Inlet channel for homogenizing a protective gas flow in an additive manufacturing device and a manufacturing device

Abstract

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.

Description

Technical FieldThe invention relates to an inflow channel for homogenizing a protective gas flow in an additive manufacturing device and to a manufacturing device for generatively manufacturing a three-dimensional component from a powder, having a construction chamber which provides a working surface and is bounded by side walls and a ceiling wall, at least one beam generating unit for generating an energy beam for the irradiation of powder in the working surface for producing the component layer by layer, and a protective gas system for providing a protective gas flow.BACKGROUND OF THE DISCLOSUREIn additive manufacturing, for example in selective laser sintering or selective laser melting, a pulverulent material, for example a metal powder or ceramic powder, is irradiated with electromagnetic radiation. Thin powder layers are successively deposited in a chamber on a build platform to form three-dimensional objects by irradiating the respective powder layers with an irradiation beam, for example a laser beam. Such devices are referred to as additive manufacturing devices, 3D printing systems, selective laser sintering machines or selective laser melting machines, and the like. With regard to the functioning of such a device, reference is made, for example, to EP 2 732 890 A2.In recent years, additive manufacturing of components has gained importance also in the industrial sector. Additive manufacturing in a powder bed (powder bed fusion, PBF), in which thin powder layers, for example of metal, ceramic or thermoplastic powder, are applied step by step and locally solidified with one or more jets in order to successively build up the component, is particularly suitable for manufacturing complex and filigran components. Machines suitable for carrying out a PBF process are referred to below as PBF machines. Lasers and electron beam systems are usually used as beam generating units. When using a laser source, one also speaks of powder bed fusion-laser based (PBF-LB). The jet can sinter or melt the powder for solidification and in the process connect it to component layers already solidified beforehand in a material-bonded manner. Depending on the beam generating unit, the term "selective laser sintering" (selective laser sintering) or electron beam sintering" is used in sintering, "selective laser melting" (selective laser melting) or electron beam melting" (electron beam melting) is used in melting. In powder-bed-based additive manufacturing of metal powder using a laser beam, for example, the designation of laser metal fusion is also known.Since the component is produced in layers, such an additive production process is relatively time-consuming. To reduce the manufacturing time, instead of a single energy beam, a plurality of energy beams, for example 2, 3, 4, 8, 12 or 16 energy beams, are used. A production device used in this case usually has at least one scanner device which is configured to displace the energy beams.By using a plurality of energy beams, it is possible that a first energy beam produces a first component in a working region of the production device, wherein a second energy beam produces a second component in the working region at the same time.In these known methods, the quality or homogeneity of the inert gas flow, which flows horizontally over the powder layer to be consolidated, is a decisive factor for the production of high-quality components over the entire construction platform. An inhomogeneous protective gas flow leads to the result that, for example. Smoke and smoke particles which are produced during the process cannot be sufficiently transported away, which has a negative effect on the further process and thus on the component quality.The object of the present invention is to transport away such byproducts as smoke and sputter particles reliably and as quickly as possible in order to avoid or at least reduce harmful effects such as local impurities of the powder bed and an attenuation of the laser beam.In general, the present disclosure is directed, at least in part, to improving or overcoming one or more aspects of the prior art systems, and more particularly to improving component quality throughout the build platform.Thus, the present disclosure is directed, at least in part, to improving or fully overcoming one or more aspects of prior systems.SUMMARY OF THE DISCLOSUREThe object is achieved by providing the present technical teaching, in particular the teaching of the independent claims and of the preferred embodiments disclosed in the dependent claims and the description.The object is achieved in particular by an inflow duct for homogenizing a protective gas flow in an additive manufacturing device, comprising: a protective gas inlet having a section on the protective gas inlet side, at which the protective gas is supplied, and a section on the protective gas outlet side, at which the protective gas is conducted into a construction chamber of the additive manufacturing device, wherein the section on the protective gas inlet side of the protective gas inlet has a cross section, wherein the section on the protective gas outlet side of the protective gas inlet has an approximately rectangular cross section, and wherein a plurality of guide blades are arranged in the section on the protective gas outlet side of the protective gas inlet, which guide blades homogenize and deflect the protective gas flow.Advantageously, the protective gas flow is homogenized by this innovative inflow channel and introduced into the construction chamber. Homogenization in this context means the variation of a protective gas stream in such a way that it is distributed uniformly on one surface and additionally has substantially the same velocity at all points.In one embodiment, the section of the inert gas inlet on the inert gas outlet side has at least one flow rectifier, such as a filter laminate, perforated sheet metal or honeycomb-shaped grid, at a section through which the inert gas is conducted into the construction chamber. As a result, the protective gas stream can be homogenized even better and a uniform protective gas stream is provided.Advantageously, the section of the inert gas inlet on the inert gas inlet side has an approximately round or angular cross section. In the case of a round cross section of the section of the inert gas inlet on the inert gas inlet side, this can be manufactured cost-effectively and nevertheless a high homogenization can be achieved.In particular, the section of the inert gas inlet on the inert gas outlet side has an approximately cuboidal cross section, wherein the height of the cuboidal cross section of the section of the inert gas inlet on the inert gas outlet side advantageously corresponds approximately to the height or the diameter of the cross section of the section of the inert gas inlet on the inert gas inlet side.Alternatively, the guide blades are arranged one behind the other in the protective gas flow direction, wherein the distance between the guide blades decreases in the protective gas flow direction, and wherein the distance between the guide blades advantageously decreases continuously, in particular linearly or polygonally, in the protective gas flow direction. In this way, a uniform pressure distribution can be achieved by adapting the local pressure loss.In one embodiment, the guide blades guide the protective gas flow through a lateral opening of the protective gas inlet-side section of the protective gas inlet into the construction chamber.Advantageously, the guide blades are oriented in the protective gas flow direction such that each guide blade accommodates a portion of the protective gas. This can ensure uniform homogenization over the entire surface. In a further embodiment, the guide blades are dimensioned such that their length increases in the inert gas flow direction, preferably linearly.Alternatively, an acceleration nozzle is attached to the section of the inert gas inlet on the inert gas outlet side, which accelerates the inert gas flow to a predetermined value and preferably further homogenized. It is advantageous here that, on the one hand, the acceleration nozzle itself homogenized the inert gas flow, since it applies a pressure gradient. On the other hand, lower pressure losses occur when deflecting slower flows. This is generally advantageous for the efficiency of the plant.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 flows above and below the acceleration nozzle.The object is also achieved by a production device for generatively producing a three-dimensional component from a powder, having a construction chamber which provides a working surface and is bounded by side walls and a ceiling wall, at least one jet-generating unit for generating an energy jet for the irradiation of powder in the working surface for layer-wise production of the component, and a protective gas system for providing a protective gas stream, wherein the protective gas system comprises the inflow duct, a suction duct and a low-pressure pump, and the protective gas stream flows from the inflow duct into the construction chamber and is suctioned out of the construction chamber by the suction duct by means of the low-pressure pump connected to the suction duct via the connection opening or the two connection openings.Advantageously, the inflow channel is arranged in or on one of the side walls or the ceiling wall of the construction chamber of the production device.Other features and aspects of this disclosure will become apparent from the following description and the accompanying drawings.Brief Description of the DrawingsThe accompanying drawings, which are incorporated herein and form 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, the following shows: FIG. 1 shows a schematic illustration of an exemplary embodiment of a production apparatus for producing at least one component, FIG. 2 shows a schematic illustration of an exemplary embodiment of an inflow channel of the production device for producing at least one component, FIG. 3 shows the inflow channel from FIG. 2 in a plan view, FIG. 4 shows a schematic illustration of an exemplary embodiment of an acceleration nozzle of the inflow channel of the production device for producing at least one component, and FIG. 5 shows the inflow duct with the acceleration nozzle in a plan view according to an exemplary embodiment of the present invention.Detailed DescriptionThe following is a detailed description of exemplary embodiments of the present disclosure. The exemplary embodiments described therein and illustrated in the drawings are intended to teach the principles of the present disclosure and to enable those of ordinary skill in the art to implement and use the present disclosure in many different environments and for many different applications. Therefore, the exemplary embodiments are not intended to limit the scope of patent protection and should not be considered as such. Rather, the scope of patent protection is to be defined by the appended claims.FIG. 1 shows a schematic illustration of an exemplary embodiment of a production apparatus 1 for producing at least one component 19 or a three-dimensional object. The manufacturing device 1 comprises an installation space 3 or a process chamber and a control unit 5. In this embodiment, the production apparatus 1 has three scanner units 9 a, 9 b, 9 c, which each deflect an energy beam 11 a, 11 b, 11 cgenerated by means of at least one beam generating unit 10 a, 10 b, 10 c. For example, each scanner unit 9 a, 9 b, 9 cfor an energy beam or laser beam can comprise a 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 9 a, 9 b, 9 cmay include a galvanometer scanner. Alternatively, the electron beam scanner unit 9a, 9b, 9c may comprise a plurality of pairs of electrodes between which an electric field may be applied to deflect the electron beam.The production device 1 further comprises a substrate plate 13 which is arranged below the scanner units 9 a, 9 b, 9 cand onto which a construction material 15, such as a powder or a powder bed, is applied in layers. 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 9 a, 9 b, 9 c, by a desired distance and then a new powder material layer or powder material layer is applied with an application device 17, such as e.g. a coater module or a powder slide. Application devices 17 also include, for example, scrapers, blades or rollers. In this particular case, the scanner units 9 a, 9 b, 9 care suitable for directing their respective energy beam 11 a, 11 b, 11 cover the entire powder material 15. Thus, in this embodiment, the entire powder material surface represents a common working plane 18 or working region in which the energy beams 11 a, 11 b, 11 cmay solidify the powder material 15. After the respective uppermost powder material layer has solidified, the substrate plate 13 can be moved again in the -Z direction and a new powder material layer is applied via the application device 17 in order to produce a component or three-dimensional object 19 in layers.The installation space 3 is gas-tight and comprises an inflow duct 21 and an extraction duct 23. There are usually one or more secondary inlets in order to support a laminar primary flow and to prevent splashing and smoke from being able to distribute themselves to undesired locations (not shown). The installation space 3 can be filled with an inert gas, for example nitrogen or argon, via the inflow duct 21 in order to prevent oxidation of the powder material 15. Together with the suction channel 23, a uniform protective gas flow can also be formed over the powder material 15 in order to transport away condensates, powder particles and other particles which are thrown into the atmosphere during solidification with energy jets and thus to reduce possible disturbances of the energy jet 11 a, 11 b, 11 c. The suction channel 23 can also be used to evacuate the installation space 3 in order that electron beams can be used as energy beams 11 a, 11 b, 11 c. For this purpose, the installation space 3 must be made vacuum-tight.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 execute all the steps necessary for the layer-by-layer additive manufacturing on the device, such as, for example, the activation or deactivation of energy beams 11 a, 11 b, 11 c, the deflection thereof with the scanner units 9 a, 9 b, 9 c, the adjustment of the substrate plate 13 along the Z axis or the triggering of a powder material application by means of the application device 17.FIG. 2 shows a schematic illustration of an exemplary embodiment of an inflow channel 21 of the production apparatus 1 for producing at least one component 19.The inflow passage 21 in this embodiment has a shielding gas inlet-side portion 212 and a shielding gas outlet-side portion 214 connected to each other, the shielding gas inlet-side portion 212 is made of a pipe having a round cross section, and the shielding gas outlet-side portion 214 is made of a pipe having a square cross section.The shielding gas outlet-side portion 214 of the inflow channel 21 has two side parts 213 a, 213 b. One of the two side parts 213 aincludes an opening which is connected to the construction chamber 3. The other side part 213 bconstitutes a wall.At the opening of the side part 213 aof the inflow channel 21, a flow rectifier 218 such as a filter laminate, perforated sheet, or honeycomb mesh is attached, through which the inert gas flows into the build chamber 3. A flow rectifier 218 (not shown) can likewise be inserted into the suction channel 23 in order to even more homogenize the inert gas flow. In the case of a filter laminate or honeycomb grid, a laminar flow aimed for process stability is also produced.In the section 214 of the inflow channel 21 on the inert gas outlet side, a plurality of guide blades 216 are mounted one behind the other in the inert gas flow direction. The guide blades guide the protective gas from the section 212 on the protective gas inlet side, through the section 214 on the protective gas outlet side and through the flow rectifier 218 into the construction chamber 3.FIG. 3 shows the inflow channel 21 from FIG. 2 in a plan view. It can be seen in particular here that the distance between the guide vanes 216 decreases, preferably decreases linearly, in the inert gas flow direction. Furthermore, the length of the guide vanes 216 increases in the inert gas flow direction, preferably linearly. This makes it possible to ensure that the protective gas is homogenized and exits two-dimensionally from the inflow duct 21 and through the flow rectifier 218 into the construction chamber 3.FIG. 4 shows a schematic illustration of an exemplary embodiment of an acceleration nozzle 220 of the inflow duct 21 of the production apparatus 1 for producing at least one component 19.As can be seen from FIG. 4, an acceleration nozzle 220 is mounted behind the inflow duct 21, i.e. the section 214 of the inert gas inlet on the inert gas outlet side, in the direction of the construction chamber 3, i.e. between the flow rectifier 218 and the construction chamber 3.The accelerating nozzle 220 has an approximately S-shaped cross section. Here, the accelerating nozzle 220 is arranged such that the inert gas flow both flows through the accelerating nozzle 220 and flows past above and below the accelerating nozzle 220.FIG. 5 shows the inflow channel 21 with the acceleration nozzle 220 in a plan view according to an exemplary embodiment of the present invention. It can be seen in particular here that the S-shaped acceleration nozzle 220 extends substantially over the entire length of the section 214 of the inert gas inlet of the inflow channel 21 on the inert gas outlet side.As can be seen from FIG. 4, the acceleration nozzle 220 can be mounted at a distance from the section 214 of the inert gas inlet on the inert gas outlet side. Alternatively, however, the acceleration nozzle 220 can also be fastened directly to the section 214 of the inert gas inlet on the inert gas outlet side, as can be seen from FIG. 5.It is expressly pointed out that all features disclosed in the description and / or the claims are to be disclosed separately and independently of one another for the purpose of original disclosure and for the purpose of restricting the claimed invention, independently of the composition of the features in the embodiments and / or the claims. It is expressly pointed out that all value ranges or details about groups of units disclose every possible intermediate value or intermediate value for the purpose of the original disclosure and for the purpose of restricting the claimed invention, in particular as limits of value ranges.Although the preferred embodiments of this invention have been described herein, improvements and modifications can be incorporated without departing from the scope of the following claims.List of reference characters1 Production device 3 Installation space or construction chamber 5 Control unit 9 a, 9 b, 9 c Scanner unit 10 a, 10 b, 10 cJet generation unit 11 a, 11 b, 11 cEner jet 13 Substrate plate 15 Powder material or construction material 17 Application device 18 Working plane 19 Component or three-dimensional object 21 Inflow duct 23 Suction duct 212 Section 213 a, 213 bSide part 214 Section 216 Guide blade 218 Flow rectifier 220 Acceleration nozzleReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 2 732 890 A2

[0002]

Claims

Inflow duct (21) for homogenizing a protective gas flow in an additive manufacturing device (1), comprising: a protective gas inlet having a section (212) on the protective gas inlet side, at which the protective gas is supplied, and a section (214) on the protective gas outlet side, at which the protective gas is conducted into a construction chamber (3) of the additive manufacturing device (1), wherein the section (212) on the protective gas inlet side of the protective gas inlet has a cross section, wherein the section (214) on the protective gas outlet side of the protective gas inlet has an approximately rectangular cross section, and wherein a plurality of guide blades (216) are arranged in the section (214) of the protective gas inlet on the protective gas outlet side, which guide blades homogenize and deflect the protective gas flow.The inflow channel (21) for homogenizing a flow of shielding gas according to claim 1, wherein the shielding gas outlet-side portion (214) of the shielding gas inlet has at least one flow rectifier (218), such as a filter laminate, perforated sheet metal or honeycomb grid, at a portion through which the shielding gas is conducted into the build chamber (3).Inflow duct (21) for homogenizing a protective gas flow according to Claim 1 or 2, wherein the section (212) of the protective gas inlet on the protective gas inlet side has an approximately round or angular cross section.Inflow duct (21) for homogenizing a protective gas flow according to one of Claims 1 to 3, wherein the section (214) of the protective gas inlet on the protective gas outlet side has an approximately cuboidal cross section.Inflow duct (21) for homogenizing a protective gas flow according to Claim 4, wherein the height of the cuboid cross section of the section (214) of the protective gas inlet on the protective gas outlet side corresponds approximately to the height or the diameter of the cross section of the section (212) of the protective gas inlet on the protective gas inlet side.Inflow duct (21) for homogenizing a protective gas flow according to one of Claims 1 to 5, wherein the guide blades (216) are arranged one behind the other in the protective gas flow direction, and wherein the distance between the guide blades (216) decreases in the protective gas flow direction.Inflow duct (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.Inflow duct (21) for homogenizing a protective gas flow according to one of Claims 1 to 7, wherein the guide blades (216) guide the protective gas flow through a lateral opening (213a) in the section (214) of the protective gas inlet on the protective gas outlet side into the construction chamber (3).Inflow duct (21) for homogenizing a protective gas flow according to one of Claims 1 to 8, wherein the guide blades (216) are oriented in the protective gas flow direction such that each guide blade (216) accommodates a portion of the protective gas.Inflow duct (21) for homogenizing a protective gas flow according to one of Claims 1 to 9, wherein an acceleration nozzle (220) is mounted on the section (214) of the protective gas inlet on the protective gas outlet side, said acceleration nozzle accelerating the protective gas flow to a predetermined value and preferably further homogenizing it.The inflow channel (21) for homogenizing a flow of shielding gas according to claim 10, wherein the accelerating nozzle (220) has an approximately S-shaped cross section.Inflow duct (21) for homogenizing a protective gas flow according to Claim 10 or 11, wherein the protective gas flow both flows through the acceleration nozzle (220) and flows past above and below the acceleration nozzle (220).Production device (1) for generatively producing a three-dimensional component (19) from a powder, having a construction chamber (3) which provides a working surface and is bounded by side walls and a ceiling wall, at least one beam generating unit (10a, 10b, 10c) for generating an energy beam (11a, 11b, 11c) for the irradiation of powder in the working surface for 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 duct (21) according to one of Claims 1 to 12, a suction channel (23) and a low-pressure pump, and the protective gas stream flows from the inflow channel (21) into the construction chamber (3) and is suctioned out of the construction chamber (3) through the suction channel (23) by means of the low-pressure pump which is fluidically connected to the suction channel (23) via the connection opening or the two connection openings.The 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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