Raw material powder supply port for additive manufacturing equipment and equipment for additive manufacturing

Abstract

The utility model relates to a raw material powder supply port (28) which is used for a device (1) for manufacturing a three-dimensional workpiece (3) by means of selective laser melting additive materials of a raw material powder bed, the raw material powder supply port (28) is provided with a container (29) serving as a buffer storage device, and the container is used for loading a coating machine (31) of the device (1) to repeatedly form the raw material powder bed in construction operation. Wherein the raw material powder supply opening (28) has a raw material powder distribution opening (30) on the lower side of the container (29), and wherein the raw material powder distribution opening (30) can be hermetically closed at least during non-construction operation.

Description

Technical Field

[0001] The present disclosure relates to a raw material powder supply port, which is used in a device for additively manufacturing a three-dimensional workpiece by selective laser melting (English: Laser Powder Bed Fusion (LPBF)) of a raw material powder bed. Background Art

[0002] The production of three-dimensional workpieces by means of a generative layer-by-layer construction method is generally referred to as 3D printing. A special form of the generative layer-by-layer construction method is selective laser melting (LPBF), in which a thin layer of the material to be processed as a powdered raw material is applied to a substrate by means of a coating machine. The powdered raw material is selectively, i.e., positionally melted or sintered by means of a laser beam and forms a layer of the workpiece after solidification. As soon as the workpiece layer is completed, the substrate is lowered by the thickness of this layer and a further raw material powder bed is applied by means of a coating machine for the next layer, which is also selectively melted or sintered by means of a laser beam. The above process is repeated in the so-called "construction operation" until all fused workpiece layers together form a three-dimensional workpiece. At this time, the base plate is gradually lowered into the workpiece chamber, which is surrounded by the workpiece chamber shell in the circumferential direction. The workpiece chamber therefore becomes larger during processing with the growing three-dimensional workpiece, wherein the workpiece chamber volume not filled by the three-dimensional workpiece is filled with unmelted raw material powder. For example, ceramic materials, metal materials or plastic materials may be used as raw material powders, or material mixtures thereof or mixtures of different types of ceramic materials, metal materials or plastic materials may be used as raw material powders.

[0003] The coating machine must be regularly loaded with a certain amount of raw material powder in the additive manufacturing system. For this purpose, a metering device in the form of an impeller gate can be used, for example, which is arranged below a container from which the raw material powder falls into the impeller gate. The container serves as a buffer store so that during a build process, sufficient raw material powder is always available to fully load the coating machine. However, the problem is that the first layer of a build process is sometimes inferior in quality to the layers processed later. Utility Model Content

[0004] Therefore, it is a task of the present disclosure to improve the first layer quality of a construction job.

[0005] This object is achieved by a raw material powder feed opening according to the invention and a device according to the invention. Preferred embodiments are given in the dependent claims, the description and the drawings.

[0006] According to a first aspect of the present disclosure, there is provided a raw material powder supply port for use in an apparatus for additive manufacturing of three-dimensional workpieces by means of selective laser melting of a raw material powder bed, wherein the raw material powder supply port has a container as a buffer storage, the container being used to load a coating machine of the apparatus with raw material powder during a building operation to repeatedly construct a raw material powder bed, wherein the raw material powder supply port has a raw material powder dispensing opening on the lower side of the container, wherein the raw material powder dispensing opening can be tightly closed at least during non-building operations.

[0007] The inventors have recognized that the reason for the quality defects of the first layer of the construction operation is that the process chamber is often opened for cleaning, maintenance or commissioning purposes for a long time of up to 30 hours or more between the construction operations, so that there is no protective gas atmosphere in the process chamber during this period. The ambient air containing moisture then enters the container that also contains the raw material powder through the raw material powder distribution opening, so that the raw material powder located in the lower part of the container condenses due to moisture and / or the fluidity of the raw material powder is reduced here. The quality of the first layer of the construction operation is affected accordingly. The above-mentioned container is preferably funnel-shaped, wherein the container tapers towards the raw material powder distribution opening.

[0008] When ambient air enters the container containing the raw material powder, not only the possible moisture in it, but also the oxygen contained in the ambient air becomes a problem. It may lead to undesired oxidation of the raw material powder. Therefore, for this reason, the entry of ambient air should also be avoided as much as possible.

[0009] It should be noted here that the term "sealed" here only requires airtightness, which does not allow the penetration of ambient air containing moisture or oxygen for a period of at least 30 hours. Of course, a small amount of diffused ambient air during this period can be allowed, as long as it does not change important process parameters such as the fluidity or coatability of the raw powder.

[0010] It should be taken into account that in the container to be sealed there may be an overpressure of the protective gas atmosphere, for example 20 mbar relative to the ambient air, so that even in the event of a leak no ambient air can enter, but only protective gas can escape. A tightly closable raw powder dispensing opening thus has the additional advantage that as little protective gas as possible is lost from the raw powder supply opening.

[0011] The container can optionally have at least one upper raw material powder feed opening, wherein the at least one upper raw material powder feed opening can be closed in a sealed manner, preferably in an airtight manner, at least when not in a construction operation. When there is no protective gas atmosphere in the container for special reasons, the container can thus be additionally closed in a sealed manner relative to a upstream raw material powder supply device. Each opening of the container is preferably closed in a sealed manner when not in a construction operation, preferably automatically and jointly, for example based on a common control signal. This is particularly advantageous so that the container can be temporarily subjected to a vacuum or negative pressure in order to dry the raw material powder therein. According to the prior art, drying of raw material powder can only be achieved in an external container specially provided for this purpose.

[0012] The raw powder dispensing opening can optionally extend longitudinally as a horizontal slot opening, which extends transversely to the horizontal direction in which the coating machine can move in order to form a raw powder bed. This makes sense for filling the metering device and the coating machine located below it, but poses a challenge to sealing.

[0013] The raw material powder supply opening can therefore optionally have a closure element extending in the longitudinal direction, wherein the closure element can be swung about the longitudinal direction from an open position to a closed position, wherein the raw material powder dispensing opening is sealed closed by the closure element in the closed position and is open in the open position. In addition, the closure element can be configured as a locking shaft or a locking plate or a stop slide that is hinged in the longitudinal direction.

[0014] The raw material powder supply opening can optionally have a metering device, which has a metering roller that can be rotated about the longitudinal direction to load the coating machine in one portion. In addition, the metering device can be used as a closing element or can be provided in addition to the closing element.

[0015] The metering device can be selectively arranged on the upper side or the lower side of the raw material powder dispensing opening. If an additional closing element is provided, it can be arranged accordingly on the upper side or the lower side of the metering device. If the metering device constitutes a closing element, the raw material powder dispensing opening can be sealed therewith from the upper side or the lower side at least when no building operation is performed.

[0016] The metering device can then selectively seal the raw powder dispensing opening at least when not in the build operation. In this case, no additional closing element is required and the metering device serves as the closing element. Furthermore, the metering device can permanently close the raw powder dispensing opening in any position of the metering roller or can only be temporarily placed in a sealed state. The metering device naturally preferably first runs idle before it stops in a certain sealed state.

[0017] The metering roller of the metering device may optionally have at least one raw powder receiver extending in the longitudinal direction over the length of the raw powder receiver, wherein the at least one raw powder receiver can be brought from the raw powder receiving position to the raw powder dispensing position by the rotation of the metering roller, wherein a first movement path of the at least one raw powder receiver leads from the raw powder receiving position to the raw powder dispensing position along the first wall portion, and wherein a second movement path of the at least one raw powder receiver leads from the raw powder dispensing position to the raw powder receiving position along the second wall portion, wherein the metering device has a seal extending in the longitudinal direction at least over the length of the raw powder receiver, wherein at least a part of the seal is located between the metering roller and the first wall portion and between the metering roller and the second wall portion, so that the raw powder dispensing opening is sealed closed at least during non-building operations. The main function of the seal during building operations is to prevent undesired leakage of raw powder.

[0018] The metering roller can selectively seal the raw powder dispensing opening continuously in any rotational position of the metering roller. The sealing effect during the build operation is possible but not necessary, because there is a protective gas atmosphere in the process chamber during the build operation. However, during non-build operation, when the metering roller is stopped, the process chamber may be opened at any time, so it is advantageous if the metering device is at least in a sealed state at this time.

[0019] The seal can be selectively adjusted and / or expanded to a sealing position, so that it seals off the raw powder dispensing opening in this sealing position. The seal can be, for example, heat-expandable, inflatable and / or radially outwardly movable, so that a sealing effect is achieved during non-building operations, when the metering roller is at rest and when no protective gas atmosphere is present in the process chamber. During building operations, if the metering roller must rotate, the seal can be brought into a movable position, for example by cooling, venting pressure from the inflated seal and / or moving the seal radially inward, in which the seal no longer has to seal tightly, but only prevents leakage of raw powder. This reduces friction and wear on the seal. When there is no protective gas atmosphere in the process chamber, the sealing effect of the seal is only required when the metering roller is at rest.

[0020] The sealing element can selectively extend in a closed manner around the axial ends thereof in the circumferential direction, wherein at least one raw material powder receiver and a raw material powder dispensing opening are arranged between the axial ends of the sealing element in the longitudinal direction. Thus, the raw material powder dispensing opening can be sealed closed at the axial ends at least when no building operation is performed.

[0021] The seal can selectively surround at least one raw material powder receiver on the first movement path in a closed and sealed manner not only in the circumferential direction but also in the longitudinal direction relative to the raw material powder dispensing position. This is advantageous because leakage from one raw material powder receiver to the next is prevented or at least significantly reduced. Furthermore, the sealing effect can be increased and the load on the seal can be distributed. As a result, the seal is subject to less wear and has a longer service life.

[0022] The seal can optionally have one or more sealing lips. The sealing lips can be designed, for example, similarly or identically to the sealing lips used for leveling the raw material powder bed on the coating machine. Preferably, in an arrangement with a plurality of sealing lips, the sealing lips of the seal are supplemented in such a way that a plurality of areas are defined which are closed and sealed around the metering roller both in the circumferential direction and in the longitudinal direction, so that the raw material powder cannot escape from these areas during the first movement path.

[0023] Optionally, the sealing lips can preferably be configured as removable strips, which are removably inserted into corresponding grooves in the first wall part and / or the second wall part or the metering roller. This is advantageous because the seal is a wearing component and must be replaced when the sealing effect decreases due to wear. At the axial end, two or more arcuate strip parts can be plugged together to form a sealing lip that is closed around in the circumferential direction.

[0024] Optionally, the radial position, radial extent and / or orientation of the seal relative to the metering roller and / or the first wall can be adjusted. This makes it possible to adjust, for example, the contact force and / or the sealing effect. This is particularly useful when the seal is worn. The adjustment can be carried out manually, for example, by means of fixing screws and / or adjusting screws. Alternatively or additionally, a mechanical, electrical and / or pneumatic adjustment device can be provided in order to adjust the radial position, radial extent and / or orientation of the seal.

[0025] Optionally, the raw powder supply port can be configured to immediately seal and close the container relative to the processing chamber when the processing chamber is opened and / or provide a signal, which prevents the processing chamber from being opened as long as the container is not sealed relative to the processing chamber. The raw powder supply port can be used in conjunction with a corresponding safety device of the device. The safety device of the device can be correspondingly configured to allow the processing chamber to be opened only when the raw powder supply port seals and closes the container, or to provide a signal when the processing chamber is opened, which signal prompts the raw powder supply port to immediately seal and close the container relative to the processing chamber.

[0026] According to a second aspect of the utility model, there is provided an apparatus for additively manufacturing three-dimensional workpieces by means of selective laser melting of a raw material powder bed, wherein a protective gas atmosphere exists in a processing chamber during a building operation, wherein the apparatus has the aforementioned raw material powder supply port, wherein the building raw material powder supply port is used to seal the container relative to the processing chamber at least when no building operation is performed.

[0027] Optionally, the raw powder supply opening can be configured such that the container is automatically sealed and closed relative to the processing chamber when there is no protective gas atmosphere in the processing chamber. The device can, for example, provide a signal when, for example, a building operation is not running, the door of the processing chamber is opened and / or there is no protective gas atmosphere in the processing chamber. The signal can then be used as a switching signal for automatically closing the raw powder dispensing opening. Alternatively, the closed state can be an initial state, wherein the device can provide a signal at the beginning of the building operation, which signal is used as a switching signal for automatically opening the raw powder dispensing opening.

[0028] In addition, the apparatus may optionally have a safety device, wherein the safety device is constructed so that the processing chamber is allowed to be opened only when the raw material powder supply port seals the container, or provides a signal when the processing chamber is opened, which signal prompts the raw material powder supply port to immediately seal the container relative to the processing chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present disclosure is further explained below with the aid of the accompanying drawings, which show exemplary embodiments of the present disclosure. The accompanying drawings show:

[0030] Figure 1 A schematic longitudinal section of a device for additively manufacturing a three-dimensional workpiece by means of selective laser melting is shown, the device having an embodiment of a raw material powder supply port according to the present disclosure;

[0031] Figure 2 A perspective interior view of a process chamber of a device for additively manufacturing three-dimensional workpieces by means of selective laser melting is shown, the device having an embodiment of a raw material powder feed according to the present disclosure;

[0032] Figure 3 A schematic cross-sectional view showing a first embodiment of a raw material powder supply port according to the present disclosure;

[0033] Figure 4 A schematic cross-sectional view showing a second embodiment of a raw material powder supply port according to the present disclosure;

[0034] Figure 5 Show according to Figure 4 A schematic longitudinal view of a second embodiment of the present invention;

[0035] Figure 6 A cross-sectional view showing a lower portion of an embodiment of a raw material powder supply port according to the present disclosure;

[0036] Figure 7 A cross-sectional view showing an upper portion of an embodiment of a raw material powder supply port according to the present disclosure;

[0037] Figure 8A cross-sectional view showing an embodiment with a closed raw powder dispensing opening;

[0038] Figure 9a Show according to Figure 8 A top view of a closure element of an embodiment with an open raw powder dispensing opening; and

[0039] Figure 9b Show according to Figure 9a A cross-sectional view of an embodiment with an open raw powder distribution opening. DETAILED DESCRIPTION

[0040] Figure 1 A device 1 is shown for producing a three-dimensional workpiece 3 by means of a generative layer-by-layer construction method. The embodiment of the device 1 shown here operates according to the selective laser melting principle (Laser Powder Bed Fusion (LPBF)). To simplify the orientation, a local right-handed Cartesian coordinate system is defined in the figure, wherein the x-axis is in the horizontal transverse direction, the y-direction is in the horizontal longitudinal direction and the z-axis extends vertically upward.

[0041] Here, the device 1 has a process chamber 5, wherein a controllable optical component 7 for coupling out one or more laser beams 9 is arranged on the upper side. The laser light is generated by a corresponding laser 11 and directed downwardly into the process chamber in a targeted manner by means of the controllable optical component 7. The laser 11 can be located directly on the process chamber 5 and only supply it with laser light. Alternatively, the laser 11 can be located away from the process chamber 5 and supply laser light to one or more process chambers 5 by means of an optical fiber and / or a beam splitter.

[0042] The process chamber 5 has an opening 13 on the bottom side, at which a workpiece container 15 adjoins the process chamber 5 from below. The workpiece container 15 can also be referred to as an exchangeable cylinder, since it is exchanged for the production of another workpiece in the process chamber 5 and is replaced by another workpiece container. In contrast to the process chamber 5, which is arranged firmly in a fixed manner in the device 1, the workpiece container 15 can be transported by means of a transport system 17. The transport system 17 is arranged in a fixed manner. Figure 1 It is only schematically shown in FIG. 1 by a profile rail on which the workpiece container 15 is held by means of one or more radially outwardly projecting projections 19 .

[0043] By means of the transport system 17, the workpiece container 15 is positioned below the opening 13 of the process chamber 5 so that the workpiece container 15 is sealed at the top with the bottom of the process chamber 5. For this purpose, a sealing device 21 is provided on the top of the workpiece container 15 which is open at the top. Alternatively or additionally, the sealing device 21 can also be arranged on the bottom of the process chamber 5.

[0044] The workpiece container 15 has a workpiece housing 23, which defines the largest workpiece chamber 25 and surrounds it on the circumferential side. In addition, the workpiece container 15 has a substrate device 27, which extends essentially horizontally and closes the workpiece chamber 25 on the bottom side. The substrate device 27 can be moved vertically relative to the workpiece chamber housing 23. At the beginning of the production process, the substrate device 27 is located at the uppermost part in the workpiece container 15 and then moves step by step downward in the workpiece housing 23 by the amount of the layer height as each layer of the workpiece 3 is completed. This results in a vertically extending layer construction direction S. Figure 1 The situation is shown in which the workpiece 3 is partially finished and the substrate arrangement 27 is located approximately at half the height of the workpiece chamber housing 23 .

[0045] The apparatus 1 also has a raw material powder supply 28, which has a container 29. If a plurality of process chambers are present in the apparatus 1, each process chamber 5 is preferably provided with a container 29. After the substrate device 27 has lowered the layer height in the workpiece chamber 25 after the previous layer has been completed, a new raw material powder layer can be applied by means of a coater 31 which can be moved horizontally along the x-axis through the opening 13 in the process chamber 5 in a controlled manner. The laser beam 9 is then selectively guided through the raw material powder layer by the optical assembly 7 in a computer-controlled manner, so that a new layer of the workpiece 3 is produced by melting or sintering the newly applied raw material powder layer. The apparatus 1 also has a gas delivery device 33, by means of which a protective gas, for example nitrogen, is introduced into the process chamber 5 in order to provide a protective gas atmosphere there.

[0046] Before the coating machine 31 is moved in the positive x-direction, it is loaded with raw material powder from the raw material powder distribution opening 30 of the raw material powder supply opening 28 arranged at the bottom side of the container 29 through the metering device 35, so as to lay a powder bed for the next layer to be produced. In addition, the coating machine 31 simultaneously acts as a scraper, with which the excess raw material powder is scraped in the positive x-direction in order to produce a powder bed that is as flat as possible. In addition, the excess raw material powder is pushed into an overflow 37 arranged behind the powder bed in the x-direction, from which the excess raw material powder falls into an overflow container 39. Afterwards, the coating machine 31 returns again in the negative x-direction below the metering device 35 in order to be reloaded with raw material powder.

[0047] In order to speed up the processing, the device can be equipped with two loading stations, each with a metering device 35, one of which is arranged in front of the powder bed in the x-direction and the other in the x-direction behind the powder bed. The coater does not have to return empty in the negative x-direction, but can be reloaded behind the powder bed, so that the powder bed can be laid not only in the positive x-direction but also in the negative x-direction. In addition, two overflows are also expediently provided, one of which is located in front of the powder bed in the x-direction and the other in the x-direction behind the powder bed. The coater can thus act as a scraper to smooth the powder bed in both x-directions.

[0048] Figure 2 The view of the process chamber 5 is shown with the negative x-direction as the viewing direction, wherein the workpiece 3 is cleaned and for illustration purposes is lifted from the workpiece chamber 25 into the process chamber 5. During operation, the workpiece 3 is located only in the workpiece chamber 25 arranged below the process chamber 5, which is formed by lowering the substrate device 27 into the opening 13.

[0049] The inventors have recognized that the reason for the quality defects of the first layer of the construction operation is that the process chamber 5 is often opened for a long time of up to 30 hours or more for cleaning, maintenance or debugging purposes between construction operations, and during this time there is no protective gas atmosphere in the process chamber 5. The ambient air containing moisture then enters the container 29 that also contains the raw material powder through the raw material powder distribution opening 30, so that the raw material powder located in the lower part of the container 29 agglomerates due to moisture. The quality of the first layer of the construction operation is affected accordingly.

[0050] Figures 3 to 5 The embodiment of the metering device 35 shown in solves this problem. Figure 3 The metering device 35 shown has a metering roller 43 in a housing 41, which can be rotated about a longitudinal direction extending in the y-direction. Figure 2 The coaxial ( Figure 2 The drive shaft 45 extends from the process chamber 5 (not visible in the housing 41), and drives the metering roller 43 in the housing 41 around the longitudinal direction y to achieve controlled rotation. The drive shaft 45 extends out of the process chamber 5 at two axial ends so as to be supported outside the process chamber 5 and driven by a motor arranged outside the process chamber 5. The drive shaft 45 can be sealed at the axial ends, for example, as described in DE 202022101837U1.

[0051] like Figures 3 to 5As shown, the metering device 35 has an upper filling cylinder 47, from which the raw material powder falls from the container 29 from above. The metering device 35 forms an impeller gate, wherein the metering roller 43 is arranged between a first wall 49 and a second wall 51. The first wall 49 and the second wall 51 each surround the metering roller 43 in the form of a cylindrical hood segment, wherein there is a radial spacing 53 between the metering roller 43 and the first wall 49 or the second wall 51. The metering device 35 has a discharge cylinder 55 on the lower side, from which the raw material powder falls from the metering device 35 into the coating machine 31.

[0052] The metering roller 43 has n=6, n∈N in the raw material powder receiver length L (see Figure 5 ) is a raw material powder receiver 57 extending in the longitudinal direction y, which is in the shape of a groove opening radially outward. Six raw material powder receivers 57 are arranged on the metering roller 43 in a six-fold rotationally symmetrical distribution in the circumferential direction. All raw material powder receivers 57 have the same volume for accommodating raw material powder, so that the coating machine 31 can be loaded in portions, wherein the volume of the raw material powder receiver 57 is one portion.

[0053] When the metering roller 43 rotates, the raw powder receiver 57 occupies an upper raw powder receiving position, in which the raw powder receiver is oriented openly upward to the filling cylinder 47 and is filled with raw powder that falls from the filling cylinder 47 into the raw powder receiver 57. The rotation can be stopped or continued for this purpose. With further rotation, the filled raw powder receiver 57 moves downward along the first wall portion 49 along the arc-shaped first movement path to the lower raw powder dispensing position. In the lower raw powder dispensing position, the raw powder receiver 57 is oriented openly downward to the output cylinder 55, so that the raw powder receiver 57 is emptied into the output cylinder 55. The rotation can be stopped or continued for this purpose. With further rotation, the emptied raw powder receiver 57 returns upward along the second wall portion 49 along the arc-shaped second movement path to the upper raw powder dispensing position for refilling.

[0054] Through the gap 53, air containing moisture can be sucked from the open process chamber 5 into the container 29 via the metering device 35. To seal the gap 53, the metering device 35 has a seal 59 extending at least over the length L of the raw material powder receiver in the longitudinal direction y, wherein at least a portion of the seal 59 is located in the gap 53 between the metering roller 43 and the first wall portion 49 in a radially sealing manner at least when not in the building operation.

[0055] Figure 3In the embodiment shown, the seal 59 has two fixed sealing lips 59a, b, wherein the first sealing lip 59a of the two sealing lips 59a, b is fixed to the first wall portion 49 and radially inwards to the metering roller 43 to seal the gap 53 on the first movement path. The second sealing lip 59b of the two sealing lips 59a, b is fixed to the second wall portion 51 opposite to the first sealing lip 59a and tightly seals the gap 53 radially inwards to the metering roller 43 on the second movement path at least in the non-building operation. The first sealing lip 59a is arranged closer to the raw material powder dispensing position in the circumferential direction than the spacing of the raw material powder receivers 57 adjacent to each other in the circumferential direction. Correspondingly, the second sealing lip 59b is arranged closer to the raw material powder receiving position in the circumferential direction than the spacing of the raw material powder receivers 57 adjacent to each other in the circumferential direction.

[0056] exist Figure 3 , the sealing lips 59a, b are each inserted detachably as a strip 61 extending in the y-direction into a groove 63 extending in the y-direction in the corresponding first wall section 49 or second wall section 51. In addition, the sealing lips 59a, b are each inclined at an angle θ in the circumferential direction of the metering roller 43 relative to the radial orientation A. Alternatively, this inclination θ can be obtained by predefining a corresponding inclination of the groove 63.

[0057] Figure 4 Another embodiment of the metering device 35 is shown, in which the seal 59' is not fixed, but is mounted on the metering roller 43 and along a first movement path, radially outwards to the first wall 49 tightly seals the radial distance 53 at least when not in the construction operation, and along a second movement path, radially outwards to the second wall 51. Here, the seal 59' has six sealing lips 59a'-f', which are arranged in a six-fold rotationally symmetrical manner in the circumferential direction between two adjacent raw material powder receivers 57 and extend in the y-direction on the metering roller 43 at least over the raw material powder receiver length L. Figure 3 The sealing lips 59a'-f' are similar to the embodiment of the present invention, each as a strip 61' extending in the y-direction, which can be removably inserted into a corresponding groove 63' extending in the y-direction in the metering roller 43. In addition, the sealing lips 59a'-f' are each oriented at an angle θ', which is tilted in the opposite direction of the circumferential direction of the metering roller 43, relative to the radial orientation A'. Alternatively, this tilt θ' can be obtained by predefining a corresponding inclination of the groove 63'.

[0058] exist Figure 5In the longitudinal view, it can be seen that both the filling cylinder 47 and the discharge cylinder 55 extend in the y-direction for a shorter distance compared to the raw powder receiver length L. The metering roller 43 and the sealing lips 59a'-f' of the seal extend beyond the raw powder receiver length L. The first wall section 49 and the second wall section 51 extend in the y-direction even longer than the seal 59'.

[0059] At the axial ends, the seal 59' has sealing lips 59g', h' respectively that are encircled and closed in the circumferential direction. The raw material powder receiver 57 is thus completely surrounded by the seal 59' in two circumferential directions and two axial directions in an airtight manner. The sealing lips 59g', h' that surround the ends can be assembled together by two or more detachable arched guide members, which are detachably inserted into the grooves that surround the metering roller 43 accordingly in the circumferential direction and supplement the sealing lips 59g', h' that are encircled and closed in the circumferential direction. In addition, the sealing lips 59g', h' at the ends are respectively oriented axially inwardly tilted at an angle θ" to obtain a better sealing effect.

[0060] exist Figures 3 to 5 In both embodiments, the sealing lips 59a, b can be adjusted and / or expanded to a certain sealing position. The sealing lips can be, for example, inflatable and / or radially outwardly movable so that a sealing effect is obtained during non-building operations, when the metering roller 43 is at rest and when no protective gas atmosphere is present in the process chamber 5. During building operations, if the metering roller 43 must rotate, the sealing lips 59a, b can be brought into a moving position, for example by venting the pressure from the inflated sealing lips 59a, b and / or by moving the sealing lips 59a, b radially inwardly, in which the sealing lips 59a, b no longer have to seal tightly, but only prevent the raw material powder from leaking out. This reduces friction and wear on the sealing lips 59a, b. When there is no protective gas atmosphere in the process chamber 5, the sealing effect of the sealing lips 59a, b is only required when the metering roller 43 is at rest.

[0061] Figure 6The lower part of an embodiment of a raw material powder supply opening 28 with a closure element 65 separate from the metering device 35 is shown. In this embodiment, the metering device 35 does not have to seal the raw material powder dispensing opening 30, but is provided with a separate closure element 65 for sealing the raw material powder dispensing opening 30 at least when not in the construction operation. Here, the metering device 35 is arranged above the raw material powder dispensing opening 30, so that the closure element 65 is correspondingly arranged below the metering device 35. In this embodiment, the raw material powder thus first falls onto the metering roller 43 of the metering device 35 and then passes through the raw material powder dispensing opening 30 in one piece. The raw material powder dispensing opening 30 extends as a horizontal slot opening in the longitudinal direction y, which extends transversely to the horizontal direction x, in which the coating machine 31 can be moved, so as to form a raw material powder bed. The closure element 65 accordingly also extends in the longitudinal direction y. Figure 6 In the embodiment shown in FIG. 1 , the closing element is configured as a locking plate hinged in the longitudinal direction y, which is as shown in FIG. Figure 6 The opening position is shown, so that the raw material powder dispensing opening 30 is opened. This is the case, for example, during the building operation, when the metering roller 43 of the metering device 35 rotates and the raw material powder falls from the container 29 into the coating machine 31 in one portion.

[0062] In order to seal the raw powder dispensing opening 30, the closing element 65 can be swung upward from the open position shown to a closed position in which the raw powder dispensing opening 30 is tightly closed by the closing element 65. In the closed position of the closing element 65, if the process chamber 5 has to be opened when no building work is being done and a protective gas atmosphere is temporarily not present there, no ambient air containing moisture can enter the container 29 through the raw powder dispensing opening 30.

[0063] Figure 7The upper part of an embodiment of a raw material powder supply opening 28 according to the invention is shown. Here, the container 29 has a plurality of raw material powder feed openings 67, through which the container 29 can be loaded with raw material powder from a raw material powder recovery system 68 and / or a raw material powder storage tank 69. The container 29 is supplied with new raw material powder from a raw material powder storage tank 69 arranged above the container, which is preferably movable and can be placed on a platform above the container 29 by a lifting device. A pipeline or hose system 71 conveys raw material powder from the raw material powder recovery system 68 and the raw material powder storage tank 69 to the raw material powder feed opening 67 on the upper side of the container 29. The pipeline or hose system 71 has a compression valve 73 from the raw material powder recovery system 68 to the raw material powder feed opening 67, with which the raw material powder feed opening 67 can be tightly closed at least when not in construction operation. In the embodiment shown, a tightly closable disk valve 75 is additionally provided at the outlet of the raw powder storage tank 69 in order to be able to control the flow of raw powder from the raw powder storage tank 69 into the pipeline or hose system 71. The raw powder storage tank 69 and the pipeline or hose system 71 together form a raw powder supply 77 upstream of the container 29, to which the container 29 can be tightly closed by means of the compression valve 73 and / or the disk valve 75. Thus, all openings of the container 29 can be tightly closed, preferably automatically and jointly, for example based on a control signal, at least when no building operation is in progress. This is particularly advantageous in order to be able to act at least temporarily on the container 29 with a vacuum or negative pressure, in order to dry the raw powder located therein if necessary.

[0064] Figure 8 An embodiment of the raw material powder supply opening 28 according to the present invention is shown, wherein the closing element 65 is configured as a locking shaft and is arranged above the metering device 35. Here, the metering device 35 is arranged below the closable raw material powder dispensing opening 30. Figure 6 In the embodiment, the raw powder distribution opening 30 extends as a horizontal slot opening in the longitudinal direction y, which extends transversely to the horizontal direction x, and the coating machine 31 can be moved in this horizontal direction to form a raw powder bed. The closing element 65, which is configured as a locking shaft here, also extends in the longitudinal direction y and can be moved from the open position (see Figure 9b ) Figure 8 In addition, the raw material powder distribution opening 30 is in the closed position shown in FIG. Figure 8 The closed position shown in FIG. 1 is tightly closed by the closing element 65 and is Figure 9b The open position shown is open.

[0065] Figure 9aThe closure element housing 83 is shown, in which the locking shaft is located. The closure element housing 83 has a horizontally circumferential seal 85 on the upper side, so that the closure element housing 83 can be attached to the container 29 from below in a sealing manner. The closure element housing 83 also has a seal (not visible here) on the lower side, so that the metering device 35 can be attached to the closure element housing 83 in a sealing manner from below. The closure element 65 is pivoted into the desired closed position or open position by means of at least one actuator 87, here in the form of a cylinder.

[0066] Description of Reference Numerals

[0067] 1 device

[0068] 3 Workpiece

[0069] 5. Processing Chamber

[0070] 7 Optical components

[0071] 9 Laser beam

[0072] 11 Laser

[0073] 13 Opening

[0074] 15 Workpiece container

[0075] 17. Transportation System

[0076] 19 Bump

[0077] 21 Sealing mechanism

[0078] 23 workpiece shell

[0079] 25 Workpiece Room

[0080] 27 substrate device

[0081] 28 Raw material powder supply port

[0082] 29 containers

[0083] 30 Raw material powder distribution openings

[0084] 31 coating machine

[0085] 33 Gas delivery device

[0086] 35 Measuring device

[0087] 37 Overflow

[0088] 39 Overflow container

[0089] 41 Shell

[0090] 43 metering roller

[0091] 45 drive shaft

[0092] 47 Filling cylinder

[0093] 49 first wall

[0094] 51 Second wall portion

[0095] 53 radial spacing

[0096] 55 output tube

[0097] 57 Raw powder receiver

[0098] 59, 59' seal

[0099] 59a, b, a'-f', g', h' sealing lip

[0100] 61, 61' strip

[0101] 63, 63' groove

[0102] 65 Closing element

[0103] 67 Raw material powder feed port

[0104] 68 Raw material powder-recovery system

[0105] 69 Raw material powder storage tank

[0106] 71 Pipe or hose system

[0107] 73 Compression valve

[0108] 75 disc valve

[0109] 77 Raw material powder supply device

[0110] 83 Closure element housing

[0111] 85 Seals

[0112] 87 Actuator

[0113] L Length of raw powder receiver

[0114] A, A' radial orientation

[0115] θ, θ', θ” tilt angles.

Claims

1. A raw material powder supply port (28) for use in an apparatus (1) for additively manufacturing a three-dimensional workpiece (3) by means of selective laser melting of a raw material powder bed, wherein: The raw powder supply port (28) has a container (29) as a buffer storage, and the container is used to load the coating machine (31) of the device (1) with raw powder during the construction operation to repeatedly form a raw powder bed, wherein the raw powder supply port (28) has a raw powder distribution opening (30) on the lower side of the container (29), wherein the raw powder distribution opening (30) can be sealed and closed at least when the construction operation is not in progress.

2. The raw material powder supply port (28) according to claim 1, wherein: The container (29) has at least one upper raw material powder feeding opening (67), wherein the at least one upper raw material powder feeding opening (67) can be sealed and closed at least when no construction operation is performed.

3. The raw material powder supply port (28) according to claim 1, wherein: Each opening of the container (29) can be sealed closed at least when no building operation is performed.

4. The raw material powder supply port (28) according to claim 3, wherein: Each opening of the container (29) can be automatically and collectively sealed closed at least when no building operation is performed.

5. The raw material powder supply port (28) according to claim 1, wherein: The raw powder distribution opening (30) extends as a horizontal slot opening in a longitudinal direction (y), which extends transversely to a horizontal direction (x), and the coating machine (31) can be moved in the horizontal direction to form a raw powder bed.

6. The raw material powder supply port (28) according to claim 5, wherein: The raw powder supply port (28) has a closing element (65) extending along the longitudinal direction (y), wherein the closing element (65) can be swung around the longitudinal direction (y) from an open position to a closed position, wherein the raw powder dispensing opening (30) is sealed and closed by the closing element (65) in the closed position and is open in the open position.

7. The raw material powder supply port (28) according to claim 5, wherein: The raw material powder supply port (28) also has a metering device (35), which has a metering roller (43) that can rotate around the longitudinal direction (y) and is used to load the coating machine (31) in batches.

8. The raw material powder supply port (28) according to claim 7, wherein: The metering device (35) is arranged above or below the raw material powder distribution opening (30).

9. The raw material powder supply port (28) according to claim 7, wherein: The metering device (35) seals and closes the raw material powder dispensing opening (30) at least when the building operation is not in progress.

10. The raw material powder supply port (28) according to claim 9, wherein: The metering roller (43) of the metering device (35) has at least one raw powder receiver (57) extending in the longitudinal direction (y) over the length (L) of the raw powder receiver, wherein the at least one raw powder receiver (57) can be brought from a raw powder receiving position to a raw powder dispensing position by the rotation of the metering roller (43), wherein a first movement path of the at least one raw powder receiver (57) leads from the raw powder receiving position to the raw powder dispensing position along a first wall portion (49), and wherein a second movement path of the at least one raw powder receiver (57) The movement path leads from the raw powder dispensing position to the raw powder receiving position along the second wall portion (51), wherein the metering device (35) has a seal (59, 59') extending along the longitudinal direction (y) at least over the length (L) of the raw powder receiver, wherein at least a part of the seal (59, 59') is located between the metering roller (43) and the first wall portion (49) and between the metering roller (43) and the second wall portion (51), so that the raw powder dispensing opening (30) is sealed closed at least when no building operation is performed.

11. The raw material powder supply port (28) according to claim 10, wherein: The metering roller (43) continuously seals and closes the raw powder dispensing opening (30) at any rotational position of the metering roller (43).

12. The raw powder supply port (28) according to claim 10, wherein the sealing member is adjustable and / or expandable to a sealing position, thereby sealingly closing the raw powder dispensing opening (30) in the sealing position.

13. The raw material powder supply port (28) according to claim 10, wherein: The seal (59, 59') extends in a closed manner in the circumferential direction at its axial ends, wherein the at least one raw material powder receiver (57) and the raw material powder distribution opening (30) are arranged between the axial ends of the seal (59, 59') in the longitudinal direction (y).

14. The raw material powder supply port (28) according to claim 10, wherein: The seal (59, 59') surrounds the at least one raw material powder receiver on the first movement path in a closed and sealed manner not only in the circumferential direction but also in the longitudinal direction (y) relative to the raw material powder dispensing position.

15. The raw material powder supply port (28) according to claim 10, wherein: The seal (59, 59') has one or more sealing lips.

16. The raw material powder supply port (28) according to claim 15, wherein: The sealing lips are each designed as a detachable strip (61, 61') which is detachably inserted into a corresponding groove (63, 63') in the first wall (49) and / or the second wall (51) or the metering roller (43).

17. The raw material powder supply port (28) according to claim 15, wherein: The radial position, radial extent and / or orientation of the seal relative to the metering roller (43) and / or the first wall portion (49) can be adjusted.

18. The raw powder supply port (28) according to claim 1, wherein the raw powder supply port (28) is constructed so that when the processing chamber is opened, the container (29) is immediately sealed and closed relative to the processing chamber (5) and / or a signal is provided, and as long as the container (29) is not sealed and closed relative to the processing chamber (5), the signal prevents the opening of the processing chamber (5).

19. A device (1) for additive manufacturing, for additively manufacturing a three-dimensional workpiece (3) by means of selective laser melting of a raw material powder bed, wherein a protective gas atmosphere is present in the process chamber (5) during the building operation, wherein: The device (1) has a raw material powder supply port (28) according to claim 1, wherein the raw material powder supply port (28) is configured to allow the container (29) to be sealed off relative to the processing chamber (5) at least when the construction operation is not in progress.

20. The device (1) according to claim 19, wherein The raw material powder supply port (28) is configured to automatically seal and close the container (29) relative to the processing chamber (5) when no protective gas atmosphere exists in the processing chamber (5).

21. The device (1) according to claim 19, wherein The apparatus has a safety device, wherein the safety device is constructed so that the processing chamber is allowed to be opened only when the raw material powder supply port (28) seals and closes the container (29), or provides a signal when the processing chamber is opened, wherein the signal prompts the raw material powder supply port (28) to immediately seal and close the container (29) relative to the processing chamber (5).

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