Suction device for sucking up process gas with a stationary gas-conveying channel and device for producing three-dimensional objects comprising such a suction device

Abstract

The invention relates to a suction device for sucking up process gas from a process chamber (16) of a device (11) for producing three-dimensional objects by selective solidification of a build-up material, applied in layers, by means of a beam (27) acting on the build-up material, comprising °a suction module (41) movable in translation; °a gas-conveying channel (74) arranged in a stationary manner and having a slot (72); °a connection module (70), which is connected to the suction module (41), is movable in the slot (72) of the gas-conveying channel (74), and fluidically connects the suction module (41) to the gas-conveying channel (74).

Description

[0001] Extraction device for extracting process gas with a stationary gas conveying channel and device for producing three-dimensional objects with such an extraction device

[0002] The invention relates to an extraction device for extracting process gas from a process chamber of a device for producing three-dimensional objects by selectively solidifying a layered build-up material by means of a jet acting on the build-up material. Furthermore, the invention relates to a device for producing three-dimensional objects by selectively solidifying a layered build-up material by means of a jet acting on the build-up material.

[0003] Mobile extraction modules are necessary, for example, for parallel coating and exposure in devices for producing three-dimensional objects by selectively solidifying a build-up material applied layer by layer using a jet acting on the build-up material. They can be connected to a stationary part of a gas circulation system using flexible hoses. Depending on the travel path of the extraction module, the length and waviness of the hose lines generate pressure losses, which reduce the performance of the circulation system.

[0004] From DE 10 2017 210 718 Al an extraction bar for a protective gas flow is known in which an outlet opening can be moved parallel to a powder bed.

[0005] DE 10 2014 214 943 A1 shows an extraction pipe which, in a stationary position outside a component platform, is operatively connected to an extraction device.

[0006] The object of the present invention is to provide an extraction device for a device for producing three-dimensional objects by selectively solidifying a layered build-up material by means of a jet acting on the build-up material, by means of which the performance of a gas circulation system can be improved. This object is achieved according to the invention by an extraction device for extracting process gas from a process chamber of a device for producing three-dimensional objects by selectively solidifying a layered build-up material by means of a jet acting on the build-up material, with

[0007] • a translationally movable suction module;

[0008] • a stationary gas conveying channel with a longitudinal slot;

[0009] • a connecting module connected to the suction module, movable in the longitudinal slot of the gas conveying channel, which fluidically connects the suction module to the gas conveying channel.

[0010] According to the invention, it is therefore possible to use a stationary gas conveying channel instead of flexible hoses guided in energy chains, in which a translationally movable connecting module is arranged, which is connected to the extraction module. Disadvantages associated with flexible hoses can thus be avoided. This is associated with lower pressure losses in the extraction tract. This leads to a significant increase in the performance of the entire gas circuit. Space-intensive energy chains for guiding hoses can be avoided. Flexible hoses with a wavy structure have a particularly detrimental effect on pressure losses, especially in swirl-assisted extraction methods.

[0011] It is particularly preferred if the gas conveying channel has sealing lips in the region of its longitudinal slot, between which the connecting module is arranged. This allows the gas conveying channel to be sealed from the environment, particularly via elongated sealing lips that compress in negative pressure. Pressure losses can thus be avoided. The connecting module performs the task of enabling a closed extraction line between an extraction / coating module during coating / exposure.

[0012] The sealing lips can be directed away from the gas supply channel toward the exhaust module. This ensures that the sealing lips are pressed against the connecting module by a vacuum, thus providing additional sealing. The sealing lips can be made of a heat-resistant material, particularly silicone. This prevents premature aging of the sealing lips due to heat exposure.

[0013] The connecting module can move toward its ends in a direction parallel to the longitudinal slot of the gas delivery channel. This ensures a good seal between the connecting module and the gas delivery channel. Furthermore, the connecting module can easily expand the sealing lips during translational movement.

[0014] The gas conveying channel can have a smooth inner wall. A smooth inner wall prevents turbulence and ensures reliable gas discharge.

[0015] The gas conveying channel can be aligned parallel to a build-up platform of the process chamber.

[0016] Further advantages arise when the connecting module includes an axial separator. The axial separator can separate particles from the process gas drawn in by the extraction module. A chute can be provided in the axial separator to separate the particles from the process gas stream. The axial separator can include a conical separator. Due to the swirl generated in the extraction module, a centrifugal force acts on the particles, allowing the outwardly drifting particles to be separated from the process gas stream by the conical separator.

[0017] At least two extraction modules can be connected to the connection module. It is conceivable to provide multiple connection modules, with one or two or more extraction modules connected to each connection module.

[0018] The connecting module can feature an eccentric gas flow detection system. This can reduce the swirl intensity when transferring the process gas flow into the gas conveying channel. In particular, an eccentric gas flow detection system can provide de-swirl in a swirl tube.

[0019] The connecting module can have a gas flow converger through which the process gas flows exiting the extraction modules can be fed together into the gas delivery channel. The process gas flows, each with a swirl, can be combined in the gas flow converger, with a type of de-swirl taking place in a common outlet opening, so that a unidirectional process gas flow subsequently leaves the connecting module into the gas delivery channel. This can subsequently reduce the pressure loss in the extraction line.

[0020] A guide can be provided for the connecting module. This could be a roller guide or a guide on rails, for example.

[0021] A drive can be provided to move the connecting module relative to the gas conveying channel. This can be a linear drive, for example. It is conceivable for the connecting module to be movable by the extraction module. Preferably, however, a drive is provided to drive the connecting module separately. The connecting module can be driven in parallel with the extraction module.

[0022] In a further embodiment of the invention, at least one actuator can be provided, by which a sealing lip can be locally raised or lowered, creating an opening to the interior of the gas conveying channel. Actuators can also be arranged on opposite sides, so that an upper and lower sealing lip are pulled apart by the actuators, creating an opening. Thus, the suction device according to the invention can be used during an inerting process to remove oxygen pockets, especially localized oxygen pockets.

[0023] The connection module can be detachably connected to the extraction module. This allows oxygen pockets to be extracted via the connection module without the need for actuators or local lifting of the sealing lips. In particular, dead zones in the process chamber can be extracted, e.g., for inerting.

[0024] The invention also includes a device for producing three-dimensional objects by selectively solidifying a layered build-up material by means of a beam acting on the build-up material, comprising at least one beam guiding source for generating a beam; • at least one beam guiding element for guiding and directing the beam onto the build-up material to be solidified

[0025] • at least one gas supply device

[0026] • a suction device according to the invention.

[0027] The invention, as well as further advantageous embodiments and developments thereof, are described and explained in more detail below with reference to the examples shown in the drawings. The features shown in the description and the drawings can be combined individually or in any combination according to the invention. They show:

[0028] Figure 1 is a schematic side view of an apparatus for producing three-dimensional objects by selectively solidifying a layered build-up material,

[0029] Figure 2 is a schematic view of an apparatus for producing three-dimensional objects, showing details of the suction device essential to the invention;

[0030] Figure 3 is a perspective view of a suction device;

[0031] Figure 4 shows a detailed view of the gas conveying channel with eccentric suction capture;

[0032] Figure 5 is a schematic plan view of the suction device;

[0033] Figure 6 is a perspective view of the suction device to illustrate the lifting of sealing lips.

[0034] Figure 1 shows a schematic side view of a device 11 for producing three-dimensional objects 12 by selectively solidifying a build-up material applied layer by layer. 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 accessed via a door (not shown in detail) or a safety lock.

[0035] A build platform 17 is provided in the process chamber 16, on which at least one three-dimensional object 12 is produced layer by layer. The size of the build platform 17 determines a build field for the production of the three-dimensional objects 12. The build platform 12 is movable vertically and in the Z direction. Overflow containers 19 or collecting containers are provided adjacent to the build platform 17, in which unused or unattached build material is collected. A process support device 21 is arranged above the build platform 17 in the process chamber 16. This process support device 21 is movable at least partially in the X direction.

[0036] A radiation source 26 is assigned to or attached to the process chamber 16, generating a beam 27, in particular a laser beam. This laser beam is guided along a beam guide 28 and deflected and directed onto the build platform 17 via a controllable beam guide element 29. The beam 27 enters the process chamber 16 via a beam inlet opening 30. The build material applied to the build platform 17 can be solidified at the point of impact 31 of the beam 27.

[0037] The process support device 21 comprises a central module 33 and an outer module 34, 35 each assigned to the central module 33. The outer modules 34, 35 can be provided in a fixed position relative to a process chamber floor 18. The central module 33 is controlled to be movable between a left and right end position 36, 37. In the view according to Figure 1, the central module 33 is positioned in the left end position 36. The outer modules 34, 35 comprise an outlet nozzle 38, which is fastened in a feed channel 39. The outlet nozzles 38 preferably have vertically aligned guide surfaces. In addition, the outlet nozzles 38 are tapered in the outlet direction. This allows a primary gas flow fed into the process chamber 16 to be homogenized and stabilized.

[0038] The central module 33 comprises two suction modules 41, each having an oppositely oriented suction opening 42. A storage container 44 for receiving build material is provided between the suction modules 41. This storage container 44 has at least one opening or dispensing slot directed toward the process chamber floor 18, so that a layer of build material can be dispensed when the central module 33 moves over the build platform 17. A coating device 46 is preferably provided between two storage containers 44, which are arranged adjacent to the suction modules 41. Preferably, the storage container 44 leading in the direction of travel of the central module 33 is filled with build material. The coating device 46 is trailing. In particular, the coating device 46 comprises at least one coating lip.

[0039] A dosing device 48 can be arranged to be movable along a Y-axis so that the storage container 44 can be filled evenly across the width of the central module 33.

[0040] The overflow container 19 is also assigned to the right and left end positions 36, 37, so that stripped build-up material can be discharged into the overflow container 19 by the coating device 46 of the center module 33 when the end position 36, 37 is assumed.

[0041] Each external module 33 is connected to a supply line 52. This supply line 52 is supplied with a primary gas 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.

[0042] Above the process chamber 16, a gas supply device 55 is provided for a secondary gas flow into the process chamber 16. This gas supply device 55 comprises two opposing supply channels 56 positioned adjacent to the beam inlet opening 30. The secondary gas flows into the process chamber 16 through at least one supply opening 57, which is associated with or surrounds the beam inlet opening 30, and is supplied from above to the build platform 17.

[0043] The process chamber 16 has lateral wall sections 60 that delimit the length of the process chamber 16. These wall sections 60 comprise flow surfaces 62 that extend toward the build platform 17 and narrow a cross-sectional area of ​​the process chamber 16. A distance 61 is provided that corresponds to, or is preferably smaller than, the length of the build platform 17 extending in the longitudinal direction. Starting from the smallest distance 61, the flow surface 62 widens. The wall sections 60 merge into a horizontal boundary surface 63. This boundary surface 63 runs parallel to the process chamber floor 18 and is provided at a distance from the process chamber floor 18 such that the process support device 21 is positioned between the boundary surface 63 and the process chamber floor 18.

[0044] 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.

[0045] Figure 2 shows the arrangement according to Figure 1 in a schematic representation, viewed in the X direction. The suction module 41 with its intake opening 42 is connected to a connecting module 70, which is translationally movable in a longitudinal slot 72 of a gas conveying channel 74. In particular, the connecting module 70 is movable together with the suction module 41. The suction module 41 is guided on linear guides 82, 84.

[0046] Process gas, which is forced into a swirling flow upon being drawn through the intake opening 42, as indicated by the arrows 76, is drawn through the connecting module 70 into the gas conveying channel 74, which is arranged in a stationary manner, i.e., in a fixed location. The extracted gas is transported away through the gas conveying channel 74. The gas conveying channel 74 has a smooth inner surface to minimize obstruction to the flow of the extracted gases.

[0047] The connecting module 70 is sealed from the gas conveying channel 74 by sealing lips 78, 80. The sealing lips 78, 80 are made of a heat-resistant material. In particular, the sealing lips 78, 80 can be made of silicone.

[0048] Figure 3 shows a schematic representation of the gas conveying channel 74, in whose slot 72 the connecting module 70 is arranged so that it can be moved. In the illustrated embodiment, the connecting module 70 is guided on a roller guide 86. In principle, the connecting module 70 can be guided on the gas conveying channel 74 or on rails.

[0049] Figure 3 shows that the connecting module 70 tapers toward its two ends 88, 90. In particular, it is pointed or wedge-shaped at the ends 88, 90. This allows the connecting module 70 to expand the sealing lips 78, 80 upon movement in the longitudinal direction of the gas conveying channel 74. The almost lens-shaped cross-section of the connecting module 70 also allows the sealing lips 78, 80 to fit tightly against the connecting module 70.

[0050] The sealing lips 78, 80 are directed away from the gas conveying channel 74 toward the suction module 41. This allows for particularly good sealing.

[0051] From the illustration in Figure 4, it can be seen that the connecting module 70 has an axial separator 92. The axial separator 92 comprises a preferably conical separator 94. Due to the swirl of the sucked-in process gas, particles are separated through the axial separator 92 into a chute 96. An eccentric suction receiver 98 is connected to the separator 94.

[0052] From the illustration in Figure 5, it can be seen that two extraction modules 41 can be connected to the connecting module 70. The gas streams are combined in a stream merging unit 100, where the swirl of the two gas streams cancels each other out, so that the gas stream enters the gas conveying channel 74 essentially swirl-free.

[0053] Figure 6 shows that actuators 102, 104, in particular a plurality of actuators 102, 104, can be provided at regular intervals along the sealing lips 78, 80. The sealing lips 78, 80 can be raised by the actuators 102, 104 or pulled apart by opposing actuators 102, 104, creating an opening 106. This allows the gas conveying channel 74 to be used during an inerting process to draw in stationary gas, in particular oxygen pockets, along the process chamber via a type of slotted suction. This makes it possible to control the gas flow during inerting in a highly controlled manner and to enable reliable flow through the entire process chamber 16.

[0054] Through significantly better detection of oxygen nests, the inerting time and the consumption of inert gas are significantly reduced.

Claims

Claims: Extraction device for extracting process gas from a process chamber (16) of a device (11) for producing three-dimensional objects by selectively solidifying a layered build-up material by means of a jet (27) acting on the build-up material, comprising: a. a translationally movable extraction module (41); b. a stationary gas conveying channel (74) having a longitudinal slot (72); c. a connecting module (70) connected to the extraction module (41) and movable in the longitudinal slot (72) of the gas conveying channel (74), which fluidically connects the extraction module (41) to the gas conveying channel (74). Extraction device according to claim 1, characterized in that the gas conveying channel (74) has sealing lips (78, 80) in the region of its longitudinal slot (72), between which the connecting module (70) is arranged.Extraction device according to claim 2, characterized in that the sealing lips (78, 80) are directed away from the gas conveying channel (74) towards the extraction module (41). Extraction device according to claim 2 or 3, characterized in that the sealing lips (78, 80) are made of a heat-resistant material, in particular silicone. Extraction device according to any one of the preceding claims, characterized in that the connecting module (70) tapers towards its ends (88, 90) in a direction parallel to the direction of the longitudinal slot (72) of the gas conveying channel (74). Extraction device according to any one of the preceding claims, characterized in that the gas conveying channel (74) has a smooth inner wall. Extraction device according to any one of the preceding claims, characterized in that the gas conveying channel (74) is aligned parallel to a mounting platform (17) of the process chamber (16). Extraction device according to any one of the preceding claims, characterized in that the connecting module (70) has at least one axial separator (92). Extraction device according to any one of the preceding claims, characterized in that at least two extraction modules (41) are connected to the connecting module (70). Extraction device according to any one of the preceding claims, characterized in that the connecting module (70) has an eccentric gas flow sensing device (98).Extraction device according to one of the preceding claims 9 or 10, characterized in that the connecting module (70) has a gas flow merging (100) through which process gas flows exiting the extraction modules (41) can be fed together to the gas conveying channel (74). Extraction device according to one of the preceding claims, characterized in that a guide for the connecting module (70) is provided. Extraction device according to one of the preceding claims, characterized in that a drive for moving the connecting module (70) relative to the gas conveying channel (74) is provided. Extraction device according to one of the preceding claims, characterized in that at least one actuator (102, 104) is provided. by which a sealing lip (78, 80) can be locally raised or lowered, creating an opening (106) around the interior of the gas conveying channel (74). Extraction device according to one of the preceding claims, characterized in that the connecting module (70) is detachably connected to the extraction module (41). Device (11) for producing three-dimensional objects by selectively solidifying a layered build-up material by means of a beam (27) acting on the build-up material, comprising: a. at least one radiation source (26) for generating a beam (27), b. at least one beam guidance element (29) for guiding and directing the beam (27) onto the build-up material to be solidified, c. at least one gas supply device (55), d. an extraction device according to one of the preceding claims.

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