CN113458421A

CN113458421A - Equipment system and method for improving powder bed quality in additive manufacturing process

Info

Publication number: CN113458421A
Application number: CN202110477529.2A
Authority: CN
Inventors: 沈李耀威
Original assignee: Yunyao Shenwei Jiangsu Technology Co ltd
Current assignee: Yunyao Shenwei Jiangsu Technology Co ltd
Priority date: 2020-07-24
Filing date: 2021-04-30
Publication date: 2021-10-01
Anticipated expiration: 2041-04-30
Also published as: DE102020004503A1; CN113458421B; CN215144707U

Abstract

The invention relates to an apparatus system and a method for improving powder bed quality in an additive manufacturing process. The equipment system (10) comprises a spatially movable powder (30) spreading device (20) and an excitation unit (40), the powder spreading device (20) being arranged to apply one or more powder layers (31) on a substrate table (16) or a powder bed (32) that has been processed with the equipment system at a processing plane (15). The excitation unit (40) is arranged to break up clusters and/or adhesions of individual powder (30) particles to each other and/or to a powder bed (32) that has been processed with the equipment system, so that the powder spreading device (20) can apply a smooth powder layer (31) to the substrate platform and/or to a previous powder layer/powder bed (31, 32).

Description

Equipment system and method for improving powder bed quality in additive manufacturing process

Technical Field

The invention relates to a device for additive manufacturing technology by using a powder system and a processing method for forming a workpiece with a complex structure by using the device.

Background

Additive manufacturing techniques, i.e. 3D printing, build complex multidimensional structures by using powders as raw materials. The powder material is melted by the focusing of high-energy light beams and is solidified and molded again, so that the specified spatial configuration is obtained. Known metal additive manufacturing processes are Laser Powder Bed Fusion (LPBF), electron beam fusion or selective laser sintering. In the LPBF process, the material to be processed is deposited in powder form by an equipment dusting system in a thin layer on a substrate platform. The powder material is completely melted and solidified locally under the laser focusing melting, and a nearly two-dimensional solid configuration is formed. The substrate platform is then lowered by a specified layer thickness (typically 20-100 μm) and again dusted and melted repeatedly from the dusting system. The whole processing process is repeated until the whole part is processed layer by layer.

However, in the additive manufacturing process of powder materials, a well-known problem is that the powder materials have different characteristics according to different production or screening processes and different particle sizes of the powder materials. The interparticle adhesion forces, particularly van der waals forces, existing between the powder particles may exceed their weight forces by orders of magnitude. During the powder spreading process, a shearing force is generated, so that the powder particles present an irregular surface bonding characteristic on the substrate platform, and finally, a smooth powder bed surface is difficult to obtain, thereby seriously affecting the forming quality of the target manufactured workpiece.

In order to smooth the powder bed surface, as provided by 3d mikroproint, germany, the technique is to apply a powder layer on the substrate platform and then apply contact pressure again on the upper surface of the powder bed. The 3D-Systems company of america uses rollers as the powder spreading device.

The disadvantage of these designs is that they are only suitable for large particle powders with predominantly spherical shapes. Both for powder materials based on fine powder particles (e.g. less than 20 microns) and for powder materials with a special shape due to production and sieving processes, clustering and blocking phenomena of the powder can lead to e.g. a roller again destroying the already smoothly applied powder bed. When contact pressure is used, the desired effect of the forming quality is not achieved for fine-grained powder, and the stability is not sufficient, for example, when printing and manufacturing extremely fine and complicated structures, the contact pressure of the upper surface of the powder bed may cause the formed and complicated workpiece to deform, deviate from the desired dimensional requirements, and in severe cases even directly cause damage to the formed workpiece.

Therefore, there is a real need for a powder additive manufacturing process that can improve the powder spreading effect in the additive manufacturing process in consideration of the physical properties of the powder, such as size and shape.

Disclosure of Invention

The purpose of the invention is as follows:

it is an object of the present invention to provide an apparatus that is effective in improving and ensuring the quality of the laydown and the surface quality of the powder bed during additive manufacturing, taking into account at least the physical properties of the powder, such as size and shape.

The technical scheme is as follows:

to achieve this object, the invention is solved by an additive manufacturing system for workpieces of complex structure, comprising a spatially movable powder-spreading device and an excitation unit. The powder spreading device is designed to spread one or more powder layers in a processing plane onto a substrate table or onto a powder bed that has been processed with the equipment system. The purpose of the activation unit is to break up clusters and/or sticking of individual powder particles to each other and/or to a powder bed that has been processed with the equipment system when applying the powder, so that the powder spreading device can apply a smooth powder layer to the substrate platform and/or to a previous powder bed. The excitation unit generates excitation stimulation to break the interaction force among the powder particles, reduce the clustering and/or adhesion phenomenon among the powder particles and effectively improve the flowability of the powder. Therefore, even small powder particles and/or powder having a deformed shape that is liable to be agglomerated can realize stable and high-quality beam melt processing. Meanwhile, the coated powder bed has smooth surface and relatively small shearing force in the surface direction, so that the powder bed can be effectively prevented from being damaged in the powder spreading process.

The additive manufacturing process is to arrange materials layer by layer on a manufacturing device, process the materials layer by layer, and finally form a three-dimensional structure part (namely 3D printing). The material is built up layer by one or more liquid or solid materials according to the specified two-dimensional size and shape and the fixed-point processing treatment of the material by a specific energy source under the control of a computer. Physical or chemical hardening or melting processes may occur during the stacking process. Typical materials for 3D printing are plastics, resins, ceramics and metals. Carbon and graphite materials may also be used for 3D printing. For metallic structural components in industrial fields, the directional melting technique and the related equipment system are more applicable, including laser powder bed melting (also called selective laser melting), electron beam melting technique and selective laser sintering technique.

Such an additive system may comprise a control unit for controlling the machining process. Such control units may comprise computer units, processors, memory units, etc. It is connected to the hardware and software of the device in a suitable manner, for example with a suitable data line or wirelessly, for example via WLAN.

The "complex-structured workpiece" refers to a part having a three-dimensional structure as a main component in any application scene. For example, the method can be applied to plastic injection molds, aviation parts, special molds and the like. The term "complex structure" includes not only finished parts but also unfinished parts in a manufacturing process, such as a complex-structured workpiece produced by deformation of parts inside a powder bed during machining.

A "powder spreading device" is a system of equipment suitable for applying powder to a substrate platform. The powder spreading device is configured to be spatially movable relative to the apparatus to transport and spread powder from one location to another. Various embodiments of the breading unit are set forth in the following paragraphs.

By "powder" is meant the material to be processed, used in powder form. For example, the powder may consist essentially of a material made of metal or polymer. During production, the powder is applied layer by layer on the substrate table. The powder-laying device applies a "powder layer" once per application, either to the substrate table (first layer) or to a layer of powder on top of it that has already been applied with the equipment system. The applied powder layer typically has a layer thickness of, for example, 10 micrometers or preferably <20 micrometers. Thus, a "powder layer" may be understood to include the composition of all powder layers that have been processed by the equipment system, and may be defined as a "powder bed". In theory, it is also possible to apply "layers of powder" before being shaped by the system of equipment (for example by laser machining). The powder may consist essentially of powder particles of the same material. However, a mixed powder material is also possible. The size, shape and particle distribution of the powder may vary. This non-uniformity of the powder is mainly caused by the production and/or post-treatment (e.g. sieving) of the powder material. Particularly fine and/or irregularly shaped powder particles tend to agglomerate with one another.

"substrate platform" refers to a build platform for placing a part to be processed. The substrate stage is designed to be spatially movable relative to the apparatus. For example, by moving (lowering) the powder layer that has already been applied by the powder application device downwards, application of a subsequent powder layer on the processing plane can be further achieved. The substrate stage is typically designed to move sealingly within a closed cell. The closure unit can be a container, wherein the container can be designed, for example, in the form of a cylinder. The container can be designed analogously to the powder container according to the invention, wherein the substrate table can be arranged analogously to the movable powder transport unit according to the invention. However, in theory, the substrate stages can also be designed to be spatially freely arranged.

The "excitation stimulus" is emitted by the excitation unit and can be used to break up clusters and/or cohesion phenomena between the powder particles, so as to eliminate powder agglomeration. During the powder laying process, the excitation stimulus generated by the excitation unit is preferably used intermittently to break up clusters and/or adhesions of the particles to each other and/or to the layer of powder that has been applied with the device. The energizing unit may further be used only for smoothing a layer of powder without any application process taking place. The excitation of the excitation unit may be, but is not limited to, vibration, and may be, for example, by a change in temperature.

The device according to the invention comprises a powder spreading means that enables a smooth powder spreading during the additive manufacturing process, the inventive means taking into account at least the physical properties of the powder, such as the actual state of size and shape.

In one embodiment, the excitation unit may include a vibration unit that may effectively break up clustering and/or sticking phenomena between the powder particles by vibration. The vibrations may be generated pneumatically and/or electromagnetically and/or ultrasonically. In use of the unit, pneumatic actuation may be by means of a gas, such as argon. The vibration unit with pneumatic excitation has the advantages of small volume and compact structure, can be integrated into the powder spreading device, does not need to excessively increase the volume and the weight, and does not need a plurality of additional components. The disadvantage of pneumatic excitation is that the powder spreading speed is relatively low (about 20mm/s) and the smoothing effect of the powder layer is inferior to that of ultrasonic excitation. The frequency of the pneumatic excitation may be around 200 Hz. The advantage of electromagnetic excitation is that no gas is required. Electromagnetic excitation is also technically simple and can be realized. It has a disadvantage that it is not suitable for all metals, for example for metals having ferromagnetic properties. The ultrasonic wave is used for excitation stimulation, and the powder spreading speed has obvious advantage and can reach more than 200 mm/s. The frequency of the ultrasonic waves may be, for example, 35 kHz, which is suitable for powder particles having a particle size of 2 μm (average diameter). The ultrasound-excited powder-laying smoothing effect is particularly good. The vibration unit may be adapted to generate a single vibration as described above and/or a combination of these types of vibrations. The excitation of the excitation unit takes place above the substrate platform (i.e. above the powder layer) in order to excite at least the uppermost powder of the already applied powder bed. The excitation should also have at least one frequency. In one embodiment, the frequency of the excitation does not coincide with the resonant frequency of the device. This prevents the apparatus from being damaged by the generation of resonance. In another embodiment, the frequency of oscillation may have a wavelength related to the grain size of the powder and/or a wavelength related to the speed of movement of the powder spreading device in the powder spreading direction. In this case, the amplitude of the oscillation is frequency-dependent and thus also the powder-laying speed of the powder-laying device, so that the size of the individual particles corresponds to the amplitude of the oscillation. This has the advantage that the dusting speed can be increased without loss of quality. Therefore, the manufacturing efficiency and the production yield can be improved by the present embodiment. In a specific embodiment, the frequency of the excitation may be between 40Hz and 100 kHz. This has the advantage that it can be applied particularly effectively to powders having a particle size of less than 20 microns.

In one embodiment, the dusting apparatus further comprises a smoothing tool. The smoothing tool is used to physically smooth the applied powder layer and/or the powder bed that has been treated with the device. The smoothing tool may comprise a grinding unit, silicone grease, plastic stick, brush or metal strip. Silica gel is particularly suitable for low frequency excitation because it is very soft. Plastic rods also have similar advantages. Whereas brushes are well suited for unstable processes. In the case when the process has been run steadily, the metal strip is very suitable. In an advantageous embodiment, the grinding unit comprises a material with a hardness which is suitable for ultrasonic grinding and/or polishing. Preferably, the grinding unit may be a conventional grinding stone. The material in the grinding unit has the characteristics of hardness particularity and high stability, and is particularly suitable for excitation in high-frequency ranges such as ultrasonic waves. Moreover, a conventional grindstone for physical grinding can be obtained at low cost. The grinding unit may be made of ceramic. Additionally, the grinding unit may also be made of alumina or diamond.

In one embodiment, the excitation unit of the inventive device system may be stationary with respect to the powder bed and/or the substrate platform. This may provide a structural advantage, for example, when the excitation unit is connected to or integrated with the substrate platform, the excitation stimulus may be achieved by vibrating the substrate platform. However, this embodiment has the disadvantage that the higher the height of the component to be machined, the less the effect of the vibration excitation. This is because when vibrating the substrate table, the substrate table gradually sinks along with the processing process, the powder layer in the upper space gradually increases, and the gradually thickened powder bed will slow down the excitation effect. In addition, the difficulty in technical implementation is that powder may flow down from the side of the substrate stage due to vibration. Thus, in another embodiment, the excitation unit may be spatially movable relative to the powder bed and/or the substrate table. An advantage of this embodiment is that the excitation intensity to the powder layer is not affected by the structural complexity and dimensional height of the machined workpiece. In addition, this embodiment also allows, for example, that the powder spreading device may comprise an excitation unit. Therefore, a compact constructional design can be adopted.

In one embodiment, the apparatus system according to the invention may comprise a damping unit configured to reduce transmission of the excitation to an apparatus component external to the excitation unit. The damping unit has the advantage that it can in particular damp vibrations of the excitation unit in unfavorable directions, thus protecting the overall system of the installation. In particular, the shaft of the device is very sensitive to the excitation, such as vibrations, generated by the excitation unit. If the excitation unit is integrated in the powder-spreading device, it is important to suppress the vibration excitation effectively above the powder layer in the direction of the movement axis of the powder-spreading device. The dusting device can be fixed on the guide rail by a support for regular movement during the dusting process, in which case the support can be designed as a damping unit or as a part thereof in the case of an excitation unit arranged in the dusting device. The support can be made of soft materials, and can well absorb vibration excitation. Thus, in addition to stabilizing and supporting the powder spreading device, the bracket may also have a shock absorbing function. The shock absorption unit is beneficial to protecting the equipment and prolonging the service life of the equipment.

The smoothness control of the powder layer surface is also complicated due to non-uniform particle size and morphology. In one embodiment, the inventive device is also suitable for smoothing a powder layer if at least a part of the powder used has the property of an agglomerated and/or profiled structure. In particular, fine particles with a particle size of <20 μm tend to agglomerate. The inventive system of equipment is therefore particularly suitable for powders with a particle size <20 microns, wherein preferably at least a part of the powder has a particle size <2 microns. Non-spherical particles and/or angular and peaked particles ("shaped shot") have shot characteristics. The shaped particles are also liable to agglomerate when the particle size is not particularly small. The particle size of the powder particles can be determined, for example, according to EN ISO 14688.

In one embodiment, the inventive apparatus system may include a powder system that provides powder from at least a first powder container, with a powder spreading process being performed by a powder spreading device. At least the first powder container comprises a movable powder transport unit which transports a quantity of powder to a processing plane (for example a beam focusing plane) for subsequent application of the powder by a powder spreading device in one or more powder layers onto a substrate table or onto a powder bed which has been treated with the equipment system. In another embodiment, the powder spreading device can push the residual powder after the powder spreading in the substrate platform area is finished into the powder overflow container. The powder overflow container may be temporarily served by the first powder container or the second powder container. The powder spreading device can alternately use the first powder container or the second powder container as the powder supply container according to the current actual state, and the first powder container or the second powder container which is not used as the powder supply container is used as a temporary powder overflow container. This has the advantage of greatly improving the efficiency of use of the powder. The powder to be transported above the processing plane of the powder container can be adapted to the layer thickness of the powder layer to be applied to the substrate table by a factor of 1.2 or more, or by a factor of 2, particularly preferably by a factor of 3 or 4. The powder container may be in the form of a cylinder. The powder container and the substrate platform (or a container comprising the substrate platform) may be arranged directly adjacent to each other.

In one embodiment, the inventive apparatus system may be configured to meet selective laser melting techniques or/and electron beam melting techniques. In particular, in these processes, powders of different particle sizes and shapes are used. This includes powders of small particle size and/or irregular structure. A smooth powder bed surface is particularly advantageous for the quality of the shaping of machined parts (complex-structured workpieces).

The powder laying device for the additive manufacturing system of the workpiece with the complex structure can further optimize the quality of the powder bed. Wherein the powder spreading device is arranged to spread one or more powder layers on the processing plane onto the substrate table or onto a powder bed already treated with the equipment system by means of spatial movement. The powder spreading device further comprises an activation unit arranged to break up clusters and/or adhesions of powder particles to each other and/or to a powder bed that has been applied by the apparatus during the powder spreading process, so that the powder spreading device can apply/level a smooth powder layer or powder bed onto the substrate platform and/or onto a previous powder bed. The arrangement of the excitation unit in the powder-spreading device allows for a precise and local excitation stimulation of the powder particles during the smoothing process, at least during the powder-spreading process. Of course, the powder laying device may perform secondary leveling of the powder layer or the powder bed without laying the powder (i.e., the powder laying device performs empty laying). This arrangement makes it possible, in particular by suitable parameter selection, such as the frequency of the exciter unit, to achieve a smooth dusting effect and a smooth powder bed surface.

Here, the powder spreading device according to the present invention can smoothly achieve a smooth powder spreading effect in the additive manufacturing process, taking into consideration at least physical properties of the powder, such as size and shape.

In one embodiment, the excitation unit may comprise a vibration unit that uses vibration excitation to break up clustering and/or sticking phenomena of the powder particles 33 to each other. The vibration excitation can be generated pneumatically and/or electromagnetically and/or ultrasonically. The vibration frequency cannot coincide with the resonance frequency of the device in order to avoid damaging the device. Furthermore, the frequency of oscillation may have a wavelength related to the grain size of the powder and/or a wavelength related to the speed of movement of the powder laying device in the powder laying direction. The amplitude of the oscillations is frequency dependent and thus the powder spreading speed, as is the size of the individual powder particles and the amplitude of the oscillations, so that the frequency of the oscillations needs to be suitably optimized. This has the advantage that the dusting speed can be increased without reducing the dusting effect. Therefore, the production efficiency can be improved by this embodiment. Preferably, the frequency of the excitation may be between 40Hz and 100 kHz.

In one embodiment, the dusting device according to the invention further comprises a smoothing tool, preferably a smoothing tool comprising a grinding unit, a silicon lip, a plastic rod, a brush and/or a metal strip. Particularly preferably, the grinding unit consists of a material with a certain hardness which is suitable for ultrasonic grinding and/or polishing, wherein more preferably the grinding unit is a conventional grinding stone, which may particularly preferably be made of ceramic. The material in the grinding unit has the characteristics of hardness particularity and high stability, and is particularly suitable for excitation in high-frequency ranges such as ultrasonic waves. The grinding unit may also be made of alumina or diamond.

In another embodiment, the dusting apparatus may comprise a smoothing tool holder configured to support a smoothing tool. The smoothing tool holder may be configured to fixedly mount a smoothing tool (e.g., a grindstone) on the powder spreading device. The smoothing tool holder may be configured to slide the smoothing tool in its holder. Depending on the configuration, the smoothing tool holder can also act as a damping unit if the excitation unit is arranged above the smoothing tool holder. In this case, it is advantageous if the smoothing tool holder consists of a soft material that provides good absorption and damping of vibrations. In an advantageous embodiment, the smoothing tool holder can be integrated into the excitation unit. This may allow a more compact design and may improve the damping effect.

In one embodiment, the powder spreading device according to the invention may comprise a damping unit for reducing or eliminating the transmission of excitation by the excitation unit to other components. In another embodiment, the powder spreading device according to the invention may comprise a bracket provided for fixing the powder spreading device on the guide rail for performing a regular movement of the powder spreading device, wherein more preferably the bracket is configured as a shock-absorbing or as a part thereof. The damping unit may be configured to assume the function of the connecting bracket and the excitation unit. The holder may be made of a soft material particularly suitable for absorbing vibration excitations. This may be a polymer and/or a combination of rubber and metal. Thus, in addition to stabilizing and supporting the powder spreading device, the bracket may also have an effective shock-absorbing function, which may make the overall powder spreading device more compact.

All the features of the dusting device according to the invention, which are associated with all the features of the system of equipment according to the invention, should have at least corresponding advantages.

According to the invention, a method for additive manufacturing of a complex-structured workpiece, comprising a spatially movable powder laying device for powder and an excitation unit, comprises the following steps: applying one or more powder layers on the processing plane above the substrate platform or above a powder bed that has been treated with the equipment system by a powder spreading device; in at least one powder-spreading process, preferably in each powder-spreading process, the agglomeration and/or cohesion phenomena between the individual powder particles and/or between the powder beds which have been treated by the excitation unit are excited and broken up by the excitation unit; and (3) carrying out troweling treatment on the powder layer and/or the powder bed through a powder spreading device.

The invention herein provides a method of achieving a smooth powder bed in an additive manufacturing process, which method takes into account at least the physical properties of the powder, such as size and shape.

All the features of the method according to the invention, which are associated with all the features of the dusting device according to the invention, should have at least corresponding advantages.

In another embodiment, the method according to the invention comprises at least one further step of performing at least a second smoothing process by means of a powder-laying device which, after application of a previous layer of powder, moves again over the already applied layer of powder without performing a new laying of powder. This has the advantage that a second smoothing can be achieved without the need to apply the powder again.

According to the invention, the method according to the invention also comprises the further step of supplying powder from at least the first powder container of the powder system for powder laying or powder bed restoration by the powder laying device (which can also be referred to as a secondary troweling process without changing the height of the powder bed), whereby a smoother powder bed surface is made possible. In another embodiment, the method according to the invention comprises the further step of conveying a quantity of powder above the processing plane by means of a movable powder conveying unit of the first or second powder container, which is currently temporarily acting as a powder supply container, for subsequent application by the powder spreading device as a powder layer on the substrate table or on a powder bed already processed with the equipment system. In addition, the method according to the invention may comprise the further step of pushing excess powder through the powdering device into the first or second powder container, which now temporarily serves as a powder overflow container, when powder is applied outside the substrate table. Preferably, the method according to the invention may comprise the further step of alternately carrying out the dusting process from the first or second powder container by the dusting device, 2 powder containers in one dusting process, one acting as a temporary powder supply container and one acting as a temporary powder overflow container.

In an advantageous embodiment, the above steps may be repeated until the final forming of the complex structured workpiece is completed.

The above-mentioned features of the invention can be combined with each other as much as possible, even if not explicitly stated above.

Drawings

FIG. 1 a) shows an embodiment of the powder application process of the powder application device of the inventive system; b) a side view of a) is shown.

FIG. 2 a) shows an embodiment of the dusting apparatus and excitation unit of the inventive device system; b) a side view of the powder spreading device is shown.

Fig. 3 a) shows an embodiment of the powder system of the invention; and b) shows one embodiment of the powder system of the present invention with a second powder container.

Fig. 4 shows an embodiment of the method of the invention.

Fig. 5 shows another embodiment of the method of the invention.

FIG. 6 shows a) a front view of the system of the apparatus of the present invention; b) one embodiment of a powder system is shown.

Fig. 7 a) shows the actual effect diagram of the powder layer after powder spreading by other traditional methods; b) a smooth powder bed after being leveled by the powder spreading device of the equipment system according to the invention is shown.

Detailed Description

Embodiments of the invention are explained in detail below, without prejudice, in particular without limitation, with reference to fig. 1 to 7. Identical elements are provided with identical reference numerals as long as they are not otherwise specified.

Fig. 1 a) shows the system of devices 10 according to the invention when the powder 30 is spread by the powder spreading device 20. The inventive system 10 is suitable for the additive production of complex-structured workpieces 11 and comprises a spatially movable powder application device 20 for a powder 30 and an excitation unit 40.

The powder spreading device 20 is used to deliver one or more powder layers 31 to the substrate table 16, or to a previous powder bed 32 that has been processed, on the work plane 15.

The excitation unit 40 is arranged to break up clusters and/or conglutinations of the powder particles 33 with each other and/or with the powder bed 32 that has been applied by the apparatus, so that the powder spreading device 20 is able to apply/level the smooth powder layer 31 or powder bed 32 onto the substrate platform 16 and/or onto the previous powder bed 32.

In the present embodiment, the powder spreading device 20 is configured as follows (from top to bottom): the powder spreading device 20 of the equipment system 10 comprises a bracket 23, which bracket 23 is fixed on a guide rail to realize regular movement of the powder spreading device 20. Since the excitation unit 40 is arranged in the powder spreading device 20 in the present embodiment, the bracket 23 may be replaced in whole or in part with the damper unit 22.

Further, the present embodiment includes a damping unit 22, the damping unit 22 being configured to reduce or eliminate transmission of excitation from the excitation unit 40 to other components. The damping unit 22 can in this embodiment additionally assume the function of a connecting bracket 23 and a smoothing tool bracket 24, as indicated by the dashed double arrow in the figure. The powder spreading device 20 includes an excitation unit 40, and the excitation unit 40 is spatially movable with respect to the powder bed 32 and/or the substrate stage 16.

The excitation unit 40 may include a vibration unit that uses vibration to break up clustering and/or sticking phenomena of the powder particles 33 to each other. The excitation unit 40 may be mounted above and connected to the smoothing tool holder 24 (dashed double arrow).

The illustrated embodiment includes a smoothing tool 21 which may be a grinding unit, silicone grease, plastic stick, brush and/or metal strip. The material of the grinding unit should have a hardness suitable for ultrasonic grinding and/or polishing, and more preferably the grinding unit is a conventional grindstone. For example, the grinding unit may be made of ceramic.

The powder spreading device 20 applies one or more layers of powder 31 onto the substrate platform 16 (if it is the first layer) or otherwise onto a previous bed of powder 32 that has been applied by the apparatus, wherein the bed of powder 32 applied by the apparatus also includes the complex-structured workpiece 11 that has been formed before.

Fig. 1 b) shows a side view of fig. 1 a), in which the powder application device 20 of the inventive device system 10 is moved in the powder application direction 25 during the powder application process. The powder spreading device moves at a defined speed of movement over the powder bed 32 or the substrate platform 16 which has been processed by the apparatus system 10, generating pneumatic and/or electromagnetic and/or ultrasonic vibration excitations during the powder spreading process, so that the individual powder particles 33 are broken up from one another and/or from sticking. But the vibration frequency cannot coincide with the resonance frequency of the device in order to avoid damaging the device. The breakup occurs both on and between the powder 30, the powder layer 31 and the powder bed 32 that has been processed by the equipment system 10. The frequency of oscillation may have a wavelength related to the grain size of the powder and/or a wavelength related to the speed of movement of the powder laying device 20 in the powder laying direction 25. The frequency is preferably in the range of 40Hz to 100 kHz. The average particle size of the powder particles 33 is typically less than 20 microns. However, in contrast to the prior art, a particular feature of the system 10 of the apparatus according to the invention is that it still achieves a smooth dusting effect in the case of powders 30 having a particle size of less than 2 μm being used.

Fig. 2 a) shows a powder spreading device 20 of an apparatus system 10 suitable for complex-structured workpiece additive manufacturing process techniques according to the present invention, wherein the powder spreading device 20 is arranged to spread one or more powder layers 31 in a processing plane 15 onto a substrate platform 16 or a powder bed 32 that has been processed with the apparatus system 10 by spatial movement. The powder spreading device 20 further comprises an excitation unit 40, which excitation unit 40 is arranged for breaking up clusters and/or adhesions of individual powder particles 33 to each other and/or to the powder bed 32 that has been treated with the apparatus system 10 during the powder spreading process, so that the powder spreading device 20 can apply a smooth powder layer 31 to the substrate platform 16 and/or to a previous powder bed 32.

Fig. 2 b) one embodiment of a side view of the dusting apparatus 20. The excitation unit 40 of the powder spreading device 20 may include a vibration unit that breaks up the attached matter by vibration. The vibration unit can be designed in analogy to the vibration units of a) and b) of fig. 1. Also similar to the embodiment of a) and b) in fig. 1, the dusting apparatus 20 can be provided with a corresponding smoothing tool 21 and smoothing tool holder 24. The excitation unit 40 may be arranged above the smoothing tool holder 24. The powder laying device 20 further comprises a damping unit 22, which damping unit 22 is adapted to reduce or eliminate the transmission of excitation by the excitation unit 40 to other components. The damping unit 22 may be disposed on at least two sides of the excitation unit 40 to damp vibrations and communicate the smoothing tool holder 24 with the other holder 23 or the damping unit 22. A bracket 23 is provided to fix the powder spreading device 20 on the guide rail to perform a defined movement of the powder spreading device 20, wherein preferably the bracket 23 is designed as a damping unit 22 or a part thereof. The damping unit 22 is also configured to connect the bracket 23 to the excitation unit 40.

Fig. 3 a) shows an apparatus system 10 according to the invention comprising a powder system 35 which supplies powder 30 from at least a first powder container 36 and the powder laying process is carried out by means of a powder laying device 20. At least the first powder container 36 comprises a mobile powder delivery unit 37, which mobile powder delivery unit 37 delivers a quantity of powder to the processing plane 15 (for example the beam focusing plane) in order to subsequently apply the powder by the powder laying device 20 in one or more layers 31 onto the substrate platform 16 or onto the powder bed 32 that has been processed with the equipment system. The residual frit 34 is pushed out of the substrate platform 16 after the frit has been spread and is collected in a frit overflow container 38 (not shown).

Fig. 3 b) shows an embodiment of a powder system 35 in which a first powder container 36 and a second powder container 39 arranged analogously thereto can alternately serve as temporary powder overflow containers 38. The powder spreading device 20 is arranged to alternately perform the powder spreading process of the powder 30 from the first and second powder containers 36, 39, respectively, in the respective appropriate powder spreading direction 25. Above the processing plane 15 of the powder containers 36, 39, the powder to be transported can be adapted to the layer thickness of the powder layer to be applied to the substrate table 16 by a factor of greater than or equal to 1.2, or by a factor of 2, particularly preferably by a factor of 3 or 4. The efficiency of the powder use is greatly increased by using this powder system 35, since the residual powder after each dusting process can continue to be received in the first or second powder container 36, 39, which serves as a temporary powder overflow container 38.

Fig. 4 shows a method 100 for producing a device according to the invention, which comprises a spatially movable dusting device 20 and an excitation unit 40. The method comprises the following steps: a powder application 110, by which one or more powder layers 31 are applied on the work plane 15 above the substrate table or above a powder bed 32 that has been treated with the equipment system 10; exciting and breaking 120, breaking up, by the exciting unit 40, clustering and/or blocking phenomena among the individual powder particles 33 and/or among the powder beds 32 that have been treated by the exciting unit 40, during at least one, preferably during each, powder laying; and (4) leveling 130, namely, flattening the powder layer 31 and/or the powder bed 32 by the powder spreading device 20.

The inventive process 100 shown in fig. 5 may be further combined with the inventive process shown in fig. 4 to obtain a smoother powder bed surface. Additional steps include: a secondary floating 140, which is performed at least by the powder spreading system 20, and after the powder layer 31 is spread, the powder spreading system is used again to move on the spread powder layer 31 (which can also be understood as the current powder bed 32), and the sinking operation of the substrate platform 16 is not performed, so that the height of the current powder bed 32 is not changed; powder container verification 150. in addition, this embodiment includes selecting and determining the current powder container 36 or 39 from powder system 35 to provide the powder for secondary troweling that may be needed for powder placement or powder bed restoration by powder placement device 20; a powder container supply 160, further steps including delivering an amount of powder above the work plane 15 by means of the movable powder delivery unit 37 of the current powder container 36 or 39 for subsequent application by the powder spreading device 20 as a powder layer 31 on the substrate platform 16 or on the powder bed 32 that has been processed with the equipment system 10; excess powder recovery 170, and further comprising pushing the residual powder 34 applied to the outside of the substrate platform 16 into the first or second powder container 36, 39, which now temporarily serves as the powder overflow container 38; and (3) alternately spreading the powder 180, wherein the further step comprises alternately spreading the powder from the first powder container 36 or the second powder container 39 by the powder spreading device 20, and the 2 powder containers are used as a powder supply container and a powder overflow container 38 in one powder spreading process.

Fig. 6 a) shows a front view of an embodiment of the device system 10 according to the invention. FIG. 6 b) shows an embodiment of the powder system 25 of the present invention, which comprises a first powder container 36 and a second powder container 39, which can alternately serve as the powder supply container 33 and the powder overflow container 38, and a container containing the substrate platform 16 (not shown), wherein the powder system 25 is integrated into the apparatus system 10 of the present invention to improve the powder utilization efficiency.

Fig. 7 a) shows a physical diagram of a powder layer (or also called "powder bed 32")31 after powder laying by a common powder laying process, the powder laying effect is poor, and the powder layer is not smooth. Fig. 7 b) shows a physical representation after the powder layer 31 or the powder bed 32 has been successfully smoothed in the system of equipment 10 by means of the powder spreading device 20 according to the invention.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Figure number notes:

10 inventive plant system

11 workpiece with complex structure

15 machining plane

16 base plate platform

20 powder paving device

21 smoothing tool

22 damping unit

23 support

24 smooth tool holder

25 powder laying direction

30 powder

31 powder layer

32 the powder layer that had been applied before (previous powder bed)

33 powder particles

34 residual powder

35 powder system

36 first powder container (which may also be referred to as first powder supply container)

37 movable powder conveying unit

38 powder overflow container

39 second powder container (may also be called second powder supply container)

40 excitation unit

100 method of operation of the invention

110 … 180 method of operation of the invention

110 spreading powder

120 stimulation and breaking

130 floating

140 secondary floating

150 powder container confirmation

160 powder supply container

170 collecting the rest powder

180 alternately spreading the powder.

Claims

1. An additive manufacturing apparatus system (10) for a complex structured workpiece (11), comprising a spatially movable powder (30) placement device (20) and an excitation unit (40); wherein the powder spreading device (20) is arranged to apply one or more powder layers (31) on the substrate table (16) or on a powder bed (32) that has been processed with the equipment system at the processing plane (15); wherein the excitation unit (40) is arranged to break up clusters and/or sticking of individual powder (30) particles to each other and/or to a powder bed (32) that has been processed with the equipment system, so that the powder spreading device (20) can apply a smooth powder layer (31) to the substrate platform and/or to a previous powder layer/powder bed (31, 32).

2. The plant system (10) according to claim 1, characterized in that the excitation unit (40) comprises a vibration unit for breaking up powder clusters and/or sticking phenomena by means of vibration excitation.

3. The device system (10) according to claim 2, characterized in that the vibration excitation is generated pneumatically and/or electromagnetically and/or by ultrasound.

4. The equipment system (10) according to claim 2 or 3, characterized in that the frequency of the vibration excitation does not overlap with the resonance frequency of the equipment system.

5. Equipment system (10) according to claim 4, characterised in that the frequency of the vibration excitation corresponds to a wavelength which is related to the particle size of the powder and/or to the powder-spreading speed of the powder-spreading device (20) in the powder-spreading direction.

6. The equipment system (10) according to claim 2, wherein the frequency of the vibration excitation is between 40Hz and 100 kHz.

7. Plant system (10) according to claim 1, characterized in that the dusting device (20) comprises a smoothing tool (21).

8. Equipment system (10) according to claim 7, characterized in that the smoothing tool (21) comprises a grinding unit, silicone grease, plastic stick, brush or metal strip.

9. The equipment system (10) according to claim 8, characterized in that the grinding unit consists of a material with a certain hardness suitable for ultrasonic grinding and/or polishing.

10. Plant system (10) according to claim 9, characterized in that the grinding unit is made of ceramic.

11. The apparatus system (10) of claim 1, wherein the excitation unit (40) is stationary relative to the powder bed (32) and/or the base platform (16).

12. The apparatus system (10) according to claim 1, wherein the excitation unit (40) is spatially movable relative to the powder bed (32) and/or the substrate platform (16).

13. Plant system (10) according to claim 12, characterized in that the dusting device (20) comprises an excitation unit (40).

14. The equipment system (10) according to claim 1, comprising a damping unit (22), the damping unit (22) being configured to reduce and/or eliminate transmission of excitation to equipment components external to the excitation unit (40).

15. Plant system (10) according to claim 14, characterized in that the dusting device (20) is fixed by means of a bracket (23) on a guide rail for performing a defined movement of the dusting device (20), the bracket (23) being designed as a damping unit (22) or as a part thereof in the case of an excitation unit (40) arranged in the dusting device (20).

16. Plant system (10) according to claim 1, characterized in that at least a portion of the powder (30) used has the characteristic of clusters and/or agglomerates and/or a profiled structure.

17. The equipment system (10) according to claim 16, wherein the particle size of the powder (30) is <20 microns and at least a portion of the powder (30) has a particle size <2 microns.

18. Plant system (10) according to claim 1, characterized by comprising a powder system (35) for supplying powder (30) from at least a first powder container (36) for a powder laying process by the powder laying device (20).

19. Equipment system (10) according to claim 18, characterised in that at least the first powder container (36) comprises a movable powder transport unit (37), which movable powder transport unit (37) transports an amount of powder into the processing plane (15) for subsequent application by the powder spreading device (20) in one or more layers of powder onto the substrate platform (16) or onto the powder bed (32) that has been treated with the equipment system.

20. Equipment system (10) according to claim 18 or 19, characterised in that the powder spreading device (20) is arranged to push residual powder (34) outside the substrate platform (16) into a powder overflow container (38) when applying the powder (30).

21. Plant system (10) according to claim 20, characterized in that the powder overflow container (38) is represented by a second powder container (39) arranged analogously to the first powder container (36), the powder spreading device (20) being arranged to alternately perform the powder spreading process from the first and second powder containers (36, 39) in respectively suitable spreading directions (25), wherein the first powder container (36) is also used as the powder overflow container (38).

22. The equipment system (10) according to claim 21, wherein the powder to be transported above the application processing plane (15) of the first and second powder containers (36, 39) is adapted to the layer thickness of the powder layer to be applied to the substrate table (16) by a factor greater than or equal to 1.2 or by an integer from among the factors 2 to 4.

23. The apparatus system (10) of claim 1, configured to satisfy a selective laser melting technique or/and an electron beam melting technique.

24. The equipment system (10) according to claim 7, wherein the powder spreading device (20) comprises a smoothing tool holder (24) configured to receive a smoothing tool (21).

25. The equipment system (10) according to claim 24, characterized in that the excitation unit (40) is arranged above the smoothing tool holder (24).

26. The equipment system (10) according to claim 24, characterized in that the smoothing tool holder (24) is designed integrally with the excitation unit (40).

27. The equipment system (10) according to claim 15, characterized in that the damping unit (22) is configured to connect the bracket (23) to the excitation unit (40).

28. A method (100) for additive manufacturing of a complex-structured workpiece of an apparatus system (10) according to claim 1, characterized in that the method comprises the steps of:

applying (110) one or more layers of powder (31) by means of a powder application device (20) onto the processing plane (15) over the substrate table (16) or over a powder bed (32) that has been treated with the equipment system (10);

excitation and breaking (120) of clustering and/or conglutination phenomena between the individual powder particles (33) and/or between the powder beds (32) that have been treated by the excitation unit (40) during at least one, preferably each, powder laying process by means of the excitation unit (40);

and (4) leveling (130) the powder layer (31) and/or the powder bed (32) by a powder spreading device (20).

29. The method according to claim 28, comprising the further step of: second troweling (140): the secondary smoothing is carried out by at least the powder spreading system (20), and after the powder layer (31) is spread, the powder spreading system is used again to move on the spread powder layer without additional powder spreading.

30. A method according to claim 28 or 29, comprising the further step of: powder container confirmation (150): the powder system (35) selects the current powder container (36, 39) to provide the required powder (30) for secondary trowelling for powder laying or powder bed repair by the powder laying device (20).

31. The method according to claim 30, comprising the further step of: powder supply (160) of the powder container: a quantity of powder is conveyed by a movable powder conveying unit (37) of the current powder container (36, 39) above the processing plane (15) for subsequent application by the powder spreading device (20) as a powder layer (31) on the substrate table (16) or on a powder bed (32) which has been treated with the system of apparatuses (10).

32. The method according to claim 31, comprising the further step of: residual powder recovery (170): the residual powder (34) applied to the outside of the substrate table (16) is pushed into a first or second powder container (36, 39) which now temporarily serves as a powder overflow container (38).

33. The method of claim 32, comprising the further step of: alternate dusting (180): the powder spreading device (20) alternately spreads powder from a first powder container (36) or a second powder container (39), and in one powder spreading process, one powder container serves as a powder supply container (36, 39) and the other powder container serves as a powder overflow container (38) in the 2 powder containers.