ADDITIVE MANUFACTURING SYSTEM

Description

Technical field

[0001] The present invention relates to an additive manufacturing system and an additive manufacturing process. Background of the invention

[0002] Additive manufacturing, particularly selective laser melting (SLM) or laser powder bed fusion (LPBF), is a generative manufacturing process belonging to the group of beam melting processes. In selective laser melting, the material to be processed is applied in powder form in a thin layer onto a base plate. The powdered material is locally and completely melted by laser radiation and, after solidification, forms a solid layer of material. The base plate is then lowered by the thickness of one layer, and more powder is applied. This cycle is repeated until all layers have been melted. The finished component is cleaned of excess powder and, if necessary, further processed or used immediately.

[0003] Conventional additive manufacturing machines are often simply designed, and therefore lack the robustness and accuracy of precision machine tools. Furthermore, such machines require time-consuming setup and preparation. For example, changing the powder material usually necessitates a very time-consuming cleaning of all powder-contaminated components and assemblies before the machine can be filled with fresh powder.

[0004] Furthermore, the powder must be manually removed from a build area of ​​the machine using protective equipment such as dust masks or gloves. During this maintenance work, the system is not productive, and costly laser and optics units are unavailable due to the manual intervention. The productivity of the conventional additive manufacturing system is therefore limited.

[0005] DE 10 2004 057865 A1 discloses a device for manufacturing a three-dimensional object. The device comprises a support for carrying the object, which is arranged in a build chamber of a container. The support has a height-adjustable carrier with an upper surface facing the object. The device further comprises an application device for applying layers of the build material to the support or a previously formed layer, a metering device for feeding the build material, and an irradiation device.

[0006] EP 3 632 592 A1 discloses an additive manufacturing system with a rotatable manufacturing unit. The additive manufacturing system includes a powder unit opening arranged on an end face or on a side face of the base section of the manufacturing system to introduce the powder unit into the additive manufacturing system.

[0007] Sisma's document, "Unveiling New PBF and DLP Solutions," reveals an additive manufacturing system with a rotatable control unit. The system is equipped with two fully overlapping laser sources that work together to fuse metal powders to produce parts. Summary of the invention

[0008] It is therefore an object of the present invention to provide an improved additive manufacturing system that increases the productivity of additive manufacturing.

[0009] This problem is solved by the additive manufacturing system and the additive manufacturing process according to the independent claims. Advantageous embodiments and further developments can be found in the dependent claims and the following description.

[0010] The present invention comprises an additive manufacturing system comprising an operator area, a loading area, and a transportable container unit. The operator area is designed for controlling the manufacturing system. The loading area is designed for loading the manufacturing system. The operator area is accessible from a first side of the manufacturing system, and the loading area is accessible from a second side of the manufacturing system, the first side being different from the second side. The transportable container unit can be inserted into the loading area. The transportable container unit comprises a powder storage container and a build container. The powder storage container is designed for storing powder, and the build container is designed for the additive manufacturing of a workpiece.

[0011] The advantage of the additive manufacturing system according to the invention lies in the fact that it ensures a flawless additive manufacturing process, thereby increasing the productivity of additive manufacturing. By separating the operator area and the loading area, contamination-free additive manufacturing and complete automation of the additive manufacturing process can be achieved without the need for personal protective equipment. This also guarantees operator and system safety.

[0012] The additive manufacturing system can be designed to produce the workpiece by selectively melting (selective laser melting (SLM) or laser powder bed fusion (LPBF)) a powder material. The additive manufacturing system can be a large-scale system divided into several areas, such as an operator area, loading area, manufacturing area, peripheral area, etc. These areas can be arranged so that they do not overlap. In other words, the areas within the additive manufacturing system can be spatially separated from one another, ensuring that operations in the operator area and the loading area do not interfere with each other.

[0013] The additive manufacturing system can be controlled from the operator area. This means that, according to the invention, the operator area has at least one control device so that operating conditions or parameters for additive manufacturing can be set. Furthermore, the operator area can provide an operator with access to the manufacturing system.

[0014] The operator is an automated system, such as a robotic arm. This access allows maintenance work, such as cleaning, repairs, etc., to be carried out.

[0015] The operator area can be located at the front of the manufacturing system.

[0016] The loading area can be configured so that the powder can be loaded into and / or unloaded from the production system. The powder can be loaded and unloaded either as powder on its own or in a powder storage container. The loading area can be located at a different point in the production system than the operator area. The loading area is positioned opposite the operator area. Therefore, the loading area can be located at the rear or on a side of the production system.

[0017] The container unit, which includes at least the powder reservoir and the build container, can be designed to be portable. In other words, the container unit can be inserted into the loading area of ​​the production system from the outside and / or removed from it. The powder reservoir and the build container can be connected and loaded into the loading area together as a single unit. Alternatively, the powder reservoir and the build container can be designed separately so that they can be inserted into and removed from the production system independently. The container unit is transported and positioned automatically.

[0018] The construction container may include a powder overflow designed to collect excess powder from the coating process.

[0019] The powder reservoir can be designed to hold freshly prepared powder, which is applied layer by layer towards the build chamber during additive manufacturing. Additive manufacturing, or selective melting, can then take place within the build chamber by selectively melting the layered powder with a laser beam. After repeating the powder application and selective melting process several times, the workpiece can finally be produced.

[0020] This approach creates a spatial and functional separation between the operator area and the loading area, which can lead to additive manufacturing of the workpiece with reduced or no contamination. "Free from contamination" means that the operator is not contaminated by powder and / or that the powder is not contaminated by the ambient atmosphere. Lids can be used as needed, which, for example, are only removed from the containers after they have been placed in the production system.

[0021] In one embodiment, the container unit further comprises a powder overflow container. The powder overflow container can be designed to collect residual powder remaining after selective melting. Additionally, weld spatter generated during additive manufacturing can be collected in the powder overflow container. The powder overflow container can be connected to the powder storage container and / or the build container, or it can be designed separately. Like the powder storage container and the build container, the powder overflow container can be designed to be portable.

[0022] The fresh powder can, for example, be applied layer by layer from the surface of the powder reservoir to the surface of the build container using a doctor blade. After the selective melting of the applied powder, the excess powder can be pushed into the powder overflow container using the doctor blade. In other words, the powder reservoir, the build container, and the powder overflow container can be arranged in this order within the container unit to allow for unidirectional powder transport by the doctor blade.

[0023] In one embodiment, the powder storage container and the construction container each comprise a base plate and a lifting rod. The lifting rod is designed to raise the base plate within the respective container. The base plate of the powder storage container and the construction container can each be designed to seal an interior space of the respective container from the outside.

[0024] Each base plate can be connected to a lifting rod to move the base plate vertically within its respective container. Preferably, the lifting rod of the powder reservoir can raise the base plate so that the freshly prepared powder can be applied evenly to the surface of the powder reservoir. Meanwhile, after each melting process or laser beam exposure, the base plate of the build container can be gradually lowered by the lifting rod to allow for the subsequent melting process of the reapplied powder.

[0025] In one embodiment, the powder overflow container can also have a base plate and a lifting rod to facilitate emptying the powder overflow container in which the residual powder and / or weld spatter are collected.

[0026] According to the invention, the build container comprises a build plate. In one embodiment, the build container further comprises a heating plate. The heating plate is arranged between the build plate and the base plate, and is designed to heat the build plate. The build plate can serve to hold the fresh powder applied layer by layer and to enable the selective melting of the powder there. Heating the build plate reduces stress on the workpiece by decreasing the temperature gradient between the material layers of the workpiece.

[0027] In one embodiment, the build plate can be arranged on the heating plate by means of a three-point support system. For example, three bolt elements can be arranged on the underside of the build plate facing the heating plate, which can rest on the heating plate. The bolt elements can project from the underside of the build plate towards the heating plate and be spaced as far apart as possible. In this way, a loosely supported yet secure three-point support of the build plate can be achieved. Additionally, the underside of the build plate can have at least one tension pin, by which, for example, the build plate can be fixed to the heating plate during post-treatment.

[0028] In one embodiment, a through-hole can be provided in each corner of the heating plate. A fastening bolt, extending from the bottom of the construction container through the heating plate and into the construction plate without making contact, can be inserted through this through-hole. This fastening bolt can be used to clamp or lock the construction plate in its lowest position within the construction container.

[0029] Additionally, a bolt element for a zero-point clamping system can be located on the underside of the heating plate to enable a firm and precise connection between the heating plate and the base plate. To accommodate the bolt element of the heating plate securely and with positive locking, the base plate can include a clamping element. The bolt element is preferably located in the center of the heating plate, and the clamping element is preferably located in the center of a top surface of the base plate facing the heating plate.

[0030] In one embodiment, the heating plate comprises heating elements and an insulating layer. The insulating layer is positioned below the heating elements to insulate them from the base plate. The heating plate can, for example, include ceramic heating elements. The heating plate allows the build plate to be heated to several hundred degrees Celsius. In particular, the build plate can be heated to 250 degrees Celsius or even 500–600 degrees Celsius. An insulating layer can be provided below the heating elements, but within the heating plate, to ensure that the heat is conducted exclusively to the build plate. In other words, the insulating layer prevents the heat from being conducted towards the base plate. This increases the efficiency and quality of additive manufacturing.In one embodiment, the base plate comprises at least one cooling line connected to an inlet and outlet of a cooling medium via the lifting rod. The cooling line, through which the cooling medium flows, can be located inside the base plate or on its underside. An inlet and outlet connection for the cooling medium, connected to the cooling line, can be integrated into the lifting rod. This ensures proper circulation of the cooling medium and, consequently, efficient cooling of the base plate. As a result, heat generated below the heating plate can be blocked, and the associated thermal expansion of the construction container, particularly in the vertical direction, can be prevented.

[0031] According to the invention, the build container comprises at least one fixing element with a spring-loaded bolt and a clamping ball. During container exchange, the clamping ball can be clamped to the build plate by the spring-loaded bolt. The fixing element is preferably located at the bottom of the build container to hold the base plate, heating plate, and / or build plate in place during container exchange and / or reconditioning. The build container preferably has two or more fixing elements to provide a reliable connection between the container bottom and the base plate, heating plate, and / or build plate.

[0032] The fixing element can comprise at least one, preferably a pair, clamping balls and a bolt connected to a spring facing the interior of the container. The fixing element can further comprise a housing that accommodates the spring-loaded bolt and the clamping ball. The housing of the fixing element can be integrated into the container housing. The spring-loaded bolt can move vertically within the housing, its movement being restricted by the spring and the clamping ball located on a lateral inner surface of the housing. In other words, the clamping ball can clamp the spring-loaded bolt against the build plate, allowing the bolt to hold the build plate in a retracted position. In the bolt's return position, the build plate can be released.

[0033] When the build container is removed from the additive manufacturing system, the base plate, heating plate, and / or build plate can shift during transport, rework, and / or refinishing of the container, potentially causing the build plate to detach from the base plate. To prevent this shifting and / or detachment, the spring-loaded bolt can be pressed into the build plate through the heating plate's through-hole into the build plate. Simultaneously, the bolt pushes the clamping ball outward. This creates a positive and non-positive connection between the build plate and the container housing, particularly the base of the build container. Since the heating plate is located between the build plate and the base plate, it can be automatically clamped in place.

[0034] During additive manufacturing, the fixing element can be in a reset position, so that the bolt is not engaged with the build plate. In this way, the build plate, heating plate and / or base plate within the build container could be raised and / or lowered by the lifting rod.

[0035] According to the invention, the additive manufacturing system further comprises a build chamber. In one embodiment, the additive manufacturing system further comprises a lifting device. The build chamber can be coupled to the container unit for applying the powder to the build plate, and the lifting device is designed to lift the transportable container unit to a base of the build chamber.

[0036] The build chamber can be designed to perform the selective melting of the powder. The lifting device can be designed to dock the container unit, which is inserted into the production system from the outside, to the bottom of the build chamber. In particular, the build plate of the build container can be coupled to the bottom of the build chamber by lifting the container unit using the lifting device and additionally by lifting the build plate using the lifting rod.

[0037] The build chamber may contain a squeegee that applies the fresh powder from the powder reservoir to the build plate of the build container in layers and transports the excess powder from the build plate to the powder overflow container. Furthermore, the build chamber may include an opening, which is sealed, for example, with an optically transparent material. The laser beam can be supplied through this opening to expose a fresh layer of powder applied to the build plate.

[0038] In one embodiment, the base of the build chamber has a sealing interface designed for a positive-locking and gas-tight connection between the container unit and the build chamber. The sealing interface can be arranged between the base of the build chamber and the container unit, which is lifted to the base of the build chamber by the lifting device. The sealing interface can include a circumferential seal surrounding an upper edge of the container unit to create a vacuum-tight connection between the container unit and the build chamber. Openings for the powder reservoir, the build container, and / or the powder overflow container can be arranged at the upper edge of the container unit.

[0039] In one embodiment, the sealing interface has a gap for collecting residual powder. This gap is coupled to a cleaning nozzle for blowing out the residual powder. The gap can be located between the container unit and the sealing interface and extend at least partially along the circumferential direction of the upper edge of the container unit. In particular, the gap can be provided between the sealing interface and the opening of the powder overflow container.

[0040] The gap can extend, at least partially, from the bottom of the build chamber towards the bottom of the container, leaving one end of the gap exposed within the build chamber. Furthermore, another end of the gap can be connected to the cleaning nozzle, through which, for example, air or inert gas is expelled. In other words, the cleaning nozzle, coupled to the gap, can be positioned between the sealing interface and the container assembly. During additive manufacturing, excess powder can be collected in the gap and, after completion of the additive manufacturing process, can be expelled from the gap by the gas to prevent powder carryover during container removal.

[0041] In one embodiment, a temperature control device can be integrated into the sealing interface. The temperature control device can be designed to prevent undesirable material expansion in the area of ​​the sealing interface, both on the build vessel and on the floor of the build chamber.

[0042] In one embodiment, the additive manufacturing system further comprises a protective gas inlet and a protective gas outlet. The protective gas inlet and the protective gas outlet are arranged relative to the build platform to generate a protective gas flow. The protective gas inlet and / or the protective gas outlet can be designed such that the protective gas flow exits only a few millimeters above the build platform, i.e., the process plane. The protective gas inlet and / or the protective gas outlet can preferably be arranged perpendicular to the direction of movement of the doctor blade. Alternatively, the protective gas inlet and / or the protective gas outlet can be arranged parallel to the direction of movement of the doctor blade.

[0043] The shielding gas inlet can be configured to supply the shielding gas into the build chamber, and the shielding gas outlet can be used to draw in the shielding gas released in the build chamber. A continuous supply and removal of the shielding gas creates a laminar and homogeneous flow within the build chamber. The doctor blade, positioned parallel to the flow direction of the shielding gas, prevents partial diversion and / or turbulence of the shielding gas flow.

[0044] In one embodiment, the protective gas inlet can include a porous element for providing a homogeneous protective gas flow. The porous element can be designed to generate a dynamic pressure within the protective gas inlet. The porous element can be understood as a filter element arranged at the protective gas inlet and extending across its entire width and height. The porous element can exhibit uniform porosity across its entire surface. The porous element can be a sintered element or a foam-like, but gas-permeable, element. Thus, a constant dynamic pressure can be generated within the protective gas inlet, and the protective gas flow can be free of velocity gradients in the inlet area. In this way, a homogeneous supply of the protective gas to the build chamber can be achieved.

[0045] Furthermore, the protective gas outlet can be designed in such a way that it completely absorbs the protective gas introduced into the build chamber and does not cause any narrowing of the laminar and homogeneous protective gas flow.

[0046] In one embodiment, the additive manufacturing system can have a protective gas inlet opening located above the build plate. This inlet allows the protective gas to be additionally supplied into the build chamber above the build plate. The inlet opening can be located on the same side as the inlet, i.e., on the opposite side from the outlet. Thus, the protective gas exiting the inlet opening can also be discharged through the outlet.

[0047] A graded porous structure can be arranged between the shielding gas inlet and the build chamber. This graded porous structure can also be positioned opposite the shielding gas outlet. The term "graded porous structure" refers to the presence of varying degrees of porosity within the porous structure. By employing this porous structure, a slight static overpressure can be generated between the shielding gas inlet and the structure, allowing the shielding gas to flow homogeneously through it. Furthermore, the graded porous structure can be used to regulate the velocity of the shielding gas flow. For example, a high-speed gas flow can be generated directly at a laser exit window, helping to prevent the accumulation of soot or weld spatter at the laser exit window.

[0048] This shielding gas flow from above can support the laminar character of the shielding gas flow near the build site, which flows from the shielding gas inlet to the shielding gas outlet. In this way, larger turbulences within the build chamber, in which soot could accumulate and which, due to its high absorption capacity, can adversely affect the laser beam, can be largely avoided by the shielding gas flow from above.

[0049] In one embodiment, the additive manufacturing system further comprises an optical bench. The optical bench includes an off-axis monitoring device and an on-axis monitoring device. The off-axis monitoring device is designed to monitor the heat distribution of an additively manufactured component layer of the workpiece and the deposition quality of a last applied powder layer. The on-axis monitoring device is designed to determine the temperature of a powder bath on the currently manufactured component layer.

[0050] The off-axis monitoring system can include one, at least one, or two high-resolution, multi-functional cameras with a high spectral bandwidth in the build chamber. These cameras, equipped with optical bandpass filters, can capture thermal process emissions during additive manufacturing. The camera image acquisition system can be designed to integrate emission data occurring and captured during the exposure of a powder layer into a single image. The resulting image can be a heat map of the currently built layer. This heat map can be used to detect thermal irregularities during additive manufacturing and, with sufficiently fast processing of this information, to implement countermeasures during a subsequent layer.This could include, for example, a dynamic adjustment of exposure sequences for scanned areas within a layer, laser power, or scan speed within specific scan areas.

[0051] Off-axis cameras can also be used to detect powder deposition defects that may occur during a coating process. Line-like structures can form in the direction of the doctor blade movement during powder application. The visibility of such powder deposition defects is greatly increased when they are illuminated from the side to create a shadow. The powder deposition defect and / or coating defect can then be indirectly detected via a characteristic shadow using the off-axis camera.

[0052] Furthermore, the off-axis monitoring device can be configured for scanner calibration. Scanner calibration can be performed before starting additive manufacturing using a clean and powder-free build plate.

[0053] The on-axis monitoring device may include a ratio pyrometer, photodiodes, and / or a high-speed camera designed to determine the temperature of the powder bath. The powder bath, which surrounds the workpiece produced by selective melting, may be located on the build plate inside the build chamber.

[0054] The ratio pyrometer can be designed to measure the maximum temperatures in the powder bath. Using the high-speed camera, the shape of the powder bath and the distribution of thermal radiation intensity within the bath can be recorded, contributing to a better overall understanding of the process. The photodiodes can also be used to measure the thermal radiation in the melt or powder bath.

[0055] In this way, precise recording of thermal process emissions in the build chamber can be achieved, thus fulfilling a prerequisite for real-time control of additive manufacturing.

[0056] In one embodiment, the powder storage container and the construction container each include a lid. The lid has a projection for gripping. To enable contamination-free transport of the container unit, particularly the powder storage container and the construction container, each container can have a lid. The lid can be configured to hermetically seal the respective container from the outside. Additionally, the powder overflow container can also have a lid. Each lid can have a projection that can be gripped manually or by a robotic arm to remove the lid from the respective container and / or to close the respective container with the lid.

[0057] According to the invention, the first side of the manufacturing system faces the second side of the manufacturing system. Thus, the operator area can be positioned relative to the build chamber opposite the loading area. In other words, the operator area can be located at the front of the manufacturing system, while the loading area can be located at the rear of the manufacturing system, and vice versa. In this way, the operator area and the loading area do not overlap, ensuring contamination-free access to the additive manufacturing system.

[0058] In one embodiment, the operator area includes a monitor for monitoring and / or controlling data and / or functions of the manufacturing system. Preferably, a user interface can be arranged on the outside of the operator area to enable control and operation of the additive manufacturing system. The monitor can be a touchscreen. The monitor can display an additive manufacturing process, an operating parameter, a status of the additive manufacturing system, and / or all necessary machine functions and data so that the operator can, for example, monitor the additive manufacturing process and control and / or maintain the additive manufacturing system according to the displayed information.

[0059] If required, various process parameters can also be parameterized via the monitor. The monitor can therefore be electronically connected to a control unit and / or various data acquisition devices to enable the monitoring and / or control of the production system.

[0060] According to the invention, the operator area has an openable access to the build chamber. This openable access can be a door or a window, allowing the operator to enter the build chamber, for example, to perform maintenance work. The access can be a laterally sliding door or an opening sealed with a transparent material. The monitor can be integrated into the openable access.

[0061] According to the invention, the loading area includes an interface for the automated insertion of the transportable container unit. In an embodiment not part of the invention, the loading area includes an interface for the manual insertion of the transportable container unit. Like the operator area, the loading area can include a door or an opening through which the transportable container unit can be inserted into and removed from the production system manually or automatically. In particular, the transport of the container unit can be carried out by means of a robotic arm or similar device to avoid potential contamination by humans.

[0062] The present invention further comprises an additive manufacturing process as defined in the attached independent claim.

[0063] Separating the operator area from the loading area enables contamination-free additive manufacturing and complete automation of the additive manufacturing process without the need for personal protective equipment. This also ensures operator and system safety.

[0064] In one embodiment, the additive manufacturing process further includes lifting the transportable container unit by means of a lifting device at the bottom of a build chamber after the container unit has been inserted into the loading area. Inserting the container unit into the manufacturing system allows the additive manufacturing process to be fully automated. The lifting device can move either individual containers or the entire container unit vertically. Thus, the container unit can be docked to the bottom of the build chamber by means of the lifting device to position freshly prepared powder, a build plate, and / or a powder overflow container into the build chamber.

[0065] In one embodiment, the additive manufacturing process further comprises the initial introduction of a protective gas into the build chamber to inertize it after lifting the transportable container unit. Inerting can be understood as the removal of unwanted gas, such as oxygen, from the build chamber by means of an evacuation device, followed by the introduction of an inert gas, such as argon, nitrogen, etc., to ensure the lowest possible oxygen content. This ensures the production of a high-quality product.

[0066] When the powder reservoir, build chamber, and powder overflow container are aligned in a process position for additive manufacturing, a protective gas can be introduced into the build chamber. The initial inerting of the build chamber can be performed without removing the lid of the respective container within the unit. The protective gas, i.e., the inert gas, can contain a very low percentage or even no oxygen.

[0067] In one embodiment, the additive manufacturing process further includes removing a lid from both the powder reservoir and the build container after the initial introduction of a protective gas. The lid of each container can also be removed automatically. To enable this, for example, a gripper or robot arm can engage a projection formed on the outer surface of the lid. The gripper can then move the lid to a storage position. The lid of the powder reservoir, the lid of the build container, and / or the lid of the powder overflow container can be removed simultaneously or sequentially and replaced on their respective containers after additive manufacturing.

[0068] In one embodiment, the additive manufacturing process further comprises vacuuming the build chamber and subsequently introducing a protective gas into the build chamber a second time to inertize the opened containers after the lid has been removed. After opening the respective lid of the container unit, the interior of the respective container within the build chamber can be exposed. This second inerting of the build chamber allows, in particular, the fresh powder contained in the powder storage container to also be inertized, thus protecting the fresh powder from oxidation.

[0069] Further features, advantages, and applications of the present invention will become apparent from the following description, the exemplary embodiments, and the figures. All features described and / or illustrated can be combined with one another, irrespective of their representation in individual claims, figures, sentences, or paragraphs. In the figures, the same reference numerals denote identical or similar objects. Brief description of the characters

[0070] Figure 1 shows an additive manufacturing system according to an embodiment of the present invention. Figures 2a and 2b show an operator area of ​​an additive manufacturing system according to an embodiment of the present invention. Figure 3 shows a loading area of ​​an additive manufacturing system according to an embodiment of the present invention. Figures 4a and 4b show a top view of an additive manufacturing system according to an embodiment of the present invention. Figures 5a and 5b show an additive manufacturing system according to an embodiment of the present invention. Figure 6 shows a container unit and a build chamber of an additive manufacturing system according to an embodiment of the present invention. Figure 7 shows a container unit of an additive manufacturing system according to an embodiment of the present invention. Figures 8a and 8b show a build container of an additive manufacturing system according to an embodiment of the present invention.Figures 9a and 9b show a fixing element of an additive manufacturing system according to an embodiment of the present invention. Figure 10 shows a powder storage container of an additive manufacturing system according to an embodiment of the present invention. Figure 11 shows an additive manufacturing system according to an embodiment of the present invention. Figures 12a and 12b show a build chamber of an additive manufacturing system according to an embodiment of the present invention. Figure 13 schematically shows a protective gas flow in a build chamber according to an embodiment of the present invention. Figure 14 shows an additive manufacturing system according to an embodiment of the present invention. Figures 15a and 15b show an optical bench of an additive manufacturing system according to an embodiment of the present invention. Detailed description of the exemplary implementations

[0071] Figure 1Figure 1 shows an additive manufacturing system 1 according to the invention. The additive manufacturing system 1 can be designed to produce a workpiece by selective laser melting (SLM) of a powder material applied layer by layer.

[0072] The additive manufacturing system 1 comprises an operator area 2, a loading area 3, and a build chamber 4. The operator area 2 is accessible from a first side 11, i.e., a front 11 of the additive manufacturing system 1, and is designed for controlling the manufacturing system 1. The loading area 3 is located opposite the operator area 2, i.e., at the rear 12 of the additive manufacturing system 1, and is designed for loading the manufacturing system 1. Selective melting of the powder applied layer by layer takes place in the build chamber 4. The additive manufacturing system 1 also comprises a peripheral area 5, which houses peripheral technologies such as a protective gas cooling system, a gas circulation pump, a vacuum pump, a soot particle filter, a cooling system, and / or a laser. The peripheral technologies are slidably mounted within the peripheral area 5.

[0073] As in Figures 2a and 2bAs shown, operator area 2 has an openable access point 41 to the build chamber 4. Access point 41 has a laterally sliding door 42. A monitor 43 is integrated into the sliding door 42. This monitor is designed for monitoring and / or controlling data and / or functions of the manufacturing system 1. The monitor 43 can display an additive manufacturing process, an operating parameter, a status of the additive manufacturing system 1, and / or all necessary machine functions and data. This allows the operator, for example, to monitor the additive manufacturing process and control and / or maintain the additive manufacturing system 1 based on the displayed information. Various process parameters can also be parameterized via the monitor 43 as needed.

[0074] Figure 3Figure 1 shows the rear side 12 of the additive manufacturing system 1, where the loading area 3 is located. The loading area 3 includes an interface for the automated or manual insertion of a transportable container unit 6. As shown in Figures 4a and 4b As shown, the container unit 6 can be inserted into the loading area 3 at the rear 12 of the manufacturing system 1. After the additive manufacturing of the workpiece is complete, the container unit 6 can be removed from the manufacturing system 1 automatically or manually via the loading area 3.

[0075] Thus, the operator area 2 and the loading area 3 are spatially separated from each other, so that access to the operator area 2 and access to the loading area 3 do not cross each other.

[0076] Once the transportable container unit 6 is inserted into the assembly chamber 4, it will be positioned onto a lifting device 7. The lifting device 7 is designed to lift the container unit 6 in order to dock it onto the assembly chamber 4, in particular onto the floor 44 of the assembly chamber 4 (see Figures 5a and 5b ).

[0077] Fig. 6Figure 6 shows the container unit 6, which is coupled to the build chamber 4. The container unit 6 comprises a powder storage container 61, a build container 62, and a powder overflow container 63. The powder overflow container 63 is integrally molded onto the build container 62. The powder storage container 61 is designed to hold freshly prepared powder material, which is applied layer by layer to a build plate 72 of the build container 62 during additive manufacturing. The build container 62 is designed to carry out the additive manufacturing of the workpiece by selectively melting the powder applied layer by layer to the build plate 72 using a laser beam (see Figure 6). Figure 7 ). After selective melting of the applied powder, the excess powder can be collected in the powder overflow container 63.

[0078] The additive manufacturing system 1 further includes a doctor blade 8, which is designed for layer-by-layer application of the powder from the powder reservoir 61 onto the build plate 72 of the build container 62 and for removing the excess powder from the build container 62 towards the powder overflow container 63. Therefore, the powder reservoir 61, the build container 62, and the powder overflow container 63 can be arranged in this order in the container unit 6.

[0079] A sealing interface 45 is arranged on the bottom 44 of the construction chamber 4, which is designed for a positive-locking and gas-tight connection of the container unit 6 to the construction chamber 4. The bottom 44 of the construction chamber 4 includes an opening 48 with which the container unit 6 can be coupled (see also Figure 11The sealing interface 45 surrounds the opening 48 and the upper edge 64 of the respective container of the container unit 6 to create a vacuum-tight connection between the container unit 6 and the assembly chamber 4.

[0080] The sealing interface 45 has a gap 46 for collecting residual powder. The gap 46 is located between the upper edge 64 of the container unit 6 and the sealing interface 45 and extends at least partially along the circumferential direction of the upper edge 64 of the container unit 6. The gap 46 extends at least partially from the bottom 44 of the build chamber 4 towards the container bottom 65, so that one end of the gap is exposed in the build chamber 4. The opposite end of the gap 46 is coupled to a cleaning nozzle 47 for blowing out the residual powder, the cleaning nozzle 47 being integrated between the sealing interface 45 and the container unit 6.

[0081] During additive manufacturing, the excess powder can be collected in the gap 46 and, after completion of the additive manufacturing process, it can be driven out of the gap 46 by the gas to prevent powder carryover during container removal. Fig. 7 Figure 62 shows the build container 62, to which the powder overflow container 63 is integrated. The build container 62 comprises a base plate 74 and a lifting rod 75. The lifting rod 75 is designed to move the base plate 74 vertically within the build container 62. The base plate 74 of the build container 62 can seal the interior of the build container 62 from the outside. Preferably, after each melting process or each exposure of the laser beam, the base plate 74 of the build container 62 can be gradually lowered by means of the lifting rod 75 to allow the subsequent melting process of the reapplied powder.

[0082] The build container 62 further comprises a heating plate 73 and a build plate 72. The build plate 72 can receive the powder applied layer by layer by the doctor blade 8 and enable the selective melting of the powder. In other words, the powder on the build plate 72 of the build container 62 is selectively melted by a laser.

[0083] The heating plate 73 is arranged between the build plate 72 and the base plate 74. The heating plate 73 comprises heating elements 81 and an insulating layer 82, and is designed to heat the build plate 72. The heating elements 81 allow the build plate 72 to be heated to several hundred °C. Heating the build plate 72 reduces stress on the workpiece by decreasing the temperature gradient between the material layers. However, the heat should not be conducted towards the base plate 74 to avoid mechanical stress. Therefore, the insulating layer 82 is arranged below the heating elements 81 to insulate the base plate 74 from the heat.

[0084] The construction container 62 further comprises a lid 71 designed to seal the construction container 62, enabling contamination-free transport and maintaining an inerted state. The lid 71 has a projection 79 for gripping. After the container unit 6 is docked to the bottom 44 of the construction chamber 4, the lid 71 of the construction container 62 can be removed manually or automatically. Preferably, the projection 79 of the lid 71 can be held by a robot arm or gripper arm to transport the lid 71 to a lid storage location 49 (see Figure 1). Figure 6 ). The robot arm can return the lid 71 to the container unit 6 after the additive manufacturing of the workpiece in order to close the construction container 62.

[0085] Figures 8a and 8bFigure 1 shows how the base plate 74, the heating plate 73, and the construction plate 72 of the construction container 62 are connected to each other. The construction plate 72 and the heating plate 73 are connected to each other by means of a three-point support system. On the underside of the construction plate 72, which faces the heating plate 73, three bolt elements 31 are arranged, which rest on the heating plate 73. The bolt elements 31 can project from the underside of the construction plate 72 towards the heating plate 73 and are spaced as far apart from each other as possible. In this way, a loosely supported yet secure three-point support of the construction plate 72 can be achieved. In addition, the underside of the construction plate 72 has at least two tension pins 35, which fix the construction plate 72 during post-processing.

[0086] Furthermore, a through-hole 32 is provided in each corner of the heating plate 73. Fastening bolts 51, which extend from the edge of the construction container 62 through the heating plate 73 and into the construction plate 72 without contact, can be inserted through the through-holes 32. These fastening bolts 51 can be used to clamp or lock the construction plate 72 in its lowest position within the construction container 62 (see Figures 9a and 9b ).

[0087] Additionally, a bolt element 33 for a zero-point clamping system is located on the underside of the heating plate 73 to achieve a firm and precise connection with the base plate 74. To enable the bolt element 33 of the heating plate 73 to be received in a force-fit and form-fit manner, the base plate 74 includes a clamping element 34.

[0088] The base plate 74 includes at least one cooling line 78, which is coupled by the lifting rod 75 to an inlet 76 and an outlet 77 of a cooling medium (see Figure 7The cooling line 78, through which a cooling medium is guided, can be located inside or on the underside of the base plate 74. Consequently, heat generated below the heating plate 73 can be blocked, and the associated thermal expansion of the construction container 62, particularly in the vertical direction, can be prevented.

[0089] Figures 9a and 9bFigure 1 shows a bottom side 65 of the construction container 62. The construction container 62 comprises at least one fixing element 50, preferably two or more fixing elements 50. The fixing element 50 comprises at least one, preferably a pair, clamping balls 54 and a bolt 51, which is connected to a spring 52 in the direction of the interior of the container 62. The fixing element 50 further comprises a housing 53 that receives the spring-loaded bolt 51 and the clamping ball 54. The housing 53 of the fixing element 50 is integrated into the container housing. The spring-loaded bolt 51 can move vertically within the housing 53, whereby the movement of the bolt 51 can be restricted by the spring 52 and the clamping ball 54, which is arranged on a lateral side of the housing 53.

[0090] During container exchange, the clamping ball 54 can be clamped to the build plate 72 by the spring-loaded bolt 51. When the build container 62 is removed from the additive manufacturing system 1, the base plate 74, the heating plate 73, and / or the build plate 72 can move during transport, rework, and / or replenishment of the container 62, which can lead to the build plate 72 detaching from the base plate 74. To prevent displacement and / or detachment of one or more of the plates, the bolt 51, with the spring 52, can be pressed into a fixing position in the build plate 72 via the through holes 32 of the heating plate 73, whereby the bolt 51 pushes the clamping ball 54 outwards (see Figure 9aConsequently, a positive and non-positive connection can be established between the construction plate 72 and the container housing, in particular the container bottom 65 of the construction container 62. Since the heating plate 73 is located between the construction plate 72 and the bottom side 65 of the construction container 62, the heating plate 73 can be automatically clamped in place.

[0091] During additive manufacturing, the fixing element 50 can be in a reset position, so that the bolt 51 is not engaged with the build plate 72. In this way, the build plate 72, heating plate 73 and / or base plate 74 could be raised and / or lowered within the build container 62 (see Figure 9b ).

[0092] Figure 10Figure 61 shows the powder storage container 61, which is designed to store freshly prepared powder. The powder storage container 61 comprises a base plate 74 and a lifting rod 75, which raises or lowers the base plate 74 within the powder storage container 61. The powder storage container 61 further comprises a bottom plate 70, which is connected to the base plate 74 by means of a zero-point clamping system, i.e., by a bolt element 33. Thus, the bottom plate 70 can be adjusted vertically with the base plate 74. Preferably, the lifting rod 75 of the powder storage container 61 can raise the base plate 74 so that the freshly prepared powder can be supplied without gaps on the surface of the powder storage container 61.

[0093] The powder storage container 61 may also have at least one fixing element 50, preferably two or more fixing elements 50, provided at its base to secure the base plate 70 to the base of the powder storage container 61, for example, during transport. The powder storage container 61 also has a lid 71 designed to seal the powder storage container 61, enabling contamination-free transport and maintaining an inerted state.

[0094] The powder storage container 61 can be the same size as, or smaller than, the construction container 62. The powder storage container 61 can be connected to the construction container 62 by both containers being formed as a single piece. Alternatively, they can be manufactured independently of each other.

[0095] The additive manufacturing system 1 further comprises a protective gas inlet 13, a protective gas outlet 14 and an optical bench 15, as shown in Figure 11 shown. In Figure 12a The protective gas inlet 13 and the protective gas outlet 14 are shown enlarged. The protective gas inlet 13 and the protective gas outlet 14 are arranged relative to the build plate 72 to generate a protective gas flow 16. The protective gas inlet 13 and the protective gas outlet 14 are arranged perpendicular to the direction of movement of the doctor blade 8.

[0096] The protective gas inlet 13 is designed to supply the protective gas into the build chamber 4. The protective gas outlet 14 will draw in the protective gas released in the build chamber 4. Furthermore, the protective gas outlet 14 can be designed to completely absorb the protective gas introduced into the build chamber 4 and not cause any narrowing of the laminar and homogeneous protective gas flow 16.

[0097] A laminar and homogeneous shielding gas flow 16 can be generated in the build chamber 4 by a continuous supply and removal of the shielding gas. The doctor blade 8 can be arranged parallel to the flow direction of the shielding gas flow 16, thus preventing partial diversion and / or turbulence of the shielding gas flow 16. The shielding gas is designed to prevent the deposition of soot or weld spatter in the build chamber 4. The shielding gas can be an inert gas such as argon or nitrogen.

[0098] As in Figure 12bAs shown, the protective gas inlet 13 has a porous element 15 for providing a homogeneous protective gas flow 16. The porous element 15 can be designed to generate a dynamic pressure within the protective gas inlet 13. The porous element 15 can be understood as a filter element arranged at the protective gas inlet 13 and extending over its entire width and height. The porous element 15 can have a uniform porosity over its entire surface. Thus, the protective gas flow 16 does not exhibit any velocity gradients in the region of the protective gas inlet 13.

[0099] Figure 13 Figure 1 schematically shows a protective gas flow 16 in the build chamber 4. The additive manufacturing system 1 can additionally have a protective gas inlet opening 17 located above the build plate 72. Through the protective gas inlet opening 17, the protective gas can also be supplied into the build chamber 4 above the build plate 72.

[0100] A graded porous structure 18 can be arranged between the protective gas inlet opening 17 and the build chamber 4. The use of the porous structure 18 allows a slight static overpressure to be generated between the protective gas inlet opening 17 and the porous structure 18, enabling the protective gas to flow homogeneously through the porous structure 18. Furthermore, the graded porous structure 18 can be used to regulate the velocity of the protective gas flow 16.

[0101] Figure 14Figure 1 shows the additive manufacturing system 1 with the optical bench 15. The optical bench 15 can be arranged opposite the build plate 72, i.e., on a top surface of the manufacturing system 1. The optical bench 15 comprises an off-axis monitoring device 92 and an on-axis monitoring device 91. The off-axis monitoring device 92 is designed to monitor the heat distribution of an additively manufactured component layer and the deposition quality of the last applied powder layer. The on-axis monitoring device 91 is designed to determine the temperature of a powder bath on the currently manufactured component layer.

[0102] As in Figure 15aAs shown, the on-axis monitoring device 91 can include a ratio pyrometer, photodiodes, and / or a high-speed camera designed to determine the temperature of the powder bath. The powder bath can be located on the build plate 72 inside the build container 62, so that the workpiece produced by selective melting is surrounded by the powder.

[0103] As in Figure 15bAs shown, the off-axis monitoring device 92 can include two high-resolution, multi-functional cameras with high spectral bandwidth, capable of capturing thermal process emissions during additive manufacturing using optical bandpass filters. The camera image acquisition system can be designed to integrate emission data from the melt pools, captured during the exposure of a powder layer, into a single image. The resulting image can be a heat map of the currently built layer. This heat map can then be used to dynamically adjust the exposure sequence of scanned areas within a layer, the laser power, or the scan speed within specific scan areas.

[0104] The on-axis monitoring device 91 and the off-axis monitoring device 92 each comprise a sensor unit 94 and an optical unit 93 with a scan head 95 and a collimator 96.

[0105] It should be further noted that "comprehensive" and "comprising" do not exclude any other elements or steps. It should also be noted that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps from other embodiments described above. Reference numerals in the claims are not to be considered as limitations.

Claims

1. An additive manufacturing system (1), comprising - an operator area (2), - a loading area (3), - a build chamber (4), and - a transportable container unit (6), wherein the operator area (2) is configured to control the manufacturing system (1), wherein the loading area (3) is configured to load the manufacturing system (1) with powder and includes an interface for the automated insertion of the transportable container unit (6) into the manufacturing system (1), wherein the operator area (2) is accessible from a first side (11) of the manufacturing system (1), the loading area (3) is accessible from a second side (12) of the manufacturing system (1), and the first side (11) is different from the second side (12), wherein the operator area (2) includes an openable access (41) to the build chamber (4) and at least one control device, wherein the transportable container unit (6) is insertable from outside into the loading area (3) and includes a powder reservoir container (61) and a build container (62), wherein the powder reservoir container (61) is configured to store powder, and wherein the build container (62) is configured for the additive manufacturing of a workpiece, wherein the first side (11) of the manufacturing system (1) is opposite the second side (12) of the manufacturing system (1), wherein the openable access (41) is arranged opposite an insertion direction of the transportable container unit (6) into the loading area (3), wherein the build container (62) includes a build plate (72), wherein the build chamber (4) is couplable to apply powder to the build plate (72) with the transportable container unit (6), and wherein the build container (62) comprises at least one fastening element (50) with a spring-preloaded bolt and a tension ball, and wherein during a container exchange, the tension ball is clampable to the build plate (72) by the spring-preloaded bolt.

2. The additive manufacturing system (1) according to claim 1, wherein the transportable container unit (6) further comprises a powder overflow container (63).

3. The additive manufacturing system (1) according to any one of the preceding claims, wherein the powder reservoir container (61) and the build container (62) each comprise a base plate (74) and a lifting rod (75), wherein the lifting rod (75) is configured to lift the base plate (74) within the respective container.

4. The additive manufacturing system (1) according to the preceding claim, wherein the build container (62) includes a heating plate (73), wherein the heating plate (73) is arranged between the build plate (72) and the base plate (74), and wherein the heating plate (73) is configured to heat the build plate (72).

5. The additive manufacturing system (1) according to the preceding claim, wherein the heating plate (73) comprises heating elements and an insulating layer, wherein the insulating layer is arranged for insulation in the direction of the base plate (74) beneath the heating elements.

6. The additive manufacturing system (1) according to any one of claims 3 to 5, wherein the base plate (74) comprises at least one cooling channel, and wherein the cooling channel is coupled to a supply and a return of a cooling medium via the lifting rod (75).

7. The additive manufacturing system (1) according to any one of the preceding claims, further comprising a lifting device (7), wherein the lifting device (7) is configured to lift the transportable container unit (6) to a base (44) of the build chamber (4).

8. The additive manufacturing system (1) according to the preceding claim, wherein the base (44) of the build chamber (4) includes a sealing interface (45), and wherein the sealing interface (45) is configured for a form-fitting and gas-tight connection of the transportable container unit (6) with the build chamber (4).

9. The additive manufacturing system (1) according to the preceding claim, wherein the sealing interface (45) includes a gap (46) for collecting residual powder, and wherein the gap (46) is coupled to a cleaning nozzle (47) for blowing out the residual powder.

10. The additive manufacturing system (1) according to any one of claims 4 to 9, further comprising a protective gas inlet (13) and a protective gas outlet (14), wherein the protective gas inlet (13) and the protective gas outlet (14) are arranged to generate a protective gas flow (16) relative to the build plate (72).

11. The additive manufacturing system (1) according to any one of the preceding claims, further comprising an optical bench (15), wherein the optical bench (15) comprises an off-axis monitoring device (92) and an on-axis monitoring device (91), and wherein the off-axis monitoring device (92) is configured to monitor a heat distribution of an additively manufactured component layer of the workpiece and a coating quality of a recently applied powder layer, and wherein the on-axis monitoring device (91) is configured to determine a temperature of a powder bed on the currently manufactured component layer.

12. The additive manufacturing system (1) according to any one of the preceding claims, wherein the powder reservoir container (61) and the build container (62) each comprise a lid (71), wherein the lid (71) is configured to seal the respective container, and wherein the lid (71) further includes a protrusion (79) for gripping the lid (71).

13. The additive manufacturing system (1) according to any one of the preceding claims, wherein the operator area (2) includes a monitor (43) for controlling and / or managing data and / or functions of the manufacturing system (1).

14. An additive manufacturing method, comprising the following steps: - Providing an additive manufacturing system (1) with an operator area, a loading area (3), and a transportable container unit (6), wherein the operator area (2) is configured to control the manufacturing system (1), wherein the loading area (3) is configured to load the manufacturing system (1) with powder and includes an interface for the automated insertion of the transportable container unit (6) into the manufacturing system (1), wherein the operator area (2) includes an openable access (41) to the build chamber (4) and at least one control device, wherein the operator area (2) is accessible from a first side (11) of the manufacturing system (1), the loading area (3) is accessible from a second side (12) of the manufacturing system (1), and the first side (11) is different from the second side (12), - wherein the first side (11) of the manufacturing system (1) is opposite the second side (12) of the manufacturing system (1), and - inserting the transportable container unit (6) from outside into the loading area (3), wherein the transportable container unit (6) comprises a powder reservoir container (61) and a build container (62), wherein the powder reservoir container (61) is configured to store powder, and the build container (62) is configured for the additive manufacturing of a workpiece, wherein the openable access (41) is arranged opposite an insertion direction of the transportable container unit (6) into the loading area (3), wherein the build container (62) includes a build plate (72), wherein the build chamber (4) is couplable to apply powder to the build plate (72) with the transportable container unit (6), wherein the build container (62) comprises at least one fastening element (50) with a spring-preloaded bolt and a tension ball, and wherein during a container exchange, the tension ball is clampable to the build plate (72) by the spring-preloaded bolt.

15. The additive manufacturing method according to the preceding claim, further comprising lifting the transportable container unit (6) using a lifting device (7) to a base of a build chamber (4) after inserting the transportable container unit (6) into the loading area.

16. The additive manufacturing method according to the preceding claim, further comprising initially introducing a protective gas into the build chamber (4) for inertizing the build chamber (4) after lifting the transportable container unit (6).

17. The additive manufacturing method according to the preceding claim, further comprising removing a lid (71) from both the powder reservoir container (61) and the build container (62) after the initial introduction of a protective gas.

18. The additive manufacturing method according to the preceding claim, further comprising evacuating the build chamber (4) and subsequently introducing a second protective gas into the build chamber (4) for inertizing the opened containers after removing the lid.