Machine tool and flow guide device

Abstract

The present invention provides a machine tool 100 for the additive construction of a workpiece, comprising a processing chamber 10 in which additive manufacturing of the workpiece takes place, a process gas device 40 configured to introduce a process gas flow 41 into the processing chamber 10 during additive manufacturing, and a flow directing element 51 for the process gas flow 41 fastened within the processing chamber 10, the flow directing element 51 being elastically deformable between a first position in which the flow directing element 51 has a first outer contour shape and a second position in which the flow directing element 51 has a second outer contour shape different from the first outer contour shape.

Description

[Technical Field]

[0001] The present invention relates to a machine tool for the layer-by-layer additive construction of a workpiece and a flow directing device for use with the machine tool.

[0002] Background of the Invention From the state of the art, one-dimensional forming methods are known for the additive manufacturing of three-dimensional workpieces, in the process of which the workpiece is built up layer by layer from a provided material.

[0003] For this purpose, the powder material is typically applied as a material layer to a carrier located in the processing chamber of the machine tool and then solidified by location-specific irradiation, for example by melting or sintering individual material particles of the material layer, to form the workpiece layer.

[0004] When the workpiece layer has solidified, a new layer of raw material is applied to the carrier or to the already produced workpiece layer, and a new location-specific irradiation is performed.

[0005] In this manner, the workpiece is successively built layer by layer from multiple layers of material applied to the carrier.

[0006] During this manufacturing process, undesirable effects typically occur that adversely affect the process conditions within the processing chamber and therefore ultimately the manufacturing quality.

[0007] Thus, the treatment space delimited by the treatment chamber is loaded with contaminants, for example, by exhaust gases generated during solidification or by swirling of unsolidified material, and on the other hand, the treatment space is continuously heated by waste heat generated during irradiation, which can lead, for example, to thermally induced deformations of individual components within the treatment chamber.

[0008] In order to counteract these adverse effects and provide optimal process conditions that hardly change during the manufacturing process, the process gas flow is usually guided through a processing chamber, via which, for example, said contaminants or the generated waste heat are exhausted from the processing chamber.

[0009] However, in this case, the process gas flow itself may cause undesirable effects, for example by causing the unsolidified material on the carrier to swirl, which not only contaminates the processing space itself but also leads to non-uniformity of the applied material.

[0010] To counter this, the process gas flow and the processing chamber are synchronized with one another, thus providing a process gas flow that is as laminar as possible without, for example, swirling. This synchronization is made more difficult by other components of the machine tool located within the processing chamber, such as, for example, a moving coater for applying material to a carrier, which may cause undesired swirling.

[0011] For this purpose, EP 3928900 A1 discloses a machine tool with a movable coater, in which the processing chamber is of substantially rectangular parallelepiped design and the flat side walls extend parallel to the introduction direction of the process gas flow introduced into the processing chamber, so that the process gas flow can flow substantially along the flat elements without swirling during processing. To eliminate the coater movable in the processing chamber as a source of undesired swirling, the coater is removed from the processing chamber after the material has been applied to the base carrier through an opening in the side wall that can be closed by a flap.

[0012] Such a solution requires the entire process chamber, designed for the process gas flow, to have a substantially purely flat boundary surface for guiding the process gas flow. As a result, on the one hand, the developer's design freedom is significantly limited, and on the other hand, additional components can hardly be introduced into the process chamber because they may cause disturbances to the process gas flow. Examples of such components may include optical systems for monitoring the manufacturing process, lighting elements or other sensors / actuators for monitoring and controlling the manufacturing process.

[0013] Summary of the Invention It is therefore an object of the present invention to provide an efficient possibility for targeted guidance of process gas flows through the processing chambers of machine tools set up for additive manufacturing, which is easily adaptable to different configurations of machine tools.

[0014] To this end, a machine tool according to claim 1 and a flow guiding device according to claim 20 are provided.

[0015] The respective dependent claims relate to preferred embodiments which may each be provided alone or in combination.

[0016] According to a first aspect of the present invention, there is provided a machine tool for additive manufacturing of a workpiece, comprising: a processing chamber in which additive manufacturing of the workpiece takes place; a process gas device configured to introduce a process gas flow into the processing chamber during additive manufacturing; and a flow directing element for the process gas flow fastened within the processing chamber, the flow directing element being elastically deformable between a first position in which the flow directing element has a first outer contour shape and a second position in which the flow directing element has a second outer contour shape different from the first outer contour shape.

[0017] The flow guiding element here functions to guide the process gas flow introduced at the inlet in a targeted manner through the processing chamber to the outlet in the form of a laminar flow with as little swirl as possible of the introduced process gas flow.

[0018] To this end, one or more portions of the outer contour of the flow directing element, at least in a first position of the flow directing element, form one or more flow boundaries for a process gas stream flowing through the processing chamber, the process gas stream starting from the inlet into the processing chamber and being guided along the flow boundaries to the outlet, where the outer contour shape refers to the shape of the outer contour.

[0019] The other flow boundary surface here can be formed by the side / ceiling or base elements of the processing chamber.

[0020] Thus, the flow guiding elements fastened within the processing chamber establish a flow boundary surface for the process gas flow that differs from the inner contour of the processing chamber, so that the process gas flow can be guided in a targeted manner through a partial region of the processing space bounded by the processing chamber (the inner space of the processing chamber).

[0021] As a result, machine tool features, elements or components within the processing area that would otherwise lead to turbulence in the process gas flow can be shielded from the process gas flow via the flow directing elements.

[0022] The inventive elastic deformability of the flow guiding element, whereby the outer contour of the flow guiding element can be transferred between a first outer contour shape and a second outer contour shape, allows the flow guiding element to be adapted to changing boundary conditions in the processing area, so that the process gas flow can always be optimally guided through the processing chamber. Traversing (i.e., moving) components of a machine tool during a manufacturing process can be mentioned as an example of said changing boundary conditions.

[0023] The magnitude of the deformation between the first and second positions is significant here, as it can be, for example, greater than 2%, preferably greater than 5%, and even more preferably greater than 20% with respect to the length or width of the portion of the flow guiding element that functions as a flow interface.

[0024] In a preferred embodiment, the flow directing element is designed such that the first outer profile corresponds substantially to a plane.

[0025] In this way, a shape is provided for guiding the process gas flow which remains particularly simple and does not introduce any swirls compared to any curved surface.

[0026] In a preferred embodiment, the flow directing element is arranged in the first position with a plane extending parallel to the introduction direction of the introduced process gas flow.

[0027] Here, parallel is to be understood to mean that the direction vector of the introduction direction runs perpendicular to the normal vector of the plane.

[0028] In this way, the flow guiding elements are subjected to thrust forces (caused by thrust stresses in the fluid, i.e., in the process gas flow) only by the parallel flowing process gas flow, which means that the load on the flow guiding elements is low, in contrast to the process gas flow which would otherwise impinge at an angle and come from the inlet.

[0029] Alternatively, however, the flow guiding element can also be designed so that the plane is at an angle to the introduction direction, in which case the flow guiding element can even be used as a deflection element to correct the direction of the introduced process gas flow, for example to compensate for assembly-related inaccuracies, in particular of the inlet.

[0030] Therefore, the first position should not be limited to a parallel arrangement, but can also be arranged at an angle to the introduction direction such that the normal vector of the introduction direction and the direction vector form an angle of 30 to less than 90 degrees with respect to each other, preferably 45 to less than 90 degrees, and particularly preferably 70 to less than 90 degrees.

[0031] Said angle is preferably adjustable via an adjustable bearing arrangement, via which the flow guiding element is fastened in the processing chamber.

[0032] In particular, the bearing device is attached to a ceiling element of the processing chamber and comprises a mounting element for mounting on the ceiling element and a holding element connected thereto and adjustable at an angle relative to the mounting element, to which the flow guiding element is fastened.

[0033] The guiding device can preferably be provided on a side element of the processing chamber, in which one or more ends of the flow guiding element are guided so as to be translationally displaceable, in particular in the displacement direction.

[0034] As a result, additional support for the flow guiding element is provided, so that there is a more stable fastening within the processing chamber, and further, the possibility of optionally providing movement of the flow guiding element is not inhibited or hindered.

[0035] In a preferred embodiment, the flow directing elements are flexible surface elements. Surface elements refer to elements whose geometric dimension in the thickness direction (thickness) is preferably smaller than their dimensions in the width and length directions (width and length).

[0036] It is preferably a thin surface element with a ratio of thickness to width or thickness to length of not more than 10%, preferably less than 5%, more preferably less than 1%, particularly preferably less than 0.1%.

[0037] Flexible here should be understood to mean that the bending stiffness of the surface element in the thickness direction is less than the tensile stiffness in the longitudinal or width direction.

[0038] To make it possible to compare the bending stiffness and the tensile stiffness in different SI units, the bending stiffness can be understood to mean the stiffness of the surface element, which represents the restoring force that counteracts the individual forces acting on a reference point of the surface element in the thickness direction. The reference points are therefore preferably located here in the central region of the surface element rather than in the edge region, in order to obtain a suitable reference value for the bending stiffness.

[0039] The ratio of bending stiffness to tensile stiffness in the longitudinal or transverse direction of the surface element is preferably less than 25%, preferably less than 10%, more preferably less than 5%, particularly preferably less than 1%.

[0040] As a result of the embodiment as a flexible surface element, the flow guiding element can be bent and deformed particularly easily and without consuming much force, which is particularly beneficial for deformation from the first position to the second position (or vice versa).On the other hand, the stiffness parallel to the surface acting as the flow boundary is very high and therefore the shear distortion due to the process gas flow is very low.

[0041] The flow directing element is therefore preferably deformable by bending between a first position and a second position.

[0042] In a preferred embodiment, the flexible surface element is a film element or a fabric element. In this way, the flow directing element can be manufactured particularly cost-effectively.

[0043] The film element can be a metal or plastic film, and the textile element can be made of woven or knitted fabrics such as fabric, plastic, carbon or metal fibers.

[0044] The sheet metal elements can be thin sheets of, for example, aluminum or steel alloys, in particular spring steel strips, in this way making it possible to provide particularly resistant flow guide elements.

[0045] In a preferred embodiment, the flow directing element, in the first position, divides the interior space of the processing chamber into a first region and a second region, the first region being a processing region where additive manufacturing occurs, and the process gas device is configured to introduce a process gas flow into the first region.

[0046] In this way, the division of the processing chamber can be particularly easily performed, and in the process, the processing area can be geometrically optimally adapted to the process gas flow, regardless of the size of the processing chamber. Furthermore, in this way, an area separated from the processing area can be provided, in which machine tool components can be arranged that would otherwise adversely affect the process gas flow, i.e., without the division. This can include, for example, additional sensor devices or filling devices for the material to be applied to the layer.

[0047] If the flow guiding element is designed as a film element, it is preferably transparent (or translucent) so that the light beam path can (for the most part) penetrate it unhindered, so that, for example, a machine operator can see through the flow guiding element into the first area (processing area) in order to follow the production there.

[0048] In a preferred embodiment, the build station of the machine tool where the additive build takes place is located entirely within the first region.

[0049] As a result, almost all sources of pollutants (swirl material, exhaust gases, combustion products) are located in the area through which the process gas flows, where they can be reliably removed by the process gas flow, while machine tool components located in other areas are shielded from said pollutants.

[0050] In a preferred embodiment, the processing chamber comprises a side housing element, an upper housing element, and a lower housing element, and the housing elements and flow guiding elements are arranged relative to each other such that, in a first position of the flow guiding element, an introduced process gas flow flows as a parallel flow along the flow guiding element through a first region of the interior space of the processing chamber.

[0051] As a result, possible causes of swirling in the first region of the interior space are reduced to a minimum, so that particularly stable flow conditions are achieved. In this way, swirling or whirling, if it occurs, decays again relatively quickly.

[0052] In a preferred embodiment, the machine tool comprises a coating device movable relative to the processing chamber between a first end position and a second end position, configured to apply a layer of material for additive manufacturing to a build area of ​​the machine tool in the processing chamber, and further configured to elastically deform the flow guiding element between the first position and the second position upon movement.

[0053] Thus, a coating device typically used to apply a material layer can be used as a component of a machine tool that can move relative to the build site in the processing chamber, without the latter representing an element that disrupts the process gas flow at its end points. The flow guide element functions here as a variably or passively adjustable separation element in the processing chamber, with the adjustment action being triggered by the coating device. Thus, the coating device can move through the first region of the processing chamber to allow access to or exit from the first region without the need to provide a complex separation element with its own drive.

[0054] The coating device can therefore reversibly displace the flow guiding element in the course of its movement to achieve an end position outside the first region without having to move the flow guiding element itself, for example via a drive unit.

[0055] In a preferred embodiment, the flow guiding element is brought into the second position when the coating device is located in the first end position of the coating device, and in the second position the flow guiding element at least partially supports the coating device and in particular partially nests relative to its outer contour.

[0056] In this way, the coating device and the flow directing element terminate flush with one another at the second position, so that the first and second regions within the processing chamber itself are relatively closely separated from one another at the second position.

[0057] In a preferred embodiment, the side surface of the coating apparatus forms a control surface for the process gas flow introduced at the first end position.

[0058] The coating device itself therefore functions as a kind of flow guiding element for the process gas flow, with the result that, inter alia, additional material for the guiding element that would otherwise have to be provided separately can be saved.

[0059] In a preferred embodiment, the side surface of the coating device in the first end position and the outer contour of the flow directing element in the first position lie in the same plane relative to the processing chamber.

[0060] In this way, the coating device in the first end position partially takes the position of the flow guiding element, so that the flow boundary surface of the process gas flow in the first position of the flow guiding element corresponds as geometrically as possible to the flow boundary surface of the process gas flow when the coating device is in the first end position. The geometric boundary conditions of the process gas flow therefore remain almost unchanged for the two configurations, and therefore different influences on the process gas flow in the two cases cannot be expected.

[0061] In a preferred embodiment, the restoring weight is fastened to the flow directing element such that the weight force of the restoring weight acts as a restoring force to restore the flow directing element to the first position.

[0062] In this way, a restoring mechanism can be provided in a particularly simple and cost-effective manner, which quickly restores the flow guiding element to the first position, for example when the coating device moves from the first end position and now loses contact with the flow guiding element.

[0063] Furthermore, the restoring weight stabilizes the flow guiding element when the process gas flow passes over it, so that vibrations of the flow guiding element can be reduced, in particular totally suppressed.

[0064] In a preferred embodiment, the flow guiding element is designed as part of a flow guiding device of the machine tool which, in addition to the flow guiding element, comprises at least one further flow guiding element for the process gas flow.

[0065] In this way, a flow guiding device with a plurality of flow guiding elements is provided in the machine tool, via which the interior of the processing chamber can be optimally adapted to the process gas flow in a plurality of regions and / or sections.

[0066] The further flow guiding element here is preferably designed, like the "first" flow guiding element, in particular as a flexible surface element, which is preferably designed as a film element, a textile element or a sheet metal element. The use of restoring weights is likewise suitable here.

[0067] In a preferred embodiment, the further flow directing element is positioned parallel to the flow directing element in the first position, which is not intended to be understood as an alignment limitation.

[0068] Thus, the parallel arrangement is particularly space-saving, although other alignments are possible as well.

[0069] In a preferred embodiment, the further flow guiding element extends parallel to the side of the coating apparatus at the first end position and terminates flush with the side, so that the side and outer contour of the further flow guiding element form a common control surface for the introduced process gas flow.

[0070] In this manner, a continuous, flush control surface for the process gas flow is provided to promote swirl-free, turbulence-free process gas flow.

[0071] In a preferred embodiment, the flow guiding device is fastened to the processing chamber and comprises a bearing device having a drive unit, by which two flow guiding elements are mounted, and the bearing device is configured to move the flow guiding elements relative to the processing chamber so that access from a first region to a second region of the interior space of the processing chamber is opened or closed.

[0072] In this way, the flow directing element itself can be moved to allow access to the processing area, for example to remove a manufactured workpiece or to clean the processing area.

[0073] The flow guiding elements are preferably raised or lowered here relative to the treatment chamber, which is particularly suitable in the case of embodiments with preferably restoring weights as flexible surface elements, since as a result it can be ensured that they do not get tangled or entangled in the course of the transfer movement.

[0074] The ascending and descending directions preferably extend here vertically, i.e. parallel to the Earth's gravitational field.

[0075] In a preferred embodiment, the bearing device of the flow guiding device comprises a drivable shaft to which the flow guiding element is fastened, and the flow guiding element can be wound onto or unwound from the shaft by rotation of the shaft so that access from a first region of the interior space of the processing chamber to a second region is open when in a wound-up state and closed when in an unwound state.

[0076] In this way, a particularly simple movement device for the flow guiding element is provided, which allows a particularly space-saving support of the flow guiding element, since the flow guiding element is "rolled up".

[0077] The machine tool preferably comprises one or more further flow guiding devices according to one of the described embodiments, which are preferably located opposite each other across the machine tool's build area and thus at least partially define a processing region within the processing chamber.

[0078] According to a second aspect of the present invention there is provided a flow directing apparatus for use in a machine tool set up for additive manufacturing, particularly according to the first aspect of the present invention.

[0079] The flow guiding device comprises at least one (first) flow guiding element and one further flow guiding element, which can be fastened in a processing chamber of a machine tool for additive manufacturing of workpieces and can be used as a guiding element for a process gas flow flowing through the processing chamber, wherein at least the (first) flow guiding element is elastically deformable between a first position in which the flow guiding element has a first outer contour shape and a second position in which the flow guiding element has a second outer contour shape different from the first outer contour shape.

[0080] In this way, existing additive manufacturing machines can be quickly and easily expanded or retrofitted with devices for guiding the process gas flow, i.e., flow guiding devices, in order to optimally adapt the interior space to the process gas flow without requiring major structural measures. The above-mentioned advantages of using flow guiding elements or flow guiding devices also apply here.

[0081] The embodiment of the flow guiding elements, for example as flexible surface elements, has already been described above and will therefore not be reproduced again here.

[0082] The flow guiding device preferably comprises a restoring weight fastened to one of the two flow guiding elements, and particularly preferably the flow guiding device comprises a restoring weight fastened to each flow guiding element.

[0083] The two flow guiding elements preferably extend for the most part parallel to one another, in particular as parallel surfaces, with the spacing between the two surfaces in the normal direction being smaller than the dimension of the flow guiding element in the longitudinal or width direction, in particular the spacing being at most 5%, preferably at most 1%, particularly preferably at most 0.1% of the length or width of one of the two flow guiding elements.

[0084] The flow guiding device preferably comprises a bearing device to which two flow guiding elements are mounted and which has a drive unit configured to move, in particular raise and / or lower, the flow guiding elements relative to the processing chamber.

[0085] The bearing device of the flow guiding device preferably comprises a drivable shaft to which the flow guiding element is fastened, so that the flow guiding element can be wound onto or unwound from the shaft by rotation of the shaft.

[0086] Further aspects and advantages thereof, as well as more specific exemplary embodiments of the above-mentioned aspects and features, are described below with the aid of the accompanying drawings. [Brief explanation of the drawings]

[0087] [Figure 1A] A first exemplary embodiment of a machine tool according to the invention is shown in different views and in different positions of the coating device of the machine tool. [Figure 1B] A first exemplary embodiment of a machine tool according to the invention is shown in different views and in different positions of the coating device of the machine tool. [Figure 2] A first exemplary embodiment of a machine tool according to the invention is shown in different views and in different positions of the coating device of the machine tool. [Figure 3]A first exemplary embodiment of a machine tool according to the invention is shown in different views and in different positions of the coating device of the machine tool. [Figure 4] 2 shows a second exemplary embodiment of a machine tool according to the invention in a side view; [Figure 5A] 3 shows a detail of a third exemplary embodiment of a machine tool according to the invention in a side view; [Figure 5B] 3 shows a detail of a third exemplary embodiment of a machine tool according to the invention in a side view; DETAILED DESCRIPTION OF THE INVENTION

[0088] It is emphasized that the present invention is in no way limited to the exemplary embodiments and their exemplary features described below: The present invention further comprises modifications of the exemplary embodiments mentioned, in particular modifications resulting from modifications and / or combinations of individual or several features of the exemplary embodiments described within the scope of protection of the independent claims.

[0089] Detailed Description of the Drawings 1A and 1B show a first exemplary embodiment of a machine tool 100 according to the present invention in side views for two different positions of a coating device 60 of the machine tool 100 in the xy plane of a right-handed x, y, z coordinate system introduced for orientation purposes.

[0090] The machine tool 100 is set up for additive manufacturing of workpieces, during which material 22 located on a carrier 21 is solidified at the height of the build area 20 of the machine tool 100 by successive irradiation, for example by melting or sintering individual material particles using a typically optical, typically laser-based irradiation device (not shown here), to form layers of the workpiece to be manufactured.

[0091] For this purpose, the machine tool 100 comprises a processing chamber 10 enclosing an internal space 30 in which the production (additive construction) of the workpiece takes place, a said building site 20 having a carrier 21 movable in the y-direction for the material 22, a process gas device 40 (see in this regard Figure 3) and a flow guide device 50.

[0092] The processing chamber 10 comprises a base element 11 which terminates substantially flush with the build site 20, four side elements 12a-d (two of which are shown in Figures 1A and 1B), and a ceiling element 13, which together with the build site 20 enclose an interior space 30 in which the build takes place. In this way, an interior space 30 is provided which is isolated from the surroundings of the machine tool 100, in which production can take place as independently as possible of the ambient conditions.

[0093] To ensure that the enclosed interior space 30 is free of contaminants and pollutants (soot, exhaust gases and other by-products of production) generated during production and thus guarantee constant production conditions within the interior space 30, the process gas device 40 is configured to introduce a process gas flow 41 into the processing chamber 10 during additive production. The process gas flow 41 carries away said contaminants and pollutants and flows, for example, as a parallel flow in the z-direction.

[0094] To guide the process gas flow 41 through the processing chamber 10 in a targeted and stable manner, at least one (first) flow directing element 51 is used, fastened within the processing chamber 10, and elastically deformable between a first position in which the flow directing element 51 has a first outer contour shape (see FIG. 1A) and a second position in which the flow directing element 51 has a second outer contour shape (see FIG. 1B) that is different from the first outer contour shape. The outer contour of the flow directing element 51 here forms a flow boundary surface for the process gas flow 41, along which the process gas flow 41 is guided from the inlet 42 to the outlet 43 of the process gas device (see FIG. 3).

[0095] Stability here should be understood as the least possible swirling, which could cause the material 22 to swirl and thus lead to a decrease in production quality. Therefore, there is a growing interest in guiding the process gas flow 41 through the processing chamber 10 to the build site 20 as stably and parallel as possible.

[0096] Here, the flow guiding element 51 divides the interior space 30 of the processing chamber 10 into at least a first region 31 (processing region) where the actual manufacturing takes place and a second region 32 separated therefrom as far as possible. The process gas flow 41 flows only through the first region 31, so that the flow guiding element 51 reliably shields any sources of interference with the process gas flow 41 (e.g., additional sensor systems or actuator systems) located in the second region 32. As a result, the design of the second region 32, in particular the selection of the arrangement and shape of the components of the machine tool 100 therein, becomes substantially independent of the process gas flow 41.

[0097] The flow guiding elements 51 extend parallel to the side elements 12a of the processing chamber 10 (in the y direction) and orthogonal to the building station 20 or base element 11 and are designed as flexible surface elements, in particular film elements.

[0098] The flow guiding element 51 is designed as part of a flow guiding device 50, which comprises a further (second) flow guiding element 53, restoring weights 52, 54, a bearing device 55 for the flow guiding elements 51, 53, and guide elements 56a, 56b for lateral support and guiding the translation movement of the flow guiding elements 51, 53. The bearing device 55 and the guide elements 56a, 56b are explained in more detail below in connection with FIG.

[0099] Restoring weights 52, 54 are fastened to the flow guiding elements 51, 53 at the bottom surface, and their weight force acts as a restoring force that constantly tries to restore the flow guiding elements 51, 53, which are designed as flexible surface elements, to the vertical alignment shown in Figure 1A.

[0100] The outer contours of the flow directing elements 51, 53 now function as a flow boundary surface for the process gas flow 41, and together they define a flow boundary surface that extends parallel to the yz-plane in the first position shown in Figure 1A and that almost completely separates the first region 31 from the second region 32. Here, the lower edge of the first flow directing element 51 terminates almost flush with the base element 11 of the processing chamber 10.

[0101] As a result of the deformable design of the first flow guiding element 51, the first flow guiding element 51 can be reversibly or elastically deformed in a simple and almost resistance-free manner between a first position shown in FIG. 1A and a second position shown in FIG. 1B.

[0102] The elastic deformation is here brought about by movement of the coating device 60, which can be moved translationally (T) parallel to the build site 20 between a first end position 61 and a second end position 62. Here, the coating device 60 applies a layer of material to the build site 20, typically via a coating lip or brush, whereby the material 22 is drawn off uniformly with a predetermined thickness. Such movement and drawing off of the material layer here must take place before each production step of the individual workpiece layers of the workpiece to be produced.

[0103] Therefore, the coating apparatus 60 is used continuously and must therefore cover as short a travel path as possible for a short production time, and it is therefore advantageous to leave the coating apparatus 60 in place rather than removing it from the processing chamber 10 and reintroducing it into the processing chamber 10 each time, which may cause interference with the process gas flow 41 through the processing chamber 10 during production.

[0104] To resolve this contradiction, the use of a deformable first flow guiding element 51 is particularly suitable, which can be pushed away from the coating device 60 as soon as the coating device 60 has moved to its first end position 61, as outlined in Figures 1A and 1B. Thus, there is no need to move the first flow guiding element 51 directly adjacent to the build space 20, so that the coating device 60 can leave the area above the build space 20, resulting in a passive adaptation of the first flow guiding element 51 to the coating device 60, which is a movable component.

[0105] If the first flow-guiding element 51 is designed here as a flexible surface element, its deformation by the coating device 60 here requires only minimal force, so that its movement is not unnecessarily hindered.

[0106] In the second position shown in FIG. 1B with the second outer contour shape of the first flow guiding element 51, the first flow guiding element is nested relative to the outer contour of the coating apparatus 60, with the overlying portion being pulled away from its vertical starting position.

[0107] When the first end position 61 is reached, the right side of the coating device 60 takes the place of the outer contour of the first flow directing element in the first position shown in FIG. 1A.

[0108] In this case, a second flow guiding element 53 is used to provide the process gas flow 41 with a flow boundary surface that extends vertically in the same plane, and in FIG. 1B the second flow guiding element 53 terminates approximately flush with and above the coating apparatus 60, forming said vertical flow boundary surface together with its right side.

[0109] On the side of the second end position 62 of the coating device, the flow boundary is realized by a rigid partition 70, which in an alternative embodiment according to Figure 4 can be replaced by a further flow guiding device, providing a third region 33 in the interior 30 of the processing chamber.

[0110] The machine tool according to the invention therefore provides, inter alia, the possibility of flow guidance of the process gas flow, which allows for the shortest possible movement paths, does not require additional actuator systems and adapts partial regions of the interior space particularly well to the process gas flow.

[0111] As a result, manufacturing time and maintenance work and associated costs can be reduced. Furthermore, a modularly constructed flow guide can be provided, which is as independent as possible of the overall shape of the processing chamber 10 and can therefore be used on multiple machine tools.

[0112] FIG. 2 shows the first embodiment machine tool 100 from FIG. 1A in a side view rotated by 90 degrees in the yz plane.

[0113] 2, the lower ends of the flow guiding elements 51, 53 are spaced apart in the vertical y-direction to allow retraction of the coating apparatus 60, the latter deforming only the first flow guiding element 51, which further terminates flush with the base element 11 of the processing chamber 10.

[0114] The side ends of the flow guiding elements 51, 53 are guided in the vertical y direction by guide elements 56a, 56b attached to the side elements 12c, 12d of the processing chamber 10 (see also Figures 1A and 1B) and fastened to the upper side via bearing devices 55 within the processing chamber 10. The first flow guiding element 51 here does not include the side guide elements 56a, 56b in the position shown in Figure 2 so as not to interfere with deformation by the coating device 60 (see Figure 1B).

[0115] The bearing device 55, here designed as a shaft 55a, is rotatably connected to the processing chamber 10 parallel to the z-direction via bearings 55b mounted on the side elements 12c, 12d. The flow guiding elements 51, 53 are fastened to the shaft 55a so that they can be wound on or unwound from the shaft 55a, so that the lower ends of the flow guiding elements 51, 53 can be raised and lowered in the vertical y-direction to open and close access from the first area 31 to the second area 32, for example, for removing manufactured workpieces from the building station 20. For this purpose, FIG. 2 shows the flow guiding elements 51, 53 in amounts 51′, 53′ partially wound on the shaft 55a.

[0116] The bearing device 55 preferably comprises an electric drive unit 55c, via which the shaft 55a can be rotated about a rotation axis R extending parallel to the z-direction in order to wind up and unwind the flow guiding elements 51, 53. In the process, the lateral guiding elements 56a, 56b serve for targeted guidance of the flow guiding elements 51, 53.

[0117] FIG. 3 shows the machine tool 100 according to the first exemplary embodiment of FIG. 1A in a plan view in the xz plane to better illustrate the process gas flow 41 through the processing chamber 10. As shown in FIG.

[0118] For this purpose, the process gas device 40 comprises an inlet 42 arranged laterally in the side element 12d, through which a process gas flow 41 is introduced into the processing chamber 10, more precisely into the first region 31 of the interior space 30. Here, the introduction direction runs parallel to the plane formed by the flow guiding elements 51, 53 in the position shown in FIG. 1A, which plane runs parallel to the yz-plane.

[0119] Starting at the inlet 42 , a process gas flow 41 , represented by selected arrows, flows through the first region 31 to the outlet 43 of the process gas system 40 .

[0120] The parallel flow boundaries of the process gas flow 41 shown in FIG. 3 are here the left-hand flow guide elements 51, 53, the sides of the coating device 60 and the partition 70, as well as the build station 20 and the base element 11 (see also FIG. 1A in this regard).

[0121] The elements are here configured to form a continuous, flat flow boundary surface along which the process gas flow flows in a turbulent, preferably flow-free manner to ensure stable, swirl-free flow conditions in the first region 31 (processing region).

[0122] This prevents the material 22 located on the build station 20 from swirling and prevents local variations in the thickness of the applied material layer, allowing for a consistent production quality of the individual workpiece layers.

[0123] FIG. 4 shows a second exemplary embodiment of a machine tool 100 according to the invention in a side view in the xy plane.

[0124] Compared to the first exemplary embodiment, the present machine tool 100 differs in that the separation element 70 on the right side in side view (see FIG. 1A) is replaced by a further flow guiding device 50 of substantially identical construction to the first left-hand flow guiding device 50.

[0125] In this way, two flow flanks of the process gas flow 41 are formed using the proposed deformable flow guiding element, between which the coating device 60 can be moved without the need to remove the coating device as the flow guiding element would cause an obstruction to the process gas flow. This allows particularly short movement paths of the coating device to be realized without the risk of destabilizing the process gas flow.

[0126] 5A and 5B show details of a third exemplary embodiment of a machine tool 100 according to the invention in side views in the xy plane for two different positions of the coating device 60. In FIG.

[0127] The machine tool 100 of this embodiment differs from the first embodiment in that the flap 72, which is rotatably mounted around the rotary joint 71, is positioned below the separation element 70 on the right side in the side view (see Figure 1A).

[0128] The upper part of the machine tool 100, which is not shown in the views of Figures 5A and 5B, is in this case identical to that of the first exemplary embodiment of Figure 1A, and the left-hand flow guide device is also of the same design, so this will not be described further here.

[0129] The flap 72 is fastened to the partition via a rotational joint 71 so that movement of the coating device 60 can rotate the partition between a vertical start position (see FIG. 5B) in which the partition separates the first region 31 from the third region 33 of the interior 30, and a horizontal position (see FIG. 5A).

[0130] The rotary joint 71 preferably includes a restoring element, e.g., a spring element, which (in addition to the gravitational force acting on it) ensures that the flap 72 returns to its vertical starting position when the flap 72 loses contact with the coating device 60 in order to again form a flat flow interface for the process gas flow 41.

[0131] In said vertical starting position, the outer contours of the partition 70 and the flap 72 preferably form a flat, in particular vertically extending, flow interface for the process gas flow 41 .

[0132] In said horizontal position, the coating device 60 has reached its second end position 62 and the flap 72 has been pushed away from the vertical start position into the third region 33. In this case, the machine tool 100 is preferably designed in such a way that the partition 70 and the outer contour of the coating device 60 in its second end position 62 form a flat, in particular vertically extending, flow interface for the process gas flow 41, as in the configuration shown in FIG. 1A.

[0133] The rotatable flap 72 thus provides the coating device 60 with closable access to the third region 33 of the interior 30, where a flat and substantially continuously flowing flow interface is always present. As a result, compared to the first exemplary embodiment, the guidance of the process gas flow 41 can be improved, at least when the coating device is located in the left-hand first end position 61.

[0134] The exemplary embodiments of the present invention and their advantages have been described in detail above with reference to the accompanying drawings.

[0135] Finally, it is emphasized once again that the present invention is in no way limited to the exemplary embodiments and their exemplary features described above: the present invention further comprises modifications of the exemplary embodiments mentioned, in particular modifications resulting from modifications and / or combinations of individual or several features of the exemplary embodiments described within the scope of protection of the independent claims.

[0136] List of reference numbers 10 Processing Chamber 11 Base Elements 12a~d Side elements 13 Ceiling Elements 20. Art Studio 21 Movable Carrier 22 Material 30. Inner space of processing chamber 31 First area (processing area) 32 Second Area 33 The Third Region 40 Process gas equipment 41 Process gas flow 42 Entrance 43 Exit 50 Flow guide device 51, 51' First flow guide element 52 First restoration weight 53, 53' Second flow guide element 54 Second restoration weight 55 Bearing device 55a shaft 55b bearing 55c Drive unit 56a,b Guidance elements 60 Coating Equipment 61 First end position 62 Second end position 70 dividers 71 Rotational Joint 72 Flap 100 Machine tools

Claims

1. A machine tool (100) for additive manufacturing of a workpiece, comprising: a processing chamber (10) in which the additive construction of the workpiece takes place; a process gas device (40) configured to introduce a process gas flow (41) into said processing chamber (10) during said additive manufacturing; Equipped with a flow guiding element (51) for the process gas flow (41) fastened within the processing chamber (10), the flow guiding element (51) being elastically deformable between a first position in which the flow guiding element (51) has a first outer contour shape and a second position in which the flow guiding element (51) has a second outer contour shape different from the first outer contour shape; A machine tool (100) characterized by:

2. 2. The machine tool (100) according to claim 1, characterized in that the flow guiding element (51) is designed such that the first outer profile corresponds to a plane.

3. 3. The machine tool (100) according to claim 2, characterized in that the flow guiding element (51) is arranged in the first position so that the plane extends parallel to the introduction direction of the introduced process gas flow (41).

4. Machine tool (100) according to at least one of claims 1 to 3, characterized in that the flow guiding element (51) is designed as a flexible surface element.

5. 5. The machine tool (100) according to claim 4, characterized in that the flexible surface element is a film element or a fabric element.

6. 5. Machine tool (100) according to claim 4, characterized in that the flexible surface elements are metal sheet elements, in particular spring-like steel strips.

7. 7. The machine tool (100) according to claim 1, wherein the flow directing element (51) in the first position at least divides the interior space (30) of the processing chamber (10) into a first area (31) and a second area (32), the first area (31) being a processing area in which the additional construction takes place, and the process gas device (40) is configured to introduce the process gas flow (41) into the first area (31).

8. 8. The machine tool (100) according to claim 7, characterized in that a building area (20) of the machine tool (100) in which the additive manufacturing is performed is arranged entirely within the first area (31).

9. 9. The machine tool (100) according to claim 7, wherein the processing chamber (10) comprises lateral housing elements (12a-d), an upper housing element (13), and a lower housing element (11), and the housing elements and the flow guiding element (51) are arranged relative to each other such that, in the first position of the flow guiding element (51), the introduced process gas flow (41) flows along the flow guiding element (51) as parallel flows through the first region (31) of the interior space (30) of the processing chamber (10).

10. 10. The machine tool (100) according to at least one of claims 1 to 9, characterized in that the machine tool (100) comprises a coating device (60), the coating device (60) being movable relative to the processing chamber (10) between a first end position (61) and a second end position (62), the coating device (60) being configured to apply a material layer for the additive manufacturing to a building site (20) of the machine tool (100) in the processing chamber (10), and the coating device (60) being configured to elastically deform the flow guiding element (51) between the first position and the second position by movement.

11. 11. The machine tool (100) according to claim 10, characterized in that the flow guiding element (51) is brought to the second position when the coating device (60) is located at a first end position (61) of the coating device (60), and the flow guiding element (51) at least partially supports the coating device (60) in the second position.

12. 12. The machine tool (100) according to claim 11, characterized in that the side surface of the coating device (60) forms a control surface for the introduced process gas flow (41) at the first end position (61).

13. 13. The machine tool (100) according to claim 1 and 12, characterized in that the side surface of the coating device (60) at the first end position (61) and the outer contour of the flow guiding element (51) at the first position are in the same plane relative to the treatment chamber (10).

14. 14. The machine tool (100) according to at least one of claims 1 to 13, characterized in that a restoring weight (52) is fastened to the flow guiding element (51) such that a weight force of the restoring weight (52) acts as a restoring force for restoring the flow guiding element (51) to the first position.

15. 10. The machine tool (100) according to at least one of the preceding claims, characterized in that the flow guiding element (51) is designed as part of a flow guiding device (50) of the machine tool (100), which comprises in addition to the flow guiding element (51) at least one further flow guiding element (53) for the process gas flow (41).

16. 16. Machine tool (100) according to claim 15, characterized in that the further flow guiding element (53) is arranged parallel to the flow guiding element (51) in the first position.

17. 17. The machine tool (100) according to claim 12 and any one of claims 15 and 16, characterized in that the further flow guiding element (53) extends parallel to the side surface of the coating device (60) at the first end position (61) and terminates flush with the side surface, such that the side surface and the outer contour of the further flow guiding element (53) form a common control surface for the introduced process gas flow (41).

18. 18. The machine tool (100) according to claim 7, and any one of claims 15 to 17, characterized in that the flow guiding device (50) comprises a bearing device (55) fastened to the processing chamber (10) and having a drive unit (55c), by means of which the two flow guiding elements (51, 53) are mounted, and the bearing device (55) is configured to move the flow guiding elements (51, 53) relative to the processing chamber (10) in order to open or close access from the first area (31) to the second area (32) of the interior space (30) of the processing chamber (10).

19. 19. The machine tool (100) according to claim 18, characterized in that the bearing device (55) of the flow guiding device comprises a drivable shaft (55a) to which the flow guiding elements (51, 53) are fastened, and the flow guiding elements (51, 53) can be wound onto or unwound from the shaft (55a) by rotation of the shaft (55a) such that the access from the first area (31) to the second area (32) of the interior space (30) of the treatment chamber (10) is open in a wound-up state (51′, 53′) and closed in an unwound state.

20. A bearing arrangement (55) for use in a machine tool (100) according to at least one of claims 15 to 19.

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