Multi-material additive manufacturing equipment and method

Abstract

The invention discloses multi-material additive manufacturing equipment and a multi-material additive manufacturing method. The multi-material additive manufacturing equipment comprises a workbench; the powder spreading mechanisms are movably arranged above the workbench, each powder spreading mechanism comprises a powder bin, an ultrasonic generator and a recovery device, the powder bin is provided with a powder falling opening, the ultrasonic generator is connected to the powder falling opening, the powder falling opening is arranged towards the workbench, one end of the recovery device is arranged towards the workbench, and the other end of the recovery device is communicated with the powder bin; the electric field generator is connected to the powder laying mechanism and the workbench, so that an electric field is formed between the powder laying mechanism and the workbench; and the ultrasonic slicking device is arranged above the working table and faces the working table. According to the powder spreading device, the powder spreading uniformity and the powder spreading efficiency are improved, powder mixing is avoided, and the effect of powder recycling is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a multi-material additive manufacturing device and method. Background Art

[0002] Powder Bed Fusion (PBF) technology is an advanced metal 3D printing technology. PBF uses energy beams such as lasers or electron beams to selectively melt materials. The additive and subtractive manufacturing technology based on PBF can manufacture parts with complex geometric shapes through laser subtraction, and has good forming accuracy and surface quality. Therefore, it is widely used in fields such as aerospace, automotive manufacturing, and medical devices, and has become one of the advanced manufacturing technologies that have attracted much attention in the current industrial community.

[0003] However, most current PBF technologies are single-material and cannot achieve target functions such as high temperature resistance, high wear resistance, corrosion resistance, and electrical conductivity in different regions of the same part, which is not conducive to improving component integration and product performance. To solve this problem, multi-material metal 3D printing technology has attracted much attention in recent years. This technology aims to integrate the components and properties of multiple metal materials inside the same part by mixing or separately spreading different metal powder materials on-site during the manufacturing process and performing material-zone printing. This can not only improve the comprehensive performance of the part but also endow it with new functions such as thermal gradient, magnetic gradient, and electrical gradient. The key to realizing multi-material metal 3D printing is to efficiently and accurately partition the forming area on the scanning path and selectively spread powder. Currently, more research is focused on using mechanical devices to achieve zone powder spreading, but there are problems such as powder confusion and pollution after printing, which are difficult to separate and reuse. Ultrasonic vibration powder spreading is a non-contact powder spreading method, but its powder spreading uniformity is poor and the powder spreading speed is slow. Therefore, in the prior art, there are problems of poor powder spreading uniformity, low efficiency, and powder confusion after printing in multi-material metal 3D printing powder spreading. Summary of the Invention

[0004] The present invention aims to solve at least one of the problems in the related art to some extent. To this end, one of the objectives of the present invention is to provide a multi-material additive manufacturing device for improving powder spreading uniformity and efficiency, avoiding powder confusion, and achieving the effect of powder recycling and reuse.

[0005] A multi-material additive manufacturing device, the multi-material additive manufacturing device includes:

[0006] A workbench;

[0007] Multiple powder spreading mechanisms, the powder spreading mechanisms are movably arranged above the workbench, each powder spreading mechanism includes a powder bin, an ultrasonic generator and a recovery device, the powder bin is provided with a powder dropping port, the ultrasonic generator is connected to the powder dropping port, the powder dropping port is arranged towards the workbench, one end of the recovery device is arranged towards the workbench, and the other end communicates with the powder bin;

[0008] An electric field generator, the electric field generator is connected to the powder spreading mechanism and the workbench, so that an electric field is formed between the powder spreading mechanism and the workbench;

[0009] An ultrasonic leveling device, the ultrasonic leveling device is arranged above the workbench and is arranged towards the workbench.

[0010] Specifically, the powder spreading mechanism is movably arranged above the workbench, which is convenient for powder spreading operations at different positions. Each powder spreading mechanism includes a powder bin, an ultrasonic generator and a recovery device. The powder dropping port of the powder bin is used to output powder, and the ultrasonic generator is connected to the powder dropping port. The ultrasonic vibration can be used to promote the uniform falling of the powder, improving the accuracy and uniformity of powder dropping. One end of the recovery device is arranged towards the workbench, which can collect the excess powder and send it back to the powder bin, realizing the recycling of the powder, avoiding waste and powder mixing. The electric field generator is connected to the powder spreading mechanism and the workbench, and an electric field is formed between them. The electric field can apply a force to the powder particles, changing the movement trajectory and distribution state of the powder during the spreading process, effectively controlling the powder spreading behavior, solving the problems of powder accumulation and slow powder spreading speed, and improving the powder spreading efficiency and quality. The ultrasonic leveling device is arranged above the workbench and is arranged towards the workbench, and uses ultrasonic vibration to perform non-contact leveling on the spread powder. This method avoids the pollution and scraper wear that may be caused by the contact between the traditional leveling tool and the powder, further improving the processing accuracy and efficiency.

[0011] Furthermore, the multiple powder spreading mechanisms are arranged side by side.

[0012] Specifically, the multiple powder spreading mechanisms are arranged side by side, so that when multi-material spreading is carried out, accurate powder spreading can be carried out on different areas in sequence according to the design order, reducing the interference of different material powders in space, facilitating the operation and management of the equipment, being beneficial to realizing the precise control of different parts of the part, and improving the manufacturing quality and performance consistency of the part. Moreover, the multiple powder spreading mechanisms can spread the same kind of powder at the same time, improving the powder spreading efficiency.

[0013] Furthermore, the powder bin further includes a nozzle, the nozzle is connected to the powder dropping port, and the ultrasonic generator is connected to the nozzle.

[0014] Specifically, after adding nozzles to the powder bin, the powder can be ejected more concentratedly and directionally through the nozzles, facilitating the precise control of the powder landing point. The ultrasonic generator is connected to the nozzles. When the powder is ejected, ultrasonic vibration is used to disperse the powder more evenly, prevent the powder from agglomerating and blocking the nozzles, and at the same time further improve the spreading uniformity of the powder on the worktable, ensuring the consistency of material distribution during the processing and enhancing the forming quality of the parts.

[0015] Further, the recycling device includes a vacuum suction device and an ultrasonic powder sieve. The suction port of the vacuum suction device faces the worktable, and the other end communicates with the powder bin. The ultrasonic powder sieve is arranged between the vacuum suction device and the powder bin.

[0016] Specifically, the suction port of the vacuum suction device faces the worktable, and the excess powder on the worktable is sucked back by the vacuum suction force to quickly clean the worktable and prepare for the next powder spreading. Its strong suction force can quickly collect the scattered powder, improving the working efficiency of the equipment. The ultrasonic powder sieve is arranged between the vacuum suction device and the powder bin, and the recycled powder is screened by ultrasonic vibration. Impurities and agglomerates in the powder can be removed, keeping the recycled powder in good particle state, ensuring the quality during reuse, and avoiding affecting the processing accuracy and part performance due to the quality problem of the recycled powder.

[0017] Further, the multi-material additive manufacturing equipment further includes a spatter collector, which is movably arranged above the worktable for collecting spattered powder.

[0018] Specifically, the spatter collector is movably arranged above the worktable, and can timely capture the spattered powder particles during the operation of the equipment, preventing them from scattering and mixing into other material powders. This not only keeps the interior of the equipment clean, reduces the cleaning work, but also avoids the confusion of different material powders, ensuring the single composition of the powder in each powder bin, which is beneficial to realizing multi-material precise processing and powder recycling and reuse.

[0019] Further, the multi-material additive manufacturing equipment further includes a mounting plate and a position driving device. A plurality of powder spreading mechanisms are all mounted on the mounting plate, and the plurality of powder spreading mechanisms are arranged side by side. The mounting plate is located above the worktable, and the position driving device is drivingly connected to the mounting plate to drive the mounting plate to move in the horizontal and vertical directions.

[0020] Specifically, the installation plate serves as the bearing platform of the powder spreading mechanism, integrating multiple powder spreading mechanisms together, which is convenient for unified management and control. It is located above the workbench, providing a stable installation foundation for the powder spreading mechanism and ensuring the stability of the powder spreading mechanism during the working process. The position driving device is drivingly connected to the installation plate, and can precisely control the movement of the installation plate in the horizontal and vertical directions. During the processing, according to the design requirements and processing progress of the part, the position of the powder spreading mechanism can be quickly adjusted to achieve precise powder spreading operations in different areas and at different heights, improving the processing ability of the equipment for complex parts and enhancing the processing efficiency and quality.

[0021] Furthermore, the number of the installation plates is multiple, and the multiple installation plates are arranged side by side along the extending direction of the workbench.

[0022] Specifically, the multiple installation plates are arranged side by side along the extending direction of the workbench, enabling the equipment to accommodate more powder spreading mechanisms simultaneously. When performing large-area or multi-region powder spreading, multiple powder spreading mechanisms can be started simultaneously to work together, greatly improving the efficiency and coverage of powder spreading. For the processing of large parts or complex parts that require the use of multiple materials in different areas, this design can better meet the production requirements and enhance the application range and practicability of the equipment.

[0023] Furthermore, the number of the ultrasonic leveling devices is multiple, and one ultrasonic leveling device is correspondingly connected to one powder spreading mechanism.

[0024] Specifically, the number of the ultrasonic leveling devices is multiple and they are connected to the powder spreading mechanisms one by one. After the powder spreading is completed, the corresponding ultrasonic leveling device can immediately level the just-spread powder. Since the powder spreading situation of each powder spreading mechanism may be slightly different, this one-to-one connection method can perform personalized leveling treatment according to the specific powder spreading state, ensuring the flatness and uniformity of the powder layer on the entire workbench and providing a good foundation for subsequent processing procedures such as laser sintering.

[0025] Furthermore, the ultrasonic leveling device is connected to the surface of the installation plate facing the workbench.

[0026] Specifically, the ultrasonic leveling device is connected to the surface of the installation plate facing the workbench. This installation position makes the ultrasonic leveling device closely connected to the powder spreading mechanism. After the powder spreading mechanism completes the powder spreading action, the ultrasonic leveling device can quickly respond and perform the leveling operation without complex mechanical adjustments. At the same time, being installed on the installation plate ensures the stability of the ultrasonic leveling device during the operation of the equipment, reducing the influence of vibration and displacement on the leveling effect and improving the overall processing accuracy and stability of the equipment.

[0027] The present invention also provides a method for a multi-material additive manufacturing device, which applies the multi-material additive manufacturing device as described above. The method for the multi-material additive manufacturing device includes the following steps:

[0028] S1. Determine the distribution of different materials according to the part design to form multi-material slices and corresponding powder feeding strategies, and determine the laser forming, machining, and heat treatment paths according to the material physical properties and interface positions;

[0029] S2. Add corresponding powders to each of the powder bins;

[0030] S3. Turn on the first powder spreading mechanism, turn on the ultrasonic generator and the electric field generator, and turn on the ultrasonic leveling device to perform powder feeding on the entire forming area of the current layer;

[0031] S4. Turn on the laser to sinter the powder;

[0032] S5. Turn on the recovery device to suck the powder into the powder bin;

[0033] S6. Sequentially turn on the other powder spreading mechanisms and repeat steps S3 to S5 until the entire part is processed.

[0034] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art:

[0035] The multi-material additive manufacturing device of the present application realizes an efficient, precise, and environmentally friendly powder bed melting process. Through the precise control of the ultrasonic generator, not only the accurate powder dropping is ensured, but also the uniformity of powder spreading is improved, thus optimizing the processing quality of the part. At the same time, the non-contact leveling technology of the ultrasonic leveling device avoids the powder contamination and scraper wear problems that may be caused by traditional leveling methods, further improving the processing efficiency and accuracy. The introduction of the electric field generator effectively controls the spreading behavior of the powder, solves the problems of powder accumulation and slow powder spreading speed, and further improves the overall performance of the device. Finally, the effective recovery function of the recovery device for residual powder not only avoids the mixing of different powders, but also realizes the complete recyclability of the powder, greatly reducing the production cost and conforming to the development trend of green manufacturing. Description of the Drawings

[0036] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments in line with the present invention, and are used together with the specification to explain the principles of the present invention.

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0038] In the drawings:

[0039] Figure 1 is a schematic structural diagram of an embodiment of the multi-material additive manufacturing equipment of the present application;

[0040] Figure 2 is a front view structural diagram of an embodiment of the multi-material additive manufacturing equipment of the present application.

[0041] Reference numerals:

[0042] 1. A multi-material additive manufacturing equipment; 10. Workbench; 20. Powder spreading mechanism; 21. Powder bin; 211. Powder dropping port; 213. Nozzle; 23. Ultrasonic generator; 25. Recycling device; 251. Vacuum suction device; 253. Ultrasonic powder sieve; 30. Electric field generator; 40. Ultrasonic scraping device; 50. Spatter collector; 60. Mounting plate. Detailed implementation manners

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0044] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0045] As Figure 1 、 Figure 2 shown, a multi-material additive manufacturing equipment 1 provided by the present application includes:

[0046] Workbench 10;

[0047] A plurality of powder spreading mechanisms 20 are movably arranged above the workbench 10. Each powder spreading mechanism 20 includes a powder bin 21, an ultrasonic generator 23 and a recovery device 25. The powder bin 21 is provided with a powder dropping port 211. The ultrasonic generator 23 is connected to the powder dropping port 211. The powder dropping port 211 is arranged facing the workbench 10. One end of the recovery device 25 is arranged facing the workbench 10, and the other end communicates with the powder bin 21;

[0048] An electric field generator 30 is connected to the powder spreading mechanism 20 and the workbench 10, so as to form an electric field between the powder spreading mechanism 20 and the workbench 10;

[0049] An ultrasonic leveling device 40 is arranged above the workbench 10 and is arranged facing the workbench 10.

[0050] In this embodiment, the workbench 10 is made of high-strength aluminum alloy, having good rigidity and stability, and being able to withstand the vibration and weight during the operation of the equipment. The powder bin 21 is generally made of stainless steel, having good corrosion resistance and sealing performance.

[0051] Optionally, the workbench 10 can be made of granite, which is precisely ground and polished, having good thermal stability, being able to reduce the thermal deformation during the processing, and ensuring the processing accuracy. Although granite is heavy, it is more suitable for some occasions with extremely high requirements for stability and where the equipment does not need to be moved frequently. It is designed as a modular splicing structure, which is composed of multiple small granite modules connected by high-precision positioning pins and bolts. In this way, it is more convenient during the transportation and installation process, and if a certain module is damaged or its accuracy decreases, it can be replaced or repaired separately, reducing the maintenance cost.

[0052] In this embodiment, the powder bin 21 is made of 304 stainless steel, having good corrosion resistance and sealing performance. Its capacity varies according to different application scenarios, generally between 0.5 - 3 liters. The top of the powder bin 21 is provided with a sealing cover, which is convenient for adding powder and at the same time prevents the powder from getting damp and polluted. The powder dropping port 211 is located at the bottom of the powder bin 21, with a diameter usually between 3 - 8 mm, and is processed by high-precision numerical control to ensure the uniformity of powder dropping. A flow regulating valve is also installed at the powder dropping port 211 to precisely control the powder flow rate.

[0053] In this embodiment, the frequency range of the ultrasonic generator 23 is 20 - 50 kHz, and the power is 100 - 500 W. It can generate stable ultrasonic vibrations, promote the uniform dispersion of the powder during the powder dropping process, and prevent agglomeration. Its connection to the powder dropping port 211 or the nozzle 213 adopts a tight threaded connection or a welding method to ensure the effectiveness of vibration transmission. The ultrasonic generator 23 is internally equipped with advanced frequency automatic tracking and power adjustment circuits, which can adjust the ultrasonic parameters in real time according to the characteristics of the powder and the powder spreading requirements, ensuring that the powder always maintains a good dispersion state during the powder dropping process and preventing the occurrence of agglomeration phenomena.

[0054] In this embodiment, the electric field generator 30 can generate an electric field with an intensity of 1 - 10 kV / cm, and the electric field intensity and direction can be adjusted. It is composed of a high-voltage power supply module and electrode plates. The electrode plates are made of copper or aluminum with good electrical conductivity and their surfaces are treated with anti-oxidation. The shape and layout of the electrode plates are designed according to the shapes of the powder spreading mechanism 20 and the workbench 10. Common ones include parallel plate electrodes and annular electrodes, etc., to achieve effective control of powder spreading. The flat plate electrode is suitable for large-area powder spreading regions and can generate a relatively uniform electric field; the arc-shaped electrode plate can be customized according to specific powder spreading paths and part shapes to achieve precise control of the powder in complex regions. The insulating bracket is made of high-strength engineering plastics, with good insulation performance and mechanical strength, ensuring the safe operation of the electric field generator 30 under high voltage.

[0055] Optionally, multiple powder spreading mechanisms 20 are designed to be annularly distributed above the workbench 10 and rotate around the center of the workbench 10. Through the rotation mechanism and positioning device, different powder spreading mechanisms 20 can be quickly switched to work, improving work efficiency, especially suitable for the processing of complex parts that require frequent material replacement for powder spreading.

[0056] Optionally, the powder bin 21 and the ultrasonic generator 23 are connected by a magnetic adsorption method, and mutually matching magnetic components are respectively installed at the powder dropping port 211 of the powder bin 21 and the vibration end of the ultrasonic generator 23. This connection method is convenient for quickly disassembling and replacing the ultrasonic generator 23. When the ultrasonic generator 23 fails, it can be replaced without complex tools, reducing the equipment downtime.

[0057] Optionally, based on the principle of electrostatic induction, electrostatic induction electrode sheets are embedded in specific parts of the surface of the workbench 10 and the powder spreading mechanism 20. By applying an external high-voltage electrostatic field, the powder can be directionally arranged and spread under the action of the electric field. Compared with the traditional electric field generator 30, this method has a simpler structure, reduces complex circuit connections and high-voltage components, and improves the safety and stability of the equipment. The electrode material is a metal electrode coated with graphene. Graphene has excellent electrical conductivity and chemical stability, which can enhance the strength and uniformity of the electric field, while reducing the corrosion and loss of the electrode during use and extending the service life of the electrode.

[0058] Optionally, the ultrasonic leveling device 40 adopts a piezoelectric ceramic array vibration structure to replace the traditional ultrasonic generator 23. The piezoelectric ceramic array can intelligently adjust the vibration frequency and amplitude according to the shape and thickness distribution of the powder layer to achieve a more precise leveling effect. For example, it automatically increases the vibration intensity in areas where the powder is thickly piled, and appropriately reduces the vibration intensity in thinner areas to avoid over-leveling or insufficient leveling.

[0059] Furthermore, multiple powder spreading mechanisms 20 are arranged side by side.

[0060] In this embodiment, when multiple powder spreading mechanisms 20 are arranged side by side, the distance between adjacent powder spreading mechanisms 20 is between 50 - 200 mm for easy installation and maintenance. Each powder spreading mechanism 20 is fixed on the mounting plate 60 by bolt connection or slot fixing to ensure that there is no displacement during the operation of the equipment. At the same time, to facilitate the distinction of different powder spreading mechanisms 20, the material name or number can be marked on their outer shells to facilitate operation and management by the operator.

[0061] Optionally, the powder spreading mechanisms 20 are arranged in a matrix pattern, that is, multiple powder spreading mechanisms 20 are arranged in a multi-row and multi-column matrix form. This arrangement is more flexible and efficient when processing large-area parts or when complex pattern powder spreading requires the simultaneous use of multiple materials. By controlling the working sequence and parameters of the powder spreading mechanisms 20 in different rows and columns of the matrix, diverse powder spreading effects can be achieved, such as manufacturing a functional structure with a gradually changing material distribution on a large plate.

[0062] Furthermore, the powder bin 21 further includes a nozzle 213. The nozzle 213 is connected to the powder dropping port 211, and the ultrasonic generator 23 is connected to the nozzle 213.

[0063] In this embodiment, the nozzle 213 is made of stainless steel or ceramic material, having good wear resistance and corrosion resistance. The outlet shape of the nozzle 213 has various options such as circular and rectangular. The outlet diameter of the circular nozzle 213 is between 1 - 5 mm, and the length and width of the rectangular nozzle 213 can be customized according to the actual powder spreading requirements. The interior of the nozzle 213 is designed as a streamline channel to reduce the resistance of the powder during spraying, ensuring that the powder can be sprayed evenly and stably.

[0064] The connection part between the ultrasonic generator 23 and the nozzle 213 is sealed with sealant or rubber gasket to prevent powder leakage and loss of ultrasonic energy. At the same time, a shock absorption device is provided at the connection part to reduce the influence of ultrasonic vibration on other components of the equipment.

[0065] Optionally, a multi - nozzle composite nozzle 213 is adopted, with multiple spray holes of different diameters and shapes integrated on one nozzle 213 body. During the powder spreading process, according to different material characteristics and powder spreading requirements, different spray holes can be selectively opened or multiple spray holes can be opened simultaneously for powder spraying, realizing the mixed spraying or layered spraying of multiple powders, and improving the flexibility and diversity of material feeding. For example, for some parts that need to form a gradient material structure in a local area, it can be achieved by controlling the powder flow rate and spraying time of different spray holes.

[0066] Optionally, an elastic coupling is used to connect the ultrasonic generator 23 and the nozzle 213. The elastic coupling can effectively transmit ultrasonic vibration, and at the same time can buffer the impact force generated by equipment vibration or the movement of the nozzle 213, protecting the connection part between the ultrasonic generator 23 and the nozzle 213, reducing connection looseness or damage caused by long - term vibration, and improving the reliability and stability of the equipment.

[0067] Furthermore, the recovery device 25 includes a vacuum suction device 251 and an ultrasonic powder sieve 253. The suction port of the vacuum suction device 251 faces the workbench 10, and the other end is connected to the powder bin 21. The ultrasonic powder sieve 253 is arranged between the vacuum suction device 251 and the powder bin 21.

[0068] In this embodiment, the suction force of the vacuum suction device 251 can reach 50 - 200 kPa and is connected to the powder bin 21 through a pipeline. The pipeline is made of high - temperature - resistant and corrosion - resistant silicone tube or polytetrafluoroethylene tube to prevent the powder from blocking the pipeline during the recovery process. The suction port is usually designed in a horn shape to increase the suction area and improve the recovery efficiency.

[0069] Optionally, an oil-free vacuum pump is used as the power source. The suction port is connected to the workbench 10 through a high-temperature and corrosion-resistant silica gel hose to ensure sufficient suction volume. An adjustable suction hood is installed at the suction port, which can adjust the suction range and angle according to the powder distribution, improving the recovery efficiency. The vacuum suction device 251 is also equipped with a pressure sensor and an automatic control system. When the suction pressure exceeds the set value, the system will automatically alarm and adjust the working state of the vacuum pump to ensure the safe operation of the equipment.

[0070] In this embodiment, the ultrasonic powder sieve 253 uses ultrasonic vibration of 30 - 60 kHz to screen the recovered powder. The aperture of the sieve mesh is between 50 - 200 meshes and can be replaced according to the particle size requirements of the powder. A vibration motor and an elastic support structure are provided inside the powder sieve to ensure the stability and high-efficiency screening performance of the sieve mesh during vibration.

[0071] The housing of the powder sieve is made of stainless steel, with good sealing performance and strength. During the screening process, the vibration condition of the sieve mesh can be monitored in real time through a vibration sensor. When the vibration is abnormal, the system will automatically issue an alarm and stop working to prevent the sieve mesh from being blocked or damaged. At the same time, the powder sieve is also equipped with an automatic screen cleaning device, which can clean the sieve mesh regularly to ensure the stability of the screening efficiency.

[0072] Optionally, the ultrasonic powder sieve 253 is also installed with a powder particle size detection sensor to monitor the particle size distribution of the screened powder in real time. When the particle size does not meet the requirements, the system will automatically adjust the vibration parameters or issue an alarm to ensure the quality of the recovered powder.

[0073] Optionally, the ultrasonic powder sieve 253 introduces intelligent image recognition technology to assist the screening process. A high-definition camera is installed inside the ultrasonic powder sieve 253 to capture the powder image on the sieve mesh in real time, and the particle size distribution and agglomeration condition of the powder are judged through image analysis algorithms. The ultrasonic vibration frequency and the vibration amplitude of the sieve mesh are automatically adjusted according to the analysis results to realize intelligent screening operation and improve the screening accuracy and efficiency.

[0074] Furthermore, the multi-material additive manufacturing equipment further includes a spatter collector 50, which is movably arranged above the workbench 10 and is used to collect spattered powder.

[0075] In this embodiment, the material of the splatter collector 50 is generally selected as transparent acrylic or polycarbonate material, which is convenient for observing the splattered powder collected inside. Its shape is funnel-shaped or box-shaped, with a large opening area, and can effectively collect the splattered powder around the workbench 10. A detachable collection box is provided inside the collector. When the collection box is full of powder, it can be conveniently taken out for cleaning. The connection method between the collector and the workbench 10 is an adjustable bracket connection, which can adjust the height and angle of the collector according to the actual processing situation to ensure the best collection effect.

[0076] Optionally, the splatter collector 50 is designed as an air flow-guided collector. A plurality of air flow nozzles 213 are arranged around the workbench 10, and the splattered powder is blown towards the collector inlet by generating a directional air flow. Compared with the traditional passive collection method, this method can expand the collection range and improve the collection efficiency, especially suitable for processing scenarios with relatively serious powder splashing. At the same time, the speed and direction of the air flow can be adjusted to adapt to different processing technologies and powder characteristics.

[0077] Optionally, the material of the splatter collector 50 is made of stainless steel fiber sintered felt. For the filtering part of the collector, the stainless steel fiber sintered felt has the advantages of high porosity, high filtering precision, good air permeability, high temperature resistance and corrosion resistance, can effectively filter and collect the splattered powder, and is convenient for cleaning and reuse.

[0078] Furthermore, the multi-material additive manufacturing equipment further includes a mounting plate 60 and a position driving device. A plurality of powder spreading mechanisms 20 are all mounted on the mounting plate 60, and the plurality of powder spreading mechanisms 20 are arranged side by side. The mounting plate 60 is located above the workbench 10, and the position driving device is drivingly connected to the mounting plate 60 to drive the mounting plate 60 to move in the horizontal and vertical directions.

[0079] In this embodiment, the mounting plate 60 is made of aluminum alloy or carbon fiber composite material, and has the characteristics of light weight and high strength. The thickness is between 10 - 30 mm, and is selected according to the number and weight of the powder spreading mechanisms 20. The mounting plate 60 is provided with positioning holes and threaded holes for accurately mounting the powder spreading mechanisms 20 and other accessories. The accuracy of the positioning holes can reach ±0.05 mm, ensuring the accurate installation position of the powder spreading mechanisms 20.

[0080] In this embodiment, the position driving device is composed of a motor, a lead screw, a guide rail and a controller. The motor can be selected as a stepper motor or a servo motor, which can achieve precise position control. The lead screw adopts a high-precision ball screw, and the guide rail is a linear guide rail, ensuring the smoothness and accuracy of the mounting plate 60 during movement. The controller can precisely control the movement path and speed of the mounting plate 60 through programming to meet the needs of different part processing.

[0081] Furthermore, the number of mounting plates 60 is multiple, and the multiple mounting plates 60 are arranged side by side along the extending direction of the workbench 10.

[0082] In this embodiment, when the multiple mounting plates 60 are arranged side by side along the extending direction of the workbench 10, the gap between adjacent mounting plates 60 is between 20 - 50 mm, which is convenient for wiring and maintenance. Each mounting plate 60 has an independent position driving device and control system, and can realize independent or coordinated movement. When machining large parts, the multiple mounting plates 60 can work simultaneously, improving the efficiency and coverage of powder spreading.

[0083] Furthermore, the number of ultrasonic leveling devices 40 is multiple, and one ultrasonic leveling device 40 is correspondingly connected to one powder spreading mechanism 20.

[0084] In this embodiment, a rigid connection or an elastic connection method is adopted between each ultrasonic leveling device 40 and the corresponding powder spreading mechanism 20. A rigid connection can ensure the movement synchronization between the leveling device and the powder spreading mechanism 20, but has high requirements for installation accuracy; an elastic connection can buffer vibration and displacement to a certain extent, reducing the wear of the equipment. An adjusting device is provided at the connection part to precisely adjust the relative position between the leveling device and the powder spreading mechanism 20, ensuring the consistency of the leveling effect.

[0085] Optionally, the ultrasonic leveling device 40 and the powder spreading mechanism 20 are connected by a flexible robotic arm. The flexible robotic arm has multiple degrees of freedom and can freely bend and extend within a certain range. This connection method enables the ultrasonic leveling device 40 to better adapt to the surfaces of powder layers with different shapes and heights, realizing all-round leveling operations, and improving the leveling effect and quality. At the same time, the flexible robotic arm can automatically adjust its position and posture during the operation of the equipment, avoiding collisions with other components, and improving the safety and reliability of the equipment.

[0086] Furthermore, the ultrasonic leveling device 40 is connected to the surface of the mounting plate 60 facing the workbench 10.

[0087] In this embodiment, the ultrasonic leveling device 40 is connected to the surface of the mounting plate 60 facing the workbench 10 by bolts or welding. Reinforcing ribs or shock pads are provided at the connection part to enhance the stability of the leveling device and reduce vibration transmission. Wiring grooves for power lines and signal lines are reserved on the mounting plate 60 to ensure the safe and reliable electrical connection of the leveling device without affecting the normal operation of the equipment.

[0088] The present invention also provides a method for a multi-material additive manufacturing device. The method for the multi-material additive manufacturing device includes the multi-material additive manufacturing device. The specific structure of the multi-material additive manufacturing device refers to the above embodiments. Since the method for the multi-material additive manufacturing device adopts all the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0089] In this embodiment, the method for the multi-material additive manufacturing device includes the following steps:

[0090] S1. Determine the distribution of different materials according to the part design to form multi-material slices and corresponding powder feeding strategies, and determine the laser forming, machining, and heat treatment paths according to the physical properties of the materials and the interface positions.

[0091] S2. Add corresponding powders to each powder bin 21.

[0092] S3. Turn on the first powder spreading mechanism 20, turn on the ultrasonic generator 23 and the electric field generator 30, turn on the ultrasonic leveling device 40, and perform powder spreading on the entire forming area of the current layer.

[0093] S4. Turn on the laser to sinter the powder.

[0094] S5. Turn on the recovery device 25 to suck the powder into the powder bin 21.

[0095] S6. Turn on the other powder spreading mechanisms 20 in sequence, and repeat steps S3 to S5 until the entire part is processed.

[0096] Step S1: When determining the distribution of different materials, use advanced CAD / CAM software for part design and material distribution planning. The software can automatically generate a multi-material slice model and corresponding powder feeding strategies according to factors such as the mechanical property requirements and thermal property requirements of the part. At the same time, by simulating and analyzing the interface bonding situation of different materials and the thermal stress distribution during the processing, optimize the laser forming, machining, and heat treatment paths to ensure the quality and performance of the part.

[0097] Step S2: When adding powder to the powder bin 21, an automatic powder feeding system or manual addition method can be used. The automatic powder feeding system transports the powder from the storage container to the powder bin 21 through pipelines and screw feeders. The manual addition method requires the operator to use special measuring tools and instruments to add the powder according to the specified weight and ratio to ensure the accurate amount and composition of the powder in each powder bin 21.

[0098] Step S3: When starting the powder spreading mechanism 20, first start the ultrasonic generator 23 and the electric field generator 30 to make them reach the predetermined working parameters. The frequency and power of the ultrasonic generator 23 can be adjusted according to the properties of the powder and the powder spreading requirements, and the electric field intensity and direction of the electric field generator 30 can also be optimized according to the particle size and fluidity of the powder. During the powder spreading process, by real-time monitoring the spreading thickness and uniformity of the powder, the parameters of the ultrasonic generator 23 and the electric field generator 30 are adjusted by using the feedback control system to ensure the quality of powder spreading.

[0099] Step S4: When starting the laser for powder sintering, the laser source can be a fiber laser or a CO2 laser. At the same time, a laser power monitoring system and a spot shaping device are equipped to ensure the stability of the laser energy and the uniformity of the spot, and improve the sintering quality.

[0100] Step S5: When starting the recovery device 25, first start the vacuum suction device 251 to suck the excess powder on the surface of the workbench 10 into the ultrasonic powder sieve 253. During the suction process, by adjusting the suction force and suction time of the vacuum suction device 251, it is ensured that the powder can be completely recovered, and at the same time, the impact on the formed part is avoided. After the ultrasonic powder sieve 253 screens the recovered powder, the qualified powder is sent back to the powder bin 21, and the unqualified powder is collected and processed to prevent it from entering the processing system again.

[0101] Step S6: When successively starting other powder spreading mechanisms 20, operate according to the design requirements of the part and the material distribution sequence. During the switching process of different powder spreading mechanisms 20, the system will automatically clean and calibrate the workbench 10 to ensure the accuracy and quality of the next powder spreading. At the same time, the working parameters and processing processes of each powder spreading mechanism 20 are recorded and stored for subsequent quality traceability and process optimization.

[0102] In another embodiment, there is also a spatter collector 50, and the method of the multi-material additive manufacturing equipment includes the following steps:

[0103] S1. Determine the distribution of different materials according to the part design, form multi-material slices and corresponding material spreading strategies, and determine the laser forming, processing and heat treatment paths according to the material physical properties and interface positions;

[0104] S2. Add the corresponding powder to each powder bin 21;

[0105] S3. Start the first powder spreading mechanism 20, start the ultrasonic generator 23 and the electric field generator 30, start the ultrasonic scraping device 40, perform powder spreading on the entire forming area of the current layer, and start the spatter collector 50 during the powder forming process;

[0106] S4. Start the laser for powder sintering;

[0107] S5. Turn on the recycling device 25 to suck the powder into the powder bin 21;

[0108] S6. Turn on other powder spreading mechanisms 20 in sequence and repeat steps S3 to S5 until the entire part is processed.

[0109] In actual operation

[0110] Example 1:

[0111] To improve the properties of NiTi materials and solve problems such as the difficulty in regulating shape memory properties, Zr is added to NiTi using a multi-material printing device to achieve property regulation. The NiTi uses uniform powder with an average particle size of 40 μm and is defined as powder A. The NiTi alloy is formed in the area of the component that requires a lower phase change temperature, and the powder of uniformly mixed NiTi and Zr is used in the area that requires a higher phase change temperature. The Zr content ranges from 10 at.% to 40 at.%, corresponding to a phase change temperature of 50°C to 250°C. According to the design requirements of the part, the phase change temperature zoning is realized on the software. The software determines the required Zr ratio according to the temperature, and at the same time, the powders are respectively defined as powders B, C, D... according to the increasing Zr ratio. And the powders are prepared. Powders A, B, C, D... are respectively placed in their respective powder bins, and the corresponding arrays of powder dropping ports 211 connected to the powder bins are defined as powder dropping port arrays A’, B’, C’, D’... Before printing this layer, the powder spreading arm moves from one side of the powder bed to the other side. According to the settings before printing, during the movement, the ultrasonic generator 23 connected to the nozzle below the A powder bin is turned on at the position where A powder is required, so that the A powder drops, and the electric field between the powder outlet and the powder bed is turned on to constrain the movement of the powder and reduce powder accumulation. At the same time, during the movement of the powder spreading arm, the high-power ultrasonic generator 23 behind the powder outlet follows above the powder bed and emits ultrasonic waves to make the powder spread evenly. The set laser forming parameters of A powder are used to form the area that requires A powder. During the forming process, the computer is used to control the splash collector to move to the downwind position of the molten spot to collect splashes and follow the forming area. After the collection is completed, the splash collector is controlled to move back to its original position. The A powder in the entire powder bed area is laser sintered with low energy to fix the powder and play a supporting role, but it can be removed by vibration decomposition after forming is completed. After forming is completed, the A powder on the powder bed is sucked and recovered by a micro-vacuum suction device, and the recovered powder is recycled to the corresponding powder bin 21 of NiTi through an ultrasonic powder sieve 253. After completion, the powder spreading arm is moved. According to the program settings, when the powder spreading arm moves above the area that requires B powder, the ultrasonic generating device and the electric field on the powder bin containing B powder are turned on to make the powder drop in the specified area and be homogenized by the ultrasonic homogenizing device on the powder spreading arm. The laser forming parameters of B powder are used to melt and form the specified area, and the splash collection device is used to collect splashes at the downwind position. After forming is completed, the vacuum suction device connected to the B powder bin is used to recover the powder on the powder bed, and it is recycled into the powder bin through an ultrasonic vibration sieve. Repeat the above steps until the forming of all areas with different Zr ratios is completed. Layer by layer and reciprocally, finally, the manufacturing of a gradient function part with different phase change temperatures in different areas is realized.

[0112] Example 2:

[0113] Use a multi-material printing device to fabricate a copper-silicon steel motor with high conductivity, high magnetism, low energy consumption, and high efficiency. First, perform slicing, path planning, and material distribution design according to the motor design. Add Fe-Si powder and copper powder into separate powder bins, and define them as powder A and powder B respectively. During the movement of the powder spreading arm, first control the falling of powder A using the ultrasonic generator 23 connected between the powder bin of powder A and the powder dropping port 211. Turn on the electric field between the powder outlet and the powder bed to reduce powder accumulation. At the same time, during the movement of the powder spreading arm, combine the high-power ultrasonic generator 23 behind the nozzle close to the upper part of the powder bed to emit ultrasonic waves to make the powder spread evenly. Use the laser forming parameters of powder A to form the powder A area. Move the splash collector to the corresponding forming position of powder A, collect the splashes during the forming process, and prevent the splashes from falling into the formed part and affecting its performance. Use low energy to laser sinter the powder A in the entire powder bed area to fix the powder and play a supporting role, but it can be removed by vibration decomposition after the forming is completed. Use a micro-vacuum suction device to suck out the remaining loose powder of the unformed powder A, and then recycle powder A to the corresponding powder bin 21 through the ultrasonic powder sieve 253. Perform the same above-mentioned operation steps for the area that needs to form the motor winding using powder B, layer by layer in a reciprocating manner, complete the printing of the copper-silicon steel motor, and finally complete the manufacturing of a motor with small volume, high efficiency, and low energy consumption.

[0114] Example 3:

[0115] The formed outer layer is a composite material strengthened by ceramic particles, and the inner layer is a high-performance part made of a high-toughness alloy material, which not only improves the hardness and wear resistance of the material surface but also ensures that the material has toughness and plasticity. First, load the high-toughness metal material into the powder bin A. Before forming the inner layer area, when the powder spreading arm passes above the area that requires the high-toughness metal material during its movement, use the ultrasonic generator 23 on the A' powder dropping array to control the powder to fall to the designated position. At the same time, turn on the electric field between the powder outlet and the powder bed to reduce powder accumulation. During the movement of the powder spreading arm, use the high-power ultrasonic generator 23 behind the nozzle to approach above the powder bed and emit ultrasonic waves to make the powder spread evenly for powder homogenization. Use the forming parameters of the high-toughness metal to form the inner area of the part. Move the splash collector to the corresponding position where the material melts to collect the splashes during the forming process and prevent the splashes from falling into the formed part and affecting its performance. Use low energy to laser sinter the high-toughness metal powder in the entire powder bed area to fix the powder and play a supporting role, but it can be removed by vibration decomposition after the forming is completed. Use a micro-vacuum suction device to suck out the excess loose powder, and recycle the recyclable metal powder to the corresponding powder bin 21 through the ultrasonic powder sieve 253. Perform the same operation steps for the outer layer area using the composite material added with ceramic particles for powder spreading and forming. After the forming is completed, do not perform sintering. Pass all the composite materials added with ceramic particles through vacuum suction, recovery, and filtration and then enter the powder bin B. Repeat layer by layer to complete the printing of the high-performance part and realize the manufacture of a high-performance sample with high hardness, high wear resistance, and high toughness.

[0116] It can be understood that the above embodiments only represent the preferred embodiments of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, all equivalent transformations and modifications made to the scope of the claims of the present invention shall fall within the scope covered by the claims of the present invention.

Claims

1. A multi-material additive manufacturing device, characterized in that: include: Workbench; A plurality of powder spreading mechanisms, each of which is movably arranged above the workbench, and each of which comprises a powder bin, an ultrasonic generator and a recovery device. The powder bin is provided with a powder drop opening, the ultrasonic generator is connected to the powder drop opening, the powder drop opening is arranged toward the workbench, one end of the recovery device is arranged toward the workbench, and the other end is connected to the powder bin; An electric field generator, the electric field generator is connected to the powder spreading mechanism and the workbench to form an electric field between the powder spreading mechanism and the workbench; An ultrasonic scraping device is arranged above the workbench and toward the workbench.

2. The multi-material additive manufacturing device according to claim 1, characterized in that: A plurality of the powder spreading mechanisms are arranged side by side.

3. A multi-material additive manufacturing device according to claim 2, characterized in that: The powder bin also includes a nozzle, which is connected to the powder drop port, and the ultrasonic generator is connected to the nozzle.

4. The multi-material additive manufacturing device according to claim 3, characterized in that: The recovery device includes a vacuum cleaner and an ultrasonic powder sifter. The air inlet of the vacuum cleaner is arranged toward the workbench, and the other end is connected to the powder bin. The ultrasonic powder sifter is arranged between the vacuum cleaner and the powder bin.

5. A multi-material additive manufacturing device according to any one of claims 1 to 4, characterized in that: The multi-material additive manufacturing equipment also includes a spatter collector, which is movably arranged above the workbench and is used to collect spattered powder.

6. A multi-material additive manufacturing device according to any one of claims 1 to 4, characterized in that: The multi-material additive manufacturing equipment also includes a mounting plate and a position driving device. Multiple powder spreading mechanisms are mounted on the mounting plate, and multiple powder spreading mechanisms are arranged side by side. The mounting plate is located above the workbench. The position driving device drives the mounting plate to drive the mounting plate to move in the horizontal and vertical directions.

7. The multi-material additive manufacturing device according to claim 6, characterized in that: There are multiple mounting plates, and the multiple mounting plates are arranged in parallel along the extension direction of the workbench.

8. A multi-material additive manufacturing device according to any one of claims 1 to 4, characterized in that: There are multiple ultrasonic scraping devices, and one ultrasonic scraping device is correspondingly connected to one powder spreading mechanism.

9. The multi-material additive manufacturing device according to claim 7, characterized in that: The ultrasonic scraping device is connected to a side surface of the mounting plate facing the workbench.

10. A method of multi-material additive manufacturing equipment, using the multi-material additive manufacturing equipment as claimed in any one of claims 1 to 9, characterized in that: The method of the multi-material additive manufacturing device comprises the following steps: S1. Determine the distribution of different materials according to part design, form multi-material slices and corresponding material delivery strategies, and determine the laser forming, processing and heat treatment paths according to the material physical properties and interface positions; S2. Add corresponding powder to each powder bin; S3, starting the first powder spreading mechanism, starting the ultrasonic generator and the electric field generator, starting the ultrasonic scraping device, and spreading the powder over the entire forming area of ​​the current layer; S4, turning on the laser to sinter the powder; S5, start the recovery device to suck the powder into the powder bin; S6. Start the other powder spreading mechanisms in sequence, and repeat steps S3 to S5 until the entire part is processed.

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