Method and device for fabricating microparts and microcomponents by additive manufacturing using micro-laser sintering

Abstract

The present invention relates to a method and a device for producing microparts and microcomponents by additive manufacturing using micro laser sintering, in which a powdered cohesive material (1) is applied in layers from a first powder reservoir (2), which is melted after application using a laser beam (4). The method is characterized in that the material (1) arranged in the first powder reservoir (2) opening towards the processing surface is a cohesive powder, the particle size (1) of the cohesive powder corresponds to at most 20 μm, and a force (F1) is applied to the cohesive material (1) in the processing area (100) towards the substrate (3) at least during the application process, and the cohesive material (1) behaves as a fluid as a result of said force while being applied. To this end, the device comprises a horizontally aligned base (5) having interruptions in at least some regions in a processing region (100) above a substrate (3), and a first powder reservoir (2) movably arranged horizontally above the base (5) and having an interior for receiving a powdered cohesive material (1) having a particle size of at most 20 μm or equivalent above the base (5). The first powder reservoir (2) comprises first means (6) therein for applying a first axial force (F1) acting in the direction of the base (5) and the substrate (3) to the powdered cohesive material (1) arranged therein, the first axial force (F1) acting on the powdered cohesive material (1) therein, the cohesive material (1) behaving as a fluid in the processing region (100) at least during the application of said force.

Description

[Technical Field]

[0001] The present invention relates to a method for producing microparts and microcomponents by additive manufacturing using 3D microprinting and micro laser sintering according to the preamble of claim 1.

[0002] Furthermore, the invention relates to a device for carrying out the method according to the invention as defined in the preamble of claim 10. [Background technology]

[0003] Micro laser sintering, also known as selective laser sintering or selective laser melting, is a powder-bed based additive manufacturing technique that is an industrial technology providing micro metal parts for a variety of industries.

[0004] Laser sintering is a process in which plastic or metal powder is completely melted layer by layer using a laser beam without the use of binders, resulting in a homogeneous material with a high density after the melt has hardened.

[0005] For this purpose, a 3D CAD model of the target shape is generated, containing all the details of the finished component. This CAD model is divided into sections, called layers. During fabrication, a thin layer of powder is applied to the substrate. This powder is selectively melted by a laser beam for each section. The substrate is then lowered, and the process of powder coating, melting, and platform lowering is repeated for each layer until the part is complete.

[0006] Micro laser sintering combines the advantages of micromachining with those of additive manufacturing. In this way, micro metal parts are produced with high precision, detail resolution, and surface quality. These advantages make it possible to produce moving parts and assemblies in a single step. The basis for these excellent results is the combination of an extremely small laser beam diameter, special micro powders, and very thin layers.

[0007] These parts are used in any industry that requires small metal parts with high precision, smooth surface finishes, excellent detail resolution, and complex geometries. Current major industries include medical, semiconductor, mechanical engineering, aerospace, energy, and chemicals, as well as jewelry and watches.

[0008] WO 2018 / 063969 A1 describes a system comprising: a deposition device configured to deposit powder particles on a substrate; a laser configured to generate a laser beam for irradiating the deposited powder particles; and an optically transparent press configured to apply mechanical pressure to the deposited powder particles during irradiation by the laser beam, which passes through the optically transparent press to irradiate the deposited powder particles. A disadvantage of this is that applying pressure during laser irradiation makes it more difficult to produce structures with irregular surfaces, since the shape of the component to be produced is predetermined by the design of the press.

[0009] CN113458421A discloses a plant system and method for improving powder bed quality in an additive manufacturing process. The plant system includes a spatially displaceable powder spreading device and an excitation unit. The spreading device is configured to apply one or more powder layers onto a processing surface of a substrate platform or powder bed processed using the plant system. The excitation unit is configured to break up clusters and / or adhesions between individual powder particles and / or between individual powder particles and the powder bed previously processed by the plant system, thereby enabling the powder spreading device to apply a smooth powder layer to the substrate platform and / or previous powder layer / powder bed.

[0010] The powder accumulation is melted by introducing vibrations which can be generated by air pressure, electromagnetic force, or ultrasonic induction.

[0011] Other publications that propose the introduction of vibrations include DE 10 2016 202 696 B4 or EP 3 292 989 A1.

[0012] DE112008000027T5 discloses a "laminate molding device" capable of producing high-precision multilayer objects with a compact design. The prior art cited in this publication discloses that a lifting table for raising and lowering a molding plate and a molding frame surrounding the lifting table are provided. The lowering of the molding plate and the lifting of the lifting table are performed in a single step. The powder has an average particle size of 20 μm, and therefore is not suitable for some applications because particles larger than 20 μm are always present.

[0013] The publication DE 102016107769 A1 relates to additive manufacturing and handling mechanisms for additive manufacturing. The publication does not discuss particle size or disclose the use of cohesive powders. In this solution, the powder must be recovered.

[0014] For example, DE102017124047A1 discloses a composition for use in additive manufacturing processes in which anti-agglomeration agents are used to prevent the powders used from agglomerating. This method requires significant effort, and these agents can change the chemical composition of the materials used. This can be a hindrance, especially in the field of medical devices, which is critical for devices that remain in the body for long periods of time, and of course for implants. Furthermore, these additives can completely or partially burn or evaporate when the metal powder is melted during the additive process. This can result in defects, cavities, or voids in the material structure of the component. There is a risk of deterioration in the mechanical, chemical, and electrical properties of the component. These risks are particularly high when fabricating small components with thin wall thicknesses at the micrometer level, as in the case of microlaser sintering. For example, a 3-micrometer defect in a 100-micrometer-thick wall corresponds to a 3% weakening and is therefore significant. A drawback of prior art methods and devices is that due to the very small particle size, a reliable and uniform application of the powder is sometimes not guaranteed, which has a negative impact on the quality of the component. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] International Publication No. 2018 / 063969 [Patent Document 2] Chinese Patent Application Publication No. 113458421 [Patent Document 3] German Patent Invention No. 102016202696 [Patent Document 4] European Patent Application Publication No. 3292989 [Patent Document 5] German Patent Application Publication No. 112008000027 [Patent Document 6] German Patent Application Publication No. 102016107769 [Patent Document 7] German Patent Application Publication No. 102017124047 Summary of the Invention [Problem to be solved by the invention]

[0016] The present invention is therefore based on the object of providing microparts and microcomponents with improved quality compared to the prior art, especially when using cohesive powders with small particle size. [Means for solving the problem]

[0017] This problem is solved by the features of independent claim 1 and by the features of independent claim 10. Further useful designs of the invention are the subject of the dependent claims.

[0018] This problem is solved by a method and device for producing microparts and microcomponents by additive manufacturing using micro laser sintering. A powder cohesive material (hereinafter referred to as powder material) is applied in layers from a first powder reservoir and then melted by a laser beam. According to the invention, the powder material in the first powder reservoir is subjected to a force, which acts when the first powder reservoir is filled, when the powder material passes over a base plate, and when the powder material is applied to a substrate.

[0019] The force applied to the powder material can be supplied mechanically, for example by a spring force and / or an electric motor, and / or pneumatically and / or hydraulically.

[0020] Specifically, the method includes the following steps: a. compressing powder material in a first powder reservoir opening toward the working surface by applying axial pressure to the powder material toward the substrate; b. Applying and forming a first powder layer of powder material on the top surface of the substrate by moving a first powder reservoir parallel to the top surface of the substrate while simultaneously applying a force to the powder material in the direction of the top surface of the substrate. c. Selectively melting the first powder layer using a laser beam. d. Lowering the substrate; and e. Applying compressed powder material from the first powder reservoir while simultaneously applying force to the powder material on the first selectively melted powder layer or on additional already formed and selectively melted powder layers to form additional selectively melted powder layers until the micropart or microcomponent is completed, wherein the substrate is lowered before each additional powder layer is applied.

[0021] Furthermore, the powder material may be stored in a second powder reservoir and transported and / or forced from the second powder reservoir into the first powder reservoir. Preferably, the powder material may be pre-compressed in the second powder reservoir and further compressed in the first powder reservoir.

[0022] Preferably, the cohesive material is forced from the second powder reservoir into the first powder reservoir with a second force of between 30N and 50N.

[0023] The application of force during application ensures that the cohesive powder is evenly applied and adheres well to the substrate.

[0024] Preferably, the first force acts constantly vertically downwards towards the substrate and base plate during the entire coating process.

[0025] This first force is constant.

[0026] This constant first force acts as it passes over the base plate and substrate, and preferably also as it fills the first reservoir.

[0027] This first force is intended to ensure that the cohesive material behaves like a fluid, especially when it is applied to a substrate and other layers above the substrate that have already melted and hardened.

[0028] Anti-agglomerating agents previously used in the prior art are no longer necessary with the solution according to the invention.

[0029] The first force to be applied is 5N to 50N, particularly in the processing range.

[0030] Tests have shown that this force causes cohesive powders with a maximum particle size of 20 μm to behave like a fluid, thereby coating more evenly.

[0031] Preferably, when compressing the powder material in the first powder reservoir, a counter force is applied simultaneously with the compressive force to ensure uniform compression. The counter force can be applied, for example, by a horizontal base plate over which the first powder reservoir is moved before the first powder layer is applied.

[0032] Preferably, the substrate is lowered according to the required layer thickness of the powder layer to be subsequently produced.

[0033] As an alternative to lowering the substrate, the processing surface and the first powder reservoir, and possibly other components present for carrying out the method, can be raised to increase their distance relative to the fixed substrate according to the required layer thickness of the next powder layer to be produced.

[0034] Preferably, the microparts or microcomponents are separated from the substrate after completion of the microparts or microcomponents. This separation is preferably carried out by wire erosion. Component residues remaining on the substrate after wire erosion are polished away and the substrate surface is structured so that the substrate can be used for a new implementation of the method of the invention.

[0035] Advantageously, the substrate is structured before the powder material is applied so that the structure of the substrate surface substantially matches the particle size of the powder material. This structuring may have recesses having a size corresponding to 0.5 to 8 times the particle size of the powder material. Advantageously, individual particles of the powder material remain in these recesses, thereby ensuring adhesion of the powder material to the substrate surface.

[0036] Preferably, an infrared fiber laser is used to melt the first powder layer and / or the further powder layer.

[0037] Laser sintering can be carried out under an inert gas, which can be, for example, argon.

[0038] Preferably, a metallic material is used as the powder material, alternatively, a ceramic powder can be used.

[0039] Additionally, various metal and / or ceramic powders can be processed.

[0040] In particular, stainless steel and / or titanium are used as powder materials.

[0041] Preferably, the particle size of the cohesive powder material is at most 20 μm.

[0042] Furthermore, this problem is solved by a device for carrying out the method according to the invention, which comprises a horizontally oriented working surface and a first powder reservoir arranged above the working surface, movable horizontally above the working surface and having an interior for containing powder material.

[0043] According to the present invention, the first powder reservoir is designed to open toward the processing surface, and the first powder reservoir has means therein for generating an axial force acting in the direction of the processing surface on the powder cohesive material placed therein, as a result of which the cohesive material behaves like a fluid at least during application in the processing area.

[0044] The means for generating an axial force is preferably a plunger having dimensions that completely or almost completely cover the cross section of the interior of the first powder reservoir. The force transmitted by the means for generating an axial force to the powder material can be supplied mechanically by a spring, and / or electrically, and / or pneumatically, and / or hydraulically.

[0045] The first powder reservoir may have a metering device therein such that the amount of powder material present in the first powder reservoir may be measured by the metering device.

[0046] In particular, the device includes a substrate positioned below the work surface for holding a first layer of powder.

[0047] Preferably, the substrate has a substrate surface that acts similarly to, for example, the surface of the cohesive powder material. Preferably, a force acts between the substrate surface and the powder material such that the applied powder material remains on the entire surface of the substrate.

[0048] The structuring of the substrate surface may comprise recesses having a size corresponding to 0.5 to 8 times the particle size of the powder material, advantageously such that individual particles of the powder material remain within the recesses of the substrate surface, thereby ensuring reliable adhesion of the powder material to the substrate surface as a first layer.

[0049] In a preferred embodiment, the device according to the invention further comprises a second powder reservoir arranged below the working surface and having an interior for containing powder material, the second powder reservoir being designed to open towards the working surface, the second powder reservoir having therein second means for generating an axial force acting in the direction of the working surface on the powder material arranged therein, the axial force acting on the powder material arranged therein to fill the first powder reservoir.

[0050] The second means for generating an axial force in the second powder reservoir can be a plunger having dimensions that completely or nearly completely cover the cross section of the interior of the second powder reservoir. The force transmitted by the second means for generating an axial force to the powder material can be mechanically supplied by a spring, electrically supplied, pneumatically supplied, and / or hydraulically supplied.

[0051] Preferably, the second powder reservoir is in the form of a cartridge pre-filled with powder, the lower base of which can be displaced towards the first powder reservoir using a second force.

[0052] While the first powder reservoir is moved horizontally above the base plate, the base plate exerts a reaction force against the axial force applied by the means or means for generating an axial force disposed in the first powder reservoir.

[0053] Advantageously, the base plate has an interruption at least partially in a processing area located above the substrate, said interruption of the base plate above the substrate allowing powder material from the first powder reservoir to be applied to the substrate surface.

[0054] The base plate may further include an interruption in at least some areas of the filling region above the second powder reservoir. The interruption in the filling region allows powder material to be forced from the second powder reservoir located below the filling region into the first powder reservoir located above the filling region. Preferably, the first and second powder reservoirs have the same opening surface for this purpose, and the interiors of the first and second powder reservoirs open toward the interruption in the base plate in the filling region through the opening surface.

[0055] Preferably, the device includes a laser for melting the first and / or further powder layers. This laser may also be used to structure the surface of the substrate. Preferably, the laser is an infrared fiber laser. The laser beam is deflected by one or more mirrors in a known manner.

[0056] The present invention advantageously utilizes forces inherent in powders that would normally cause undesirable aggregation / clumping. In particular, the application of energy to the powder material overcomes otherwise problematic powder compaction forces.

[0057] The present invention will now be described in more detail with reference to exemplary embodiments and associated drawings, without however limiting the invention thereto. [Brief explanation of the drawings]

[0058] [Figure 1] 1A-1D illustrate method steps for micro laser sintering according to the prior art. [Figure 2]FIG. 10 is a schematic diagram of the filling process of the first powder reservoir. [Figure 3] FIG. 1 illustrates the application of a first powder layer using a first reservoir. [Figure 4] FIG. 1 illustrates melting of desired areas of the first layer using a laser beam. [Figure 5] FIG. 10 shows the application of a further layer of powder with the substrate lowered. [Figure 6] FIG. 1 shows a device for unidirectional application of powder using recesses located on one side in a base plate. [Figure 7] FIG. 1 shows a device for bidirectional application of powder using recesses located on either side of a substrate in a base plate. [Figure 8] FIG. 1 shows a device for bidirectional application of powder with barriers on two bars in a base plate and in recesses located on either side of the substrate. [Figure 9] FIG. 1 shows a device for bidirectional application of powder using barriers on the upper surface of a base plate and on two bars located on either side of the substrate. [Figure 10] FIG. 1 shows a tilted first powder reservoir. DETAILED DESCRIPTION OF THE INVENTION

[0059] FIG. 1 illustrates the steps of a method for manufacturing a component according to the prior art. A three-dimensional CAD model M of the product is generated, and then the component is fabricated from this CAD model M by additive manufacturing using micro-laser sintering. For this purpose, in a first step, as shown in FIG. A, a powder reservoir 2' containing fine-particle powder material 1' is moved above the surface of a substrate 3' on which a thin powder layer is deposited. Then, in step B, the powder material 1' on the substrate is melted by a laser beam 4' at the positions to be hardened. In step C, the substrate 3' is lowered by the amount of the thickness of the next layer to be produced. A further layer of material 1' is applied to this first layer by using the powder reservoir 2', which moves horizontally above the already hardened layer. This layer is then also melted and hardened by the laser beam 4' (not shown). The substrate 3' is then lowered again (FIG. D) and coated again with powder material 1', etc., and finally, a component B according to the CAD model M is completed by micro-laser sintering using the laser beam 4', as shown in FIG. E. The unfused powder is removed. Figure F shows the finished component B separated from the substrate.

[0060] One drawback of the prior art is that the powder does not adhere to the entire surface during application, which can result in defects.

[0061] FIG. 2 shows a schematic diagram of the first step of the method according to the invention implemented in a device according to the invention.

[0062] The device has a base plate 5 having an upper surface 5a, a first powder reservoir 2 disposed above the upper surface 5a, and a second powder reservoir 7 disposed below the upper surface 5a. In Figure 2, both the first powder reservoir 2 and the second powder reservoir 7, which is preferably provided as a pre-filled cartridge, are located in a loading area 200 of the device, and the base plate 5 has an unspecified interruption in this loading area 200.

[0063] Within the first powder reservoir 2 there is a first means 6 for generating an axial force F1, which first means 6 causes the powder material 1 inside the first powder reservoir 2 to be subjected to an axial force F1 in the direction of the base plate 5.

[0064] Inside the second powder reservoir 7, there is a powder material 1, which is acted upon by second means 8 for generating a second axial force F2 acting in the direction of the first powder reservoir 2 as indicated by the arrow in the figure. In the embodiment shown, the second means 8 for generating a second axial force F2 is a plunger, which can be, for example, the bottom of the cartridge (forming the second reservoir 7). The plunger is axially adjustable in the direction of the first reservoir 2 within a surrounding wall (not shown).

[0065] In this way, the powder material 1 is transferred from the second reservoir 7 into the first powder reservoir 2 and compressed therein.

[0066] Since both the first powder reservoir 2 and the second powder reservoir 7 are open towards the base plate 5 in the filling area 200, the powder material 1 is pushed into the inside of the first powder reservoir 2 when F2 is greater than F1.

[0067] Once the first powder reservoir 2 is filled, it is moved horizontally above the base plate 5 towards the processing area 100 of the device, indicated by the dashed arrow. The base plate 5 has an interruption above the substrate 3 in the processing area 100. The substrate 3 has an upper surface 3a. A scanner is arranged above the substrate, with a deflection mirror 4.2 for deflecting the laser beam 4, indicated by the dashed line, of the laser 4.1. Here, the laser 4.1 is not yet activated.

[0068] A constant force F 1 acts on the cohesive material 1 in the first reservoir 1 as it passes above the base plate 5 and substrate 3 .

[0069] 3 shows a schematic diagram of a step of the method according to the invention when applying a first powder layer S1 to the upper surface 3a of the substrate. In this step, the first powder reservoir 2 is moved to the right in the direction of the arrow above the upper surface 5a of the base plate 5 and the upper surface 3a of the substrate 3. The first powder reservoir 2 moves above the substrate 3. The upper surface 3a of the substrate 3 is positioned slightly below the upper surface 5a of the base plate 5, preferably exactly below the thickness of the first powder layer S1 to be produced or as low as the thickness to be obtained. When a further downward axial force is applied by the plunger 6 to the powder cohesive material 1, the cohesive material 1 is applied to the upper surface of the substrate 3 with a force F1, where the cohesive material 1 behaves like a fluid.

[0070] A first powder layer S1 of material 1 remains on the upper surface 3a of the substrate 3. The upper surface 1a of the first powder layer S1 forms a processing surface for selectively melting the first powder layer S1 by a laser beam 4 shown in the drawing after the substrate 3 has been provided with the first powder layer S1 over its entire surface.

[0071] After application, the upper surface 1a of the first powder layer S1 is located slightly above the upper surface 5a of the base plate 5, preferably 20 to 200 μm above the upper surface 5a of the base plate 5.

[0072] Preferably, the top surface 3a of the substrate has a surface finish that ensures that the first powder layer S1 of the powder material 1 remains over the entire surface.

[0073] The scanner's laser 4.1 and deflection mirror 4.2 are arranged above the substrate 3.

[0074] After the first powder reservoir 2 has been completely moved above the substrate 3, the first powder layer S1 of the powder material 1 applied to the substrate 3 is selectively melted in the locations to be hardened by the laser beam 4 of the laser 4.1 and deflection of this laser beam 4 by the scanner 4.2, and after cooling a solid laser-sintered metal layer 1.1 is formed in at least some areas (see Figure 4).

[0075] The substrate 3 is then lowered according to the required layer thickness of the next powder layer to be produced (see FIG. 5), and a further powder layer, in this case a second powder layer S2 produced from powder material 1, is applied to the first layer S1 by axial movement (dashed arrow) of the first powder reservoir 2, again under the action of force F1. At this point, the upper surface 2a of the second powder layer S2 forms a new work surface. The second layer S2 is then partially melted so that a solid laser-sintered metal layer is formed in at least some areas.

[0076] During the horizontal movement of the first powder reservoir 2 above the base plate 5, the powder material 1 located in the first powder reservoir 2 is preferably further compressed by the first means 6 for generating an axial force F1 and is subjected to a constant force F1 in the direction of the base plate 5 and the substrate 3 or the applied laser-sintered layer. Preferably, the base plate 5 is designed such that no or almost no powder material 1 remains on the base plate 5 while the first powder reservoir 2 passes above it.

[0077] The laser 4.1 is preferably a fiber laser. For example, an infrared laser or a laser with a different wavelength can be used. It may also be possible to use a different energy source, such as an electron beam or a light beam emitted by an LED.

[0078] 6 shows a modified example of the device according to the present invention. The base plate 5 has a recess 5.1 adjacent to the substrate 3 in the application direction (arrow direction), and this recess 5.1 forms a barrier B. This prevents the powder from being applied to the upper surface 5a of the base plate 5. In addition, here, the upper surface 1a of the first layer S1 applied to the upper surface 3a of the substrate 3 forms a processing surface above the substrate 3. Preferably, the upper surface 1a is located 20 μm to 200 μm above the upper surface 5a of the substrate 3.

[0079] In one variant shown in FIG. 6, powder in the form of a cohesive material 1 is applied unidirectionally in the direction of the arrow under the action of a first force F1.

[0080] Laser sintering is then performed and the next powder layer is applied in the direction of the arrow. The return movement of the first powder reservoir 2 is performed in the opposite direction to the arrow before or after laser sintering. In this unidirectional operation mode, no powder layer is applied during the return movement.

[0081] In a further variant, the powder 1 is applied and then partially melted as the powder reservoir 2 is moved back and forth in each direction. Thus, the powder 1 is applied and partially melted in one direction, then applied and partially melted in the opposite direction. In this bidirectional application, in which the first force F1 always acts on the cohesive material 1, the squeegees 9 present below the reservoir preferably have the same height at their lower edges 9.1 (see Figures 7 to 9). The substrate 3 is lowered before each powder layer is applied.

[0082] This bidirectional process allows barrier B to be formed in each process direction.

[0083] 7 shows a variant for bidirectional application, in which a recess 5.1 is likewise present in the base plate 5, which now extends on both sides of the substrate 3. This results in a barrier B in the form of a shoulder being formed in both directions of movement of the first reservoir 2.

[0084] According to Figure 8, the barrier B is formed by bars L, which are arranged in recesses 5.1 of the base plate 5 on either side of the substrate 3 and transversely to the direction of movement of the first powder reservoir 2. The side of the bar L facing towards the second powder reservoir 2 forms the barrier B.

[0085] 9 shows an embodiment variant in which the base plate 5 does not have a recess. In this embodiment, bars L on the upper surface 5a of the base plate 5 are likewise positioned on either side of the substrate 3, the sides of the bars L facing the second powder reservoir 2 again forming barriers B for the powder layer of powder 1 to be applied.

[0086] In the three variants described above, the powder 1 is applied by the first reservoir 2 in both directions, ie alternately back and forth in the direction of the dashed arrows.

[0087] When using a bar L with a barrier B, such as shown in Figures 8 and 9, it is possible to adjust the bar L in the directions indicated by the arrows towards and away from the substrate 3. This positionally adjustable configuration of the barrier B makes it possible to adapt the distance of the barrier B relative to the substrate 3 to the coating properties of the powder 1 or the cohesion properties of the powder 1.

[0088] According to some variants of the embodiment not shown, the use of an adjustable position barrier can also be used for unidirectional application according to FIG.

[0089] In the variation shown in Figure 10, the powder material is applied in one direction to have a higher height and then withdrawn in the opposite direction to the desired height h. The powder material 1 is applied in one direction from left to right and removed from right to left.

[0090] For this purpose, the powder reservoir 2 has a first squeegee 9 located at the bottom, with its lower edge 9.1 facing in the application direction, and a second squeegee 10, with its lower edge 10.1 facing in the opposite removal direction (arrow direction). The lower edge 9.1 of the first squeegee 9 is located at a shorter distance from the upper surface 5a of the base plate 5 than the lower edge 10.1 of the second squeegee 10.

[0091] When passing over the substrate 3 in the application direction, i.e., in this case to the right, a higher first layer S1 having a higher upper surface 1a' is applied to the substrate 3 according to the height of the second squeegee 10. Then, during a subsequent removal in the opposite direction, i.e., in this case to the left, the powder is removed by the first squeegee 9 to the level of the working surface 1a and then melted.

[0092] The different heights of the squeegees 9, 10 can be set, for example, by tilting the powder reservoir 2 in the application direction by an angle α between the longitudinal axis A of the powder reservoir 2 and the upper surface 5a of the base plate 5. When the first reservoir 2 is pulled back in the withdrawal direction, the excess powder is leveled / pulled off to the correct height h by the first squeegee 9. The powder 1 is then melted at the working surface of the upper surface 1a of the first layer S1 located above the substrate 3.

[0093] The height H of the applied powder 1 in the unidirectional application described above with reference to FIG. 10 is about 2 to 10 times the height h of the removed layers S1...S2...etc.

[0094] Preferably, the thickness of each of the leveled layers S1, S2, . . . before laser processing is 1 to 4 times the particle diameter of the powder 1.

[0095] After completion of the microparts or microcomponents, the microparts or microcomponents are separated from the substrate 3, for example by wire erosion.

[0096] Preferably, the substrate is made of a metallic material, such as stainless steel, titanium, or ceramic. After separating the component from the substrate, the surface of the substrate can be processed so that it can be reused as a substrate in further processes for producing microcomponents. For this purpose, the surface of the substrate can be polished and then structured, for example, using a laser. [Explanation of symbols]

[0097] Reference Numbers for Figure 1 - Prior Art 1' powder material 2' Powder Reservoir 3' substrate 4' laser beam B Component M 3D CAD model Reference numbers for Figs. 2 to 7 1 Powder material 1a Upper surface / machined surface of first powder layer S1 1a' Upper surface of the applied layer S1 in the application direction 1.1 Solid laser sintered metal layer 2. First powder reservoir 2a Upper surface / machined surface of second powder layer S2 3. Circuit Board 3a Top surface of the board 4. Laser beam 4.1 Laser 4.2 Scanner deflection mirrors 5 Base Plate 5.1 Recesses 5a Top of base plate 6. First means for generating axial force 7 Second powder reservoir 8 Second means for generating axial force 9. First Squeegee 9.1 Lower edge of first squeegee 10 Second Squeegee 10.1 Lower edge of the second screenshot 100 processing areas 200 filling area B Barrier F1 First axial force F2 Second axial force L Bar S1 First layer S2 Second layer α Incline angle

Claims

1. 1. A method for producing microcomponents and microparts by additive manufacturing with micro laser sintering, in which a powder cohesive material (1) is applied in layers from a first powder reservoir (2) and melted after application by a laser beam (4), characterized in that the material (1) arranged in the first powder reservoir (2) opening in the direction of the processing surface is a cohesive powder and has a particle size (1) of at most 20 μm, and the cohesive material (1) is subjected to a constant first force (F1) in the direction of the substrate (3), the processing area and the base plate (5) during the entire application process, as a result of which the cohesive material (1) behaves like a fluid during application, and the force (F1) is between 5 N and 50 N at least during the application process of the cohesive material (1).

2. The force (F1) acts both when filling the first powder reservoir (2) and when passing over the base plate (5) and the substrate (3) in the processing area (100), the first powder reservoir (2) being filled in the filling area (200) from a second powder reservoir (7) arranged below the processing surface and designed to open towards the processing surface, in which a second axial force (F2) acting in the direction of the processing surface is applied by a front powder reservoir (7) arranged inside.

2. The method according to claim 1, wherein the powder material (1) is pressed by an interruption of the base plate (5) in the filling area (200) from the second powder reservoir (7) arranged below the filling area (200) into the first powder reservoir (2) arranged above the filling area (200) when the second force (F2) at the second powder reservoir (7) is greater than the first force (F1) at the first powder reservoir (2).

3. a) compressing the powder material (1) in a first powder reservoir (2) opening towards the working surface by applying an axial pressure with the first force (F1) to the powder coherent material (1) in the working area (100) towards the substrate (3); b) applying and forming a first powder layer of the powder cohesive material (1) on the structured top surface (3 a) of the substrate (3) by moving the first powder reservoir (2) parallel to the top surface (3 a) of the substrate while simultaneously applying a force to the powder cohesive material (1) in the direction of the top surface (3 a) of the substrate (3); c. Selectively melting the first powder layer (S1) by a laser beam (4); d. Lowering the substrate (3); e. applying the compressed powder coherent material (1) from the first powder reservoir (2) while simultaneously applying a force to the powder material (1) on the first selectively melted powder layer or on additional already formed selectively melted powder layers to form additional selectively melted powder layers until the micropart or microcomponent is completed, the substrate (3) being lowered before each additional powder layer is applied; 3. The method of claim 1 or 2, comprising:

4. 4. The method according to claim 1, wherein the first powder reservoir (2) is moved horizontally above the base plate (5) and the substrate (3) after filling with the powder cohesive material (1) and compressing the powder material (1), and the constant first force (F1) is applied.

5. 5. The method according to any one of claims 1 to 4, wherein after completion of the micropart or microcomponent, the micropart or microcomponent is separated from the substrate (3), said separation being preferably carried out by wire erosion.

6. 6. The method according to any one of claims 1 to 5, wherein an infrared fiber laser is used to melt the first and / or further powder layers of the cohesive material (1).

7. 7. The method according to any one of claims 1 to 6, wherein a metallic or ceramic material is used as the cohesive cohesive material (1) in powder form.

8. 7. A device for carrying out the method according to any one of claims 1 to 6, comprising a horizontally aligned base plate (5) that is interrupted in at least a certain area in a processing area (100) above a substrate (3), and a first powder reservoir (2) that is arranged above the base plate (5) and that can be moved horizontally above the base plate (5) and has an interior for containing a powder cohesive material (1), the first powder reservoir (2) being oriented in the direction of the base plate (5) and the direction of the base plate (5). A device designed to open towards a substrate (3) placed inside, the first powder reservoir (2) having first means (6) therein for generating a constant axial first force (F1), the first force (F1) acting on the powder cohesive material (1) placed inside and having a particle size of at most 20 μm in the direction of the base plate (5) and in the direction of the substrate (3), so that the cohesive material (1) behaves like a fluid at least in the processing area (100), the first force (F1) being between 5 N and 50 N.

9. the first powder reservoir (2) has therein first means (6) for generating the axial force (F1) acting on the powder cohesive material (1) disposed therein in the direction of the base plate (5) and the substrate (3), the axial force (F1) also acting in a filling region (200) when filling the first powder reservoir (2); the device has a second powder reservoir (7) having an interior for accommodating the powder cohesive material (1), the second powder reservoir (7) having second means for generating a second force (F2) acting on the powder material (1) disposed therein in the direction of the first powder reservoir (2).

9. The device according to claim 8, wherein the base plate (5) has an interruption in the filling area (200), and both the first powder reservoir (2) and the second powder reservoir (7) are designed to open towards the base plate (5), and the powder cohesive material (1) can be pushed from the second powder reservoir (7) arranged below the filling area (200) into the first powder reservoir (2) arranged above the filling area (200) when the second force (F2) on the second powder reservoir (7) is greater than the first force (F1) on the first powder reservoir (2).

10. 10. The device according to claim 8 or 9, characterized in that the device has a substrate (3) in the processing area (100), the substrate (3) being arranged below a processing surface and having a structured upper surface (3a) for accommodating a first powder layer (S1), the processing surface being formed by an upper surface (1a) of the powder material (1) applied to the area of ​​the substrate (3).

11. 11. The device according to claim 8, wherein the upper surface (3a) of the substrate (3) is structured such that the structure of the substrate surface is adapted to the particle size of the powder cohesive material (1), the structuring having recesses with a size corresponding to 0.5 to 8 times the particle size of the powder material.

12. 12. A device according to any one of claims 8 to 11, characterized in that it comprises a base plate (5) arranged below the working surface.

13. 13. The device according to any one of claims 8 to 12, characterized in that the base plate (5) has a recess (5.1) adjacent to the substrate (3) in the application direction, whereby a barrier (5.2) is formed, which prevents the powder from being pushed beyond it.

14. 14. A device according to any one of claims 8 to 13, characterized in that in the case of bidirectional powder application transverse to the direction of movement, the first powder reservoir (2) has squeegees (9) on both sides of the first powder reservoir (2), the lower edges (9.1) of each of the squeegees having the same distance from the upper surface (5a) of the base plate (5).

15. 15. A device according to any one of claims 8 to 14, characterized in that in the case of unidirectional powder application, the first powder reservoir (2) has a first squeegee (9) in one application direction and a second squeegee (10) in the opposite removal direction, the lower edge (9.1) of the first squeegee (9) being located at a shorter distance from the upper surface (5a) of the base plate (5) than the lower edge (10.1) of the second squeegee.

16. 16. A device according to any one of claims 8 to 15, characterized in that the second powder reservoir (7) is designed in the form of a cartridge pre-filled with powder, the bottom of which can be displaced in the direction of the first powder reservoir by the second force (F2) by a motor.

17. 17. The device according to any one of claims 8 to 16, further comprising a laser and a scanner (4.1) for melting the first and / or further powder layers and for structuring the substrate (3).

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