Flow-modification element, flow device and flow method for an additive manufacturing device

Abstract

The invention relates to a flow device for an additive manufacturing device (1), comprising a gas-supply apparatus for generating a gas flow (33) at least in a process chamber (3) of the manufacturing device, a feed line (30) for supplying the gas flow to the process chamber, and a flow-modification element (31) for introducing the gas flow from the feed line (30) into the process chamber (3). The flow-modification element (31) comprises at least one first gas-conducting element (144a, 144b) extending from a gas-inlet side (141) to a gas-outlet side (142) and a plurality of ducts (143a, 143b, 143c), each of the ducts allowing for gas to be transported from the gas-inlet side (141) to the gas-outlet side (142). A number of first ducts and a number of second ducts are at least partly defined by the first gas-conducting element (144a, 144b), which ducts are mutually spaced in such a way that the number of second ducts, in a direction perpendicular to the build area (10), is arranged closer to the build area than the number of first ducts. A total opening cross-sectional area of the number of first ducts on the gas-outlet side differs from a total opening cross-sectional area of the number of second ducts on the gas-outlet side, and the total opening cross-sectional areas of the number of first ducts and the number of second ducts on the gas-inlet side have substantially the same size. Alternatively or additionally, at least one partial gas flow (61) which is introduced from the number of first ducts into the process chamber during operation of the flow device is directed towards one plane of the build area (10).

Description

[0001] Flow modification element, flow device and flow method for an additive manufacturing device

[0002] The present invention relates to a flow modification element and a flow device for an additive manufacturing device, as well as a flow method and an additive manufacturing method.

[0003] Devices and processes of this type are used, for example, in rapid prototyping, rapid tooling, or additive manufacturing. One example of such a process is known as "selective laser sintering or laser melting." In this process, a thin layer of a powdered build material is repeatedly applied, and the build material is selectively solidified in each layer by selectively irradiating areas corresponding to a cross-section of the object to be manufactured with a laser beam.

[0004] The energy input during selective solidification can generate contaminants such as spatter, smoke, vapors, and gases, which spread from the build area where selective solidification is performed into the process chamber. Additionally, when using a powdered build material, contamination can arise from powder or powder dust being stirred up in the process chamber. Contaminants can negatively impact the manufacturing process, for example, by absorbing, scattering, or deflecting the scanning laser beam, condensing on a laser beam coupling window, or depositing on a build material layer. To meet the high quality and efficiency requirements of the manufacturing process, such contaminants must therefore be removed from the process chamber as quickly as possible.For this purpose, a gas flow is typically generated in the process chamber, which transports contaminants out of the process chamber. DE 10 2018 215 301 A1 describes an additive manufacturing device with a flow device for generating a gas flow in the manufacturing device. A gas inlet element for introducing the gas flow into the process chamber comprises a plurality of channels that penetrate a body of the gas inlet element from a gas inlet side to a gas outlet side.

[0005] DE 10 2018 219 304 A1 describes an additive manufacturing device with a flow device comprising a gas supply line provided outside a process chamber of the manufacturing device for introducing gas into the process chamber through a gas inlet. The gas supply line comprises a line section adjoining the gas inlet, extending over a length that is at least half the width of the line section, and comprising a flow rectification unit for aligning the gas flow in an extension direction of the line section.

[0006] US 2018 / 0126460 A1 describes a device for 3D printing, wherein a three-dimensional object can be produced on a platform, and a gas inlet section and a gas outlet section are provided for generating a gas flow on or near the platform surface. The gas inlet section has a baffle for deflecting the gas flow, and the gas outlet section has a shape that tapers toward an outlet opening.

[0007] The object of the present invention is to provide an alternative or improved flow modification element and an alternative or improved flow device for an additive manufacturing device, as well as an alternative or improved additive manufacturing device, an alternative or improved flow method, and an alternative or improved additive manufacturing method, with which, in particular, the effectiveness of the removal of contaminants from the process chamber can be increased. This object is achieved by a flow device according to claim 1 or 9, a flow modification element according to claim 8, an additive manufacturing device according to claim 16, a flow method according to claim 17 or 18, and a manufacturing method according to claim 19. Further developments of the invention are specified in the subclaims.The methods can also be further developed using the features below or the features of the devices set out in the subclaims, and vice versa. The features of the devices can also be used for further development. Likewise, the features of the methods can be used for further development.

[0008] A flow device according to the invention according to a first aspect serves for a manufacturing device for the additive production of a three-dimensional object by layer-by-layer selective solidification of a building material in a build area in a process chamber of the manufacturing device. The flow device comprises a gas supply device for generating a gas flow at least in the process chamber, a supply line for supplying the gas flow to the process chamber, and a flow modification element for introducing the gas flow from the supply line into the process chamber. The flow modification element has a gas inlet side facing the supply line, a gas outlet side facing away from the supply line, at least one first gas guide element extending from the gas inlet side to the gas outlet side, and a plurality of channels, wherein each of the channels allows gas to be transported from the gas inlet side to the gas outlet side.wherein a number of first channels and a number of second channels are at least partially defined by the first gas guide element, which are spaced apart from one another such that the number of second channels is arranged closer to the construction field in a direction perpendicular to the construction field than the number of first channels, and wherein the first gas guide element is designed such that a total opening cross-sectional area assigned to the number of first channels on the gas outlet side differs from a total opening cross-sectional area assigned to the number of second channels on the gas outlet side, and a total opening cross-sectional area assigned to the number of first channels on the gas inlet side and a total opening cross-sectional area assigned to the number of second channels on the gas inlet side are substantially the same size, and / or wherein the first gas guide element is designed such that at least one partial gas flow,which is introduced into the process chamber from the number of first channels during operation of the flow device, is directed towards a plane of the construction field.

[0009] The process chamber is understood to be a cavity partially bounded by the build area and preferably comprising the build area for constructing the object. The build area preferably forms part of a floor area on a lower side of the process chamber. The process chamber can be a cavity that is essentially closed during operation, with the exception of a gas inlet, which is formed, for example, by the flow modification element, and a gas outlet, and optionally further gas inlets and / or gas outlets.

[0010] The flow modification element can be provided in a wall of the process chamber, which delimits the interior of the process chamber and thus encloses the cavity. It can, for example, be offset from the process chamber or protrude into the process chamber or be set back. Preferably, the flow modification element is designed and / or arranged such that a main extension direction of the channels between the gas inlet and gas outlet sides, or a longitudinal direction of the flow modification element, and / or a central outflow direction in which the gas enters the process chamber during operation of the flow device, is substantially perpendicular to a plane of the process chamber wall and / or substantially parallel to a plane of the build field and / or a width direction of the flow modification element is substantially horizontal and / or parallel to a nearest build field side (particularly in the case of a rectangular build field).A width direction of the flow modification element can in particular be transverse, preferably perpendicular, to the longitudinal direction of the flow modification element. Preferably, a dimension of the flow modification element in the width direction is at least as large as a maximum dimension of the build field in the width direction. Preferably, a dimension of the flow modification element in the width direction is a multiple of a dimension of the flow modification element in a height direction perpendicular to the longitudinal and height directions. In a plane of the process chamber wall or parallel to the process chamber wall, the channels can in particular be arranged in a grid pattern, i.e. in the form of rows and columns above and below one another. The rows and / or columns can also be offset from one another.

[0011] The supply line is preferably a rigid, i.e., non-flexible, line or a rigid duct, e.g., a sheet metal duct. In particular, the supply line can be designed according to the features described below. The gas supply device can, for example, comprise a drive means for moving a gas volume, e.g., a fan. The process chamber and the supply line can—optionally with further elements, such as, e.g., a gas discharge line for discharging gas from the process chamber—form a closed process gas circuit. A gas flow is preferably understood to mean a gas volume that is moved in a targeted manner in a preferred direction.

[0012] Preferably, the gas supply to the process chamber is formed entirely by the supply line and the flow modification element. In other words, during operation of the flow device, the gas flow is introduced directly from the supply line through the flow modification element into the process chamber. Preferably, the gas supply to the process chamber is free of further flow-modifying elements between the supply line and the flow modification element, as well as between the flow modification element and the process chamber, in particular the interior of the process chamber. The channels preferably form essentially the only gas-permeable connections through the flow modification element, from its gas inlet side to its gas outlet side.

[0013] The fact that the gas guide element at least partially defines the number of first channels and the number of second channels means in particular that the gas guide element at least partially delimits the number of first channels and the number of second channels. Further elements of the flow modification element, in particular further gas guide elements and / or a wall of the flow modification element, can be provided for defining or delimiting the channels. In particular, a number of channels means at least one channel, i.e. a single channel or multiple channels. In particular, the number of first channels can comprise a plurality of channels arranged next to one another in a row, and the number of second channels can comprise a plurality of second channels arranged next to one another in a row, wherein the row of first channels and the row of second channels are arranged substantially parallel to one another and one above the other with respect to the construction field.It is not excluded that the channels of the first row are offset from one another, or that the channels of the second row are offset from one another, or that the first channels are offset with respect to the second channels. These statements apply analogously to the third channels described below and their arrangement with respect to the first and second channels. The first gas guide element can thus in particular divide the number of first and second channels in a direction parallel to the plane of the construction field, i.e. preferably horizontally. The first gas guide element is preferably a gas guide element arranged essentially parallel to the plane of the construction field, i.e. preferably horizontally. The first gas guide element preferably extends essentially over an entire length and width of the flow modification element parallel to the plane of the construction field.

[0014] A total opening cross-sectional area assigned to the number of first (likewise: second or third) channels on the gas inlet side can, for example, be defined as the sum of the opening areas of the respective channels on the gas inlet side. Analogously, a total opening cross-sectional area assigned to the number of first (likewise: second or third) channels on the gas outlet side can, for example, be defined as the sum of the opening areas of the respective channels on the gas outlet side. In the event that one or more of the channels do not extend completely to the gas inlet side and / or gas outlet side, the total opening cross-sectional area assigned to the respective channels on the gas inlet or gas outlet side can be defined by the first and / or second gas guide element, which at least partially defines the respective channels, and / or any further structures of the flow modification element, in particular its wall.In particular, the associated total opening cross-sectional area in this case can be an opening area of ​​a slot-shaped opening defined by the first and / or second gas-guiding element on the gas inlet and / or gas outlet side of the flow modification element. The case that one or more of the channels do not extend completely to the gas inlet and / or gas outlet side can occur in particular if the flow modification element, as described in detail below, further comprises at least one third gas-guiding element, which extends substantially perpendicular to a plane of the construction field and ends at a distance from the gas inlet and / or gas outlet side, in particular at a distance from the gas outlet side.

[0015] An opening area of ​​a channel on the gas inlet side or gas outlet side can be defined as the area enclosed by the gas guide element(s) delimiting the channel on the gas inlet side or gas outlet side and any wall of the flow modification element. Alternatively or additionally, an opening area of ​​a channel can be defined as the cross-sectional area of ​​the channel in a plane perpendicular to the longitudinal direction of the flow modification element and / or perpendicular to the plane of the construction field, and / or by a projection of the gas guide elements onto this plane.

[0016] If the build area is part of a floor area of ​​the process chamber, the flow modification element can be arranged, in particular, vertically above the build area. A partial gas flow directed toward the plane of the build area therefore refers, in particular, to a partial gas flow directed downwards. An angle formed by the partial gas flow directed toward the build area with the horizontal or a plane parallel to the build area can be, for example, at least 5°, preferably at least 10°, particularly preferably at least 15° and / or at most 30°, preferably at most 25°, particularly preferably at most 20°.

[0017] Because the total opening cross-sectional area of ​​the first and second channels on the gas inlet side is essentially the same, a substantially equal volume flow of gas can be passed through the first and second channels. In other words, an incoming gas volume is divided into essentially equal volume portions between the first and second channels.

[0018] Due to the different total opening cross-sectional areas on the gas outlet side, the outflow velocities of the partial gas volumes introduced into the process chamber from the first channels and the second channels can be adjusted independently of one another and, in particular, differently from one another. Because the partial gas flow introduced into the process chamber through the first (upper) channels is directed downwards toward the build area, a concentration of the overall gas flow can be achieved, for example. Overall, the above-described design of the flow modification element can achieve improved homogenization of the gas flow introduced into the process chamber, in particular by reducing eddies or turbulence occurring in the gas flow.

[0019] Preferably, the flow modification element further comprises a second gas guide element extending from the gas inlet side to the gas outlet side, which second gas guide element at least partially defines a number of third channels, wherein the number of third channels is spaced from the number of first channels and the number of second channels such that the number of third channels is arranged closer to the construction field in a direction perpendicular to the construction field than the number of second channels.

[0020] Preferably, the second gas guide element is a gas guide element arranged substantially parallel to the plane of the construction field, ie preferably horizontally, and / or substantially parallel to the first gas guide element. Preferably, the second gas guide element extends substantially over an entire length and width of the flow modification element parallel to the plane of the construction field. The first and second gas guide elements can, for example, also be referred to as horizontal partition walls of the flow modification element. Together with the first gas guide element, the second gas guide element preferably defines or delimits a number of first, second and third channels, which are arranged one above the other perpendicular to the construction field, iethe first channels are arranged at the top, the second channels in the middle, and the third channels at the bottom, with the first gas guiding element dividing the number of first and second channels and the second gas guiding element dividing the number of second and third channels. Thus, in particular, three levels of channels lying one above the other are provided. This makes it possible, for example, to define differentiated partial gas flows which are introduced separately from one another into the process chamber through the flow modification element and together form an overall gas flow in the process chamber that flows through this at least in part. This subdivision of the introduced overall gas flow into individual partial gas flows enables, for example, a targeted optimization of the individual partial gas flows with regard to their speed and / or direction as they flow into the process chamber.

[0021] Preferably, the first gas guide element and the second gas guide element are designed such that the total opening cross-sectional area assigned to the number of second channels on the gas outlet side is larger than the total opening cross-sectional area assigned to the number of first channels on the gas outlet side and / or a total opening cross-sectional area assigned to the number of third channels on the gas outlet side. Further preferably, a total opening cross-sectional area assigned to the number of first channels on the gas inlet side and / or a total opening cross-sectional area assigned to the number of second channels on the gas inlet side and / or a total opening cross-sectional area assigned to the number of third channels on the gas inlet side is substantially the same size.Alternatively or additionally, the first gas guide element and the second gas guide element are further preferably designed such that the total opening cross-sectional area assigned to the number of first and / or second and / or third channels on the gas outlet side is in each case smaller than the total opening cross-sectional area assigned to the number of first or second or third channels on the gas inlet side.

[0022] As described above, a uniform total opening cross-sectional area of ​​the first, second, and third channels on the gas inlet side can, for example, provide essentially equal partial volumes in the first, second, and third channels. By designing the total opening cross-sectional area of ​​the number of second channels on the gas outlet side larger, the partial gas stream flowing into the process chamber through the second channels can have a lower (average) velocity than corresponding partial gas streams flowing in through the number of first and third channels. At the same time, the gas can be introduced through the largest possible area in the central region. In conjunction with the first partial gas stream coming from above, the homogeneity of the overall flow in the process chamber can be increased, in particular by reducing turbulence.For example, reducing the channel cross-sectional areas from the gas inlet side to the gas outlet side can cause the gas flow to accelerate.

[0023] For example, the total opening cross-sectional area assigned to the number of second channels on the gas outlet side can be substantially 1.3 times to 2.5 times the total opening cross-sectional area assigned to the number of first channels and / or the number of third channels on the gas outlet side. A total opening cross-sectional area assigned to the respective number of channels on the gas outlet side can, for example, be in the range of 50% to 99% in relation to the total opening cross-sectional area assigned to the respective number of channels on the gas inlet side; for the number of first and / or third channels, for example, in particular in the range of 50% to 70%, and for the number of second channels, for example, in the range of 90% to 98%.

[0024] Preferably, the first and / or the second gas guide element has a first section adjacent to the gas inlet side, which has a shape that tapers towards the gas inlet side, and / or a second section adjacent to the gas outlet side, which has a shape that tapers towards the gas outlet side. More preferably, an extension of the first section between the gas inlet side and the gas outlet side is greater than an extension of the second section between the gas inlet side and the gas outlet side. Alternatively or additionally, an expansion angle of the second section is further preferably greater than an expansion angle of the first section. Alternatively or additionally, the first gas guide element and / or the second gas guide element further preferably extends over an entire extension of the flow modification element from the gas inlet side to the gas outlet side.

[0025] The tapered sections are further preferably designed to be substantially stepless, i.e., they taper strictly monotonously and preferably with a smooth surface. This makes it possible, for example, to avoid corners and / or edges in the flow path where turbulence could arise, thus achieving an overall homogenization of the gas flow.

[0026] An expansion angle can be defined, for example, as an angle formed by tangents on opposite sides or surfaces (e.g., the top and bottom) of the respective gas guide element. Alternatively or additionally, an expansion angle can be defined, for example, as an angle formed by straight lines representing the average gradient of the opposite sides or surfaces (e.g., the top and bottom) of the gas guide element. This definition is therefore preferably based on the gradient or average gradient of the tapered sections. The actual gradient of the tapered sections can be linear or, in general, follow any strictly monotonic function, i.e., be curved.

[0027] In general, a gas guide element is preferably designed such that it has a first cross-section at a first end facing the gas inlet side, widens over the first section to a second cross-section whose area is larger than that of the first cross-section, and tapers over the second section in the direction of the gas outlet side up to a second end to a third cross-section, wherein an area of ​​the third cross-section is smaller than that of the second cross-section.

[0028] Preferably, the third gas guide element is substantially drop-shaped, with a tip of the drop facing the gas inlet side. The tip on the gas inlet side can be flattened.

[0029] The configurations of the gas guide element described here can be applied not only to the first and / or second gas guide element, but also to further gas guide elements of the flow modification element, in particular one or more third gas guide elements described below. An expansion angle of the first and / or second section can, for example, be in the range of 1° to 3°.

[0030] Preferably, the flow modification element further comprises at least one third gas guide element extending substantially perpendicular to a plane of the construction field. Further preferably, the third gas guide element extends from the gas inlet side toward the gas outlet side of the flow modification element and ends at a distance from the gas outlet side, and / or the third gas guide element extends over a length corresponding to at most two-thirds of the extension of the flow modification element from the gas inlet side to the gas outlet side.

[0031] Alternatively or additionally, it is further preferred that the third gas guide element has a first section adjacent to the gas inlet side, which has a shape tapering towards the gas inlet side, and / or a second section provided downstream of the first section, which has a shape tapering towards the gas outlet side, wherein preferably an extension of the first section between the gas inlet side and the gas outlet side is greater than an extension of the second section between the gas inlet side and the gas outlet side and / or wherein preferably an expansion angle of the second section is greater than an expansion angle of the first section.

[0032] Preferably, the at least one third gas guide element is a gas guide element arranged substantially perpendicular to the plane of the construction field, i.e. preferably vertically. Preferably, the at least one third gas guide element extends substantially over an entire height of the flow modification element perpendicular to the plane of the construction field. The third gas guide element can also be referred to, for example, as a vertical partition wall of the flow modification element. The at least one third gas guide element preferably subdivides the number of first, second, and third channels into a plurality of channels arranged next to one another parallel to the construction field. Preferably, a plurality of third gas guide elements is provided in order to define a horizontal subdivision of the flow modification element into channels.By such a horizontal subdivision of the flow modification element, for example, a further improvement of the gas flow flowing through the flow modification element can be achieved, in particular by more clearly defining a portioning of the volume flow along a side of the construction field extending transversely to the main flow direction, preventing an influence on the gas flow in adjacent channels, or limiting the size of any turbulence to the individual channels.

[0033] Because the third gas guide element ends at a distance from the location of the gas outlet on the gas outlet side, the partial gas volumes divided by the channels can, for example, be reunited at least horizontally before entering the process chamber.

[0034] The tapered sections of the third gas guide element are further preferably designed to be substantially stepless, i.e., they taper strictly monotonously and preferably with a smooth surface. This allows, for example, corners and / or edges in the flow path where turbulence could occur to be avoided, thus achieving an overall homogenization of the gas flow.

[0035] Overall, the tapered shape of the third gas guiding element and / or the fact that it ends at a distance from the gas outlet side can, for example, reduce the occurrence of turbulence in the gas flow introduced into the process chamber by the flow modification element, i.e. it can, in particular, have a turbulence-reducing effect. Preferably, a first gas flow flowing through the flow modification element, in which the third gas guiding element(s) extends to the gas outlet side and / or does not have a substantially drop-shaped shape, has a first degree of turbulence, and a second gas flow flowing through the flow modification element, in which the third gas guiding element(s) ends at a distance from the gas outlet side and / or has a substantially drop-shaped shape, has a second degree of turbulence, wherein the second degree of turbulence is smaller than the first degree of turbulence.A measure of turbulence can, for example, be a swirling of the gas flow and / or a measure of a spatial and / or temporal inhomogeneity of the flow properties of the gas flow.

[0036] Preferably, the first and / or the second gas guide element is designed as a substantially horizontally arranged flat body, and / or the third gas guide element is designed as a substantially vertically arranged flat body. Further preferably, at least the flat body, and further preferably the entire flow modification element, is manufactured using an additive manufacturing process.

[0037] A flat body is, in particular, a body that essentially has a first and a second main direction of extent and that extends perpendicular to the first and second main direction of extent over a thickness that is many times smaller than the dimensions of the body in the first and second main direction of extent. The thickness of the flat body does not have to be constant. In particular, the tapered shape of the gas guide element(s) described above can be formed over the thickness of the flat body.

[0038] The production of the flow modification element or at least its gas guiding elements in an additive manufacturing process can, for example, enable a very precise production of the desired geometries in a simple and / or fast manner.

[0039] A flow modification element according to the invention serves for a manufacturing device for the additive production of a three-dimensional object by layer-by-layer selective solidification of a build material in a build area in a process chamber of the manufacturing device. The flow modification element is designed to introduce a gas flow from a supply line into the process chamber. The flow modification element has a gas inlet side facing the supply line, a gas outlet side facing away from the supply line, at least one first gas guide element extending from the gas inlet side to the gas outlet side, and a plurality of channels, each of the channels allowing gas to be transported from the gas inlet side to the gas outlet side.The first gas guide element at least partially defines a number of first channels and a number of second channels, which are spaced apart from one another such that the number of second channels is arranged closer to the construction field in a direction perpendicular to the construction field than the number of first channels, and the first gas guide element is designed such that a total opening cross-sectional area assigned to the number of first channels on the gas outlet side differs from a total opening cross-sectional area assigned to the number of second channels on the gas outlet side, and a total opening cross-sectional area assigned to the number of first channels on the gas inlet side and a total opening cross-sectional area assigned to the number of second channels on the gas inlet side are substantially the same size.Alternatively or additionally, the first gas guiding element is designed such that at least one partial gas flow which is introduced into the process chamber from the number of first channels during operation of the flow device is directed towards a plane of the construction field.

[0040] The flow modification element can be further developed, in particular, according to one or more of the features described above with regard to the air flow device. This can, for example, provide a flow modification element with which an existing air flow device or additive manufacturing device can be equipped and / or retrofitted.

[0041] A second aspect of the invention provides a flow device for a manufacturing device for the additive production of a three-dimensional object by selectively solidifying a build material layer by layer in a build area in a process chamber of the manufacturing device. The flow device comprises a gas supply device for generating a gas flow at least in the process chamber, a supply line for supplying the gas flow to the process chamber, and a flow modification element for introducing the gas flow from the supply line into the process chamber.The supply line comprises at least a first line section which is spaced from the flow modification element and which is substantially S-shaped and / or Z-shaped, and the supply line comprises at least a second line section which is provided between the first line section and the flow modification element, preferably directly adjoining the first line section and the flow modification element, and which extends along a first direction of extent which is substantially parallel to a plane of the construction field, over a length which is at least five times, preferably at least ten times, a height, preferably an average height, of the second line section transverse to the first direction of extent and substantially perpendicular to a plane of the construction field.

[0042] In particular, the air supply device according to the second aspect can be further developed by one or more of the features described above with respect to the air supply device of the first aspect.

[0043] An average height of the second line section can be used to determine the ratio of the length to the height of the second line section, particularly if the height of the second line section is not constant over its length. A non-constant height of the second line section can be caused, for example, by a subsection connecting the first and second line sections, in particular a curved subsection, extending into the second line section. Preferably, however, such a connecting section is not considered part of the second line section, so that the height of the second line section is constant over its entire length.

[0044] The s-shape and / or z-shape of the supply line can be formed in particular in a plane substantially perpendicular to the plane of the construction field of the manufacturing device and / or with respect to a vertical direction.

[0045] The S-shape or Z-shape of the first line section, for example, can provide the longest possible path for the gas flow to be introduced into the process chamber, while simultaneously minimizing the space required by the first line section (in a horizontal direction) in the additive manufacturing device due to the S- or Z-shape. In general, a long path length for the gas flow before it is introduced into the process chamber can calm or even out the flow of the gas flow, particularly in combination with the second line section, which is provided directly upstream of the process chamber or the flow modification element, and in which the gas flow essentially no longer undergoes a change in direction.

[0046] Preferably, the second line section extends along its first direction of extension over a length that is at least as large as half the width of the second line section transverse to the first direction of extension and substantially parallel to a plane of the construction site. Further preferably, the length of the second line section is at least as large as the width of the second line section, even more preferably at least one and a half times, even more preferably at least twice, and particularly preferably at least three times greater than the width of the second line section.

[0047] This can, for example, provide a sufficient length of the gas flow immediately before the gas inlet or flow modification element, which can cause the flow to calm or even out.

[0048] Preferably, the first line section comprises at least a first (41 a) and at least a second sub-section, which are arranged substantially parallel to one another and / or parallel to a plane of the construction field and / or which are in fluid communication with one another via a curved sub-section of the first line section, wherein a total length of the first line section, which comprises at least a first length of the first sub-section and a second length of the second sub-section in a direction substantially parallel to a plane of the construction field, preferably parallel to the first direction of extent, is at least as large as three times, preferably ten times, a width of the flow modification element and / or of the second line section transverse to the first direction of extent and substantially parallel to a plane of the construction field.The phrase "in fluid communication" specifically refers to a gas-conducting connection between the two line sections during operation. The curved section can, for example, create an S-shaped or Z-shaped supply line, thus reducing the space required for the supply line.

[0049] Preferably, a cross section of the second line section in a plane transverse to the first extension direction is substantially as large as a cross section of the flow modification element on a gas inlet side of the flow modification element adjoining the second line section, and / or has substantially the same geometric shape, in particular a rectangular shape.

[0050] This can, for example, reduce or prevent turbulence in the gas flow when entering the flow modification element.

[0051] Preferably, in a direction parallel to the plane of the construction field, a width of at least one partial section of the first line section adjoining the second line section is substantially equal to the width of the second line section, wherein the partial section of the first line section further preferably comprises at least two-thirds of a total extension of the first line section.

[0052] In other words, it is preferable to provide a line section that is as long as possible and where the width does not change. This can, for example, lead to a further improvement in the flow properties, e.g., homogenization, of the gas flow.

[0053] Preferably, a height of the first line section decreases in a direction perpendicular to the plane of the construction field toward the second line section, preferably continuously or stepwise, and / or a height of the second line section is substantially constant in a direction perpendicular to the plane of the construction field. Such a reduction in the cross-sectional height, particularly while maintaining a constant cross-sectional width, can result in an overall reduction in the cross-sectional area, which in turn can lead to an increase in the flow velocity of the gas stream flowing through the first line section during operation of the flow device.

[0054] As described above, the first line section can comprise at least a first subsection and at least a second subsection, which are arranged substantially parallel to one another and / or parallel to a plane of the construction field and / or which are in fluid communication with one another via a curved subsection of the first line section. In this case, it is particularly preferred that the first subsection is spaced further from the second line section than the second subsection, and that the first subsection has a first height and the second subsection has a second height that is smaller than the first height of the first subsection. More preferably, the height of the second line section is smaller than the second height of the second subsection. The first height of the first subsection and / or the second height of the second subsection and / or the height of the second line section is preferably in each case constant.Thus, according to this preferred embodiment, the height of the supply line decreases gradually from one to the next downstream section of the supply line.

[0055] Preferably, in the flow device according to the first and / or second aspect, the flow modification element is provided substantially in a lower height region of the process chamber.

[0056] In other words, the gas flow is preferably introduced at a height of the process chamber close to the build area. Further preferably, a gas outlet through which the gas flow is discharged from the process chamber is also provided at a lower height of the process chamber, preferably directly adjacent to the floor of the process chamber. Overall, this allows the gas flow to flow through the process chamber near the build area, for example, in order to remove any contaminants as close to their source as possible, thus preventing, for example, the spread of contaminants into the process chamber as efficiently as possible.

[0057] The lower height range of the process chamber can, for example, correspond to a lower third, preferably a lower fifth, particularly preferably a lower tenth of a maximum distance of the construction field from a process chamber ceiling.

[0058] Alternatively or additionally, the flow modification element or another gas inlet for introducing a gas flow may be provided in an upper height region of the process chamber.

[0059] A manufacturing device according to the invention serves for the additive production of a three-dimensional object by layer-by-layer selective solidification of a building material in a building field in a process chamber, and comprises a flow device described above according to the first and / or second aspect, or a flow modification element described above.

[0060] This makes it possible, for example, to achieve the effects described above with regard to the air flow device even with an additive manufacturing device.

[0061] A flow method according to the invention according to a first aspect serves to generate a gas flow in a manufacturing device for the additive production of a three-dimensional object by layer-by-layer selective solidification of a building material in a construction field in a process chamber of the manufacturing device.

[0062] The flow process includes the following steps:

[0063] Generating a gas flow at least in the process chamber by means of a gas supply device,

[0064] Supplying the gas flow to the process chamber by means of a supply line and introducing the gas flow from the supply line through a flow modification element into the process chamber. The flow modification element has a gas inlet side facing the supply line, a gas outlet side facing away from the supply line, at least one first gas guiding element extending from the gas inlet side to the gas outlet side, and a plurality of channels, wherein each of the channels allows transport of gas from the gas inlet side to the gas outlet side. A number of first channels and a number of second channels are at least partially defined by the first gas guiding element, which are spaced apart from one another such that the number of second channels is arranged closer to the build field in a direction perpendicular to the build field than the number of first channels.The first gas guide element is designed such that a total opening cross-sectional area assigned to the number of first channels on the gas outlet side differs from a total opening cross-sectional area assigned to the number of second channels on the gas outlet side, and a total opening cross-sectional area assigned to the number of first channels on the gas inlet side and a total opening cross-sectional area assigned to the number of second channels on the gas inlet side are substantially equal. Alternatively or additionally, the first gas guide element is designed such that at least one partial gas flow, which is introduced into the process chamber from the number of first channels during operation of the flow device, is directed toward a plane of the build field.

[0065] A second aspect of the invention's flow method serves to generate a gas flow in a manufacturing device for the additive production of a three-dimensional object by selectively solidifying a build material layer by layer in a build area in a process chamber of the manufacturing device. The flow method comprises the following steps:

[0066] Generating a gas flow at least in the process chamber by means of a gas supply device,

[0067] Supplying the gas flow to the process chamber by means of a supply line and introducing the gas flow from the supply line through a flow modification element into the process chamber.

[0068] The supply line comprises at least a first line section which is spaced apart from the flow modification element and which is substantially S-shaped and / or Z-shaped. The supply line further comprises at least one second line section which is provided between the first line section and the flow modification element, preferably directly adjoining the first line section and the flow modification element, and which extends along a first direction of extent which is substantially parallel to a plane of the construction field over a length which is at least five times, preferably at least ten times, a height, preferably an average height, of the second line section transverse to the first direction of extent and substantially perpendicular to a plane of the construction field.

[0069] A manufacturing method according to the invention serves for the additive production of a three-dimensional object in a process chamber of a manufacturing device and comprises the step of layer-by-layer application of a building material in a construction field, selectively solidifying the applied layer and repeating the steps of layer-by-layer application and selective solidification until the three-dimensional object is produced, wherein at least temporarily during the production of the three-dimensional object, a flow method described above according to the first and / or second aspect is carried out.

[0070] This makes it possible, for example, to achieve the effects described above with regard to the flow device and / or the flow modification element and / or the additive manufacturing device also in a flow process and / or in an additive manufacturing process.

[0071] Further features and advantages of the invention will become apparent from the description of embodiments with reference to the accompanying drawings.

[0072] Fig. 1 shows a schematic, partially sectioned view of an apparatus for additively manufacturing a three-dimensional object according to an embodiment of the present invention,

[0073] Fig. 2 shows a schematic perspective view of a supply line of the device shown in Fig. 1, Fig. 3 shows a schematic view of the supply line shown in Fig. 2 in section,

[0074] Fig. 4a, 4b and 4c show schematic views of a flow modification element of the device shown in Fig. 1, wherein Fig. 4a shows a perspective view of the flow modification element, Fig. 4b a plan view of a gas inlet side of the flow modification element, and Fig. 4c a plan view of a gas outlet side of the flow modification element,

[0075] Fig. 5a shows a schematic view of the flow modification element shown in Fig. 4a-4c in section, wherein the section plane runs along the line AA shown in Fig. 4a,

[0076] Fig. 5b shows schematically an enlarged section of a gas guiding element shown in Fig. 5a in section,

[0077] Fig. 6a shows a schematic sectional view of the flow modification element shown in Fig. 4a-4c, wherein the sectional plane runs along the line CC shown in Fig. 4a,

[0078] Fig. 6b shows schematically an enlarged section of a gas guiding element shown in Fig. 6a in section,

[0079] Fig. 7a shows a sectional view of a section of the manufacturing device shown in Fig. 1 with sections of a process chamber wall and the supply line shown in Figs. 2 and 3, and with the flow modification element shown in Figs. 4a to 6b,

[0080] Fig. 7b shows a sectional view of a section of the flow modification element shown in more detail in Figs. 4a to 6b and a portion of the process chamber of the device shown in Fig. 1 during operation of the flow device. A device according to the present invention is described below with reference to Fig. 1. The device shown in Fig. 1 is a laser sintering or laser melting device 1. For building an object 2, it contains a process chamber 3 with a chamber wall 4.

[0081] Below the process chamber 3, a build container 5 with an upwardly open container wall 6 is arranged. In the build container 5, a carrier 7 is arranged, which is movable in a vertical direction V and to which a base plate 8 is attached, which closes off the build container 5 at the bottom and thus forms its base. The base plate 8 can be a plate formed separately from the carrier 7 and fastened to the carrier 7, or it can be formed integrally with the carrier 7. Depending on the build material and process used, a build platform 9 can be attached to the base plate 8 as a build base, on which the object 2 is built. However, the object 2 can also be built on the base plate 8 itself, which then serves as the build base.

[0082] A work plane 16 is defined by the upper opening of the build container 5, wherein the area of ​​the work plane 16 lying within the opening, which can be used to build the object 2, is referred to as the build field 10. The work plane 16 can also be the upper surface of a work plate facing the interior of the process chamber 3 (not shown in Fig. 1). The work plate, not shown, also forms the floor of the process chamber 3 and preferably surrounds the build container 5 on all sides. The work plane 16 is spaced apart from a ceiling 4a of the chamber wall 4 by a process chamber height T. In the event that the process chamber height T is not uniform over the entire area of ​​the process chamber, for example due to a non-uniform height of the process chamber ceiling 4a, e.g. due to slopes, and / or a e.g.lowered area of ​​the worktop, the process chamber height T can be defined as the maximum clear height of the process chamber. The plane of the build area 10 or the work plane 16 defines an xy-plane of a Cartesian coordinate system, with the y-direction in the device shown in Fig. 1 corresponding to the direction of movement H of a coater 14 (see below). The z-direction of the Cartesian coordinate system is defined by the process chamber height T.

[0083] In Fig. 1, the object 2 to be formed in the construction container 5 on the construction platform 9 is shown below the working level 16 in an intermediate state with several solidified layers, surrounded by unsolidified building material 13.

[0084] To generate a gas flow 33 in the process chamber 3, the chamber wall 4 has a gas inlet 32 ​​for introducing the gas flow into the process chamber, and a gas inlet 34 for discharging the gas flow. In Fig. 1, the gas inlet 32 ​​and the gas outlet 34 are provided on opposite sides of the chamber wall 4, spaced apart in the x-direction, with the build area 10 being provided between the gas inlet 32 ​​and the gas outlet 34. The gas inlet 32 ​​and the gas outlet 34 are provided in a lower height region of the process chamber 3, for example, within a region of the process chamber 3 adjacent to the build area 10, which region comprises a height extension of 20% or 10% of the process chamber height T. The gas inlet 21 and the gas outlet 34 do not have to be adjacent to the working plane 16, but can also be spaced from it, ie arranged vertically above it.

[0085] In Fig. 1, the gas inlet 32 ​​and the gas outlet 34 are shown flush with the chamber wall 4, but they can also protrude into the process chamber 3 or be set back from the chamber wall 4.

[0086] The gas inlet 32 ​​is in gas-conducting communication via a supply line 30 and a flow modification element 31 with a gas supply device not shown in the figures, e.g. in the form of a fan. The gas inlet 32 ​​can in particular be formed by gas-conducting openings on a gas outlet side of the flow modification element 31, as described further below. The supply line 30 is provided outside the process chamber 3 in Fig. 1. The supply line 30 comprises in Fig. 1 a first supply line section 36 and a second supply line section 37, wherein the first supply line section 36 is provided upstream of the second supply line section 37. The first supply line section 36 is designed in Fig. 1 as a substantially vertically extending tube with a substantially constant cross-sectional area, e.g. a round cross-section, but it can also have any other suitable shape and arrangement.The second supply line section 37 comprises, for example, a housing 37a (see Figs. 2, 3), depicted in the figures as a substantially cuboid-shaped housing, with a gas-conducting configuration inside the housing, which is described in more detail below with reference to Figs. 2 and 3. The flow modification element 31, which is described in more detail below with reference to Figs. 4a to 6b, adjoins the second supply line section 37.

[0087] Furthermore, the gas outlet 34 is connected to the gas supply device (not shown) via a discharge line 35. Preferably, the supply line 30, the flow modification element 31, the process chamber 3, and the discharge line 35, together with the gas supply device, form a substantially closed process gas circuit. Only sections of the supply line 30 and the discharge line 35 are shown in Fig. 1.

[0088] The gas used is preferably a protective gas that essentially does not enter into any chemical reaction with the build-up material (inert gas), for example nitrogen or argon, depending on the build-up material used.

[0089] The laser sintering device 1 further contains a storage container 12 for a powdered building material 13 that can be melted or solidified by electromagnetic radiation, and a coater 14 that is movable in a horizontal direction H (y-direction) for applying the building material 13 within the build field 10. The coater 14 preferably extends transversely to its direction of movement over the entire area to be coated. In the device 1 shown in Fig. 1, the direction of movement H of the coater 14 runs into the plane of the drawing (indicated by a circle with a cross), but it can also run out of the plane of the drawing. The coater 14 is preferably arranged in the device 1 so that it can be moved in two opposite directions.

[0090] Optionally, a radiant heater (not shown in Fig. 1) can be arranged in the process chamber 3, which serves to heat the applied build material 13. An infrared radiator, for example, can be provided as the radiant heater.

[0091] The laser sintering device 1 further comprises a solidification device in the form of an exposure device 20 with a laser 21 which generates a laser beam 22 which is deflected via a deflection device 23 and directed onto the working plane 16 by a focusing device 24, for example an F-theta lens, via a coupling window 15 which is mounted in the ceiling 4a of the chamber wall 4.

[0092] The laser sintering device 1 further includes a control unit 29, via which the individual components of the device 1 are controlled in a coordinated manner to carry out the building process. Alternatively, the control unit can also be mounted partially or entirely outside the device. The term "control unit" refers in particular to any computer-based control device capable of controlling the operation of the additive device or a component thereof. For example, the control unit can be a computer. The control unit can contain a CPU whose operation is controlled by a computer program (software). The computer program can be stored separately from the additive manufacturing device in a storage device, from where it can be loaded into the additive manufacturing device, in particular into the control unit, e.g., via a network or by wireless transmission.

[0093] Various types of powder can be used as build-up material, including metal powder, plastic powder, ceramic powder, sand, filled powder, or mixed powder. Instead of powder, other suitable materials can also be used as build-up material.

[0094] In the following, the supply line 30 is described in more detail with reference to Figures 2 and 3, wherein Fig. 2 shows a perspective view of the second supply line section 37 and Fig. 3 shows a cross-sectional view of the second supply line section 37. The sectional planes in Fig. 3 run parallel to the xz plane, ie perpendicular to the construction field 10 in Fig. 1.

[0095] As described above, the second supply line section 37 is designed as a substantially cuboid-shaped housing 37a. For supplying the gas from the first supply line section 36 (see Fig. 1), the housing 37a has a connection element 38 which is designed to be connected to the first supply line section 36. A geometric shape of the connection element 38 preferably corresponds to a geometric shape of an adjacent section of the first supply line section 36, for example, the connection element 38 is designed as a circular opening. The connection element 38 preferably has fastening elements (not shown in detail in the figures) for fastening the first supply line section 36 thereto, or is formed integrally with the first supply line section 36.

[0096] Within the housing 37a, a gas-conducting connection is provided, which comprises a first line section 41 and a second line section 42 (see Fig. 3) for conducting gas from the connection element 38 to a gas outlet 39 of the second supply line section 37. A fastening element 40 is provided at the gas outlet 39 for fastening the flow modification element 31 (see Fig. 1) to the supply line.

[0097] The first line section 41 is spaced from the gas outlet 39 of the second supply line section 37 and thus from the flow modification element 31 (see Fig. 1) and preferably connects directly to the connection element 38. The second line section 42 is provided between the first line section 41 and the gas outlet 39 or the flow modification element 31 (see Fig. 1); preferably, it connects directly to the first line section 41 and the gas outlet 39 or the flow modification element 31.

[0098] The second line section 42 extends along a first direction of extension, which is substantially parallel to a plane of the construction field 10 in Fig. 1 and preferably runs parallel to the x-direction, over a length As. Transversely, preferably perpendicularly, to the first direction of extension and perpendicular to the plane of the construction field 10 in Fig. 1 , i.e. in the yz-plane, the second line section 42 has a substantially rectangular cross-section. The cross-section has a width B in the y-direction, i.e. parallel to the construction field 10 in Fig. 1 , and a height Hs in the z-direction. The width B of the second line section 42 preferably corresponds to at least one maximum dimension of the construction field 10 in the y-direction (see Fig. 1 ). The cross-section, and thus the width B and height Hs, is preferably constant over the entire length As of the second line section 41 and corresponds to a cross-section of the flow modification element orthe gas-permeable opening area of ​​the flow modification element 31 on its gas inlet side (see below). The length As of the second line section 42 is at least five times, preferably at least ten times, its height Hs. The length As of the second line section 42 is at least half its width B, preferably several times, in particular at least three times, greater than the width B of the second line section 42.

[0099] The first line section 41 shown in the figures is essentially S-shaped in the xz plane. In detail, the first line section 41 in the present embodiment has a first subsection 41a and a second subsection 41b, which are arranged essentially parallel to one another and one above the other in the z direction. The first subsection 41a and the second subsection 41b are in gas-conducting communication with one another via a curved subsection 43a of the first line section. The second subsection 41b is in gas-conducting communication with the adjoining second line section 42 via a further curved subsection 43b.

[0100] In the figures, the first and second sections 41a, 41b extend over a first length Ai and a second length A2, respectively, parallel to the first extension direction (x-direction) of the second line section 42. A cross-section of the first and second sections 41a, 41b perpendicular to the first extension direction, i.e., parallel to the yz plane, is rectangular in the present embodiment. The width B of the first and second sections 41a, 41b, as well as of the curved sections 43a, 43b, can be constant over the entire length of the first line section 41 and, in particular, equal to the width B of the second line section 42.However, it can also vary over the length of the first line section 41, wherein it is preferred that the width of the first line section 41, at least in a partial section adjoining the second line section 42, which preferably comprises at least two-thirds of a total length of the first line section 41, is substantially constant and equal to the width B of the second line section 42. The total length of the first line section 41 comprises at least the first length A1 and the second length A2 of the partial sections 41a, 41b. The total length of the first line section 41 is at least three times, preferably ten times, the width B of the second line section 42.

[0101] In the z-direction, i.e. perpendicular to its length and width, the first line section 41 has a height that decreases from a region of the connection element 38 to the second line section 42. In Fig. 3, the height of the first line section decreases step by step, with the first sub-section 41a having a first height Hi and the second sub-section 41b having a second height H2, where: Hi > H2 > H3 applies. Alternatively, the height of the first line section 41 can, for example, decrease continuously from an initial height to the height H3 of the second line section 42, or it can be constant.

[0102] In the present embodiment, the first line section 41 is substantially S-shaped parallel to the x-z plane, with mutually parallel partial sections 41a, 41b and curved partial sections 43a, 43b. Alternatively, the first line section 41 can also be Z-shaped, for example, or the partial sections 41a, 41b can be arranged obliquely to the first extension direction of the second line section 42 and / or obliquely to the x-direction and / or not parallel with respect to one another. The first line section 41 can also be S-shaped or Z-shaped, for example in a plane other than the xz plane.

[0103] Furthermore, the first line section can also be formed without a second sub-section 41 b, ie it can, for example, have only a first sub-section 41 a and a curved line section, or more than two sub-sections 41 a, 41 b, which are connected to one another via respective curved sub-sections.

[0104] The second supply line section 37 can also be designed without the housing 37a, for example, and be formed by corresponding pipes. In the figures, the shape of the housing 37a deviates from a cuboid shape in that an extension of the housing is provided in a lower section of the cuboid, into which the second line section 42 extends. The housing 37a can also deviate from the shape described here.

[0105] The flow modification element 31 shown in Fig. 1 is described in more detail below with reference to Figs. 4a-4c, 5a, 5b, 6a and 6b. Fig. 4a shows a perspective view of the flow modification element with a gas outlet side 142 facing forward towards the viewer in Fig. 4a and a gas inlet side 141 located at the rear in Fig. 4a. Figs. 4b and 4c show the flow modification element 31 in a plan view of the gas inlet side 141 (Fig. 4b) and the gas outlet side 142 (Fig. 4c). Fig. 5a shows a perspective sectional view of the flow modification element 31 along a height h of the flow modification element 31 (line AA in Fig. 4a), and Fig. 6a shows a sectional view of the flow modification element 31 along a width b of the flow modification element 131 (line CC in Fig.4a), wherein both sectional planes of Figures 5a and 6a run parallel to an extension of the flow modification element 31 from its gas inlet side 141 to its gas outlet side 142, ie its length L.

[0106] In the installed state of the flow modification element 31, the gas inlet side 141 faces the supply line 30 or the second line section 42 (see Figs. 1, 3), and the gas outlet side 142 faces away from the supply line 30 and toward the interior of the process chamber 3 (see Fig. 1). Thus, in the installed state, the flow modification element 31 extends along its length L from the gas inlet side 141 to the gas outlet side 142, preferably in the x-direction. The flow modification element 31 has a plurality of channels 143a, 143b, 143c, which are at least partially delimited by horizontal and vertical gas guide elements, as well as a wall 31a of the flow modification element 31, and which allow a transport of gas from the gas inlet side 141 to the gas outlet side 142. Laterally, e.g.in the direction of the width b, the flow modification element 31 has optional fastening devices 147 for fastening the flow modification element to the chamber wall 4 of the process chamber 3 (see Fig. 1 ) and / or to the supply line 30 (see Fig. 2, 3).

[0107] In detail, the channels 143a, 143b, 143c in the flow modification element 31 shown in Fig. 4a to 6b are arranged one above and next to each other in rows and columns, i.e. the flow modification element 31 has a row of first channels 143a, a row of second channels 143b and a row of third channels 143c. With respect to the build field 10, i.e. when the flow modification element 31 is installed in the device 1 in Fig. 1, the first channels 143a are the upper channels in the vertical direction (z-direction), i.e. furthest from the build field 10, and the third channels 143c are the lowest channels, i.e. closest to the build field 10, and the second channels 143b are arranged as middle channels between the first channels 143a and the third channels 143c.Between the first channels 143a and the second channels 143b, a first gas guide element 144a is provided, which delimits the first (upper) channels 143a at the bottom and the second (middle) channels 143b at the top. Furthermore, between the second channels 143b and the third channels 143c, a second gas guide element 144b is provided, which delimits the second (middle) channels 143b at the bottom and the third (lower) channels 143c at the top. In the present embodiment, the first channels 143a are delimited at the top by the wall 31a of the flow modification element 31, and the third channels 143c are delimited at the bottom by the wall 31a. In the present embodiment, the first and second gas guide elements 144a, 144b extend substantially over the entire length L from the gas inlet side 141 to the gas outlet side 142 (ie in the x-direction) of the flow modification element 31 (see Fig.5a) and in the y-direction over the entire width b of the flow modification element 31 (see Fig. 4a-4c). The first and second gas guide elements 144a, 144b are thus essentially horizontally arranged gas guide elements. Between adjacent channels of a series of channels, a third gas guide element 144c is provided, which at least partially delimits respective adjacent channels along the width b of the flow modification element (y-direction), and optionally together with the wall 31a of the flow modification element 31. In the present embodiment, the third gas guide elements 144c do not extend over the entire length L of the flow modification element 31, but only over a portion of the length L, from the gas inlet side 141 to the gas outlet side 142 (i.e. in the x-direction) of the flow modification element 31 (see Fig.6a and the explanations thereon below), and in the z-direction over the entire height h of the flow modification element 31 (see Figs. 4a-4c). The third gas guide elements 144c are thus essentially vertically arranged gas guide elements.

[0108] The shape of the horizontal gas guide elements 144a, 144b is described in more detail below with reference to Figs. 5a and 5b, and the shape of the vertical gas guide elements 144c with reference to Figs. 6a and 6b.

[0109] As shown in Fig. 5a, 5b, the first and second gas guide elements 144a, 144b each have, perpendicular to their longitudinal extent (i.e. in a plane parallel to the xz plane), a first section 151 adjacent to the gas inlet side 141 and a second section 152 adjacent to the gas outlet side 142. The first section 151 extends from the inlet side 141 in the direction of the outlet side 142 over a first extent xi and has a shape that tapers towards the gas inlet side 141 with a first widening angle ai. The second section 152 extends from the direction of the inlet side 141 to the outlet side 142 over a second extent X2 and has a shape that tapers towards the gas outlet side 142 with a second widening angle θ2.The first extension xi of the first section 151 is greater than the second extension x2 of the second section 152, and the first widening angle ai of the first section 151 is smaller than the second widening angle θ2 of the second section 152. The widening angles can, for example, be in the range from 1° to 3°. The widening angles ai, θ2 can, for example, be defined as the angle formed by the tangents adjacent to the top and bottom of the gas guiding elements 144a, 144b. Alternatively, the widening angles can be defined, for example, as an angle formed by the average slope of the top and bottom of the gas guiding elements. Preferably, the first and second gas guide elements 144a, 144b are each formed entirely by the first section 151 and the second section 152 and extend over the entire length L of the flow modification element 31, ie L = xi + X2.Fig. 5b alternatively shows the first or the second gas guide element 144a, 144b, although these are generally not identical in design, but differ from each other in their geometric shape and, for example, their expansion angle.

[0110] As shown in Fig. 6a, 6b, the third gas guide elements 144c have an extension parallel to the construction field 10, i.e., parallel to the xy plane, between the gas inlet side 141 and the gas outlet side 142 (i.e., in the x-direction) that is less than the length L of the flow modification element 31. More precisely, the third gas guide elements 144c each extend, starting at the gas inlet side 141, in the direction of the gas outlet side 142 over a length L' that is less than the length L of the flow modification element, so that they end at a distance D = LL' from the gas outlet side 142. Preferably, the length L' of the third gas guide elements 144c is at most two-thirds of the length L of the flow modification element 31.

[0111] Analogous to the design of the first and second gas guide elements 144a, 144c (see above), the third gas guide element 144c in the cross-sectional view of Fig. 6a, 6b also has a first section 153 adjacent to the gas inlet side and a second section 154 provided downstream of the first section 153 in the flow direction of the flow modification element 31, which each extend over a first extent X3 and a second extent X4, overall over the length L' = X3 + X4 of the third gas guide element 144c. The first section 153 has a shape that tapers towards the gas inlet side 141 with a first widening angle ß1, and the second section 154 has a shape that tapers towards the gas outlet side 142 with a second widening angle ß2.Preferably, the second expansion angle ß2 of the second section 154 is greater than the first expansion angle ßi of the first section 153, and the first extension X3 of the first section 153 is greater than the second extension X4 of the second section 154.

[0112] Optionally, a width b of the flow modification element 31 on the gas inlet side may differ from a width b' on the gas outlet side 142. In particular, the width b' on the gas outlet side 142 may be greater than the width b on the gas inlet side.

[0113] Each first channel 143a has an inlet opening 155a (see Fig. 4b) on the gas inlet side 141. Likewise, the second and third channels 143b, 143c have respective inlet openings 155b and 155c on the gas inlet side (Figs. 4b, 4c). The inlet openings 155a-c, 156a-c are delimited by the gas guide elements 144a-c and, if appropriate, the wall 31a. The inlet openings have respective opening cross-sectional areas in a plane of the gas inlet side 141 and / or in the yz plane. In Fig. 5a, the opening cross-sectional areas of the first, second, and third channels 143a, 143b, 143c on the gas inlet side 141 are represented by the respective heights zi, Z2, and Z3 of the channels in the z-direction. The total opening cross-sectional area of ​​the row of first channels 143a on the gas inlet side 141 is the sum of the opening cross-sectional areas of the inlet openings 155a of the first channels 143a.Analogously, total opening cross-sectional areas of the rows of second and third channels 143b, 143c on the gas inlet side are defined.

[0114] At the gas outlet side 142, a total opening cross-sectional area of ​​the row of first channels 143a is defined by the outlet opening 156a (see Fig. 4c), which is formed by the first gas guide element 144a and the upper wall 31a of the flow modification element 31 at the gas outlet side 142. In Fig. 5a, the total opening cross-sectional area of ​​the row of first channels 143a is represented by the height zi', ie the distance between the wall 31a and the first gas guide element 144a in the z-direction. Analogously, total opening cross-sectional areas of the series of second and third channels 143b, 143c are defined by respective outlet openings 156b, 156c on the gas outlet side (see Fig. 4c), wherein the outlet openings 156b, 156c are formed by the first and second gas guide elements 144a, 144b and the second gas guide element 144b and the lower wall 31a on the gas outlet side 142, and in Fig. 5a by respective heights Z2 1and zs' are shown. The outlet openings 156a, 156b, 156c can, for example, be elongated and / or slit-shaped. Preferably, they each extend over the entire width b' of the flow modification element 31 on the gas outlet side 142.

[0115] As shown in Fig. 4b and 5a, the first gas guide element 144a and the second gas guide element 144b are designed such that the total opening cross-sectional areas of the rows of first, second and third channels 143a, 143b and 143c on the gas inlet side 141 are substantially equal, represented in Fig. 5a by substantially equal heights zi , Z2 and zs of the channels on the gas inlet side 141.

[0116] As shown in Fig. 4c and 5a, the first gas guide element 144a and the second gas guide element 144b, and preferably additionally the wall 31a, are designed such that the total opening cross-sectional areas of the rows of first, second and third channels 143a, 143b and 143c on the gas outlet side 142 differ from each other, represented in Fig. 5a by different heights zi', Z2 1 and zs'. In detail, the total opening cross-sectional area of ​​the second (middle) channels 143b is larger than the respective total opening cross-sectional area of ​​the first (upper) channels 143a and the third (lower) channels 143c at the gas outlet side 142, in Fig. 5a: Z2 1 > zi' and Z2 1> zs'. For example, on the gas outlet side, a total opening cross-sectional area of ​​the first (upper) channels 143a or the third (lower) channels 143c can be between 50% and 70% of the total opening cross-sectional area of ​​the second (middle) channels 143b. The total opening cross-sectional areas of the first (upper) channels 143a and the third (lower) channels 143c on the gas outlet side 142 can be substantially equal or differ from each other.

[0117] For each row of channels 143a-c, the respective total opening cross-sectional area on the gas inlet side 141 is preferably larger than on the gas outlet side 142. Furthermore, the first gas guide element 144a, and optionally the wall 31a delimiting the row of first channels 143a, is designed such that a first gas partial flow 61, which is introduced into the process chamber 3 from the first channels 143a during operation, is directed towards the working plane 16 or the plane of the construction field 10, as shown in Fig. 7b. The first gas guide element 144a, the second gas guide element 144b, and optionally the wall 31a delimiting the third channels 143c are designed such that a second gas partial flow 62 and a third gas partial flow 63 (see Fig. 7b), which are introduced during operation through the second channels 143b and third channels 143c, are essentially horizontal, iein the x-direction, or at least have a smaller upward or downward directional component than the first partial gas flow 61 flowing in through the first channels 143a.

[0118] For example, an angle y formed by the inflowing first gas partial stream 61 with the x-direction may be approximately 30°.

[0119] The flow modification element 31, or at least the gas guiding elements 144a, 144b, 144c, can, for example, be an object manufactured using an additive manufacturing process.

[0120] In the present embodiment, the flow modification element 31 has seven third (vertical) gas guide elements 144c, so that each row of channels is formed from a total of eight channels (see Figs. 4a-4c, 6a). However, the flow modification element 31 can also have more or fewer than seven third gas guide elements, or be formed without the third gas guide element. Likewise, the flow modification element 31 can have only a single horizontal gas guide element instead of the two horizontal gas guide elements (first and second gas guide elements 144a, 144b), or more than two horizontal gas guide elements, and accordingly a number of rows of channels other than two.

[0121] Fig. 7a shows a section of the device 1 shown in Fig. 1 in a cross-sectional view perpendicular to the construction field with sections of the chamber wall 4, the first and second supply line sections 41, 42 of the supply line in the housing 37a, and with the flow modification element 31. The gas outlet side 142 of the flow modification element 31 is arranged in Fig. 7a offset from a plane of the chamber wall 4 into the process chamber, and the outlet openings 156a-c (see Fig. 4c; not shown in Fig. 7a) form the gas inlet 32 ​​through which the gas flows into the process chamber 3 during operation of the flow device. The flow modification element 31 is directly connected to the second line section 42 of the supply line.

[0122] The operation of the laser sintering or laser melting device 1 is described below with reference to Figures 1 to 7b. First, to apply a powder layer, the carrier 7 is lowered by a height corresponding to the desired layer thickness. The coater 14 moves to the storage container 12 and takes from it a quantity of the building material 13 sufficient to apply a layer. The storage container 12 does not have to be arranged above, as shown in Fig. 1, but can also be arranged below the working plane 16 and can be designed, for example, as a dosing stamp that feeds a specific quantity of the building material 13 to the coater 14 at a time. The coater 14 then moves over the build field 10, applies building material 13 to the build base or a previously existing powder layer, and draws it out into a powder layer.The application takes place at least over the entire cross-section of the object 2 to be produced, preferably over the entire construction area 10, i.e., the area delimited by the container wall 6. Optionally, the applied build material is heated to a working temperature using a radiant heater (not shown).

[0123] The cross-section of the object 2 to be produced is then scanned by the laser beam 22, so that the powdery building material 13 is solidified at locations that correspond to the cross-section of the object 2 to be produced. The powder grains are partially or completely melted at these locations by means of the energy introduced by the radiation, so that after cooling they are present as a solid, bonded to one another. These steps are repeated until the object 2 is completed and can be removed from the process chamber 3. During the layer-by-layer construction of the object 2, a gas is at least temporarily introduced into the process chamber 3 by the gas supply device (not shown) through the supply line 30 and the flow modification element 31 through the gas inlet 32 ​​and is guided out of the process chamber 3 again through the gas outlet 34 and the discharge line 35.sucked out of this, so that a gas flow 33 is generated in the process chamber 3. This flows through the process chamber above the working level 16 at least along the build field 10. The gas enters the process chamber in the form of gas inlet partial flows, wherein the first gas partial flow 61 is introduced through the first row of channels 143a, and the second and third gas partial flows 62, 63 are introduced through the second and third rows of channels 143b, 143. As described above, the first (upper) gas partial flow 61 exits the row of first (upper) channels 143a at an angle downwards towards the build field 10. As a result, the entire gas flow 33, which is formed from the partial gas flows 61, 62, 63, is directed towards the plane of the construction field 10, at least initially, ie after the gas has been introduced into the process chamber, and / or a bundling of the partial gas flows 61, 62, 63 can be achieved.This allows, for example, effective removal of contaminants directly at their source (the construction area). Since the directional component is caused by the upper partial gas flow 61, a splitting of the entire gas flow 33 can be prevented, which can reduce turbulence in the gas flow 33.

[0124] In Fig. 7b, the directional components of the partial gas streams 61, 62, and 63 are shown purely schematically by arrows. However, the partial gas streams 61, 62, and 63 are not limited to these flow paths.

[0125] The present invention is not limited to the embodiment described above. For example, the flow modification element can also be used with a differently designed supply line instead of the supply line described with reference to Figures 1 to 3. Likewise, the supply line can also be used in combination with a different gas inlet or a flow modification element other than those described with reference to Figures 4a to 6b, for example a grid, perforated plate, or the like. The arrangement of the gas inlet or the flow modification element, as well as the gas outlet, is not limited to a lower height region of the process chamber. For example, the gas inlet and / or the flow modification element and / or the gas outlet can alternatively or additionally be provided in an upper height region of the process chamber. More than one gas inlet and / or more than one gas outlet can also be provided for introducing or discharging the gas.Discharge of the gas flow should be provided.

[0126] Although the present invention has been described with reference to a laser sintering or laser melting device, it is not limited to laser sintering or laser melting. It can be applied to any method for the additive production of a three-dimensional object by layer-by-layer application and selective solidification of a build-up material.

[0127] The exposure device can, for example, comprise one or more gas or solid-state lasers or any other type of laser such as laser diodes, in particular VCSEL (Vertical Cavity Surface Emitting Laser) or VECSEL (Vertical External Cavity Surface Emitting Laser), or a line of these lasers. In general, any device with which energy can be applied selectively to a layer of the build material as wave or particle radiation can be used as the exposure device. Instead of a laser, for example, another light source, an electron beam or any other energy or radiation source suitable for solidifying the build material can be used. Instead of deflecting a beam, exposure with a movable line exposure device can also be used.The invention can also be applied to selective mask sintering, in which an extended light source and a mask are used, or to high-speed sintering (HSS), in which a material is selectively applied to the build material that increases (absorption sintering) or decreases (inhibition sintering) radiation absorption at the corresponding locations, and then exposed non-selectively over a large area or with a movable line exposure unit. Instead of introducing energy, the selective solidification of the applied build material can also be achieved by 3D printing, for example by applying an adhesive. In general, the invention relates to the generative production of an object by means of layer-by-layer application and selective solidification of a build material, regardless of the manner in which the build material is solidified.

Claims

Claims 1. Flow device for a manufacturing device (1) for the additive manufacturing of a three-dimensional object (2) by layer-by-layer selective solidification of a build material in a build area (10) in a process chamber (3) of the manufacturing device, wherein the flow device comprises: a gas supply device for generating a gas flow (33) at least in the process chamber (3), a supply line (30) for supplying the gas flow to the process chamber, and a flow modification element (31) for introducing the gas flow from the supply line (30) into the process chamber (3), wherein the flow modification element (31) has a gas inlet side (141) facing the supply line (30), a gas outlet side (142) facing away from the supply line, at least one first gas guide element (144a, 144b) extending from the gas inlet side (141) to the gas outlet side (142), and a Multiple channels (143a, 143b, 143c),wherein each of the channels allows the transport of gas from the gas inlet side (141) to the gas outlet side (142), wherein the first gas guiding element (144a, 144b) at least partially defines a number of first channels (143a) and a number of second channels (143b) which are spaced apart from each other such that the number of second channels (143b) is arranged closer to the building area (10) in a direction perpendicular to the building area than the number of first channels (143a), and wherein the first gas guiding element (144a, 144b) is designed such that a total opening cross-sectional area associated with the number of first channels (143a) at the gas outlet side differs from a total opening cross-sectional area associated with the number of second channels (143b) at the gas outlet side,and the total opening cross-sectional area associated with the number of first channels (143a) on the gas inlet side and the total opening cross-sectional area associated with the number of second channels (143b) on the gas inlet side are substantially equal, and / or wherein the first gas guiding element (144a, 144b) is designed such that at least one partial gas flow (61), which in operation of the flow device consists of the number, The first channel (143a) is introduced into the process chamber (3) and is directed towards a plane of the construction site (10).

2. Flow device according to claim 1, wherein the flow modification element (31) further comprises a second gas guide element (144b) extending from the gas inlet side (141) to the gas outlet side (142), which at least partially defines a number of third channels (143c), wherein the number of third channels (143c) is spaced apart from the number of first channels (143a) and the number of second channels (142b) such that the number of third channels (143c) is arranged closer to the build area (10) in a direction perpendicular to the build area than the number of second channels (142b).

3. Flow device according to claim 2, wherein the first gas guiding element (144a) and the second gas guiding element (144b) are configured such that the total opening cross-sectional area associated with the number of second channels (143b) at the gas outlet side (142) is larger than the total opening cross-sectional area associated with the number of first channels (143a) at the gas outlet side (142) and / or a total opening cross-sectional area associated with the number of third channels (143c) at the gas outlet side (142), wherein preferably a total opening cross-sectional area associated with the number of first channels (143a) at the gas inlet side (141) and / or a total opening cross-sectional area associated with the number of second channels (143b) at the gas inlet side (141) and / or a total opening cross-sectional area associated with the number of third channels (143c) at the gas inlet side (141) the total opening cross-sectional area assigned is essentially the same,and / or wherein the first gas guiding element and the second gas guiding element are designed such that the total opening cross-sectional area associated with the number of first and / or second and / or third channels on the gas outlet side (142) is in each case smaller than the total opening cross-sectional area associated with the number of first or second or third channels on the gas inlet side (141).

4. Flow device according to one of claims 1 to 3, wherein the first and / or the second gas guiding element (144a, 144b) has a first section (151) adjoining the gas inlet side (141) which extends towards the gas inlet side having a tapered shape, and / or a second section (152) adjoining the gas outlet side (142), which has a shape tapering towards the gas outlet side, wherein preferably an extent (xi) of the first section (151) between the gas inlet side and the gas outlet side is greater than an extent (X2) of the second section between the gas inlet side and the gas outlet side and / or wherein preferably an expansion angle (02) of the second section (152) is greater than an expansion angle (ai) of the first section (151) and / or wherein the first gas guiding element and / or the second gas guiding element extends over an entire extent (L) of the flow modification element from the gas inlet side to the gas outlet side.

5. Flow device according to one of claims 1 to 4, wherein the flow modification element (31) further comprises at least one third gas guide element (144c) extending substantially perpendicular to a plane of the build area (10), wherein the third gas guide element (144c) preferably extends from the gas inlet side (141) towards the gas outlet side (142) of the flow modification element (31) and terminates at a distance (D) from the gas outlet side (142), further preferably wherein the third gas guide element (144c) extends over a length (L) 1 ) extends, which corresponds to at most two thirds of the extension (L) of the flow modification element (31 ) from the gas inlet side to the gas outlet side.

6. Flow device according to claim 5, wherein the third gas guiding element (144c) has a first section (153) adjacent to the gas inlet side (141) and having a shape tapering towards the gas inlet side, and / or a second section (154) provided downstream of the first section and having a shape tapering towards the gas outlet side (142), wherein preferably an extent (xs) of the first section (153) between the gas inlet side and the gas outlet side is greater than an extent (X4) of the second section (154) between the gas inlet side and the gas outlet side and / or wherein preferably an expansion angle (ß2) of the second section (154) is larger than an expansion angle (ßi) of the first section (153).

7. Flow device according to one of claims 1 to 6, wherein the first and / or the second gas guiding element (144a, 144b) is designed as a substantially horizontally arranged planar body and / or wherein the third gas guiding element (144c) is designed as a substantially vertically arranged planar body, wherein preferably at least the planar body, more preferably the entire flow modification element (31), is manufactured in an additive manufacturing process.

8. Flow modification element for a manufacturing device (1) for the additive manufacturing of a three-dimensional object (2) by layer-by-layer selective solidification of a build material in a build area (10) in a process chamber (3) of the manufacturing device, wherein the flow modification element (31) is configured to introduce a gas flow (33) from a supply line (30) into the process chamber (3), wherein the flow modification element (31) has a gas inlet side (141) facing the supply line (30), a gas outlet side (142) facing away from the supply line, at least one first gas guide element (144a, 144b) extending from the gas inlet side to the gas outlet side, and a plurality of channels (143a, 143b, 143c), wherein each of the channels transports gas from the gas inlet side (141) to the gas outlet side. (142) permitted, whereby the first gas guiding element (144a,144b) a number of first channels (143a) and a number of second channels (143b) are at least partially defined, which are spaced apart from each other such that the number of second channels (143b) is arranged closer to the construction area in a direction perpendicular to the construction area (10) than the number of first channels (143a), and wherein the first gas guiding element (144a, 144b) is designed such that a total opening cross-sectional area associated with the number of first channels (143a) at the gas outlet side (142) differs from a total opening cross-sectional area associated with the number of second channels (143b) at the gas outlet side, and one of the approach, the total opening cross-sectional area assigned to the number of first channels (143a) on the gas inlet side (141) and the total opening cross-sectional area assigned to the number of second channels (143b) on the gas inlet side (141) are essentially the same size, and / or wherein the first gas guiding element (144a, 144b) is designed such that at least one partial gas flow (61) which is introduced into the process chamber (3) from the number of first channels (143a) during operation of the flow device is directed towards a plane of the build area (10).

9. Flow device for a manufacturing device (1) for the additive manufacturing of a three-dimensional object (2) by layer-by-layer selective solidification of a build material in a build area (10) in a process chamber (3) of the manufacturing device, wherein the flow device comprises: a gas supply device for generating a gas flow (33) at least in the process chamber (3), a supply line (30) for supplying the gas flow to the process chamber, and a flow modification element (31) for introducing the gas flow from the supply line (30) into the process chamber (3), wherein the supply line (30) comprises at least a first line section (41) which is spaced apart from the flow modification element (31) and which is substantially s-shaped and / or z-shaped, and the supply line comprises at least a second line section (42) which is provided between the first line section (41) and the flow modification element (31). is,preferably connects directly to the first conduit section (41) and the flow modification element (31), and extends along a first direction of extension, which is substantially parallel to a plane of the construction area (10), over a length (As) that is at least five times, preferably at least ten times, a height (Hs) of the second conduit section (42) transverse to the first direction of extension and substantially perpendicular to a plane of the construction area (10).

10. Flow device according to claim 9, wherein the second conduit section (42) extends along its first direction of extension over a length (As) which is at least as large as half a width (B) of the second conduit section (42) transverse to the first direction of extension and substantially parallel to a plane of the construction area (10), preferably wherein the length (As) of the second conduit section (42) is at least as large as the width (B) of the second conduit section (42), further preferably at least one and a half times, even more preferably at least twice, particularly preferably at least three times greater than the width of the second conduit section (42).

11. Flow device according to claim 9 or 10, wherein the first conduit section (41) comprises at least a first subsection (41a) and at least a second subsection (41b) which are arranged substantially parallel to each other and / or parallel to a plane of the construction area (10) and / or which are fluidically connected to each other via a curved subsection (43a) of the first conduit section (41), wherein a total length of the first conduit section (41), which comprises at least a first length (Ai) of the first subsection (41a) and a second length (A2) of the second subsection (41b) in a direction substantially parallel to a plane of the construction area (10), preferably parallel to the first extension direction, is at least three times, preferably ten times, a width (B,b) of the flow modification element and / or the second conduit section transverse to the first direction of extension and substantially parallel to a plane of the construction site (10)., 12. Flow device according to one of claims 9 to 11, wherein a cross-section of the second conduit section (42) in a plane transverse to the first extension direction is substantially as large as a cross-section of the flow modification element (31) at a gas inlet side (141) of the flow modification element adjoining the second conduit section, and / or has substantially the same geometric shape, in particular a rectangular shape.

13. Flow device according to one of claims 9 to 12, wherein in a direction parallel to the plane of the construction area (10) a width (B) of at least one sub-section of the first line section (41) adjoining the second line section (42) is substantially the same as the width (B) of the second line section (42), wherein the sub-section of the first line section (41) preferably comprises at least two-thirds of a total extent of the first line section (41).

14. Flow device according to one of claims 9 to 13, wherein in a direction perpendicular to the plane of the construction area (B) a height (Hi , H2) of the first conduit section (41 ) decreases towards the second conduit section (42), preferably continuously or stepwise, and / or wherein a height (H3) of the second conduit section (42) is substantially constant in a direction perpendicular to the plane of the construction area (10).

15. Flow device according to one of claims 1 to 7 or 9 to 14, wherein the flow modification element (31) is provided substantially in a lower height region of the process chamber (3).

16. Manufacturing device for the additive manufacturing of a three-dimensional object (2) by layer-by-layer selective solidification of a build material in a build area (10) in a process chamber (3), comprising a flow device according to one of claims 1 to 7 or 9 to 15, or a flow modification element according to claim 8.

17. Flow method for generating a gas flow (33) in a manufacturing device (1) for the additive manufacturing of a three-dimensional object (2) by layer-by-layer selective solidification of a build material in a build area (10) in a process chamber (3) of the manufacturing device, wherein the flow method comprises the following steps: Generating a gas flow (33) at least in the process chamber (3) by means of a gas supply device, Supplying the gas flow to the process chamber (3) by means of a supply line (30) and Introducing the gas flow from the supply line (30) through a flow modifying element (31) into the process chamber (3), wherein the flow modifying element (31) has a gas inlet side (141) facing the supply line (30), a gas outlet side (142) facing away from the supply line, at least one first gas guiding element (144a, 144b) extending from the gas inlet side to the gas outlet side, and a plurality of channels (143a, 143b, 143c), wherein each of the channels allows transport of gas from the gas inlet side (141) to the gas outlet side (142), wherein the first gas guiding element (144a, 144b) at least partially defines a number of first channels (143a) and a number of second channels (143b) that are spaced apart from each other such that the number of second channels (143b) can be divided into a direction perpendicular to the construction area (10) is arranged closer to the construction area than the number of first channels (143a), and wherein the first gas guiding element (144a, 144b) is designed such thatthat the total opening cross-sectional area associated with the number of first channels (143a) at the gas outlet side (142) differs from the total opening cross-sectional area associated with the number of second channels (143b) at the gas outlet side (142), and the total opening cross-sectional area associated with the number of first channels (143a) at the gas inlet side (141) and the total opening cross-sectional area associated with the number of second channels (143b) at the gas inlet side (141) are substantially the same size, and / or wherein the first gas guiding element (144a, 144b) is designed such that at least one partial gas flow (61) introduced into the process chamber (3) from the number of first channels (143a) during operation of the flow device is directed towards a plane of the build area (10).

18. Flow method for generating a gas flow (33) in a manufacturing device (1) for the additive manufacturing of a three-dimensional object (2) by layer-by-layer selective solidification of a build material in a build area (10) in a process chamber (3) of the manufacturing device, wherein the flow method comprises the following steps: Generating a gas flow (33) at least in the process chamber (3) by means of a gas supply device, Supplying the gas flow to the process chamber via a supply line (30) and Introducing the gas flow from the supply line (30) through a flow modification element (31) into the process chamber (3), wherein the supply line (31) comprises at least a first line section (41) which is spaced apart from the flow modification element (31) and which is substantially s-shaped and / or z-shaped, and the supply line comprises at least a second line section (42) which is provided between the first line section (41) and the flow modification element (31), preferably each directly adjoining the first line section (41) and the flow modification element (31), and which extends along a first direction of extension, which is substantially parallel to a plane of the construction area (10), over a length (As) which is at least five times, preferably at least ten times,a height (Hs) of the second conduit section (42) transverse to the first extension direction and substantially perpendicular to a plane of the construction site (10)., 19. Manufacturing process for the additive manufacturing of a three-dimensional object (2) in a process chamber (3) of a manufacturing device (1 ) comprising the steps: layer-by-layer application of a build material in a build area (10), selective solidification of the applied layer and Repeating the steps of layer-by-layer application and selective solidification until the three-dimensional object (2) is produced, wherein at least temporarily during the production of the three-dimensional object a flow process according to one of claims 17 or 18 is carried out.

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