CN113458421B

CN113458421B - Equipment system and method for improving quality of powder bed in additive manufacturing process

Info

Publication number: CN113458421B
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: 2024-02-27
Anticipated expiration: 2041-04-30
Also published as: CN215144707U; DE102020004503A1; CN113458421A

Abstract

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

Description

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

Technical Field

The invention relates to a device for forming a workpiece with a complex structure by using a powder system through additive manufacturing technology and a processing method for forming the workpiece with the 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 focusing 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 techniques (LPBF), electron beam fusion techniques or selective laser sintering techniques. In the LPBF process, the material to be processed is deposited in powder form as a thin layer on a substrate stage by an apparatus powder laying system. The powder material is melted by laser focusing to realize partial complete melting and solidification, so as to form a near two-dimensional solid configuration. The substrate table is then lowered by a specified layer thickness (typically 20-100 μm) and is again dusted and repeatedly melted from the powder-laying 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 the production or sieving process and the particle size of the powder materials themselves. The inter-particle adhesion, in particular van der Waals forces, between powder particles can exceed their weight by several orders of magnitude. Shear force is also generated in the powder spreading process, so that powder particles have irregular surface bonding characteristics on a substrate platform, and finally, a smooth powder bed surface is difficult to obtain, so that the molding quality of a target manufactured workpiece is seriously affected.

In order to smooth the powder bed surface, a technique such as that provided by 3dmikro print, germany is to apply a powder layer on the base plate platform and then apply a contact pressure again to the upper surface of the powder bed. The U.S. 3D-Systems company uses rollers as powder spreading devices.

The disadvantage of these designs is that they are only suitable for large particle powders, which are predominantly spherical. Both for powder materials with predominantly fine powder particles (e.g. less than 20 microns) and for powder materials with profiled features caused by the production and sieving process, the phenomenon of powder clusters and sticking can lead to e.g. rollers again breaking the powder bed which has been spread smoothly. When using contact pressure, the desired forming quality effect is not achieved for fine particle powders, and the stability is insufficient, for example, when printing and manufacturing very small complex structures, the contact pressure of the upper surface of the powder bed can cause deformation of the already formed complex workpiece, deviate from the desired size requirements, and even directly cause damage to the formed workpiece in severe cases.

There is therefore a real production need to be able to promote the powder spreading effect in additive manufacturing processes taking into account the physical properties of the powder, such as size and shape.

Disclosure of Invention

The invention aims to:

it is an object of the present invention to provide an apparatus which is capable of effectively improving and guaranteeing the powder laying quality and the powder bed surface quality in an additive manufacturing process, taking at least into account 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 a complex-structured workpiece, comprising a spatially movable powder spreading device and an excitation unit. The powder spreading device is designed to spread one or more powder layers onto a substrate table in a processing plane 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 adhesions of individual powder particles to each other and/or to the powder bed that has been treated with the equipment system when applying the powder, so that the powder spreading device is able to apply a smooth powder layer to the substrate stage and/or to the previous powder bed. The exciting unit is used for generating excitation to break the interaction force among the powder particles, so that the phenomenon of clusters and/or adhesion among the powder particles is reduced, and the flowability of the powder is effectively improved. Thus, stable and high quality beam melt processing can be achieved even with small powder particles and/or powders having a shaped profile that is prone to caking. Meanwhile, the coated powder bed has a smooth surface and relatively small shearing force in the surface layer direction, so that the powder bed can be effectively prevented from being damaged in the powder laying process.

Additive manufacturing refers to arranging materials layer by layer on manufacturing equipment, processing layer by layer, and finally forming a component with a three-dimensional structure (namely 3D printing). Layer-by-layer build-up is performed by a computer controlled, fixed-point processing of one or more liquid or solid materials in a specified two-dimensional size and shape by a specific energy source. 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. The applicability of directional melting technology and related equipment systems to metal structural components in the industry is greater, including laser powder bed melting (also known as selective laser melting), electron beam melting technology, and selective laser sintering technology.

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

By "complex structured workpiece" is meant a component that is primarily of three-dimensional structure, in any application scenario. 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 parts that are not finished during production, such as parts that deform inside the powder bed during processing to produce a complex structure workpiece.

A "powder spreading device" is a system of equipment adapted to spread powder onto 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 powder spreading device 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. In the production process, the powder is coated on the substrate platform layer by layer. Each time the powder spreading device applies a "powder layer" is applied to the substrate platform (first layer) or the last powder layer that has been applied with the equipment system. The powder layer applied generally 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 equipment system (e.g. by laser processing). The powder may consist essentially of powder particles of the same material. However, a mixed powder material is also possible. The powder may vary in size, shape and particle distribution. Such 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 structured powder particles tend to agglomerate with one another.

"substrate stage" 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, the application of a subsequent powder layer on the working plane can be further achieved by moving (lowering) the powder layer after it has been applied by the powder spreading device downwards. The substrate stage is typically designed to move sealingly within a closed cell. The closing unit may be a container, wherein the container may be designed for example in the form of a cylinder. The container may be analogically designed with the powder container of the invention, wherein the substrate stage may be analogically configured with the movable powder delivery unit of the invention. However, in theory, the substrate stage may be designed to be spatially free.

An "excitation stimulus" is a phenomenon that the excitation unit emits that can be used to break up clusters and/or adhesions between powder particles to eliminate powder agglomeration. The excitation stimulus generated by the excitation unit is preferably used intermittently during the powdering process to break clusters and/or adhesions of particles to each other and/or to the powder layer that has been applied with the apparatus. The excitation unit may further be used only for smoothing a layer of powder without any smearing process taking place. The excitation of the excitation unit may be vibration, but is not limited to vibration, but may also be performed by a change in temperature, for example.

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

In one embodiment, the exciting unit may include a vibrating unit that may effectively break up clusters and/or sticking phenomena between 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 performed 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 paving device, does not need to excessively increase the volume and the weight, and does not need a lot of extra parts. The disadvantage of pneumatic excitation is the relatively low powder laying speed (about 20 mm/s) and the smoothing effect of the powder layer is inferior to ultrasonic excitation. The frequency of the pneumatic excitation may be around 200 Hz. Electromagnetic excitation has the advantage that no gas is required. Electromagnetic excitation is also technically simple and can be achieved. It has a disadvantage that it is not suitable for all metals, for example metals with ferromagnetism. The ultrasonic wave is used for excitation stimulation, has obvious advantages in powder spreading speed, and can reach more than 200 mm/s. The frequency of the ultrasonic waves may be, for example, 35 kHz, which applies to powder particles having a particle size of 2 μm (average diameter). The ultrasonic excitation powder spreading smoothing effect is particularly good. The vibration unit may be adapted to produce 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 stage (i.e. above the powder layer) so as to excite at least the uppermost powder of the powder bed that has been applied. 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 device from being damaged by 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 oscillations is frequency dependent and thus also the powder laying speed of the powder laying device, and thus the size of the individual particles corresponds to the amplitude of the oscillations. This has the advantage that the powder laying speed can be increased without losing 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 of being particularly effective for use with powders having a particle size of less than 20 microns.

In one embodiment, the powdering device further includes a smoothing tool. Smoothing means are used to physically smooth the smeared 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 rods, brushes or metal strips. Silica gel is particularly suitable for low frequency excitation because it is very soft. Plastic rods have similar advantages. While brushes are well suited for unstable processes. Metal strips are very suitable when the process is already running steadily. In an advantageous embodiment, the grinding unit comprises a material having a certain hardness, which material is suitable for ultrasonic grinding and/or polishing. Preferably, the grinding unit may be a conventional grinding stone. The hardness specificity and high stability of the material in the grinding unit are particularly suitable for excitation in a high-frequency range such as ultrasonic wave. Moreover, the conventional grindstone for physical grinding can be obtained at low cost. The grinding unit may be made of ceramic. In addition, the grinding unit may also be made of alumina or diamond.

In one embodiment, the excitation unit of the inventive apparatus system may be stationary with respect to the powder bed and/or the substrate table. This may provide structural advantages, for example, excitation stimulation may be achieved by vibrating the substrate platform when the excitation unit is connected to or integrated into the substrate platform. However, this embodiment has the disadvantage that the higher the height of the part to be machined, the less the effect of the vibration excitation. This is because when the substrate stage is vibrated, the substrate stage gradually sinks with the process, the upper space powder layer gradually increases, and the gradually thickened powder bed will slow down the excitation effect. In addition, the difficulty of the technical implementation is that the powder may flow down 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 base platform. The advantage of this embodiment is that the excitation intensity to the powder layer is not affected by the complexity and size height of the machined workpiece structure. In addition, this embodiment also allows, for example, that the powdering device can include an excitation unit. Thus, a compact constructional design can be employed.

In one embodiment, a device system according to the present invention may include a shock absorbing unit configured to reduce transmission of an excitation to a device component external to the excitation unit. The damping unit has the advantage that vibrations of the excitation unit in unfavourable directions can be damped in particular, so that the overall system of the apparatus is protected. 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 particularly important that the vibration excitation is effectively suppressed above the powder layer in relation to the direction of the axis of motion of the powder spreading device. The powder spreading device may be fixed on the guide rail by a bracket for regular movement of the powder spreading process, in which case the bracket may be designed as a damping unit or a part thereof in case the excitation unit is arranged in the powder spreading device. The support can be made of soft materials and can absorb vibration excitation well. Therefore, besides stabilizing and supporting the powder spreading device, the bracket can also have a shock absorbing function. The damping unit is advantageous for protecting the equipment and for extending the service life of the equipment.

The smoothness control of the powder layer surface is also complicated due to non-uniformity of the powder particle size and morphology. In one embodiment, the apparatus arrangement of the invention is also suitable for trowelling a powder layer if at least a part of the powder used has agglomerated and/or profiled properties. Particularly fine particles having a particle size of <20 microns are susceptible to caking. The apparatus system of the invention is therefore particularly suitable for powders having a particle size of <20 microns, wherein preferably at least a portion of the powder has a particle size of <2 microns. Non-spherical particles and/or angular and peak particles ("shaped particles") have particulate properties. The shaped powder particles are also prone to caking when the particle size is not particularly small. The particle size of the powder particles may be determined, for example, according to EN ISO 14688.

In one embodiment, the apparatus system of the present invention may comprise a powder system that provides powder from at least a first powder container, the powder laying process being carried out by a powder laying device. At least the first powder container comprises a movable powder delivery unit that delivers a quantity of powder to a processing plane (e.g. a beam focusing plane) for subsequent application of the powder by a powder spreading device in one or more powder layers onto a substrate stage or onto a powder bed that has been processed with the equipment system. In another embodiment, the powder spreading device may push the residual powder after the powder spreading in the substrate stage area is completed into the powder overflow container. The powder overflow container may temporarily be served by the first powder container or the second powder container. The powder spreading device may 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 or second powder container, which is not used as the powder supply container, may serve as the temporary powder overflow container. The advantage of this is that the efficiency of use of the powder is greatly improved. The powder to be transported above the working plane of the powder container can be subjected to a coefficient adaptation with the layer thickness of the powder to be applied to the substrate platform, the adaptation coefficient being greater than or equal to 1.2, or a coefficient of 2, particularly preferably a coefficient of 3 or 4. The powder container may be in the form of a cylinder. The powder container and the substrate platform (or the container comprising the substrate platform) may be arranged directly adjacent.

In one embodiment, the device system of the present invention 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 shaped structure. The smooth powder bed surface is particularly advantageous for the quality of the shaping of the machined part (complex structured workpiece).

The powder spreading device in the additive manufacturing system for the workpieces with complex structures can further optimize the quality of a powder bed. Wherein the powder spreading device is arranged to spread one or more powder layers onto the substrate table or onto a powder bed which has been treated with the equipment system by means of a spatial movement on the processing plane. The powder spreading device further comprises an excitation unit arranged to break up clusters and/or adhesions of powder particles to each other and/or to the powder bed that has been applied with the apparatus during the powder spreading process, thereby enabling the powder spreading device to apply/planarize a smooth powder layer or powder bed onto the substrate stage and/or onto a previous powder bed. The arrangement of the stimulation unit in the powder spreading device allows for a precise and local stimulation of the powder particles during the trowelling process (at least during the powder spreading process). Of course, the powder spreading device may also perform secondary trowelling of the powder layer or powder bed without spreading the powder (i.e., the powder spreading device performs empty spreading). This arrangement allows a smooth powder spreading effect and a smooth powder bed surface to be achieved, in particular by a suitable choice of parameters, such as the frequency of the excitation unit.

The powder spreading device according to the invention enables a smooth spreading of the powder to be achieved in the additive manufacturing process, which takes at least into account the 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 clusters and/or sticking phenomena of the powder particles 33 to each other. The vibration excitation may be generated pneumatically and/or electromagnetically and/or ultrasonically. The vibration frequency cannot coincide with the resonant frequency of the device so as not to damage the device. Furthermore, the frequency of the oscillation may have a wavelength related to the grain size of the powder and/or a wavelength related to the moving speed of the powder spreading device in the powder spreading 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 magnitude of the oscillation amplitude, and therefore the frequency of the oscillations needs to be suitably optimized. The advantage of this is that the powder spreading speed can be increased without reducing the powder spreading effect. Therefore, the production efficiency can be improved by the present embodiment. Preferably, the frequency of the excitation may be between 40Hz and 100 kHz.

In one embodiment, the powdering device according to the present invention further comprises a smoothing tool, preferably comprising a grinding unit, a silicon lip, a plastic rod, a brush and/or a metal strip. It is particularly preferred that the grinding unit consists of a material with a certain hardness which is suitable for ultrasonic grinding and/or polishing, wherein it is more preferred that the grinding unit is a conventional grinding stone, which may particularly preferably be made of ceramic. The hardness specificity and high stability of the material in the grinding unit are particularly suitable for excitation in a high-frequency range such as ultrasonic wave. The grinding unit may also be made of alumina or diamond.

In another embodiment, the powdering device may include 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 grinding stone) on the powdering device. The smoothing tool holder may be configured to slide the smoothing tool in its holder. Depending on the configuration, if the excitation unit is arranged above the smoothing tool holder, the smoothing tool holder may also serve as a damping unit. In this case, it is advantageous if the smoothing tool holder is composed of a soft material which provides good absorption and damping of vibrations. In an advantageous embodiment, the smoothing tool holder may be integrated into the excitation unit. This allows a more compact design and possibly increases the damping effect.

In one embodiment, the powder spreading device according to the present invention may comprise a damping unit for reducing or eliminating the transmission of excitation from the excitation unit to other external components. In another embodiment, the powdering device according to the present invention may include a bracket provided for securing the powdering device to the rails to perform regular movements of the powdering device, wherein, more preferably, the bracket is configured to dampen or be part of. The damping unit may be configured to assume the functions of the connection bracket and the excitation unit. The support may be made of a soft material particularly suitable for absorbing vibration excitations. This may be a combination of a polymer and/or rubber and metal. Therefore, besides stabilizing and supporting the powder spreading device, the support can also have an effective damping function, so that the whole powder spreading device is more compact.

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

According to the invention, an additive manufacturing method of a complex-structured workpiece comprises a spatially movable powder spreading device for powder and an excitation unit, the method comprising the following steps: applying one or more powder layers on a processing plane above a substrate platform or above a powder bed which has been treated with the equipment system by a powder spreading device; during at least one powder application, preferably during each powder application, the clusters and/or sticking phenomena of the individual powder particles to each other and/or to the powder bed which has been treated by the stimulation unit are stimulated and broken up by the stimulation unit; and trowelling the powder layer and/or the powder bed by a powder paving device.

The invention herein provides a method of achieving a smooth powder bed in an additive manufacturing process that 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 powder spreading 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, namely at least a secondary trowelling process by a powder spreading device which, after the application of the upper powder layer, is moved again over the already applied powder layer without a new powder spreading. This has the advantage that a secondary trowelling can be achieved without the need to apply the powder again.

According to the invention, the method according to the invention comprises the further step of providing powder from at least a first powder container of the powder system for laying or repairing the powder bed by the powder laying device (also referred to as performing a secondary trowelling process without changing the height of the powder bed), whereby a smoother powder bed surface is possible. In a further embodiment, the method according to the invention comprises the further step of transporting a quantity of powder above the processing plane by means of a movable powder transport unit of the first or second powder container, which currently temporarily serves as a powder supply container, in order to subsequently spread the quantity of powder as a powder layer by a powder spreading device on the substrate platform or on the powder bed which has been processed with the equipment system. In addition, the method according to the invention may further comprise the step of pushing excess powder through the powder spreading device into the first or second powder container, which currently temporarily acts as a powder overflow container, when the powder is applied outside the substrate stage. Preferably, the method according to the invention may comprise the further step of alternating the powder laying process from the first powder container or the second powder container by the powder laying device, one of the 2 powder containers acting as temporary powder supply container and one as temporary powder overflow container during one powder laying process.

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

The above-described features of the present invention may be combined with each other as much as possible even if not described in detail above.

Drawings

FIG. 1 a) shows one embodiment of a powder paving process of the powder paving apparatus of the facility system of the present invention; b) A side view of a) is shown.

Fig. 2 a) shows an embodiment of the powdering device and excitation unit of the apparatus system of the present invention; 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 a further embodiment of the method of the invention.

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

Fig. 7 a) shows a graph of the actual effect of the powder layer after the powder is applied by other conventional methods; b) A smooth powder layer is shown after the powder spreading device of the equipment system according to the invention has been smoothed.

Detailed Description

Embodiments of the invention are described in detail below, without prejudgement, in particular without limitation, with reference to fig. 1 to 7. Identical elements are provided with identical reference numerals, unless otherwise specified.

Fig. 1 a) shows the situation of the apparatus system 10 according to the invention when laying powder 30 by means of the powder laying device 20. The inventive system 10 is suitable for additive production of workpieces 11 of complex construction, comprising a spatially movable powder-spreading device 20 for the 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 stage 16 on the processing plane 15 or to a previous powder bed 32 that has been processed.

The activation unit 40 is arranged to break up clusters and/or adhesions of powder particles 33 to each other and/or to the powder bed 32 that has been applied with the device, thereby enabling the powder spreading device 20 to apply/planarize a smooth powder layer 31 or powder bed 32 onto the substrate stage 16 and/or onto a previous powder bed 32.

In the present embodiment, the powder spreading device 20 is configured as follows (from top to bottom): the powdering device 20 of the facility system 10 includes a carriage 23, the carriage 23 being fixed to the rail to effect regular movement of the powdering device 20. Since the excitation unit 40 is arranged within the powdering device 20 in the present embodiment, the support 23 may be replaced in whole or in part with the shock absorbing unit 22.

Further, the present embodiment includes a damper unit 22, and the damper unit 22 serves to reduce or eliminate transmission of excitation from the excitation unit 40 to other external components. The damping unit 22 may 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. The powder paving apparatus 20 includes an excitation unit 40, the excitation unit 40 being spatially movable relative to the powder bed 32 and/or the substrate stage 16.

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

The embodiment shown comprises a smoothing tool 21, which may be a grinding unit, a silicone grease, a plastic rod, a brush and/or a metal strip. The material of the grinding unit should have a certain 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 placement device 20 applies one or more powder layers 31 to the substrate stage 16 (if it is the first layer) or else to a previous powder bed 32 that has been applied by the apparatus, wherein the powder bed 32 that has been applied by the apparatus also includes the complex-structured workpiece 11 that has been previously shaped.

Fig. 1 b) shows a side view of fig. 1 a), wherein the powder spreading device 20 of the inventive apparatus system 10 moves in the powder spreading direction 25 during the powder spreading process. The powder spreading device is moved with a defined movement speed over the powder bed 32 or the substrate table 16 which has been processed by the apparatus system 10, during which pneumatic and/or electromagnetic and/or ultrasonic vibration excitations are generated, so that clusters and/or adhesions of individual powder particles 33 with respect to each other are broken up. But the vibration frequency cannot coincide with the resonant frequency of the device so as not to damage the device. The break-up occurs both on the powder 30, the powder layer 31 and the powder bed 32 that has been processed by the apparatus system 10 and between them. 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 20 in the powder spreading 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, a particular feature of the device system 10 according to the invention compared to the prior art is that it still allows a smooth powder spreading effect in case the particle size of the powder 30 used is less than 2 microns.

Fig. 2 a) shows a powder spreading device 20 according to the present invention for an apparatus system 10 for complex-structured workpiece additive manufacturing process technology, wherein the powder spreading device 20 is arranged to spread one or more powder layers 31 in a processing plane 15 onto a substrate table 16 or a powder bed 32 which has been processed with the apparatus system 10 by means of a spatial movement. The powder spreading device 20 further comprises an activation unit 40, which activation 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 equipment system 10 during the powder spreading process, so that the powder spreading device 20 is able to spread a smooth powder layer 31 onto the substrate stage 16 and/or onto the previous powder bed 32.

Fig. 2, b) is an embodiment of a side view of the powder spreading device 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 vibrating unit can be designed in analogy to the vibrating units of a) and b) in fig. 1. Also similar to the embodiment of fig. 1 a) and b), the powdering device 20 may be configured 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 spreading device 20 further comprises a damping unit 22, which damping unit 22 serves to reduce or eliminate the transmission of excitation by the excitation unit 40 to other components outside. The damping unit 22 may be disposed on at least two sides of the exciting unit 40 to dampen vibration and communicate the smoothing tool holder 24 with another 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 prescribed 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 further 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 providing powder 30 from at least a first powder container 36, the powder laying process being carried out by a powder laying device 20. At least the first powder container 36 comprises a movable powder transport unit 37, which movable powder transport unit 37 transports a quantity of powder to the processing plane 15 (e.g. the beam focusing plane) for subsequent application of the powder by the powder spreading device 20 as one or more powder layers 31 onto the substrate stage 16 or onto the powder bed 32 which has been processed with the equipment system. Residual powder 34 is pushed out of substrate stage 16 after powder placement and collected in a powder overflow container 38 (not shown).

Fig. 3 b) illustrates an embodiment of a powder system 35 in which both a first powder container 36 and a second powder container 39, which are similarly configured, 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 suitable powder spreading directions 25. Above the working plane 15 of the powder container 36, 39, the powder to be transported can be adapted by a factor to the layer thickness of the powder layer to be applied to the substrate stage 16, the adaptation factor being 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 powder use is greatly increased by the use of this powder system 35, because the residual powder after the end of each powder laying process can continue to be subjected to the first or second powder container 36, 39, which serves as a temporary powder overflow container 38.

Fig. 4 shows a process 100 of the device according to the invention, comprising a spatially movable powder spreading device 20 and an excitation unit 40. The method comprises the following steps: powder 110, by means of which one or more powder layers 31 are applied above the substrate table on the processing plane 15 or above the powder bed 32 which has been treated with the apparatus system 10; the stimulation and disruption 120, during at least one powder application, preferably during each powder application, by the stimulation unit 40, disrupting clusters and/or adhesions of individual powder particles 33 to each other and/or to the powder bed 32 which has been treated by the stimulation unit 40; trowelling 130, leveling process is performed on powder layer 31 and/or powder bed 32 by powder paving apparatus 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 trowelling 140, at least the secondary trowelling 140 performed by the powder spreading system 20, wherein after the powder layer 31 is smeared, the powder spreading system is utilized to move on the smeared powder layer 31 (also known as the current powder bed 32) again, 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, further, this embodiment includes selecting a determined current powder container 36 or 39 from powder system 35 to provide powder for secondary trowelling as may be needed for powder placement or repair of the powder bed by powder placement device 20; the powder container supply 160, the further step further comprises delivering a quantity of powder above the processing plane 15 by means of the movable powder delivery unit 37 of the current powder container 36 or 39, in order to subsequently spread the quantity of powder as a powder layer 31 by the powder spreading device 20 onto the substrate stage 16 or onto the powder bed 32 which has been processed with the apparatus system 10; residual powder recovery 170, in addition, the method includes pushing residual powder 34 applied outside of substrate stage 16 into first or second powder container 36, 39, which is currently temporarily acting as powder overflow container 38; alternate laying 180, a further step includes alternating laying by the laying device 20 from either the first 36 or second 39 powder containers, one of the 2 powder containers acting as a powder supply container and one acting as a powder overflow container 38 during a single laying.

Fig. 6 a) shows a front view of an embodiment of the device system 10 according to the invention. Fig. 6 b) illustrates an embodiment of the powder system 25 of the present invention including a first powder container 36 and a second powder container 39, which may alternately serve as a powder supply container 33 and a powder overflow container 38, and a container including a substrate stage 16 (not shown), the powder system 25 being integrated into the apparatus system 10 of the present invention to increase the utilization efficiency of the powder.

Fig. 7 a) shows a physical image of the powder layer (or also referred to as "powder bed 32") 31 after powder is spread by a general powder spreading process, the powder spreading effect is poor, and the powder layer is not smooth. Fig. 7-b) shows a physical view of the powder bed 32 after the powder layer 31 or powder bed 32 has been successfully smoothed in the plant system 10 using the powder spreading device 20 according to the invention.

The foregoing embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the present invention and to implement the same according to the present invention, not to limit the scope of the present invention. All changes and modifications that come within the meaning and range of equivalency of the invention are to be embraced within their scope.

Figure number notes:

10. the equipment system of the invention

11. Workpiece with complex structure

15. Plane of working

16. Substrate platform

20. Powder spreading device

21. Smoothing tool

22. Shock absorbing unit

23. Support frame

24. Smoothing tool support

25. Powder spreading direction

30. Powder

31. Powder layer

32. The powder layer (previous powder bed) being applied before

33. Powder particles

34. Residual powder

35. Powder system

36. First powder container (also referred to as first powder supply container)

37. Movable powder conveying unit

38. Powder overflow container

39. A second powder container (also referred to as a second powder supply container)

40. Excitation unit

100. The operation method of the invention

110 … steps of the method of operation of the invention

110. Powder paving

120. Excitation and breaking up

130. Trowelling up

140. Secondary trowelling

150. Powder container confirmation

160. Powder container for supplying powder

170. Collecting residual powder

180. And (5) alternately laying powder.

Claims

1. Additive manufacturing equipment system (10) for complex structured workpieces (11), characterized by comprising a spatially movable powder (30) laying device (20), an excitation unit (40) and a damping unit (22); wherein the powder spreading device (20) is arranged to spread one or more powder layers (31) onto the substrate table (16) or onto a powder bed (32) which has been treated with the equipment system at the processing plane (15); wherein the excitation unit (40) is arranged to break up clusters and/or adhesions of individual powder (30) particles to each other and/or to the powder bed (32) that has been treated with the equipment system, so that the powder spreading device (20) is capable of spreading a smooth powder layer (31) onto the substrate table and/or onto a preceding powder layer/powder bed (31, 32); wherein the damping unit (22) is configured to reduce and/or eliminate transmission of the excitation to equipment components external to the excitation unit (40);

the excitation unit (40) comprises a vibration unit for breaking up powder clusters and/or sticking phenomena by vibration excitation; wherein the vibration excitation is generated pneumatically and/or electromagnetically and/or ultrasonically; the frequency of the vibration excitation has a wavelength related to the particle size of the powder and/or to the powder laying speed of the powder laying device (20) in the powder laying direction and does not overlap with the resonance frequency of the equipment system.

2. The equipment system (10) according to claim 1, wherein the frequency of vibration excitation is between 40Hz and 100 kHz.

3. The plant system (10) according to claim 1, wherein the powder spreading device (20) comprises a smoothing tool (21).

4. A plant system (10) according to claim 3, characterized in that the smoothing tool (21) comprises a grinding unit, silicone grease, a plastic rod, a brush or a metal strip.

5. The equipment system (10) according to claim 4, characterized in that the grinding unit consists of a material with a certain hardness that is suitable for ultrasonic grinding and/or polishing.

6. The equipment system (10) according to claim 5, wherein the grinding unit is made of ceramic.

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

8. The apparatus system (10) of claim 1, wherein the excitation unit (40) is spatially mobile relative to the powder bed (32) and/or the substrate table (16).

9. The plant system (10) according to claim 8, wherein the powder spreading device (20) comprises an excitation unit (40).

10. The plant system (10) according to claim 1, characterized in that the powder spreading device (20) is fixed by means of a bracket (23) to a guide rail for carrying out a defined movement of the powder spreading device (20), the bracket (23) being designed as a damping unit (22) or as part thereof in the case of an excitation unit (40) arranged in the powder spreading device (20).

11. The plant system (10) according to claim 1, characterized in that at least a part of the powder (30) used has the characteristics of clusters and/or agglomerates and/or profiled structures.

12. The equipment system (10) of claim 11, wherein the particle size of the powder (30) is <20 microns and the particle size of at least a portion of the powder (30) is <2 microns.

13. The plant system (10) according to claim 1, comprising a powder system (35) for providing powder (30) from at least a first powder container (36) for a powder laying process by the powder laying device (20).

14. The equipment system (10) according to claim 13, characterized in that at least the first powder container (36) comprises a movable powder delivery unit (37), which movable powder delivery unit (37) delivers a quantity of powder into the processing plane (15) for subsequent application by the powder spreading device (20) as one or more powder layers onto the substrate platform (16) or onto the powder bed (32) which has been processed with the equipment system.

15. The apparatus system (10) according to claim 13 or 14, wherein the powder spreading device (20) is arranged to push residual powder (34) outside the substrate platform (16) into the powder overflow container (38) when applying the powder (30).

16. The plant system (10) according to claim 15, characterized in that the powder overflow container (38) is represented as a second powder container (39) which is configured analogically 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 powder spreading directions (25), wherein the first powder container (36) is also used as powder overflow container (38).

17. The apparatus system (10) of claim 16, wherein above the application process plane (15) of the first and second powder containers (36, 39), the powder to be delivered is coefficient-adapted to the 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 an integer of a factor of 2 to 4.

18. The equipment system (10) according to claim 1, characterized in that it is configured to satisfy selective laser melting technology or/and electron beam melting technology.

19. An equipment system (10) according to claim 3, characterized in that the powdering device (20) comprises a smoothing tool holder (24) configured to house a smoothing tool (21).

20. The equipment system (10) according to claim 19, wherein the excitation unit (40) is arranged above the smoothing tool holder (24).

21. The equipment system (10) according to claim 19, characterized in that the smoothing tool holder (24) is designed integrally with the excitation unit (40).

22. The device system (10) of claim 10, wherein the shock absorbing unit (22) is configured to connect the bracket (23) to the excitation unit (40).

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

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

the stimulation and disruption (120) is such that during at least one powder application, preferably during each powder application, clusters and/or adhesions of individual powder particles (33) to each other and/or to the powder bed (32) which has been treated by the stimulation unit (40) are disrupted by the stimulation unit (40);

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

24. The method of claim 23, comprising the further step of: second trowelling (140): at least the secondary trowelling by the powder spreading system (20), after the powder layer (31) is applied, the powder spreading system is used again to move over the applied powder layer without additional powder application.

25. The method according to claim 23 or 24, comprising the further step of: powder container confirmation (150): a powder system (35) selects a current powder container (36, 39) to provide the required powder (30) for secondary trowelling for powder laying or repair of the powder bed by a powder laying device (20).

26. The method of claim 25, comprising the further step of: powder container powder supply (160): a quantity of powder is transported above the processing plane (15) by means of a movable powder transport unit (37) of the current powder container (36, 39) in order to be subsequently applied as a powder layer (31) by a powder spreading device (20) onto the substrate platform (16) or onto the powder bed (32) which has been processed with the equipment system (10).

27. The method of claim 26, comprising the further step of: residual powder recovery (170): residual powder (34) applied outside the substrate stage (16) is pushed into the first or second powder container (36, 39) which now temporarily serves as a powder overflow container (38).

28. The method according to claim 27, comprising the further step of: powder (180) is alternately paved: powder is alternately spread from a first powder container (36) or a second powder container (39) by a powder spreading device (20), and one of the 2 powder containers serves as a powder supply container (36, 39) and the other serves as a powder overflow container (38) in one powder spreading process.