoater garage volume defines a halt position of the recoater.

[0031]

[0012] Preferably, the door volume may fill at least partly, preferably most part of, an upper part of the front volume section above the recoater garage volume. This is particularly beneficial for the second door panel

[0032] 20 to complement with an inner recoater garage volume door a flush separating wall between the front volume section and the rear volume section. Such a flush separating wall is advantageous to not interfere with a homogenous inert gas flow in the rear volume section during additive manufacturing. Alternatively, it may be beneficial if the separating wall defines a guiding surface for guiding the inert gas flow to have a desired well-defined influence on the inert gas flow in the rear volume section during additive manufacturing. The guiding surface may have a specifically designed shape to achieve the desired guiding effect.

[0033] 30

[0013] To more efficiently deposit layers of raw material powder, it is advantageous that the movable recoater has another halt position at the

[0034] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025 rear side of the rear volume section, so that the layers can be laid out in forward and backward moving direction of the recoater.

[0035]

[0014] Optionally, the recoater garage may comprise a recoater gar¬

[0036] 5 age ceiling, wherein the recoater garage ceiling is fixed in the process chamber and defines a separating wall between the recoater garage and an upper part of the front volume section, wherein the door volume fills at least partly the upper part of the front volume section when the proceed chamber is closed,

[0037] 10 and / or movable as part of the process chamber door, wherein the recoater garage ceiling is at least part of a process chamber door bottom panel extending between the first door panel and the second door panel and defining a separating wall between the door volume and the recoater garage volume when the process chamber door is closed. Preferably, the separating wall extends horizontally between the upper part of the front volume section and the recoater garage volume when the process chamber door is closed.

[0038] 20

[0015] Optionally, the process chamber may further comprise an inert gas flow system configured to provide a defined inert gas flow in the rear volume section during additive manufacturing of the three-dimensional object, wherein the second door panel and / or the recoater define a guiding surface for guiding the inert gas flow. As will be described in more detail later, a fixed frame portion may be located between the front volume section and the rear volume section, so that the second door panel and the fixed frame portion may complement one another to define, preferably together with the recoater garage, the separating wall as a guiding surface for guiding the inert gas flow when the process chamber

[0039] 30 door is closed.

[0040] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025

[0016] Optionally, the first door panel may comprise a first window having a transmission coefficient above 50% in the visible light wavelength range of 0.4 to 0.7 microns, wherein the second door panel comprises a second window having a transmission coefficient above 50% in the visi¬

[0041] 5 ble light wavelength range of 0.4 to 0.7 microns, wherein the second window is larger than the first window. This is particularly beneficial for operating staff to be able to observe the additive manufacturing process through the closed process chamber door.

[0042] 10

[0017] Optionally, the first window and / or the second window may comprise at least two thermally decoupled window panes. This is particularly beneficial for the first door panel to prevent an outer window pane of the first door panel to heat up too much.

[0043]

[0018] Optionally, the first window and the second window are thermally decoupled from each other. The door atmosphere between the first window and the second window preferably constitutes an efficient insulation between the first window and the second window.

[0044] 20

[0019] Optionally, the first window and / or the second window, or a combination of both, have a transmission coefficient below 50% for short wave infrared electromagnetic radiation in the wavelength range of 0.9 to 3.0 microns or / and have a transmission coefficient below 50% for infrared radiation in the wavelength range of 1.0 to 12.0 microns. This is particularly beneficial to keep heat radiation out of the door volume as much as possible. Furthermore, a low transmissivity of the first window and / or the second window for radiation in the wavelength range of the laser beam wavelength prevents harmful and dangerous laser radiation from escaping. Therefore, the first window and / or the second window

[0045] 30 and / or a combination of both may also be configured as laser protection windows in order to fulfil laser protection requirements for safe laser operation in accordance with current standards, such as DIN EN 207, DIN

[0046] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025 EN 12254 or DIN EN 60825-4. A low transmissivity of the first window and / or the second window may also be achieved by a corresponding surface coating of the window surface of the first window and / or the second window that faces the rear volume area, whereby the surface coating

[0047] 5 advantageously has a high reflectivity for radiation in the laser beam wavelength range and / or in the infrared wavelength range. The surface coating is configured to reflect at least 70 %, 80 % or 90 % of radiation in the laser beam wavelength range and / or in the infrared wavelength range.

[0048] 10

[0049]

[0020] Optionally, the second door panel may define a door volume height and a door volume width, wherein a distance between the first door panel and a second door panel defines a door volume depth, wherein the door volume depth is at least 10%, preferably 20%, most preferably 30% of the door volume height and / or of the door volume width. This is advantageous to save a significant volume of the inert gas process atmosphere by filling it with a large door volume.

[0050]

[0021] Optionally, the door volume may have at least one gas opening

[0051] 20 allowing a gas to flow through the door volume. For example, the at least one gas opening may be a vent for the door atmosphere to escape when the door atmosphere expands upon heating up during additive manufacturing.

[0052]

[0022] Optionally, the at least one gas opening may be at least one of a first gas opening and a second gas opening, wherein the first gas opening is arranged below the second gas opening to allow a convection flow into the first gas opening and out of the second gas opening. A circulation flow of the door atmosphere is beneficial to prevent the door

[0053] 30 atmosphere from heating up too much.

[0054] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025

[0023] Optionally, the process chamber may further comprise at least one valve being arranged and configured to influence a flow of the gas through at least one of the at least one gas opening.

[0055] 5

[0024] Optionally, the process chamber may further comprise at least one fan being arranged and configured to drive a flow of the gas through at least one of the at least one gas opening. This is particularly beneficial to increase a circulation flow of the door atmosphere if a conviction flow is not sufficient or reliable enough.

[0056] 10

[0057]

[0025] Preferably, the gas is ambient air, so that the door atmosphere is ambient air. Alternatively, the gas may be an inert gas isolated from the inert gas process atmosphere. For instance, the inert gas of the door atmosphere may have a different composition than the inert gas process atmosphere. For example, the gas may be a specific gas provided by a gas source connected to the least one gas opening. The specific gas may have optimised properties for cooling and / or thermal insulation and / or absorption of short-wave infrared electromagnetic heat radiation.

[0058] 20

[0059]

[0026] Optionally, the separating wall between the front volume section and the rear volume section may comprise a fixed frame portion, wherein the second door panel and the fixed frame portion complement one another to define a separating wall when the process chamber door is closed.

[0060]

[0027] Optionally, the separating wall may comprise, when the process chamber door is closed, a flush rear surface facing towards the rear volume section. Such a flush rear surface is particularly beneficial to not in¬

[0061] 30 terfere with a homogenous inert gas flow in the rear volume section during additive manufacturing. Alternatively, it may be beneficial if the separating wall defines a guiding surface for guiding the inert gas flow to

[0062] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025 have a desired well-defined influence on the inert gas flow in the rear volume section during additive manufacturing. The guiding surface may have a specifically designed shape to achieve the desired guiding effect.

[0063] 5

[0064]

[0028] Optionally, the process chamber may further comprise at least one heat shield wherein the at least one heat shield faces the door volume and is arranged on a rear surface of the first door panel and / or on a front surface of the second door panel. The heat shield may effectively

[0065] 10 shield the first door panel and / orthe second door panel from heating up too much.

[0066]

[0029] Optionally, the process chamber may further comprise a heat sink in thermal contact with the front volume section, in particular with a ceiling of the front volume section. Such a heat sink may, for example, be a cooling plate or a pillow plate that comprises hollow structures through which a cooling gas flow may circulate.

[0067] SUMMARY OF THE DRAWINGS

[0068] 20

[0069]

[0030] Embodiments of the present disclosure will now be described by way of example with reference to the following figures of which:

[0070] Figs, l a-b show schematically longitudinal cut side views through an example of a process chamber according to the present invention with a closed process chamber door and an opened process chamber door;

[0071] Figs. 2a-b show schematically longitudinal cut top views of an exam¬

[0072] 30 ple of a process chamber according to the present invention with a closed process chamber door and an opened process chamber door;

[0073] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025 Figs. 3a-b show schematically the process chamber of figures 2a, b with two other opening degrees of the process chamber door;

[0074] 5

[0075] Figs. 4a-b show schematically a longitudinal cut side view of another example of a process chamber according to the present invention with the process chamber door closed and the proceed chamber door opened;

[0076] 10

[0077] Figs. 5a-b show schematically the process chamber of figures 4a, b with the recoater being positioned at another halt position;

[0078] Figs. 6a-b show schematically a longitudinal cut side view of another example of a process chamber according to the present invention without a recoater garage door and with the recoater being positioned at different halt positions;

[0079] 20 Fig. 7 shows schematically a perspective front view of another example of a process chamber according to the present invention without the process chamber door; and

[0080] Fig. 8 shows a preferred embodiment of a process chamber according to the present invention.

[0081] DETAILED DESCRIPTION

[0082]

[0031] Fig. 1 shows schematically a process chamber 1 of an additive

[0083] 30 manufacturing apparatus for additively manufacturing a three-dimensional object 3. To facilitate the orientation in the figures, a right-handed Cartesian coordinate system is shown in each figure, wherein the z-axis

[0084] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025 extends essentially vertically upward, the x-axis extends essentially horizontally backward, and the y-axis extends essentially horizontally sideways to the left when seen backwardly from a position in front of the process chamber 1 . It should be noted that these axes can be arbitrarily

[0085] 5 defined and constitute no limitation regarding the spatial orientation of the process chamber 1. The spatial terms “forward”, “backward”, “front”, “rear”, “up”, “bottom”, etc. thus follow an arbitrarily defined convention in this disclosure. The process chamber 1 comprises a front opening 5 for manual access to the process chamber 1 . The process chamber

[0086] 10 I comprises a process chamber door 7 to close the front opening 5 of the process chamber 1 as shown in Fig. l a. The process chamber 1 defines a front volume section 9 and a rear volume section 1 1. The front volume section 9 comprises the front opening 5. The rear volume section

[0087] I I has a bottom opening 13 configured to receive vertically movable building platform 15 on which the three-dimensional object 3 is additively manufactured within an inert gas process atmosphere.

[0088]

[0032] The additive manufacturing is performed by a laser system (not shown) arranged at a process chamber ceiling 17 for directing one or

[0089] 20 preferably more laser beams downward onto a raw material powder bed for selectively sintering / melting the raw material powder to add layer-by-layer to the three-dimensional object 3. Once a layer is finished, the vertically movable building platform 15 is lowered by one layer-thickness into a build cylinder 18 arranged underneath the bottom opening 13 of the rear volume section 1 1 of the process chamber 1 . Then, a new layer of raw material powder is deposited on the previously manufactured layer. The deposition of new layers of raw material powder is performed by a recoater 19 that is movable forward and backward along the x-axis to lay out a fresh layer of raw material powder. Excess raw ma¬

[0090] 30 terial powder is pushed by the recoater 19 into a raw material powder bin 21 for recycling and / or damping. The recoater 19 is shown in Fig. 1 a in a rear halt position underneath a raw material powder buffer tank 23

[0091] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025 containing raw material powder 25 for refilling the recoater 19 with raw material powder. During additive manufacturing, a homogenous inert gas flow 27 in a sideways direction (along the y-axis) keeps the manufacturing process clean of smoke and other contaminations. It is im¬

[0092] 5 portant to note that the homogenous inert gas flow 27 is only needed in the rear volume section 1 1 of the process chamber 1 and not in the front volume section 9.

[0093]

[0033] The process chamber door 7 comprises a first door panel 29 and

[0094] 10 a second door panel 31. As shown in Fig. l a, the first door panel 29 is configured to close the front opening 5 of the front volume section 9 when the process chamber door 7 is closed. A sealing 33 may circumferentially surround the front opening 5 of the front volume section 9 to achieve a gas tight seal between the first door panel 29 and the process chamber 1 . The second door panel 31 defines at least part of a separating wall 35 between the front volume section 9 and the rear volume section 1 1 when the process chamber door 7 is closed. It should be noted that, in case the second door panel 31 defines the complete separating wall 35 as shown in Figs. l a,b, there is no distinct border between the

[0095] 20 front volume section 9 and the rear volume section 1 1 when the process chamber door 7 is opened.

[0096]

[0034] The process chamber door 7 defines a door volume 37 between the first door panel 29 and the second door panel 31 . The door volume 37 comprises a door atmosphere that is isolated and preferably different from the inert gas process atmosphere within the rear volume section 1 1 . The door volume 37 fills a large part of, or almost completely, the front volume section 9 when the process chamber door 7 is closed as shown in Fig. 1 a. The opening of the process chamber door 7 is better visible in

[0097] 30 the Figs. 2a, b and 3a, b, which show the processed chamber 1 from a top perspective. It becomes clear that the door volume 37 fills a large

[0098] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025 part of the front volume section 9 when the process chamber door 7 is closed as shown in Figs, l a and 2a.

[0099]

[0035] Figs. 4a, b and 5a, b show a preferred embodiment of the process

[0100] 5 chamber 1 , wherein the recoater 1 has another halt position in the front volume section 9 of the process chamber 1 . The front halt position of the recoater 19 is defined by a recoater garage volume 39 that constitutes a lower part of the front volume section 9. In this embodiment, the recoater 19 contains sufficient raw material powder for at least two layers,

[0101] 10 so that is does not need to return to the rear halt position for a refill after a layer was deposited forwardly. Another raw material powder bin 41 is placed underneath the recoater garage volume 39 to receive excess raw material powder that is pushed by the forwardly, i.e. in negative x- direction, moving recoater 19 into the raw material powder bin 41. Like the raw material powder collected in the rear raw material bin 21 , the raw material powder collected in the front raw material powder bin 41 may be used for recycling or damped.

[0102]

[0036] The door volume 37 in the example shown in Figs. 4a, b and 5a, b is

[0103] 20 somewhat smaller than in the example shown in Figs. l a,b, 2a, b and 3a, b. It only fills an upper part of the front volume section 9 above the recoater garage volume 39. However, when the process chamber door 7 is closed as shown in Figs. 4a, a recoater garage door 42 and the second door panel 31 complement each other to define a flush surface as a separating wall 35 that has a minimal interference with the inert gas flow 27 within the rear volume section 1 1 during additive manufacturing. The recoater garage door 42 is, in the shown example, hinged to a bottom of the second door panel 31 to be able to pivot between a vertical closing position (see Fig. 4a) and a horizontal opening position (see Fig.

[0104] 30 5a). When the recoater moves forwardly into the recoater garage volume 39, it pushed the recoater garage door 42 to hinge backward and up into the horizontal opening position to allow the recoater 19 to enter

[0105] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025 the recoater garage volume 39. It is then a rear side of the recoater 1 that complements, as shown in Fig. 5a, with the second door panel 31 to define a flush surface as a separating wall 35 that has a minimal interference with the inert gas flow 27 within the rear volume section 1 1 during

[0106] 5 additive manufacturing. It should be noted that the recoater garage door 42 is optional. The recoater garage volume 39 may be open to the rear volume section 1 1 during additive manufacturing when the recoater is currently in the rear halt position. Analogously, it is preferable, but optional that a rear recoater garage volume at the rear halt position

[0107] 10 is closed to the rear volume section 1 1 when the recoater is currently in the front halt position.

[0108]

[0037] Figs. 6a, b show another example of the process chamber 1 that does not comprise a recoater garage door 42. Fig. 6a shows the recoater 19 in the rear halt position within the rear recoater garage volume and Fig. 6b shows the recoater 19 in the front halt position within the front recoater garage volume 39. Also, as can be seen in Fig. 6b, the rear recoater garage volume is not closed when the recoater has left the rear halt position. The process chamber door 7 is shown closed in both Fig. 6a

[0109] 20 and Fig. 6b. As can be seen, the recoater garage volume 39 is here defined by an indentation into the door volume 9.

[0110]

[0038] Fig. 7 shows the process chamber 1 without the chamber door 7 from a front perspective. Also, the recoater 19 is not shown in Fig. 7. The separating wall 35 between the front volume section 9 and the rear volume section 1 1 comprises here a fixed frame portion 43 with an inner cutout into which the second door panel 31 fits when the process chamber door 7 is closed. Together with recoater garage door 42 or a rear side of the recoater 19, the separating wall 35 is preferably completely flush to

[0111] 30 have the least interference with the inert gas flow 27 during additive manufacturing.

[0112] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025

[0039] Fig. 8 shows an advantageous embodiment of the process chamber door 7 in a closed position. The process chamber door 7, as shown in Fig. 8, comprises several features for thermal management to prevent a front side of the process chamber door 7 from becoming too hot. One,

[0113] 5 more or all these features may be sufficient to achieve a desired safety effect. The first door panel 29 comprises here a first window 45 in form of a double-pane window. The second door panel 31 comprises a second window 47 that is larger than the first window 45 of the first door panel 29. In the shown example, the second window 47 is a single-pane window.

[0114] 10 The first window 45 and the second window 47 are thermally decoupled by the door atmosphere within the door volume 37. The transmission coefficient of the panes of the first window 45 and the second window 47 may be such that they are transparent enough for operating staff to be able to visually observe a manufacturing process through both windows 45, 47 while reflecting significant portions of short-wave infrared electromagnetic heat radiation back into the rear volume section 1 1. Heat shields 49 are installed at an inner surface of the first door panel 29 to protect the first door panel 29 from direct heat radiation as much as possible. Gas openings 51 , 53 allow a circulation of ambient air into the door

[0115] 20 volume 37 and out of the door volume 37. Thereby, the door atmosphere 37 is prevented from heating up too much and protected against overpressure. A further measure to prevent the first door panel 29 from heating up too much is a heat sink 55 in a thermal contact with the front volume section 9 of the process chamber 1 . Here, the heat sink 55 is implemented in a form of a pillow plate through which a gas, e.g. air, may circulate to transport thermal energy away from the front volume section 9 of the process chamber 1 .

[0116]

[0040] Where, in the foregoing description, integers orelements are men¬

[0117] 30 tioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference

[0118] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025 should be made to the claims for determining the true scope of the present disclosure, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the disclosure that are described as optional, preferable, advan¬

[0119] 5 tageous, convenient or the like are optional and do not limit the scope of the independent claims.

[0120]

[0041] The above embodiments are to be understood as illustrative examples of the disclosure. It is to be understood that any feature de¬

[0121] 10 scribed in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. While at least one exemplary embodiment has been shown and described, it should be understood that other modifications, substitutions and alternatives are apparent to one of ordinary skill in the art and may be changed without departing from the scope of the subject matter described herein, and this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.

[0122] 20

[0123]

[0042] In addition, "comprising" does not exclude otherelements or steps, and "a" or "one" does not exclude a plural number. Furthermore, characteristics or steps which have been described with reference to one of the above exemplary embodiments may also be used in combination with other characteristics or steps of other exemplary embodiments described above. Method steps may be applied in any order or in parallel or may constitute a part or a more detailed version of another method step. It should be understood that there should be embodied within the scope of the patent warranted hereon all such modifications as reason¬

[0124] 30 ably and properly come within the scope of the contribution to the art. Such modifications, substitutions and alternatives can be made without departing from the spirit and scope of the disclosure, which should be determined from the appended claims and their legal equivalents.

[0125] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025

[0043] List of reference numerals:

[0126] I process chamber

[0127] 3 three-dimensional object

[0128] 5 5 front opening

[0129] 7 process chamber door

[0130] 9 front volume section

[0131] I I rear volume section

[0132] 13 bottom opening

[0133] 10 15 movable support platform

[0134] 17 process chamber sealing

[0135] 18 build cylinder

[0136] 1 recoater

[0137] 21 rear raw material powder bin

[0138] 23 raw material powder buffer tank

[0139] 25 raw material powder

[0140] 27 homogenous inert gas flow

[0141] 29 first door panel

[0142] 31 second door panel

[0143] 20 33 sealing

[0144] 35 separating wall

[0145] 37 door volume

[0146] 39 recoater garage volume

[0147] 41 front raw powder bin

[0148] 42 recoater garage door

[0149] 43 fixed frame portion

[0150] 45 first window

[0151] 47 second window

[0152] 49 heat shield

[0153] 30 51 gas opening

[0154] 53 gas opening

[0155] 55 heat sink

[0156] Patentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025

Claims

Claims1. A process chamber (1 ) for an additive manufacturing apparatus, wherein the process chamber (1 ) comprises: a front volume section (9) having a front opening (5) for man¬5 ual access to the process chamber ( 1 ), a rear volume section (1 1 ) having a bottom opening (13) configured to receive a vertically movable building platform (15) on which a three-dimensional object (3) is additively manufacturable within an inert gas process atmosphere, and a process chamber door (7), wherein the process chamber door (7) comprises a first door panel (29) and a second door panel (31 ), wherein the first door panel (29) is configured to close the front opening (5) of the front volume section (9) when the process cham¬15 ber door (7) is closed, wherein the second door panel (31 ) defines at least part of a separating wall (35) between the front volume section (9) and the rear volume section (1 1 ) when the process chamber door (7) is closed, wherein the process chamber door (7) defines a door volume (37) between the first door panel (29) and the second door panel (31 ), wherein the door volume (37) comprises a door atmosphere that is isolated from the inert gas process atmosphere, wherein the door volume (37) fills at least a part of the front volume section (9) when the process chamber door (7) is closed.25 2. The process chamber ( 1 ) of claim 1 , wherein the second door panel (31 ) is fixed relative to the first door panel (29).

3. The process chamber ( 1 ) of claim 1 or 2, further comprising a movable recoater (19) configured to deposit layers of raw material powder into the rear volume section (1 1 ) for layer-wise atentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025additive manufacturing of the three-dimensional object (3), and a recoater garage volume (39) being a lower part of the front volume section, wherein the recoater garage volume (39) de¬5 fines a halt position of the recoater (19).

4. The process chamber (1 ) of claim 3, wherein the recoater garage comprises a recoater garage ceiling, wherein the recoater garage ceiling is fixed in the process chamber ( 1 ) and defines a separating wall10 between the recoater garage and an upper part of the front volume section (9), wherein the door volume (37) fills at least partly the upper part of the front volume section (9) when the process chamber door (7) is closed, and / or movable as part of the process chamber door (7), wherein the recoater garage ceiling is at least part of a process chamber door bottom panel extending between the first door panel (29) and the second door panel (31 ) and defining a separating wall between the door volume (37) and the recoater garage volume (39) when the process chamber door (7) is closed.20 5. The process chamber (1 ) of any of the preceding claims, further comprising an inert gas flow system configured to provide a defined inert gas flow (27) in the rear volume section (1 1 ) during additive manufacturing of the three-dimensional object (3), wherein the second door panel (31 ) and / or the recoater (19) define a guiding25 surface for guiding the inert gas flow (27).

6. The process chamber (1 ) of any of the preceding claims, wherein the first door panel (29) comprises a first window (45) having a transmission coefficient above 50% in the visible light wavelength range of 0.4 to 0.7 microns, wherein the second door panel (31 ) comprises atentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 2025a second window (47) having a transmission coefficient above 50% in the visible light wavelength range of 0.4 to 0.7 microns, wherein the second window (47) is larger than the first window (45).

7. The process chamber (1 ) of claim 6, wherein the first window (45)5 and / or the second window (47) comprise at least two thermally decoupled window panes.

8. The process chamber (1 ) of claim 6 or 7, wherein the first window (45) and the second window (47) are thermally decoupled from each other.10 9. The process chamber ( 1 ) of any of the claims 6 to 8, wherein the first window (45) and / or the second window (47), or a combination of both, have a transmission coefficient below 50% for short-wave infrared electromagnetic radiation in the wavelength range of 0.9 to 3.0 microns or / and have a transmission coefficient below 50% for infrared radiation in the wavelength range of 1.0 to 12.0 microns.

10. The process chamber (1 ) of any of the preceding claims, wherein the second door panel (31 ) defines a door volume height and a door volume width, wherein a distance between the first door panel (29) and a second door panel (31 ) defines a door volume depth,20 wherein the door volume depth is at least 10%, preferably 20%, most preferably 30% of the door volume height and / or the door volume width.1 1. The process chamber (1 ) of any of the preceding claims, wherein the door volume (37) has at least one gas opening (51 , 53) allowing25 a gas to flow through the door volume (37). atentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 202512. The process chamber (1 ) of claim 1 1 , wherein the at least one gas opening (51 , 53) is at least one of a first gas opening (51 ) and a second gas opening (53), wherein the first gas opening (51 ) is arranged below the second gas opening (53) to allow a convection5 flow into the first gas opening (51 ) and out of the second gas opening (53).

13. The process chamber (1 ) of claim 1 1 or 12, further comprising at least one valve being arranged and configured to influence a flow of the gas through at least one of the at least one gas opening (51 , 53).

14. The process chamber ( 1 ) of any of the claim 1 1 to 13, further comprising at least one fan being arranged and configured to drive a flow of the gas through at least one of the at least one gas opening (51 , 53).15 15. The process chamber (1 ) of any of the claim 1 1 to 14, wherein the gas is ambient air.

16. The process chamber ( 1 ) of any of the claim 1 1 to 14, wherein the gas is an inert gas separated from the inert gas process atmosphere.

17. The process chamber ( 1 ) of any of the claim 1 1 to 14, wherein the gas is a specific gas provided by a gas source connected to the at least one gas opening.

18. The process chamber (1 ) of any of the preceding claims, wherein the separating wall (35) between the front volume section (9) and25 the rear volume section (1 1 ) comprises a fixed frame portion (43), atentanwdlte Hemmer Lmdfeld Frese SLMP 3808 WO, 10 / 07 / 202522 / 23 wherein the second door panel (31 ) and the fixed frame portion (43) complement one another to define the separating wall (35) when the process chamber door (7) is closed.

19. The process chamber (1 ) of claim 18, wherein the separating wall5 (35) comprises, when the process chamber door (7) is closed, a flush rear surface facing towards the rear volume section (1 1 ).

20. The process chamber (1 ) of any of the preceding claims, further comprising at least one heat shield (49), wherein the at least one heat shield (49) faces the door volume (37) and is arranged on a10 rear surface of the first door panel (29) and / or on a front surface of the second door panel (31 ).

21. The process chamber (1 ) of any of the preceding claims, further comprising a heat sink (55) in thermal contact with the front volume section (9), in particular with a ceiling of the front volume section15 (9). atentanwdlte Hemmer Lindfeld Frese SLMP 3808 WO, 10 / 07 / 2025

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