Inflow channel for homogenising a protective gas flow in an additive manufacturing device, and a manufacturing device

Abstract

The invention relates to an inflow channel (21) for homogenising a protective gas flow in an additive manufacturing device (1) comprising: a protective gas inlet having a protective-gas-inlet-side portion (212) at which the protective gas is supplied and a protective-gas-outlet-side portion (214) at which the protective gas is guided into a building chamber (3) of the additive manufacturing device (1), wherein the protective-gas-inlet-side portion (212) of the protective gas inlet has a cross section, wherein the protective-gas-outlet-side portion (214) of the protective gas inlet has an approximately rectangular cross section, and wherein in the protective-gas-outlet-side portion (214) of the protective gas inlet a plurality of guide vanes (216) are arranged which homogenise and deflect the protective gas flow.

Description

[0001] Inlet channel for homogenizing a protective gas flow in an additive

[0002] Manufacturing device and a manufacturing device

[0003] Technical area

[0004] The invention relates to an inflow channel for homogenizing a protective gas flow in an additive manufacturing device and a manufacturing device for the generative production of a three-dimensional component from a powder with a construction chamber providing a working surface and delimited by side walls and a ceiling wall, at least one beam generation unit for generating an energy beam for the irradiation of powder in the working surface for layer-by-layer production of the component and a protective gas system for providing a protective gas flow.

[0005] Background of the Revelation

[0006] In additive manufacturing, e.g., selective laser sintering or selective laser melting, a powdered material, e.g., a metal or ceramic powder, is irradiated with electromagnetic radiation. Thin powder layers are successively applied in a chamber on a build platform to form three-dimensional objects by irradiating the respective powder layers with an irradiation beam, e.g., a laser beam. Corresponding devices are referred to as additive manufacturing devices, 3D printing systems, selective laser sintering machines, or selective laser melting machines, and the like. For the operation of such a device, see, for example, EP 2 732 890 A2.

[0007] In recent years, the additive manufacturing of components has also gained importance in industrial settings. Additive manufacturing in a powder bed (Powder Bed Fusion, PBF), in which thin layers of powder, e.g., made of metal, ceramic, or thermoplastic powder, are gradually applied and locally solidified with one or more beams to successively build up the component, is particularly suitable for the production of complex and delicate components. Machines suitable for performing a PBF process are referred to below as PBF machines. Lasers and electron beam systems are typically used as beam generation units. When a laser source is used, the process is also referred to as Powder Bed Fusion - Laser Based (PBF-LB). The beam can sinter or melt the powder to solidify it, thereby bonding it to previously solidified component layers.Depending on the beam generation unit, sintering is referred to as selective laser sintering or electron beam sintering, while melting is referred to as selective laser melting or electron beam melting. Powder-bed-based additive manufacturing of metal powder using a laser beam is also known as laser metal fusion.

[0008] Since the component is produced layer by layer, such an additive manufacturing process is relatively time-consuming. To reduce production time, multiple energy beams—for example, 2, 3, 4, 8, 12, or 16—are used instead of a single energy beam. A manufacturing device used in this process typically has at least one scanner device configured to shift the energy beams.

[0009] By using multiple energy beams, it is possible for a first energy beam to produce a first component in a work area of ​​the manufacturing device, while at the same time a second energy beam produces a second component in the work area.

[0010] In these known processes, the quality and homogeneity of the shielding gas flow, which flows horizontally over the powder layer to be solidified, is a crucial factor for producing high-quality components across the entire build platform. An inhomogeneous shielding gas flow leads to, for example, smoke and spatter particles generated during the process not being adequately removed, which negatively impacts the subsequent process and thus the component quality.

[0011] The present invention is based on the object of removing such by-products such as smoke and spatter particles reliably and as quickly as possible in order to avoid or at least reduce harmful effects such as local contamination of the powder bed and attenuation of the laser beam.

[0012] In general, the present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems, and more particularly, to improving part quality across the entire build platform. Thus, the present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems.

[0013] Summary of Revelation

[0014] The object is achieved by providing the present technical teaching, in particular the teaching of the independent claims as well as the preferred embodiments disclosed in the dependent claims and the description.

[0015] The object is achieved in particular by an inflow channel for homogenizing a protective gas flow in an additive manufacturing device, comprising: a protective gas inlet with a protective gas inlet-side section to which the protective gas is supplied and a protective gas outlet-side section to which the protective gas is guided into a build chamber of the additive manufacturing device, wherein the protective gas inlet-side section of the protective gas inlet has a cross-section, wherein the protective gas outlet-side section of the protective gas inlet has an approximately rectangular cross-section, and wherein a plurality of guide vanes are arranged in the protective gas outlet-side section of the protective gas inlet, which guide vanes homogenize and deflect the protective gas flow.

[0016] This innovative inlet channel advantageously homogenizes the shielding gas flow and feeds it into the build chamber. In this context, homogenization means modifying a shielding gas flow so that it is evenly distributed over a surface and has essentially the same velocity at all points.

[0017] In one embodiment, the shielding gas outlet-side section of the shielding gas inlet has at least one flow straightener, such as a filter laminate, perforated sheet, or honeycomb grid, at a portion through which the shielding gas is directed into the build chamber. This allows for even better homogenization of the shielding gas flow and provides a uniform shielding gas flow.

[0018] Advantageously, the shielding gas inlet-side section of the shielding gas inlet has an approximately round or square cross-section. If the shielding gas inlet-side section of the shielding gas inlet has a round cross-section, it can be manufactured cost-effectively while still achieving a high degree of homogenization. In particular, the shielding gas outlet-side section of the shielding gas inlet has an approximately cuboid cross-section, wherein the height of the cuboid cross-section of the shielding gas outlet-side section of the shielding gas inlet advantageously corresponds approximately to the height or diameter of the cross-section of the shielding gas inlet-side section.

[0019] Alternatively, the guide vanes are arranged one behind the other in the direction of the shielding gas flow, with the distance between the guide vanes decreasing in the direction of the shielding gas flow, and with the distance between the guide vanes advantageously decreasing continuously, in particular linearly or polygonally, in the direction of the shielding gas flow. This allows a uniform pressure distribution to be achieved by adjusting the local pressure loss.

[0020] In one embodiment, the guide vanes direct the shielding gas flow through a lateral opening in the shielding gas outlet-side section of the shielding gas inlet into the build chamber.

[0021] Advantageously, the guide vanes are aligned in the direction of the shielding gas flow so that each vane absorbs a portion of the shielding gas. This ensures uniform homogenization across the entire surface. In a further embodiment, the guide vanes are dimensioned so that their length increases, preferably linearly, in the direction of the shielding gas flow.

[0022] Alternatively, an acceleration nozzle is attached to the shielding gas outlet section of the shielding gas inlet, which accelerates the shielding gas flow to a predetermined value and preferably further homogenizes it. This is advantageous because, on the one hand, the acceleration nozzle itself homogenizes the shielding gas flow by imposing a pressure gradient. On the other hand, lower pressure losses occur when redirecting slower flows. This is generally beneficial for the efficiency of the system.

[0023] In particular, the acceleration nozzle has an approximately S-shaped cross-section, wherein the protective gas flow advantageously flows both through the acceleration nozzle and above and below the acceleration nozzle.

[0024] The object is also achieved by a manufacturing device for the generative production of a three-dimensional component from a powder, having a build chamber providing a work surface and delimited by side walls and a ceiling wall, at least one beam generation unit for generating an energy beam for irradiating powder in the work surface for layer-by-layer production of the component, and a protective gas system for providing a protective gas flow, wherein the protective gas system comprises the inflow channel, a suction channel, and a low-pressure pump, and the protective gas flow flows from the inflow channel into the build chamber and is suctioned out of the build chamber through the suction channel by means of the low-pressure pump fluidically connected to the suction channel via the connection opening or the two connection openings.

[0025] Advantageously, the inflow channel is arranged in or on one of the side walls or the ceiling wall of the construction chamber of the manufacturing device.

[0026] Other features and aspects of this disclosure will become apparent from the following description and the accompanying drawings.

[0027] Brief description of the drawings

[0028] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure. In the drawings:

[0029] Fig. 1 is a schematic representation of an embodiment of a manufacturing device for producing at least one component,

[0030] Fig. 2 is a schematic representation of an embodiment of an inflow channel of the manufacturing device for producing at least one component,

[0031] Fig. 3 the inlet channel from Fig. 2 in a plan view,

[0032] Fig. 4 is a schematic representation of an embodiment of an acceleration nozzle of the inlet channel of the manufacturing device for producing at least one component, and

[0033] Fig. 5 shows the inlet channel with the acceleration nozzle in a plan view according to an embodiment of the present invention. Detailed description

[0034] The following is a detailed description of exemplary embodiments of the present disclosure. The exemplary embodiments described herein and illustrated in the drawings are intended to teach the principles of the present disclosure and to enable one of ordinary skill in the art to implement and use the present disclosure in a variety of environments and for a variety of applications. Therefore, the exemplary embodiments are not intended to be, and should not be considered, a limiting description of the scope of patent protection. Rather, the scope of patent protection is to be defined by the appended claims.

[0035] Figure 1 shows a schematic representation of an embodiment of a manufacturing device 1 for producing at least one component 19 or a three-dimensional object. The manufacturing device 1 comprises a build space 3 or a process chamber and a control unit 5. The control unit 5 has a data storage medium for storing control programs. In this embodiment, the manufacturing device 1 has three scanner units 9a, 9b, 9c, each deflecting an energy beam 11a, 11b, 11c generated by at least one beam generation unit 10a, 10b, 10c. For example, each scanner unit 9a, 9b, 9c for an energy beam or laser beam can comprise one scanner mirror (not shown) that can be rotated in two directions or two scanner mirrors that can be rotated in one direction. For example, the scanner unit 9a, 9b, 9c can comprise a galvanometer scanner.Alternatively, the electron beam scanner unit 9a, 9b, 9c may comprise several pairs of electrodes between which an electric field may be applied to deflect the electron beam.

[0036] The production device 1 further comprises a substrate plate 13, which is arranged beneath the scanner units 9a, 9b, 9c and onto which a building material 15, such as a powder or a powder bed, is applied layer by layer. For this purpose, the substrate plate 13 is adjusted in the Z-direction, i.e. in the direction of increasing distance from the scanner units 9a, 9b, 9c, by a desired distance and then a new layer or layers of powder material are applied using an application device 17, such as a coater module or a powder slide. Scrapers, blades or rollers, for example, can also be considered as application devices 17. In this specific case, the scanner units 9a, 9b, 9c are suitable for directing their respective energy beams 11a, 11b, 11c over the entire powder material 15. Thus, in this embodiment, the entire powder material surface forms a common working plane 18 orThis represents a working area in which the energy beams 11a, 11b, 11c can solidify the powder material 15. After the respective uppermost layer of powder material has solidified, the substrate plate 13 can be moved again in the Z direction, and a new layer of powder material is applied via the application device 17 in order to produce a component or three-dimensional object 19 layer by layer.

[0037] The build chamber 3 is gas-tight and comprises an inlet channel 21 and an exhaust channel 23. Usually, there are one or more secondary inlets to support a laminar primary flow and prevent splashes and smoke from spreading to undesired locations (not shown). The build chamber 3 can be filled with an inert gas, e.g., nitrogen or argon, via the inlet channel 21 to prevent oxidation of the powder material 15. Together with the exhaust channel 23, a uniform protective gas flow can also be formed over the powder material 15 to remove condensates, powder particles, and other particles that are ejected into the atmosphere during solidification with energy beams, thus reducing potential interference with the energy beam 11a, 11b, 11c. The suction channel 23 can also be used to evacuate the build space 3 so that electron beams can be used as energy beams 11a, 11b, 11c.For this purpose, the installation space 3 must be made vacuum-tight.

[0038] The control unit 5 can also have a data interface, via which, for example, control programs can be imported. When executing a control program via a control interface, the control unit 5 can perform all steps necessary for layer-by-layer additive manufacturing on the device, such as activating or deactivating energy beams 11a, 11b, 11c, deflecting them with the scanner units 9a, 9b, 9c, adjusting the substrate plate 13 along the Z-axis, or triggering a powder material application using the application device 17.

[0039] Figure 2 shows a schematic representation of an embodiment of an inflow channel 21 of the manufacturing device 1 for producing at least one component 19.

[0040] In this embodiment, the inflow channel 21 has a protective gas inlet-side section 212 and a protective gas outlet-side section 214 which are connected to one another, wherein the protective gas inlet-side section 212 consists of a tube with a round cross-section and the protective gas outlet-side section 214 consists of a tube with a square or cuboid cross-section.

[0041] The protective gas outlet-side section 214 of the inflow channel 21 has two side parts 213a, 213b. One of the two side parts 213a comprises an opening connected to the build chamber 3. The other side part 213b forms a wall.

[0042] A flow straightener 218, such as a filter laminate, perforated sheet, or honeycomb grid, is attached to the opening of the side part 213a of the inlet channel 21, through which the shielding gas flows into the build chamber 3. A flow straightener 218 (not shown) can also be inserted into the exhaust channel 23 to further homogenize the shielding gas flow. In the case of a filter laminate or honeycomb grid, a laminar flow is also created, which is desirable for process stability.

[0043] In the shielding gas outlet-side section 214 of the inlet channel 21, several guide vanes 216 are arranged one behind the other in the direction of the shielding gas flow. The guide vanes guide the shielding gas from the shielding gas inlet-side section 212 through the shielding gas outlet-side section 214 and through the flow straightener 218 into the build chamber 3. The shielding gas flow is homogenized and redirected, in this embodiment by an angle of 90°.

[0044] Figure 3 shows the inflow channel 21 from Figure 2 in a top view. It is particularly evident that the distance between the guide vanes 216 decreases in the direction of the shielding gas flow, preferably linearly. Furthermore, the length of the guide vanes 216 increases in the direction of the shielding gas flow, preferably linearly. This ensures that the shielding gas exits the inflow channel 21 and through the flow straightener 218 into the build chamber 3 in a homogenized and flat manner.

[0045] Figure 4 shows a schematic representation of an embodiment of an acceleration nozzle 220 of the inflow channel 21 of the manufacturing device 1 for producing at least one component 19.

[0046] As can be seen from Figure 4, an acceleration nozzle 220 is mounted behind the inflow channel 21, i.e. the protective gas outlet-side section 214 of the protective gas inlet in the direction of the build chamber 3, i.e. between the flow straightener 218 and the build chamber 3.

[0047] The acceleration nozzle 220 has an approximately S-shaped cross-section. The acceleration nozzle 220 is arranged such that the shielding gas flow flows both through the acceleration nozzle 220 and above and below the acceleration nozzle 220.

[0048] Figure 5 shows the inflow channel 21 with the acceleration nozzle 220 in a plan view according to an embodiment of the present invention. It is particularly evident that the S-shaped acceleration nozzle 220 extends substantially over the entire length of the protective gas outlet-side section 214 of the protective gas inlet of the inflow channel 21.

[0049] As can be seen from Figure 4, the acceleration nozzle 220 can be mounted at a distance from the shielding gas outlet-side section 214 of the shielding gas inlet. Alternatively, the acceleration nozzle 220 can also be attached directly to the shielding gas outlet-side section 214 of the shielding gas inlet, as can be seen from Figure 5.

[0050] It is expressly understood that all features disclosed in the description and / or the claims are intended to be disclosed separately and independently of one another for the purpose of original disclosure and for the purpose of limiting the claimed invention, regardless of the composition of the features in the embodiments and / or the claims. It is expressly understood that all ranges of values ​​or indications of groups of units disclose every possible intermediate value or intermediate value for the purpose of original disclosure and for the purpose of limiting the claimed invention, in particular as limits of ranges of values.

[0051] Although the preferred embodiments of this invention have been described herein, improvements and modifications may be incorporated without departing from the scope of the following claims.

[0052] 1 manufacturing device

[0053] 3 Build space or build chamber

[0054] Control unit

[0055] 9a, 9b, 9c Scanner unit

[0056] 10a, 10b, 10c beam generation unit

[0057] 11a, 11b, 11c Energy beam

[0058] 13 Substrate plate

[0059] 15 Powder material or building material

[0060] 17 Application device

[0061] 18 working level

[0062] 19 Component or three-dimensional object

[0063] 21 Inlet channel

[0064] 23 Suction channel

[0065] 212 protective gas inlet side section

[0066] 213a, 213b side panel

[0067] 214 protective gas outlet side section

[0068] 216 guide vane

[0069] 218 flow straighteners

[0070] 220 acceleration nozzle

Claims

Claims 1. Inflow channel (21) for homogenizing a protective gas flow in an additive manufacturing device (1), comprising: a protective gas inlet with a protective gas inlet-side section (212) to which the protective gas is supplied and a protective gas outlet-side section (214) to which the protective gas is guided into a build chamber (3) of the additive manufacturing device (1), wherein the protective gas inlet-side section (212) of the protective gas inlet has a cross-section, wherein the protective gas outlet-side section (214) of the protective gas inlet has an approximately rectangular cross-section, and wherein a plurality of guide vanes (216) are arranged in the protective gas outlet-side section (214) of the protective gas inlet, which guide vanes homogenize and deflect the protective gas flow.

2. Inlet channel (21) for homogenizing a protective gas flow according to claim 1, wherein the protective gas outlet-side section (214) of the protective gas inlet has at least one flow straightener (218), such as a filter laminate, perforated plate or honeycomb grid, at a section through which the protective gas is guided into the build chamber (3).

3. Inlet channel (21) for homogenizing a protective gas flow according to claim 1 or 2, wherein the protective gas inlet-side section (212) of the protective gas inlet has an approximately round or square cross-section.

4. Inlet channel (21) for homogenizing a protective gas flow according to one of claims 1 to 3, wherein the protective gas outlet-side section (214) of the protective gas inlet has an approximately cuboid cross-section.

5. Inlet channel (21) for homogenizing a protective gas flow according to claim 4, wherein the height of the cuboid cross section of the protective gas outlet-side section (214) of the protective gas inlet approximately corresponds to the height or the diameter of the cross section of the protective gas inlet-side section (212) of the protective gas inlet.

6. Inlet channel (21) for homogenizing a protective gas flow according to one of claims 1 to 5, wherein the guide vanes (216) are arranged one behind the other in the protective gas flow direction, and wherein the distance between the guide vanes (216) decreases in the protective gas flow direction.

7. Inlet channel (21) for homogenizing a protective gas flow according to claim 6, wherein the distance between the guide vanes (216) decreases continuously, in particular linearly or polygonally, in the protective gas flow direction.

8. Inlet channel (21) for homogenizing a protective gas flow according to one of claims 1 to 7, wherein the guide vanes (216) guide the protective gas flow through a lateral opening (213a) in the protective gas outlet-side section (214) of the protective gas inlet into the construction chamber (3).

9. Inlet channel (21) for homogenizing a protective gas flow according to one of claims 1 to 8, wherein the guide vanes (216) are aligned in the protective gas flow direction such that each guide vane (216) receives a portion of the protective gas.

10. Inlet channel (21) for homogenizing a protective gas flow according to one of claims 1 to 9, wherein an acceleration nozzle (220) is attached to the protective gas outlet-side section (214) of the protective gas inlet, which accelerates the protective gas flow to a predetermined value and preferably further homogenizes it.

11. Inlet channel (21) for homogenizing a protective gas flow according to claim 10, wherein the acceleration nozzle (220) has an approximately S-shaped cross-section.

12. Inlet channel (21) for homogenizing a protective gas flow according to claim 10 or 11, wherein the protective gas flow flows through the acceleration nozzle (220) as well as above and below the acceleration nozzle (220).

13. Manufacturing device (1) for the generative production of a three-dimensional component (19) from a powder, comprising a construction chamber (3) providing a working surface and delimited by side walls and a ceiling wall, at least one beam generation unit (10a, 10b, 10c) for generating an energy beam (11a, 11b, 11c) for the irradiation of powder in the work surface for the layer-by-layer production of the component (19) and a protective gas system for providing a protective gas flow, wherein the protective gas system comprises an inflow channel (21) according to one of claims 1 to 12, a suction channel (23) and a low-pressure pump and the protective gas flows from the inflow channel (21) into the construction chamber (3) and is sucked out of the construction chamber (3) through the suction channel (23) by means of the low-pressure pump fluidically connected to the suction channel (23) via the connection opening or the two connection openings.

14. Manufacturing device according to claim 13, wherein the inflow channel (21) is arranged in or on one of the side walls or the ceiling wall of the construction chamber (3) of the manufacturing device (1).

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