Powder bed fusion device with reduced powder supply

Abstract

A device for producing a component by additive manufacturing, comprising: means for producing a component from the first material, wherein the first material forms a thin powder bed, and means for depositing a second material below the thin powder bed, wherein the second material is such that it displaces the first material upwards during the layer-by-layer additive manufacturing of the component from the first material; wherein the second material is not integrated into the manufactured component.

Description

TECHNICAL AREA

[0001] The invention described here relates to the field of additive manufacturing. In particular, the invention relates to a device for producing components from a thin powder bed by means of powder bed-based melting of metal with a laser beam, wherein the thin powder bed layer is supported in a manner that minimizes material consumption. STATE OF THE ART

[0002] Additive manufacturing (AF) is one of the most promising new manufacturing technologies with the potential to revolutionize the manufacturing sector. AF technologies are used in numerous industries, including automotive, aerospace, transportation, energy, electronics, medical, food, and defense. Powder bed fusion (PBF-LB / M) or selective laser melting (SLM) can potentially produce arbitrarily complex shapes layer by layer, such as lattice structures, cellular porous structures (bone scaffolds), and metamaterials that cannot be manufactured using conventional methods. Different material classes can be processed using powder particles, including alloys based on aluminum, titanium, nickel, iron, copper, and cobalt, as well as other material classes such as metallic glasses and high-entropy alloys (HEAs).However, the number of materials that can be processed using PBF-LB / M or SLM is limited. Therefore, the development of alloys for SLM is crucial, as it can facilitate the application of this process in many industries. However, the cost of powder particle production is quite high, and only a small fraction of the particles used interact with the laser beam to manufacture parts, while the remaining powder can be reused. It is worth noting that powder particle reuse is a major concern for engineers and researchers in powder-based AF processes, as the particles may have different properties, such as morphology and chemical composition, than new particles. Powder production is time-consuming and expensive, which limits the application of AF technologies. This is of great importance for further developing the SLM process and using a smaller quantity of powder particles.Manufacturing parts / structures from powder particles that almost correspond to the weight of the manufactured parts / structures will greatly improve PBF-LB / M efficiency.

[0003] In layer-based additive manufacturing processes like PBF-LB / M, powder particles are distributed in each layer, with layer thickness typically between 20 and 60 µm. The laser beam then selectively melts the particles layer by layer to build a 3D component. Despite considerable design freedom, geometric limitations or pre-sintering or partial solidification of the powder after the build process can leave particles trapped in the component cavities. This trapped powder can be problematic during post-processing, as it can completely sinter during hot isostatic pressing (HIP) and heat treatment, or block the cooling channels of a turbine blade or injection mold.Although avoiding powder inclusions in AF structures is of great importance, suitable methods and strategies for preventing powder particle entrapment or removing them from manufactured components are still lacking. PBF-LB / M has the potential to revolutionize the manufacturing industry. However, some of the aforementioned barriers limit the application of the process in various industries. Therefore, there is a need to overcome the limitations of PBF-LB / M, particularly those mentioned above. PRESENTATION OF THE INVENTION

[0004] The present invention provides a device for the additive manufacturing of components with highly complex geometries using PBF-LB / M. Techniques for additive manufacturing from powder particles are disclosed here, wherein the mass of the required powder corresponds to the mass of the component / structure. The complex components can be manufactured from a thin powder bed with significantly reduced costs and time expenditure. The production of such components using AF processes and these techniques represents an economic advantage and a significant breakthrough in the field of additive manufacturing, overcoming the limitations of PBF-LB / M.

[0005] The techniques described here involve the additive manufacturing of components from a small quantity of powder particles, where the mass of the powder particles corresponds to the mass of the components / structures. This device utilizes a special build platform for part production to reduce the required amount of powder particles. Compared to conventional SLM machines, significantly less mass of the starting material is needed. The complex components are built layer by layer from a thin powder bed. The area beneath the thin powder layer is supported in a material-saving manner. For example, various particles with different properties are introduced beneath the thin powder bed. These particles can, for instance, have a high melting point and / or magnetic properties, or be in the nanoscale range with a spherical morphology.The powder particles from the thin powder bed (starting material) are distributed onto the preceding layer, with the required quantity of particles being lifted and redistributed by a recoater in each or every few layers. After the laser has exposed and selectively melted the metallic powder particles (starting material), particles with different properties are pushed upwards from below the powder bed to lift the metallic powder particles (starting material). Again, the recoater redistributes the suspended powder particles, allowing the part to be manufactured from a thin powder bed. Similar to the available SLM machine, the recoater redistributes the particles, and the suspended particles are redistributed. The process continues until the manufacturing process is complete.The laser therefore melts only the powder particles (starting material) from a thin powder bed in each layer, so only a small amount of powder is required. The amount of powder needed is estimated to be almost equal to the weight of the AF components.

[0006] The material used to fill the base of the starting powder particles in additively manufactured components can be in powder form. However, with PBF-LB / M, high precision is required to lift the metallic powder particles, as the layer thickness can range from 20 to 60 µm, which affects the resolution for part production. When filling the underside of the starting powder particles in AF objects with reusable powder particles, these particles can be small to prevent penetration or settling of the starting particles. These particles should, however, exhibit high flowability. The materials used to fill the underlying thin layer of metal powder can have different physical properties, such as melting points.The melting point of these materials must be high enough to withstand the platform temperature (due to heat conduction) during the manufacturing process. DRAWINGS

[0007] The present invention is illustrated in the figures of the accompanying drawings by way of example and without limitation. Fig. illustrates a flowchart of the system and its functional sequence for the additive manufacturing of parts using powder bed-based melting of metal with a laser beam from a thin layer of powder particles. Fig. shows an example of the construction of a manufacturing plant for 3D parts using the AF process, consisting of a thin layer of powder particles and the inlet, which is to be filled with reusable powder particles below the powder bed. DETAILED DESCRIPTION OF THE INVENTION

[0008] The embodiments and various aspects of the present invention are explained with reference to the details described below. The drawings illustrate the embodiments of the invention. The following explanation and the drawings serve to illustrate the present invention and are not to be understood as limiting the present invention. Various specific details are described to enable a comprehensive understanding of the embodiments of the invention. Some examples have been explained in the present invention; however, conventional or known details are not explained in order to allow a concise discussion of the embodiments. The documents contained in the present invention are incorporated by reference in their entirety. In this invention, grammatical conjunctions are defined as all disjunctive and conjunctive combinations of connected clauses, words, sentences, etc.Unless otherwise stated or evident from the context, the term "or" should generally be understood as "and / or", etc.

[0009] Fig. Figure 1 shows the flowchart of the system for the additive manufacturing of components using powder bed fusion (PBF) by melting metal from a thin powder bed using a laser beam. In general, the typical 3D printing process (102) can be used for the selective melting of the powder particles. For example, the printer (102) may include PBF-LB / M, selective laser sintering (SLS), or another system for the production of 3D components (106). Layer-by-layer additive manufacturing (102) can be used to produce a component (106) from powder particles such as metal powder, ceramic, etc., and combinations thereof. Various alloys can be used as build materials. A thin layer of powder particles (starting material) can be used to produce parts.The thickness of the thin powder particle layer can be kept constant on the upper AF components / structures by injecting / adding reusable powder particles beneath the thin powder particles (starting material) in every one or every few layers. The reusable powder particles lift the powder particles (starting material) of the thin powder bed, and the melting / sintering process can be carried out with only a small amount of powder (108). The lifting operation, or the injection / adding of reusable powder particles, can be performed every few melt layers of the powder (starting material); however, high precision and controllability are required. In this respect, a system can be designed to lift in the build direction, raising the powder particles (starting material).

[0010] A piston in a cylindrical mold, filled with reusable powder particles, can lift (push upwards) the starting material and additively manufacture the parts. In this case, the parts / structures can be produced on a net mold platform, and the thin powder bed can be located on the additively manufactured parts / structures, covering their top surface in the build direction. The lifting of the piston to push upwards and produce a part with a thin powder layer should be in the micrometer range (from approximately 20 µm to around 100 micrometers). The quantity of (reusable) powder particles can be calculated based on the surface area occupied by the parts / structures; thus, the required amount of powder to be injected / added under the starting material can be estimated accordingly.

[0011] The filling process section can be used with or without pressure below the powder bed of the 3D component, employing a suitable setup for particle transport. The introduction of reusable powder particles for filling below the powder bed using one of the AF processes 102 can be performed under pressure 104 (e.g., pneumatic pressure). 108 can be designed based on the sensitivity, shape, size, and type of the PBF-LB / M components and the 3D printer. The powder particle distribution stage 108 could comprise one or more systems for lifting the metallic powder particles (or the powder bed) 102 to produce a component for layer-by-layer additive manufacturing.

[0012] During the powder particle distribution phase, specific metallic materials or composites can be added / inserted below the powder bed in each or every few layers, and the process continues until the final parts / structures are formed. Alternatively, a printing process can be used to add / inserte powder particles below the powder bed. Alternatively, particles smaller than AF powder particles (for the fabrication of 3D components) can be added and / or inserted below the powder bed, filling it and lifting the powder particles (starting material). In this context, a mixture of ceramic and metal particles can be used to fill the powder bed. For example, silicon dioxide particles can be used to fill the powder bed.Alternatively, nanoparticles or a mixture of powder particles and nanoparticles can be used to fill the powder bed (108).

[0013] Furthermore, it is advantageous to use a variety of other materials for filling below the powder particle distribution stage (108). For example, ceramic particles can be used for filling below the powder bed to produce three-dimensional (3D) components with complex geometries. The area below the powder bed (102) in the powder particle distribution stage (108) can be filled with more than one material. Alternatively, non-metallic nanoparticles can be used for filling below the thin powder bed.

[0014] In another aspect, the material used to fill the space beneath the powder particles (starting material) can have magnetic properties, allowing the arrangement to be designed so that the material floats beneath the thin powder particles (starting material). In each layer of the additive manufacturing process, these materials float and cover the top of the manufactured parts to selectively melt the metallic powder particles (starting material). A constant and stable levitation force ensures sufficient distribution of the starting material. Furthermore, third-party materials can be used between the starting material and the magnetic material to guarantee a reliable manufacturing process and avoid problems such as instability, poor controllability, or contamination.

[0015] In another aspect, the powder particle distribution stage 108 could be coupled with monitoring systems to improve process quality, controllability, and reliability, and to reduce errors and failures. The powder particle distribution stage 108 could incorporate cameras, thermocouples, or pressure sensors for process monitoring within this stage. Furthermore, the pressure within the powder particle distribution stage 108 could be monitored and controlled via pressure sensors. Finally, the powder particle distribution stage 108 could be coupled with a vacuum system to extract the reusable powder particles from beneath the metallic powder bed. The pressure within the powder particle distribution stage 108 could be monitored and controlled via pressure sensors.

[0016] The production of layer-based AF components can begin with the provision of a 3D model for printing. This 3D model can contain complex geometries suitable for use in various industries. To design and fabricate the parts / structures using a thin powder bed, the area beneath the powder bed can be designed to be filled with (reusable) powder particles. To achieve adequate distribution of the metallic powder particles (starting material) on the AF component and / or platform, and to produce a nearly or completely dense component, the (reusable) powder particles must completely fill the area beneath the powder bed. This should therefore be considered during the design phase. This step should include planning for the input of the materials in the form of powder particles.Furthermore, several inputs could be taken into account to facilitate the filling of the thin powder bed with particles.

[0017] The device described here provides a general framework for additive manufacturing and is applicable in various contexts. The present invention describes the fabrication of components from a thin powder bed using PBF-LB / M. A material-saving support structure is located beneath the thin powder bed layer. PBF-LB / M, made from thin metal powder particles, overcomes the limitations of additive manufacturing processes, where the price of some metal powder particles can be quite high. In particular, alloy development can be a costly process, and the proposed device can reduce the time and costs involved. EXAMPLE OF EXECUTION

[0018] The following example shows embodiments of certain aspects of the described invention, and it is understood that the devices and systems described here can be modified and / or scaled for use with other materials, processes, etc.

[0019] Additively manufactured components made of thin metal powder particles can be produced using the described device, whereby the thin powder layer is supported beneath the powder bed in a material-saving manner. Various materials can be used to fill the area beneath the powder bed and to raise the starting material layer by layer or every few layers. All components can be manufactured according to the specifications in Fig. explained device and the one in Fig.The system diagram shown is used to manufacture the components. The devices and systems described here can be used to produce various components; the AF components are built up from a thin powder bed (200). The systems shown enable the additive manufacturing of parts or structures using PBF-LB / M from a thin powder bed and significantly reduce manufacturing costs compared to conventional SLM machines.

[0020] The additively manufactured parts / structures can be produced on the manufacturing platform 204, which can be a mesh-shaped work platform (mesh plate). A thin layer of metallic powder particles can cover the first powder layer on and below the platform. After selective melting of the powder particles, the platform can be lowered (the platform is moved in the Z-direction), and the reusable particles 208 can be injected / added to lift the metallic powder particles 212. The reusable powder particles (212) can be placed in 202 below the work platform 204. The recoater distributes the metallic powder particles onto the first / previous layer, and the process continues until the parts / structures are completed. Alternatively, the reusable particles can be recoated every few layers (e.g.,Three or four layers are added or injected, and for these layers, the powder particles (starting material) are sprinkled with fresh powder particles using the recoater. Alternatively, a solid platform 204 can be constructed, and the reusable powder particles are added / injected through the opening. These openings can be designed according to the size of the platform and the parts / structures, the number of parts / structures, etc.

[0021] The device described here serves only for illustration and is not limiting. The steps described may be adapted, extended, omitted, and / or rearranged within the scope of this disclosure unless expressly stated otherwise. Many variations, additions, omissions, and other modifications are obvious to the person skilled in the art. Unless expressly required or otherwise apparent from the context, the sequence or arrangement of the components described and illustrated is not to be considered limiting.

[0022] The device described in this disclosure encompasses all possible implementation approaches, provided they satisfy the requirements of the following claims, unless otherwise specified or the context requires a different interpretation. The devices and systems described in the present invention serve as illustrative examples and are not to be understood as limiting. People skilled in the art can make numerous modifications, including additions, omissions, and changes, without departing from the scope of protection of this disclosure. The described embodiments serve for illustration, and it is obvious to those skilled in the art that changes in form, execution, or technique can be made without exceeding the scope of the invention set forth in the claims. These claims are to be interpreted to the fullest extent permitted by applicable law.

Claims

[1] A device for producing a component by additive manufacturing, comprising: means for producing a component from the first material, wherein the first material forms a thin powder bed, and means for depositing a second material below the thin powder bed, wherein the second material is such that it displaces the first material upwards during the layer-by-layer additive manufacturing of the component from the first material; wherein the second material is not integrated into the manufactured component. [2] Device according to claim 1, wherein the AF 3D printing components are made from a powder mass, wherein the mass of the required powder particles is equal to the mass of the manufactured components. [3] Device according to claim 1, wherein materials are positioned under the thin powder bed to occupy a volume that would otherwise be occupied by powder, thereby reducing the amount of powder required during the manufacture of the AF component. [4] Device according to claim 1, wherein a reusable material is positioned under the thin powder bed to reduce the amount of powder required in the additive manufacturing of parts. [5] Device according to claim 1, wherein the materials are positioned under a thin powder bed during the production of the additive manufacturing components in order to substantially prevent the retention of powder particles in internal cavities of the components after completion of the build. This prevention results from avoiding geometric configurations in which the powder particles would otherwise be trapped. [6] Device according to claim 1, wherein the materials are positioned under a thin powder bed during the production of additively manufactured components, the thin powder bed being configured to reduce impurities, oxidation, morphological changes and phase changes of fresh powder particles caused by cyclic heating and cooling during layer-by-layer additive manufacturing. [7] The device according to claim 1, wherein materials with non-spherical or irregular morphology are positioned under a thin powder bed during the production of the additive manufacturing components. [8] Device according to claim 7, wherein the materials comprise nanoparticles, flake particles or combinations thereof. [9] Device according to claim 7, wherein the materials which are positioned under a thin powder bed during the manufacture of additively manufactured components have different physical properties than the powder bed material. [10] Device according to claim 7, wherein the material comprises components with different magnetic properties. [11] Device according to claim 7, wherein the material comprises components with a density and particle size selected to achieve a predetermined performance characteristic. [12] Device according to claim 1, wherein the material positioned under the thin powder bed comprises a non-solid, non-liquid intermediate phase material having both viscous and elastic properties, wherein the material is selected from the group consisting of gels, pastes, viscoelastic compositions, semi-solids, slurries, amorphous materials and combinations thereof. [13] Device according to claim 12, wherein the materials are deposited in a controllable manner during the layer-by-layer additive manufacturing process. [14] Device according to claim 1, wherein the thin powder bed is used to produce additively manufactured components with overhanging features, internal channels or lattice structures suitable for applications in the aerospace, biomedicine or automotive industries. [15] Device according to claim 1, wherein the device comprises a monitoring system configured to control the process and the thickness of the powder bed. [16] Device according to claim 1, wherein the device further comprises the use of a monitoring system configured to control the filling process below the thin powder bed. [17] Device according to claim 1, wherein during the production of the additive manufacturing components magnetic materials are positioned under a thin powder bed and wherein the powder particles and the material located under the powder bed are held magnetically in suspension to cover the top surface of each layer in the layer-by-layer additive manufacturing process. [18] Device according to claim 17, wherein the device further comprises the use of a constant and stable magnetic suspension arrangement for controlling the distribution of the starting material. [19] Device according to claim 17, integrated with a monitoring system for controlling the magnetic suspension and the thin powder bed.

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