Multi-station powder dispensing and forming apparatus and method

Abstract

The application relates to the technical field of material preparation equipment, and provides a multi-station powder powder preparation and forming device and a multi-station powder gradient powder preparation and forming method.The device comprises a powder conveying mechanism, a powder laying mold assembly, a powder preparation execution mechanism and a control system.The powder conveying mechanism comprises a spiral discharging assembly and a piston pushing assembly.The powder laying mold assembly comprises a forming cavity array, a support plate and a flexible anti-sticking layer, the support plate is internally provided with a vacuum channel and a micropore array to adsorb the flexible anti-sticking layer through negative pressure.The control system is configured to execute a time-space separation powder preparation strategy, and control the powder preparation execution mechanism to move according to a preset path and to drop powder according to a layering time sequence.The application realizes high-precision conveying of trace powder, non-adhesion forming and high-fidelity construction of composition gradient.

Description

Technical Field

[0001] This application relates to the field of material preparation equipment technology, specifically to a multi-station powder mixing and forming device and a multi-station powder gradient mixing and forming method. Background Technology

[0002] Currently, in the field of materials preparation equipment technology, traditional materials research and development typically employs a trial-and-error approach, which suffers from problems such as low powder mixing accuracy, low sample throughput, weak parallel screening capability for process parameters, long development cycles, and high costs. Existing technologies, such as Chinese patent application CN120572000A, disclose a high-throughput materials preparation system that achieves automated sample transport and processing; and Chinese patent application CN122231274A discloses a multi-channel powder dispensing device that improves powder dispensing efficiency. However, the existing solutions still have significant drawbacks when handling trace powders: on the one hand, traditional powder conveying mechanisms mostly use gravity feeding or simple screw feeding, lacking precise mechanical linkage and reset mechanisms, resulting in low conveying accuracy of milligram-level trace powders and susceptibility to powder agglomeration; on the other hand, existing molding dies are mostly in rigid contact, making it easy for trace powders to adhere to the die surface, causing not only difficulty in demolding but also cross-contamination between different batches or different workstations; furthermore, when performing multi-layer gradient powder mixing, existing equipment lacks effective spatiotemporal isolation control strategies, and powders of different components are prone to interlayer mixing during the spreading process, leading to distortion of the preset component gradient and seriously affecting the accuracy and reliability of materials genome engineering data. Therefore, there is an urgent need for a multi-station powder mixing and molding device that can simultaneously achieve precise micro-volume conveying, non-adhesive molding, and high-fidelity gradient construction. Summary of the Invention

[0003] To address the problems of low precision in micro-powder delivery, easy adhesion and contamination of molds, and interlayer mixing of gradient powders in existing technologies, this application achieves high-precision quantitative delivery of micro-powders, flexible and non-stick molding without cross-contamination, and spatiotemporal separation construction of component gradients through a multi-station powder mixing and molding device and a multi-station gradient powder mixing and molding method.

[0004] To achieve the above objectives, this application adopts the following technical solution: A multi-station powder dispensing and forming device includes a powder conveying mechanism, a powder spreading mold assembly, a powder dispensing execution mechanism, and a control system; The powder conveying mechanism includes a screw discharge assembly and a piston pusher assembly. The piston pusher assembly is configured to drive the screw discharge assembly to rotate during the advance to output powder, and to reset by an elastic reset member during the return stroke. The powder spreading mold assembly includes a molding cavity array, a support plate, and a flexible anti-stick layer. The support plate has a vacuum channel inside and a micropore array communicating with the vacuum channel on its surface. The micropore array is configured to adsorb the flexible anti-stick layer by negative pressure to cover the bottom of the molding cavity array. The control system is configured to execute a spatiotemporal separation powder distribution strategy: control the powder distribution execution mechanism to move along a preset spatial path, and control the powder conveying mechanism to drop powder onto the forming cavity array according to a preset layering sequence.

[0005] The above solution transforms linear motion into rotary quantitative dispensing through the mechanical linkage of the spiral discharge assembly and the piston pusher assembly. Combined with the automatic return of the elastic reset component, it eliminates the impact of transmission gaps on the accuracy of micro-feeding. The negative pressure generated by the vacuum channel and micropore array in the support plate ensures that the flexible anti-stick layer adheres tightly to the bottom of the molding cavity. By utilizing the low surface energy characteristics and physical adsorption of the flexible material, the problem of micro-powder sticking to the mold and residual contamination is fundamentally solved. The spatiotemporal separation powder distribution strategy executed by the control system physically isolates powders of different components in terms of spatial path and temporal sequence, avoiding interlayer mixing during the multi-layer gradient powder spreading process and ensuring high fidelity of the component gradient.

[0006] In one embodiment, the support plate further includes a substrate layer and a sealing layer, a vacuum channel is disposed inside the substrate layer, and the micropore array penetrates the sealing layer and communicates with the vacuum channel; The support plate is also connected to a negative pressure generating unit, which is configured to generate negative pressure in the vacuum channel so that the flexible anti-adhesive layer adheres to the surface of the sealing layer and seals the micropore array.

[0007] This preferred solution, through the structural design of the substrate layer and the sealing layer, not only ensures the structural strength and airtightness of the vacuum channel, but also facilitates the precision processing and maintenance of the microporous array; the continuous negative pressure provided by the negative pressure generating unit ensures that the flexible anti-adhesive layer remains flat and adhered during the powder spreading and tableting process, preventing uneven sample thickness or molding defects caused by wrinkling of the flexible anti-adhesive layer.

[0008] In one embodiment, the powder spreading mold assembly further includes a mold sleeve plate and a base. The mold sleeve plate has a plurality of through holes arranged in a matrix, and the plurality of through holes and the support plate together define the molding cavity array. The base is slidably connected to the mold plate via a slide rail mechanism. The base is equipped with multiple drive cylinders, which are arranged diagonally below the support plate and configured to synchronously drive the support plate to rise and fall relative to the mold plate.

[0009] This preferred solution effectively counteracts the off-center load torque that may be generated by unilateral drive by using multiple diagonally arranged drive cylinders to lift the plate in a coordinated manner, thus ensuring the parallelism and stability of the support plate during the lifting process under heavy load, thereby ensuring that the forming density of all stations is uniform.

[0010] In one embodiment, the powder conveying mechanism further includes a conveying cavity, the spiral discharge assembly is disposed inside the conveying cavity, and the outer surface of the spiral discharge assembly is provided with a spiral groove; The piston feeding assembly includes a piston rod and a limiting pin. The linear pushing motion of the piston rod is converted into the rotational motion of the spiral discharging assembly through the limiting pin, so as to quantitatively discharge the powder contained in the spiral groove. The elastic reset element is a compression spring sleeved on the outer periphery of the spiral discharge assembly. The conveying cavity has a stepped hole at one end near the piston rod. The elastic reset element is a compression spring sleeved on the outer periphery of the spiral discharge assembly and located in the stepped hole. It is configured to drive the spiral discharge assembly to return when the propulsive force is removed.

[0011] This preferred solution utilizes the volumetric quantitative principle of the spiral groove, combined with the motion conversion of the gear set, to achieve a precise linear correspondence between the powder conveying volume and the piston stroke; the constant restoring force provided by the compression spring eliminates the mechanical backlash, ensuring the repeatability and positioning accuracy of continuous cyclic conveying.

[0012] In one embodiment, the powder conveying mechanism further includes a powder storage chamber and a rotary stirring system, wherein the bottom of the powder storage chamber tapers in a conical shape and communicates with the conveying chamber; The rotary stirring system includes a drive motor and a stirring rod. The stirring rod extends into the powder storage chamber, and the surface of the stirring rod is provided with multiple sets of branch structures, configured to break up powder agglomerates during rotation to prevent bridging and clogging.

[0013] This preferred design, through the action of the conical bottom structure and the multi-branched stirring rod, disrupts the van der Waals force agglomeration and arching effect between powder particles, ensuring the fluidity and looseness of the powder before entering the conveying cavity, thus providing a stable material basis for subsequent micro-precision conveying.

[0014] As one implementation method, the process of the control system executing the spatiotemporal separation powder distribution strategy includes: The molding cavity array is divided into multiple powder-spreading areas, and a preset spatial traversal path is generated that traverses all the powder-spreading areas. In each powder layer, the powder dispensing mechanism is controlled to move along the preset spatial traversal path, and the powder conveying mechanism is triggered to perform a single powder dropping action when it reaches each powder layer area. After all powder-spreading areas of the current powder-spreading layer have been covered with powder, the powder-spreading layer number is updated and the powder-spreading action of the next powder-spreading layer is repeated to achieve physical isolation between layers of powders with different components.

[0015] This preferred scheme discretizes continuous gradient changes into independent powder spreading actions layer by layer and region by region, cutting off the exposure window of different component powders in the time dimension and establishing a clear interlayer interface in the spatial dimension, thereby achieving high-resolution component gradient construction.

[0016] As one embodiment, it also includes a tableting unit, which includes an upper pressure plate, a lower pressure plate, and multiple pressure heads; Multiple pressure heads are evenly distributed on the bottom surface of the lower pressure plate, and each pressure head has a boss structure on its bottom surface, configured to synchronously press multiple forming cavities in the forming cavity array under hydraulic drive.

[0017] This preferred solution combines rotary indexing with a multi-head synchronous pressing structure to achieve parallel operation of the tableting and powder preparation processes, significantly improving the production throughput. The boss structure design ensures that the pressure can be transmitted vertically and evenly to each molding cavity, avoiding the density difference of the preform caused by the edge effect.

[0018] As one implementation, a precision weighing unit is also included, which includes a single-axis slide rail and an electronic balance; The electronic balance is slidably mounted on the single-axis slide rail and is configured to move along the single-axis slide rail to the material taking area of ​​the powder dispensing execution mechanism after receiving the powder output by the powder conveying mechanism and completing the quantitative weighing.

[0019] This preferred solution integrates weighing and transfer functions into the same motion module, reducing intermediate steps and spillage risks during material transfer, and achieving a seamless connection from micro-volume delivery to precise powder dispensing.

[0020] Furthermore, this application also provides a multi-station powder gradient mixing and forming method, applied to the multi-station powder mixing and forming apparatus described above, comprising the following steps: S100: The piston pushing assembly of the powder conveying mechanism drives the screw discharge assembly to rotate, so as to output the powder in a quantitative manner; S200: A flexible non-stick layer is laid on the surface of the support plate of the powder spreading mold assembly, and the flexible non-stick layer is adsorbed and adhered to the bottom of the molding cavity array by the negative pressure generated by the negative pressure generating unit in the micropore array. S300: Control the powder dispensing mechanism to move according to the preset spatial traversal path, and control the powder dispensing mechanism to dispense powder to the forming cavity array according to the preset layering sequence to construct a gradient powder layer; S400: Perform synchronous pressing on the forming cavity array after the powder has been dispensed to form a powder blank.

[0021] The above method transforms the mechanical advantages of the device into actual preparation efficiency through hardware and software collaborative process timing control. While ensuring the accuracy of micro-powder delivery and the anti-sticking performance of the mold, it ensures the repeatability and data consistency of gradient material preparation through standardized spatiotemporal separation operation procedures.

[0022] As one implementation method, step S300 specifically includes: S310: Set the speed of the powder dispensing actuator to match the rotation frequency of the screw discharge assembly to ensure that the amount of powder dispensed in a single pass meets the preset thickness requirement; S320: When the powder dispensing actuator reaches above the target powder spreading area, the negative pressure generating unit is triggered to start. The vacuum response time of the negative pressure generating unit is less than the powder falling duration of the powder dispensing actuator, and the negative pressure value generated by the negative pressure generating unit increases as the powder particle size decreases, so as to prevent the powder from flying before adsorption and bonding. S330: After completing the powder application in all powder application areas of the current powder layer, control the powder distribution actuator to raise the preset height along the Z-axis, update the powder layer sequence number, and then execute the powder application action of the next powder layer, wherein the preset height is greater than the compaction thickness of a single layer of powder.

[0023] This preferred scheme establishes a closed-loop synergistic relationship between powder drop volume, adsorption force, and interlayer spacing through dynamic matching of motion parameters and negative pressure parameters. This effectively suppresses the flying and rebound of fine powder, ensuring the clarity of the gradient interface and the accuracy of layer thickness control.

[0024] Beneficial effects: 1. This application utilizes a linkage mechanism that drives the rotation of the spiral discharge assembly through the piston pusher assembly, combined with the automatic return of the elastic reset component, to transform the traditional continuous feeding into discrete volumetric quantitative conveying. This eliminates the coupling effect of mechanical transmission gaps and powder flow fluctuations on conveying accuracy, achieving high-precision and high-repeatability output of milligram-level micro powders, and providing a reliable material basis for high-throughput material screening.

[0025] 2. This application utilizes the negative pressure generated by the vacuum channel inside the support plate and the micropore array on the surface to enable the flexible anti-stick layer to actively adsorb and tightly adhere to the bottom of the molding cavity, thus constructing a dual anti-stick system of "flexible interface + physical adsorption". This structure not only utilizes the low surface energy characteristics of flexible materials to reduce powder adhesion, but also eliminates the gap between the film and the mold through negative pressure adsorption, avoiding the problems of difficult demolding and residual contamination of traditional rigid molds, and significantly improving the purity of the sample and the molding yield.

[0026] 3. This application uses a spatiotemporal separation powder distribution strategy executed by the control system to discretize the continuous gradient construction process into independent powder spreading actions layer by layer and region by region, establishing physical isolation barriers between powders of different components in the temporal and spatial dimensions. This method fundamentally blocks the interlayer diffusion and mixing paths, so that the component gradient resolution is no longer limited by the natural diffusion coefficient of the powder, but is determined by the motion control precision of the equipment, thereby realizing high-fidelity, programmable component gradient material preparation.

[0027] 4. This application integrates functional units such as precision weighing, micro-volume delivery, anti-stick molding, and synchronous tableting, and realizes full-process automation and collaboration through a unified control system; the seamless connection and parameter matching between units not only significantly shorten the preparation cycle of a single batch of samples, but also eliminate the random errors introduced by manual operation, meeting the urgent need of materials genome engineering for massive and high-quality experimental data. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall layout structure of the multi-station powder mixing and forming device according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the powder spreading mold assembly and the tableting unit according to an embodiment of this application; Figure 3 This is a cross-sectional view of the powder spreading mold assembly according to an embodiment of this application; Figure 4 yes Figure 3 A partial schematic diagram of A in the middle; Figure 5 This is a schematic diagram of the overall structure of the powder conveying mechanism according to an embodiment of this application; Figure 6 This is a partial structural schematic diagram of the powder conveying mechanism according to an embodiment of this application; Figure 7 yes Figure 6 A sectional view; Figure 8 yes Figure 7 A partial schematic diagram of B in the diagram; Figure 9 This is a schematic diagram of the tablet compression unit according to an embodiment of this application; in: 100 - Powder conveying mechanism; 110 - Screw discharge assembly; 120 - Piston pusher assembly; 121 - Piston rod; 122 - Limit pin; 130 - Conveying chamber; 140 - Elastic reset element; 150 - Powder storage chamber; 160 - Rotary stirring system; 200-Powder spreading mold assembly; 210-Forming cavity array; 220-Support plate; 221-Vacuum channel; 222-Micropore array; 223-Substrate layer; 224-Sealing layer; 230-Mold sleeve plate; 240-Base; 250-Drive cylinder; 300 - Powder mixing execution mechanism; 400 - Tableting unit; 420 - Upper pressure plate; 430 - Lower pressure plate; 440 - Pressure head; 500 - Precision weighing unit; 510 - Single-axis slide rail; 520 - Electronic balance. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0031] Example 1 like Figure 1 As shown, this embodiment provides a multi-station powder dispensing and forming device. The device mainly includes a powder conveying mechanism 100, a powder spreading mold assembly 200, a powder dispensing execution mechanism 300, and a control system. These modules are spatially arranged in a circular or linear array, collectively forming an automated preparation platform integrating micro-volume conveying, precision weighing, gradient powder spreading, and forming. It should be understood that although... Figure 1 One specific spatial layout is shown, but in other embodiments, the relative positions of the modules can be adjusted according to the needs of the factory space or process flow, as long as the logical connectivity of material flow is maintained.

[0032] like Figure 5-7As shown, the powder conveying mechanism 100 includes a screw discharge assembly 110 and a piston pusher assembly 120. The piston pusher assembly 120 is configured to drive the screw discharge assembly 110 to rotate and output powder during the advance, and to reset via an elastic reset member 140 during the return stroke. Specifically, the powder conveying mechanism 100, as the micro-metering source of the entire system, has the core function of converting continuous linear driving force into discrete rotary volumetric discharge actions. This linkage mechanism differs from traditional gravity feeding or motor-driven screw feeding. It ensures a strict linear correspondence between the single discharge volume and the piston stroke through the inherent constraints of the mechanical structure, while the elastic reset member 140 eliminates the return stroke gap, ensuring the repeatability accuracy of milligram-level powder conveying. In this embodiment, the powder conveying mechanism 100 can be configured as multiple independent units, each storing raw material powders of different compositions to meet the preparation requirements of multi-gradient materials.

[0033] like Figure 2-4 As shown, the powder spreading mold assembly 200 includes a molding cavity array 210, a support plate 220, and a flexible anti-stick layer. The support plate 220 has a vacuum channel 221 inside and a microporous array 222 on its surface that communicates with the vacuum channel. The microporous array 222 is configured to adsorb the flexible anti-stick layer through negative pressure to cover the bottom of the molding cavity array 210. Specifically, the powder spreading mold assembly 200 is the key execution end that determines the sample molding quality and purity. The flexible anti-stick layer can be made of polyimide film, polytetrafluoroethylene film, or other flexible materials with low surface energy properties. It is actively adsorbed by the negative pressure generated by the microporous array 222 and flatly adhered to the surface of the support plate 220, thereby creating a soft yet stable interface at the bottom of the molding cavity. This design utilizes the physical anti-stick properties of flexible materials and the mechanical fixing effect of negative pressure adsorption, fundamentally solving the problems of easy sticking and difficult demolding of trace amounts of powder and the resulting cross-contamination. The molding cavity array 210 is usually arranged in a matrix, such as an 8×8 array, to achieve high-throughput parallel preparation.

[0034] The control system is configured to execute a spatiotemporal separation powder dispensing strategy: controlling the powder dispensing actuator 300 to move along a preset spatial path and controlling the powder conveying mechanism 100 to dispense powder into the forming cavity array 210 according to a preset layering sequence. The control system communicates with each actuator in real time via a bus, transforming the abstract gradient formula into specific motion commands and timing signals. The spatiotemporal separation powder dispensing strategy refers to the control system not only planning a traversal path covering all workstations in space (such as a serpentine or zigzag path) when constructing a multi-layer gradient structure, but also strictly executing the layering operation logic in the time dimension. That is, only after all powder dispensing actions in all areas of the current layer are completed will the layer number be updated to enter the powder spreading process of the next layer. This strategy physically cuts off the exposure and contact opportunities of different component powders within the same time window, effectively preventing interlayer diffusion and mixing, and is the core control logic for achieving high-fidelity component gradient construction. The powder dispensing actuator 300 can be a six-axis robotic arm, a Cartesian robot, or other multi-degree-of-freedom motion platform, with a material picking and powder dispensing tool at its end, responsible for executing the above-mentioned spatiotemporal separation strategy.

[0035] Furthermore, the device in this embodiment also includes a precision weighing unit 500, which includes a single-axis slide rail 510 and an electronic balance 520. The electronic balance 520 is slidably mounted on the single-axis slide rail 510 and is configured to move along the single-axis slide rail 510 to the material handling area of ​​the powder dispensing execution mechanism 300 after receiving the powder output from the powder conveying mechanism 100 and completing quantitative weighing. Specifically, the precision weighing unit 500 acts as a precision connection hub between the powder conveying mechanism 100 and the powder dispensing execution mechanism 300. The electronic balance 520 has a weighing capability with milligram-level or even higher precision, and can complete weight verification immediately after receiving the powder. It then accurately delivers the weighed powder to the working range of the powder dispensing execution mechanism 300 through the rapid linear movement of the single-axis slide rail 510. This integrated weighing and transfer design reduces the risk of spillage and contamination that may occur when materials are transferred between different containers, while also shortening the process cycle and ensuring seamless closed-loop control from micro-volume output to precise powder dispensing. It should be understood that the single-axis slide rail 510 can also be replaced with other linear drive modules, as long as they can achieve precise reciprocating positioning of the electronic balance 520 between the weighing position and the material picking position.

[0036] Through the coordinated operation of the above modules, this embodiment constructs a complete hardware execution framework, realizing high-precision delivery and non-adhesive molding of micro-powders. Furthermore, it establishes the process benchmark for gradient material preparation through a spatiotemporal separation control strategy, significantly improving the data reliability and preparation efficiency of material research and development.

[0037] like Figure 2 As shown in this embodiment, Figure 2-4The support plate 220 shown also includes a substrate layer 223 and a sealing layer 224. A vacuum channel 221 is disposed inside the substrate layer 223, and a micropore array 222 penetrates the sealing layer 224 and communicates with the vacuum channel. Specifically, the substrate layer 223 is usually made of high-strength metal materials (such as maraging steel or aluminum alloy), mainly undertaking the functions of structural support and containing complex internal gas paths, and its thickness is large to ensure rigidity; while the sealing layer 224 serves as a functional interface that directly contacts the powder and the flexible anti-stick layer, and can be independently prepared using materials that are easy to precision machine and have a high surface finish. The pore size of the micropore array 222 can be adapted according to the powder particle size. For example, for micron-sized powders, the pore size can be set between 0.1 mm and 0.5 mm, which can ensure sufficient adsorption force and prevent the flexible anti-stick layer from being drawn into the pores and causing deformation. It should be understood that although this embodiment shows a composite structure of the substrate layer and the sealing layer, in other embodiments, if the manufacturing process allows, the two can also be combined into one by diffusion welding or brazing, as long as the communication between the internal vacuum channel and the surface micropores is maintained.

[0038] The support plate 220 is also connected to a negative pressure generating unit, which is configured to generate negative pressure within the vacuum channel to cause the flexible anti-adhesive layer to adhere to the surface of the sealing layer 224 and seal the micropore array 222. Specifically, the flexible anti-adhesive layer is preferably a flexible material with low surface energy properties, such as polyimide film or polytetrafluoroethylene film. When the negative pressure generating unit is activated, the micropore array 222 on the surface of the sealing layer 224 forms a uniform adsorption field, pressing the flexible anti-adhesive layer tightly onto the surface of the sealing layer, making it the dynamic bottom surface of the molding cavity array 210. This dual mechanism of "negative pressure adsorption + flexible interface" reduces powder adhesion by utilizing the chemical inertness of the flexible material, and eliminates the tiny gaps between the film and the mold through physical adsorption, avoiding sample damage or residual contamination caused by the high demolding resistance of traditional rigid molds. In addition, since the sealing layer 224 is an independent component, when the micropores on its surface wear or become clogged due to long-term use, only the sealing layer needs to be replaced without scrapping the entire support plate, significantly reducing the maintenance cost of the equipment.

[0039] Furthermore, the powder spreading mold assembly 200 also includes a mold sleeve 230 and a base 240. The mold sleeve 230 has multiple through holes arranged in a matrix, which, together with the support plate 220, define a molding cavity array 210. Specifically, the array of through holes on the mold sleeve 230 determines the number and arrangement of samples, for example, it can be set to an 8×8 64-station array. The mold sleeve 230 and the support plate 220 are precisely fitted to ensure that each through hole is accurately aligned with the corresponding area on the surface of the support plate, preventing powder leakage or cross-contamination.

[0040] The base 240 is slidably connected to the mold sleeve plate via a slide rail mechanism. Multiple drive cylinders 250 are installed inside the base 240, arranged diagonally below the support plate 220, and configured to synchronously drive the support plate 220 to rise and fall relative to the mold sleeve plate 230. Specifically, in the lifting and lowering motion of large-size array molds, if single-point drive or same-side drive is used, uneven force can easily generate off-center load moments, leading to tilting of the support plate, slide rail jamming, or even seal failure. This embodiment utilizes geometric symmetry to construct a mechanical balance system by arranging multiple drive cylinders 250 along the diagonal direction of the support plate 220. When the cylinders operate synchronously, the thrust on the diagonal forms mutually canceling couples, effectively eliminating overturning moments and ensuring the parallelism of the support plate 220 throughout its stroke. This structural advantage directly translates into improved molding quality: it ensures uniform pressure distribution at all stations during the pressing process, avoiding differences in blank density between edge and center stations due to mold posture deviations. It should be understood that although the figure shows three drive cylinders distributed in a triangle or diagonal, in larger mold applications, a rectangular arrangement of four cylinders located at the four corners can also be used, as long as the principle of multi-point synchronous lifting and the center of force coinciding with the center of gravity of the mold are met, it falls within the protection scope of this application.

[0041] like Figure 7-8 As shown, in this embodiment, the powder conveying mechanism 100 further includes a conveying cavity 130, and a spiral discharge assembly 110 is disposed within the conveying cavity 130. The outer surface of the spiral discharge assembly 110 is provided with a spiral groove. Specifically, the conveying cavity 130 serves as the core container for powder metering. A precise fit clearance is maintained between its inner wall and the outer surface of the spiral discharge assembly 110. This clearance allows the spiral discharge assembly 110 to rotate freely while effectively preventing powder leakage from non-working areas, thereby ensuring the accuracy of metering. The geometric parameters of the spiral groove (such as pitch, groove depth, and helix angle) directly determine the theoretical powder discharge volume per rotation, which is the physical basis for achieving volumetric metering. It should be understood that although this embodiment demonstrates a single-head spiral groove structure, in other embodiments, multi-head spirals or variable pitch designs can also be used to adapt to the conveying requirements of powders with different flowability.

[0042] The piston feeding assembly 120 includes a piston rod 121 and a limiting pin 122. The linear pushing motion of the piston rod 121 is converted into the rotational motion of the screw discharge assembly 110 through the limiting pin 122, so as to quantitatively discharge the powder contained in the screw groove. Specifically, the limiting pin 122 is located on the inner wall of the conveying cavity and is slidably connected to the screw groove of the screw discharge assembly 110. When an external driving force pushes the piston rod 121 forward in a linear axial direction, the limiting pin 122 forces the screw discharge assembly 110 to rotate synchronously, so that the powder filled in the screw groove is continuously and uniformly pushed to the discharge port. This mechanically rigid linkage mechanism has a fundamental advantage over the traditional technology that uses two independent motors to drive the piston and screw respectively: it ensures a strict linear correspondence between the linear stroke and the rotation angle from a physical structure perspective, completely eliminating the cumulative metering deviation caused by differences in motor response, delays in control algorithms, or encoder feedback errors, and providing a reliable mechanical guarantee for achieving high-precision conveying of milligram-level micro-powder.

[0043] The elastic reset element (140) is a compression spring sleeved on the outer periphery of the spiral discharge assembly (110). The conveying cavity 130 has a stepped hole at one end near the piston rod 121. The elastic reset element (140), a compression spring, is sleeved on the outer periphery of the spiral discharge assembly (110) and located within the stepped hole, configured to drive the spiral discharge assembly (120) back when the propulsive force is removed. Specifically, the elastic reset element 140 not only returns the spiral discharge assembly 110 to its initial position to prepare for the next feeding cycle, but more importantly, it utilizes the continuously applied axial preload of the compression spring to automatically eliminate any mechanical backlash that may exist in the limit pin and transmission chain. In micro-powder conveying scenarios, even a small transmission backlash can lead to significant measurement errors. The constant force of the spring ensures that the transmission pair remains tightly engaged during forward propulsion and reverse reset, thereby guaranteeing repeatability and positioning accuracy under continuous cyclic operation. It should be understood that the elastic reset element 140 can also be replaced by other elastic elements such as disc springs, gas springs or tension springs, as long as they can provide a stable and resettable restoring force.

[0044] Furthermore, the powder conveying mechanism 100 also includes a powder storage chamber 150 and a rotary stirring system 160. The bottom of the powder storage chamber 150 tapers in a conical shape and communicates with the conveying chamber 130. Specifically, the powder storage chamber 150 is made of a transparent material, allowing operators to easily observe the remaining powder and its flow status in real time. Its conical taper structure at the bottom conforms to the principles of bulk mechanics, effectively guiding the powder towards the central outlet, reducing dead zone residue, and providing a stable gravity feeding pressure for the conveying chamber 130 below.

[0045] The rotary stirring system 160 includes a drive motor and a stirring rod. The stirring rod extends into the powder storage chamber 150, and its surface has multiple sets of branched structures configured to break up powder agglomerates during rotation to prevent bridging and blockage. Specifically, for micron- or even nano-sized functional powders, the extremely strong van der Waals forces between particles can easily lead to agglomeration or the formation of stable arched structures at the outlet of the storage hopper, causing interruptions in feeding or flow fluctuations. This directly undermines the prerequisites for subsequent precise metering. In this embodiment, the stirring rod is made of wear-resistant and chemically inert materials such as PVDF. Its multiple sets of branched structures can apply multi-dimensional shear and disturbance forces to the powder during rotation, actively breaking up agglomerates and disrupting the mechanical balance of the arched structures, ensuring that the powder remains in a loose and uniform fluidized state. This pretreatment mechanism ensures that the powder entering the conveying chamber 130 has a constant loose density, thereby enabling the volumetric-based screw metering to accurately reflect the mass flow rate and achieving systematic coordinated control from macroscopic mechanical structure to microscopic powder behavior.

[0046] In this embodiment, the process of the control system executing the spatiotemporal separation powder distribution strategy specifically includes: dividing the molding cavity array 210 into multiple powder-spreading areas and generating a preset spatial traversal path that traverses all powder-spreading areas; in each powder-spreading layer, controlling the powder distribution execution mechanism 300 to move along the preset spatial traversal path, and triggering the powder conveying mechanism 100 to perform a single powder dropping action when reaching each powder-spreading area; after all powder-spreading areas of the current powder-spreading layer have completed powder dropping, updating the powder-spreading layer number and repeating the powder dropping action of the next powder-spreading layer to achieve interlayer physical isolation of powders with different components.

[0047] Specifically, this strategy transforms the abstract gradient formulation into a discretized hardware execution sequence. Its core lies in strictly controlling the temporal and spatial mixing paths of different powder components through rigorous timing constraints. In step S301, the control system first logically partitions the molding cavity array 210 according to preset sample throughput and gradient resolution requirements. For example, for an 8×8 array of 64 stations, it can be treated as a single powder-spreading area and traversed point by point, or it can be divided into several strip-shaped or block-shaped sub-regions based on the gradient change direction. This region partitioning is essentially a mapping of data indexes, rather than a change in physical structure, thus adapting to different experimental design requirements without changing the mold. Subsequently, the system generates a preset spatial traversal path based on the partitioning results. This path preferably uses a serpentine or zigzag scanning method. Compared to random access or line-by-line scanning, this continuous path planning significantly reduces the number of sudden stops and starts of the powder dispensing actuator 300 during reversals, reduces the risk of powder spillage due to inertial vibration, and shortens idle travel time, thereby improving overall powder spreading efficiency.

[0048] During the execution of step S302, the control system strictly adheres to the atomized operation principle of "only proceeding to the next layer after completing the traversal of a single layer." This means that when the powder dispensing actuator 300 is laying the k-th layer of powder, regardless of how the target component ratio changes at the target station, the system only calls the single powder source or premixed powder source corresponding to the current layer for powder dispensing; only when all powder-laying areas covered by the k-th layer have completed the powder dispensing action and been confirmed by the sensor will the layer counter be automatically incremented to the k+1 layer, and the system will switch to the powder conveying channel corresponding to the next layer. This mechanism establishes an absolute isolation window in the time dimension, meaning that the exposure time of component A powder and component B powder do not overlap at all; in the spatial dimension, since each layer is an independent and complete planar coverage, a clear physical interface is formed between layers, completely avoiding the lateral diffusion and interlayer penetration phenomena commonly found in traditional multi-point synchronous powder laying or continuous gradual powder laying. It should be understood that although this embodiment is illustrated using two-layer or multi-layer discrete powder spreading as an example, in practical applications, if the gradient change is extremely gentle, multiple layers can also be merged into one logic layer for one-time powder spreading, as long as the consistency of powder composition within the same logic layer is guaranteed. This is an equivalent substitution within the scope of protection of this application.

[0049] To illustrate the technical effects of this strategy more intuitively, let's take the preparation of an AB binary gradient material as an example. Assume we need to construct a composition gradient from pure A to pure B across 64 workstations, with each workstation consisting of 10 layers of powder. The control system first executes the first layer of powder spreading, driving the powder dispensing mechanism 300 to sequentially visit the 64 workstations along a serpentine path, triggering the powder conveying mechanism 100 at each workstation to drop a fixed amount of A component powder. After all 64 workstations are completed, the Z-axis is raised and the layer number is updated to 2. In the second layer, according to the gradient formulation, the first 32 workstations continue spreading component A, while the last 32 workstations switch to spreading component B (or a specific proportion of premixed powder). The system also strictly executes the traversal of all workstations in this layer before proceeding to the third layer. This cycle continues until the 10th layer is completed. Through this control mode of "layer-by-layer global traversal + inter-layer component switching", even if the composition differences between adjacent workstations are extremely large, the vertical gradient fidelity within each workstation can be guaranteed to reach ±0.5 at.%, and there is no lateral crosstalk between workstations. This effect is not achieved solely by mechanical precision, but stems from the spatiotemporal reconstruction of the material transport process by the control strategy, which is the key difference between this application and existing technologies.

[0050] In this embodiment, as Figure 9As shown, the device also includes a tableting unit 400, which comprises an upper pressure plate 420, a lower pressure plate 430, and multiple pressure heads 440. Specifically, the tableting unit 400, as the core execution module of the molding process, functions to densify the loose powder that has undergone gradient powder spreading into a blank with a certain strength. While one set of stations is performing pressing, another set of stations can simultaneously perform powder spreading or demolding operations, thereby significantly improving the overall production throughput of the machine.

[0051] Multiple pressure heads 440 are evenly distributed on the bottom surface of the lower pressure plate 430. Each pressure head 440 has a boss structure on its bottom surface, configured to simultaneously press multiple forming cavities in the forming cavity array 210 under hydraulic drive. Specifically, the number and layout of the pressure heads 440 are usually matched with the forming cavity array 210 in the powder spreading mold assembly 200, for example, corresponding to 32 or 64 stations. The boss structure on the bottom surface of the pressure head 440 is a key detail for achieving high-quality forming in this embodiment. The cross-sectional shape and size of the boss are adapted to the inner cavity of the forming cavity, and the height of the boss is precisely calculated to accommodate the powder filling depth. Compared with traditional flat pressure heads, the boss structure can accurately guide the hydraulic driving force into the interior of the forming cavity, effectively avoiding edge effects and pressure loss caused by the gap between the pressure head and the mold plate. At the same time, the sidewall of the boss can also play a secondary guiding and sealing role during the pressing process, preventing fine powder from overflowing from the gaps and ensuring the uniformity of the blank density and the accuracy of the dimensions. In addition, the multi-head synchronous pressing mechanism ensures that all samples in the same batch are subjected to completely consistent molding pressure and holding time, eliminating the drift of process parameters caused by pressing one by one, and providing a reliable process benchmark for subsequent horizontal comparison of material performance data.

[0052] To ensure the alignment accuracy of multi-station synchronous pressing, the tablet pressing unit 400 is also equipped with a high-precision guiding mechanism. Specifically, several guide pillars are provided between the upper pressure plate 420 and the lower pressure plate 430. The surfaces of the guide pillars are hard anodized or chrome-plated and used in conjunction with self-lubricating bearings or linear bushings to ensure the parallelism and coaxiality of the upper and lower pressure plates during the mold closing process. This rigid guiding structure can effectively resist the lateral forces that may be generated during the pressing process, preventing damage to the pressing head or sample rejection due to mold misalignment. Regarding the driving method, although this embodiment preferably uses a servo hydraulic system to achieve stable output and precise closed-loop control of high-tonnage pressure, with a pressure adjustment range covering 0 to 10 MPa or even higher to meet the densification requirements of different powder systems, in other embodiments, for applications with small size or extremely high cleanliness requirements, a servo electric cylinder or a pneumatic-hydraulic booster cylinder can also be used as the power source, as long as it can provide stable and adjustable pressing force and meet the response speed requirements, it falls within the protection scope of this application. Through the above structural design, the tableting unit 400 not only achieves high-throughput parallel molding, but also solves the common problems of uneven density and edge damage in micro-powder pressing through the combination of boss structure and precision guidance, further improving the overall yield of gradient material preparation.

[0053] Example 2 This embodiment provides a multi-station powder gradient mixing and forming method. This method is applied to the multi-station powder mixing and forming apparatus described in any of the foregoing embodiments, aiming to transform the hardware capabilities of the apparatus into repeatable preparation efficiency through standardized process sequences. Specifically, the method includes the following steps: Step S100: The piston pushing assembly 120 of the powder conveying mechanism 100 drives the spiral discharging assembly 110 to rotate, thereby quantitatively outputting the powder. Specifically, this step is the metering benchmark establishment stage for the entire gradient powder dispensing process. During execution, the external driving force pushes the piston rod 121 to feed linearly along the axial direction, and the internal limiting pin forces the spiral discharging assembly 110 to rotate synchronously, so that the powder filled in the spiral groove is continuously and uniformly pushed to the discharge port. This mechanically rigid linkage mechanism ensures a strict linear correspondence between the single discharge amount and the piston stroke, eliminating the cumulative error that may exist in traditional independent motor drives. It should be understood that although this embodiment uses a piston-spiral linkage structure as an example, in other embodiments, piezoelectric ceramic drive, voice coil motor direct drive, or other micro-feeding methods that can achieve milligram-level precise metering can also be used, as long as the requirement for consistency of single-point powder drop volume in subsequent gradient construction can be met. The technical effect of this step is to ensure the accuracy and stability of powder supply from the source, laying the material foundation for the preparation of high-fidelity gradient materials.

[0054] Step S200: A flexible anti-stick layer is laid on the surface of the support plate 220 of the powder spreading mold assembly 200. The negative pressure generated by the negative pressure generating unit in the micropore array 222 causes the flexible anti-stick layer to adhere to the bottom of the molding cavity array 210. Specifically, this step is a crucial pre-process for constructing a dynamic anti-stick interface. The operator or automated mechanism first covers the surface of the support plate 220 with a flexible material such as a polyimide film. Then, the negative pressure generating unit is activated, causing the micropore array 222 on the surface of the sealing layer 224 to form a uniform adsorption field, tightly pressing the flexible anti-stick layer and sealing the micropores. This process must be completed before step S300 begins and must maintain a negative pressure state throughout the entire powder spreading and subsequent pressing process to prevent the film from shifting, wrinkling, or falling off due to powder impact or pressing reaction force. This step utilizes the low surface energy characteristics of flexible materials and the mechanical fixing effect of negative pressure adsorption to fundamentally solve the problems of easy adhesion and difficult demolding of trace amounts of powder, as well as the resulting cross-contamination. It should be understood that the material selection for the flexible anti-adhesive layer is not limited to polyimide. Any flexible film material that is chemically inert, has low surface energy, and has a certain degree of air permeability or can be adsorbed and fixed by micropores (such as modified PTFE film, FEP film, etc.) can be used in this method, as long as it can be stably attached to the surface of the support plate under negative pressure.

[0055] Step S300: The powder dispensing actuator 300 is controlled to move according to a preset spatial traversal path, and powder is dispensed into the forming cavity array 210 according to a preset layering sequence to construct a gradient powder layer. Specifically, this step is the core process for achieving high-fidelity construction of the component gradient, essentially transforming the abstract gradient formula into a discrete spatiotemporal execution sequence. During execution, the control system first generates a preset spatial traversal path (such as a serpentine or zigzag path) covering all powder-spreading areas based on preset sample throughput and gradient resolution requirements. Subsequently, the powder dispensing actuator 300 visits each station sequentially along this path, and triggers the powder conveying mechanism 100 to perform a single powder dispensing action upon reaching the target position. More importantly, this step strictly adheres to the layering sequence principle of "entering the next layer only after the entire area of ​​a single layer has been traversed," meaning that only after all powder dispensing actions in all areas of the current layer are completed is the layer number updated and the system switched to the powder source corresponding to the next layer for operation. This spatiotemporal separation operation mode cuts off the simultaneous exposure window of powders with different components in the time dimension and establishes a clear physical interface between layers in the spatial dimension, completely avoiding the lateral diffusion and interlayer penetration phenomena commonly found in traditional multi-point synchronous powder spreading or continuous gradual powder spreading. It should be understood that although this embodiment takes layer-by-layer discrete powder spreading as an example, in practical applications, if the gradient change is extremely gentle or the powder has excellent flowability, multiple layers can be merged into a single logical layer for one-time powder spreading, or a partitioned parallel powder spreading strategy can be adopted. As long as the consistency of powder composition within the same logical layer is guaranteed and there is an effective physical isolation mechanism between different component layers, it falls within the equivalent substitutions within the scope of protection of this application.

[0056] Step S400: Simultaneous pressing is performed on the powder-feeding molding cavity array 210 to form a powder preform. Specifically, this step is a molding process that densifies loose gradient powder into a preform with a certain strength. During the pressing process, multiple pressing heads 440 of the tableting unit 400 simultaneously apply vertical pressure to all stations in the molding cavity array 210 under hydraulic drive, causing powder particles to rearrange and undergo plastic deformation, thereby obtaining the expected density and dimensional accuracy. Due to the multi-head synchronous pressing mechanism, all samples in the same batch are subjected to completely consistent molding pressure and holding time, eliminating the drift of process parameters caused by pressing one sample at a time, and ensuring the lateral comparability of gradient material performance data. Simultaneously, the synergistic effect of the boss structure on the bottom surface of the pressing head and the flexible anti-stick layer effectively prevents lateral overflow and interlayer slippage of powder during the pressing process, ensuring the integrity of the gradient interface. It should be understood that the setting of the pressing pressure needs to be optimized according to the compression characteristics of the powder system. For brittle ceramic powders, a lower pressure can be used in conjunction with subsequent sintering and densification, while for metal or polymer powders, a higher pressure may be required to achieve cold welding or mechanical interlocking. In addition, the pressing method is not limited to hydraulic synchronous pressing. Servo electric cylinders, pneumatic-hydraulic booster cylinders, or even isostatic pressing can all be used as alternative implementation schemes for this step, as long as they can achieve uniform densification of powders in multiple stations without destroying the preset gradient structure.

[0057] Through the aforementioned sequence of steps S100 to S400, this embodiment constructs a logically rigorous and time-controllable gradient powder preparation and molding method. There are strict logical dependencies between each step: the precise metering provided by S100 is the material prerequisite for gradient construction in S300; the anti-sticking interface established in S200 ensures the smooth execution of S300 and successful demolding in S400; and the spatiotemporal separation strategy of S300 is the decisive factor in achieving a high-fidelity gradient. This method not only fully leverages the hardware advantages of the aforementioned device embodiment but also eliminates random errors introduced by human intervention through standardized operating procedures, significantly improving the data reliability and experimental repeatability of high-throughput material screening.

[0058] In this embodiment, step S300 includes sub-steps S310 to S330, which solve problems such as uneven powder distribution, dust flying and interlayer damage that are prone to occur in the process of high-speed automated powder spreading of micro powder through the dynamic coupling of multi-dimensional parameters.

[0059] In sub-step S310, the speed of the powder dispensing actuator 300 is matched with the rotation frequency of the screw discharge assembly 110 to ensure that the amount of powder dispensed per cycle meets the preset thickness requirement. Specifically, this matching is not a simple linear proportional relationship, but a dynamic mapping model based on the principle of volumetric metering. In actual operation, the control system determines the powder dispensing quality based on the preset target powder dispensing mass per station. Powder bulk density and the effective volume of the spiral groove The target number of rotations required for the screw discharge assembly 110 to remain or pass through a single station is calculated. Simultaneously, based on the moving speed of the powder dispensing actuator 300... and workstation spacing Determine the effective powder drop time window The system adjusts the rotation frequency of the screw discharge assembly 110 in real time accordingly. To satisfy The relationship is as follows. For example, when the moving speed of the powder dispensing actuator 300 increases from 10 mm / s to 20 mm / s, the rotation frequency of the screw discharge assembly 110 also doubles accordingly, thereby ensuring that the amount of powder released per unit displacement remains constant. This rigid coordination of speed and frequency eliminates the difference in powder thickness caused by fluctuations in movement speed, so that even in non-uniform movement stages (such as acceleration and deceleration zones), the powder dispensing accuracy can be maintained through frequency feedforward compensation, providing a fundamental process guarantee for the compositional uniformity of gradient materials.

[0060] In sub-step S320, when the powder dispensing actuator 300 reaches above the target powder-spreading area, the negative pressure generating unit is activated. The vacuum response time of the negative pressure generating unit is less than the powder-dropping duration of the powder dispensing actuator 300, and the negative pressure value generated by the negative pressure generating unit increases as the powder particle size decreases to prevent the powder from flying away before adsorption and bonding. Specifically, the "vacuum response time" here is defined as the time interval from when the control system sends the start signal until the actual negative pressure value on the surface of the microporous array 222 reaches more than 90% of the target set value. For milligram-level micro-powder spreading scenarios, a single powder-dropping action is often completed within tens of milliseconds. If the negative pressure establishment is delayed, the powder particles that fall earlier will bounce or drift disorderly under gravity and airflow disturbance, resulting in positioning failure. Therefore, this embodiment requires that the negative pressure response time must be strictly less than the powder-dropping duration, preferably controlled within 50ms, to ensure that the first batch of powder to touch the bottom is immediately adsorbed and locked. In addition, the negative pressure value is not fixed for powders with different physical properties. For lightweight powders with small particle sizes (e.g., D50 < 10 μm), their large specific surface area and susceptibility to aerodynamic effects necessitate the application of higher negative pressure values ​​(e.g., -60 kPa to -80 kPa) to provide sufficient normal adsorption force to overcome the tendency for separation. Conversely, for heavy powders with larger particle sizes (e.g., D50 > 50 μm), excessively high negative pressure may cause the flexible anti-adhesive layer to deform excessively and become embedded in the micropores. Therefore, a lower negative pressure value (e.g., -20 kPa to -40 kPa) is sufficient to achieve stable adhesion. This adaptive negative pressure control strategy based on particle size characteristics ensures both the anti-separation effect and the flatness and lifespan of the flexible interface.

[0061] In sub-step S330, after all powder areas of the current powder layer have been covered, the powder dispensing mechanism 300 is raised along the Z-axis to a preset height, and the powder layer number is updated before the powder dispensing action of the next powder layer is executed. The preset height is greater than the compacted thickness of a single layer of powder. Specifically, this step is a key safety mechanism to ensure the integrity of the multi-layer gradient structure. Since the newly laid powder layer is in a loosely packed state, its loose thickness is much greater than the compacted thickness after subsequent pressing. If the Z-axis lifting height is only equal to or less than the theoretical compacted thickness, the end tool or follower of the powder dispensing mechanism 300 is very likely to scrape, drag, or even damage the loose powder layer that has just been laid but not yet pressed during lateral movement, resulting in blurred layer interfaces or mixed components. Therefore, in this embodiment, the preset height of the Z-axis lifting is set to be significantly greater than the compacted thickness of a single layer, usually 1.5 to 3 times the compacted thickness, or at least an absolute safety gap of 0.5 mm is maintained. For example, when the target single-layer compaction thickness is 100μm, the Z-axis lifting height can be set to 300μm to 500μm. Although this redundant design increases the idle travel time of the Z-axis to some extent, it fundamentally eliminates the risk of mechanical interference and ensures that each layer of powder enters the next process in an independent and undamaged state, which is a necessary process condition for achieving high-fidelity vertical gradient construction.

[0062] To more intuitively demonstrate the practical application of the aforementioned synergistic control strategy, the preparation of perovskite oxide gradient materials is used as an example. Assume three precursor powders (A, B, and C) with average particle sizes of 5 μm, 15 μm, and 30 μm, respectively. The goal is to construct a gradient sample with a total thickness of 2 mm and a layer thickness of 50 μm (after compaction) across 64 stations. During execution S310, the system locks the movement speed of the powder dispensing actuator 300 at 15 mm / s based on the loose density calibration curves of each powder, and sets the reference frequency of the screw discharge assembly 110 to 2 Hz. The measured single-point powder drop deviation is less than ±0.5%. During execution S320, for the 5 μm A powder, the system automatically adjusts the negative pressure target value to -75 kPa and activates the fast response mode (response time <30 ms); for the 30 μm C powder, the negative pressure is reduced to -30 kPa, and the response time is relaxed to 80 ms to accommodate the slower settling velocity. When executing S330, considering the compaction thickness of 50μm, the system uniformly sets the Z-axis lifting height after each layer of powder to 150μm. This ensures sufficient safety margin while avoiding excessive idle travel loss. Through the coordinated operation of this parameter combination, the final prepared gradient sample, verified by EDS line scanning, shows sharp transitions between layers with no obvious mixing bands, and a surface smoothness error of less than 2%, fully demonstrating the effectiveness and practicality of the parameter coordinated control strategy described in this embodiment. It should be understood that the specific values ​​mentioned above are merely illustrative. In practical applications, operators can make adaptive adjustments based on powder characteristics, equipment performance, and product quality requirements. As long as the coordinated principles of speed-frequency matching, negative pressure-particle size adaptation, and lifting-thickness correlation are followed, they all fall within the protection scope of this application.

[0063] This embodiment provides a specific application scenario for preparing perovskite-type oxide gradient materials using the aforementioned multi-station powder mixing and forming device, aiming to verify the actual effectiveness of this device in high-throughput material research and development. It should be noted that the material systems, process parameters, and equipment configurations listed below are merely illustrative and do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that, based on the technical principles disclosed in this application, this device is also applicable to the gradient preparation and screening of other functional ceramic systems such as solid-state fuel cell electrolytes, catalysts, and sensor materials.

[0064] In this application scenario, the goal is to prepare 64 perovskite oxide (ABO3) samples with continuous compositional gradients in a single batch to study the effect of the A-site cation doping ratio on the electrochemical performance of the materials. First, raw material preparation is performed by loading three precursor powders of different particle sizes (A-source, B-source, and dopant C-source, respectively) into the powder storage chambers 150 of three independent powder conveying mechanisms 100. A rotary stirring system 160 continuously operates to prevent agglomeration of fine powders and ensure consistent material flowability. An electronic balance 520 of a precision weighing unit 500 reciprocates on a single-axis slide rail 510, sequentially receiving each component powder and providing real-time weighing feedback. The measured weighing accuracy is consistently within ±0.1 mg, and the repeatability is ±0.1 mm. This high-precision front-end metrology lays the material foundation for subsequent gradient construction and effectively eliminates systematic errors caused by fluctuations in the raw material ratio.

[0065] The core gradient powder spreading stage then commences. The control system, based on the preset gradient formula, drives the powder dispensing actuator 300 to strictly execute a spatiotemporal separation powder dispensing strategy. For the 64 forming cavity arrays 210 arranged in an 8×8 matrix, the system discretizes the construction process of each sample into 20 independent powder spreading layers. In each layer, the powder dispensing actuator 300 traverses all 64 stations along a serpentine path and precisely triggers the corresponding powder delivery mechanism 100 to dispense powder based on the target component at the current position. Due to the strict layer-by-layer timing control—that is, switching to the next layer only after completing powder spreading at all 64 stations of the current layer—powders of different components are completely isolated on the time axis, thoroughly avoiding the interlayer diffusion and mixing phenomena common in traditional continuous powder spreading methods. EDS line scan detection shows that the final prepared gradient sample exhibits sharp component transitions, with an actual component gradient resolution of ±0.5 at.%, and no lateral crosstalk between adjacent stations, fully demonstrating the technical advantages of the spatiotemporal separation strategy in high-fidelity gradient construction.

[0066] After powder preparation, the mold assembly automatically transfers to the tableting unit 400 for densification. The pressure head 440, driven by hydraulic pressure, simultaneously applies an adjustable pressure of 0-10 MPa to both mold assemblies (64 samples in total). Thanks to the synergistic effect of the boss structure on the bottom of the pressure head and the flexible anti-stick layer, the preform demolding integrity rate exceeds 99%, and the density deviation among samples within the same batch is less than 1%. The entire powder preparation and tableting process operates in fully automated mode, with the preparation cycle for a single batch of 64 samples controlled within 45 minutes, representing an efficiency improvement of over 70% compared to traditional manual powder preparation and tableting processes.

[0067] Finally, the robotic arm automatically transfers the pressed green body to a four-zone tubular sintering furnace for heat treatment. The sintering furnace can reach a maximum temperature of 1600℃ with a temperature control accuracy of ±2℃, and is equipped with a three-channel automatic atmosphere switching system (O2 / N2 / H2-Ar) to meet the phase stability requirements of perovskite oxides under different oxygen partial pressures. The fully automated operation mode not only significantly reduces random errors introduced by manual operation but also ensures the traceability and consistency of experimental data. In summary, this embodiment verifies the comprehensive capabilities of the device in precise micro-volume delivery, cross-contamination-free molding, and high-fidelity gradient construction through specific applications, providing an efficient and reliable hardware support platform for materials genome engineering.

[0068] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A multi-station powder mixing and forming device, characterized in that, It includes a powder conveying mechanism (100), a powder spreading mold assembly (200), a powder dispensing actuator (300), and a control system; The powder conveying mechanism (100) includes a screw discharge assembly (110) and a piston pusher assembly (120), the piston pusher assembly (120) being configured to drive the screw discharge assembly (110) to rotate during the advance to output powder, and to be reset by an elastic reset member (140) during the return stroke; The powder spreading mold assembly (200) includes a molding cavity array (210), a support plate (220), and a flexible anti-stick layer. The support plate (220) has a vacuum channel (221) inside and a micropore array (222) communicating with the vacuum channel on its surface. The micropore array (222) is configured to adsorb the flexible anti-stick layer by negative pressure to cover the bottom of the molding cavity array (210). The control system is configured to execute a spatiotemporal separation powder distribution strategy: control the powder distribution execution mechanism (300) to move along a preset spatial path, and control the powder conveying mechanism (100) to drop powder onto the forming cavity array (210) according to a preset layering sequence.

2. The multi-station powder mixing and forming device according to claim 1, characterized in that, The support plate (220) further includes a substrate layer (223) and a sealing layer (224). A vacuum channel (221) is disposed inside the substrate layer (223). The micropore array (222) penetrates the sealing layer (224) and communicates with the vacuum channel. The support plate (220) is also connected to a negative pressure generating unit, which is configured to generate negative pressure in the vacuum channel so that the flexible anti-adhesive layer adheres to the surface of the sealing layer (224) and seals the micropore array (222).

3. The multi-station powder mixing and forming device according to claim 2, characterized in that, The powder spreading mold assembly (200) also includes a mold sleeve plate (230) and a base (240). The mold sleeve plate (230) is provided with a plurality of through holes arranged in a matrix. The plurality of through holes and the support plate (220) together define the molding cavity array (210). The base (240) is slidably connected to the mold sleeve plate via a slide rail mechanism. The base (240) is provided with multiple drive cylinders (250). The multiple drive cylinders 250 are arranged diagonally below the support plate (220) and configured to synchronously drive the support plate (220) to rise and fall relative to the mold sleeve plate (230).

4. The multi-station powder mixing and forming device according to claim 1, characterized in that, The powder conveying mechanism (100) further includes a conveying cavity (130), and the spiral discharge assembly (110) is disposed inside the conveying cavity (130). The outer surface of the spiral discharge assembly (110) is provided with a spiral groove. The piston pusher assembly (120) includes a piston rod (121) and a limiting pin. The linear pushing motion of the piston rod (121) is converted into the rotational motion of the spiral discharge assembly (110) through the limiting pin, so as to quantitatively discharge the powder contained in the spiral groove. The elastic reset member (140) is a compression spring sleeved on the outer periphery of the spiral discharge assembly (110). The conveying cavity 130 has a stepped hole at one end near the piston rod 121. The elastic reset member (140) is a compression spring sleeved on the outer periphery of the spiral discharge assembly (110) and located in the stepped hole. It is configured to drive the spiral discharge assembly (120) to return when the propulsion force is removed.

5. The multi-station powder mixing and forming device according to claim 4, characterized in that, The powder conveying mechanism (100) further includes a powder storage chamber (150) and a rotary stirring system (160), wherein the bottom of the powder storage chamber (150) is tapered and communicates with the conveying chamber (130); The rotary stirring system (160) includes a drive motor and a stirring rod. The stirring rod extends into the powder storage chamber (150), and the surface of the stirring rod is provided with multiple sets of branch structures, configured to break up powder agglomerates during rotation to prevent bridging and clogging.

6. The multi-station powder mixing and forming device according to claim 1, characterized in that, The process by which the control system executes the spatiotemporal separation powder distribution strategy includes: The molding cavity array (210) is divided into multiple powder-spreading areas, and a preset spatial traversal path is generated to traverse all the powder-spreading areas; In each powder layer, the powder dispensing mechanism (300) is controlled to move along the preset space traversal path, and the powder conveying mechanism (100) is triggered to perform a single powder dropping action when it reaches each powder layer area; After all powder-spreading areas of the current powder-spreading layer have been covered with powder, the powder-spreading layer number is updated and the powder-spreading action of the next powder-spreading layer is repeated to achieve physical isolation between layers of powders with different components.

7. The multi-station powder mixing and forming device according to claim 6, characterized in that, It also includes a tableting unit (400), which includes an upper pressure plate (420), a lower pressure plate (430) and multiple pressure heads (440). Multiple pressure heads (440) are evenly distributed on the bottom surface of the lower pressure plate (430). Each pressure head (440) has a boss structure on its bottom surface, configured to simultaneously press multiple forming cavities in the forming cavity array (210) under hydraulic drive.

8. The multi-station powder mixing and forming device according to claim 1, characterized in that, It also includes a precision weighing unit (500), which includes a single-axis slide rail (510) and an electronic balance (520). The electronic balance (520) is slidably mounted on the single-axis slide rail (510) and is configured to move along the single-axis slide rail (510) to the material taking area of ​​the powder dispensing execution mechanism (300) after receiving the powder output by the powder conveying mechanism (100) and completing the quantitative weighing.

9. A multi-station powder mixing and forming method, applied to the multi-station powder mixing and forming apparatus according to any one of claims 1-8, characterized in that, Includes the following steps: S100: The piston pusher assembly (220) of the powder conveying mechanism (200) drives the screw discharge assembly (210) to rotate so as to output the powder in a metered manner; S200: A flexible non-stick layer is laid on the surface of the support plate of the powder spreading mold assembly (200), and the flexible non-stick layer is adsorbed and attached to the bottom of the molding cavity array (210) by the negative pressure generated by the negative pressure generating unit in the micropore array (222). S300: Control the powder dispensing actuator (300) to move according to the preset spatial traversal path, and control the powder dispensing actuator (300) to dispense powder to the molding cavity array (210) according to the preset layering sequence, so as to construct a gradient powder layer; S400: Perform synchronous pressing on the molding cavity array (210) after the powder has been dispensed to form a powder blank.

10. The multi-station powder preparation and forming method according to claim 9, characterized in that, Step S300 specifically includes: S310: Set the speed of the powder dispensing actuator (300) to match the rotation frequency of the screw discharge assembly (210) to ensure that the amount of powder dispensed at one time meets the preset thickness requirement; S320: When the powder dispensing actuator (300) reaches above the target powder spreading area, the negative pressure generating unit is triggered to start. The vacuum response time of the negative pressure generating unit is less than the powder falling duration of the powder dispensing actuator (300), and the negative pressure value generated by the negative pressure generating unit increases as the powder particle size decreases, so as to prevent the powder from flying before adsorption and bonding. S330: After completing the powder application in all powder application areas of the current powder layer, control the powder distribution actuator (300) to raise the preset height along the Z-axis and update the powder layer sequence number, and then execute the powder application action of the next powder layer, wherein the preset height is greater than the compaction thickness of a single layer of powder.

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