Aluminum alloy powder production method and equipment for metal 3D printer

Abstract

The invention discloses an aluminum alloy powder production method for a metal 3D printer and equipment thereof, and relates to the technical field of aluminum alloy powder production, the method comprises the following steps: raw material pretreatment and accurate proportioning: strictly screening aluminum and various alloy element raw materials, and removing surface impurities, oxides and other foreign matters; through precise raw material pretreatment and proportioning and in combination with the vacuum induction melting technology, the problems that in the prior art, aluminum alloy components are not uniform and the purity is low are solved, full and uniform fusion of all alloy elements can be ensured by precisely controlling the melting temperature and the high-vacuum environment, oxidation and impurity introduction are reduced, and the production efficiency is improved. And the efficient screening process of ultrasonic vibration screening equipment is adopted, aluminum alloy powder with the accurate and uniform particle size can be obtained, the powder fluidity and powder laying uniformity in the 3D printing process are ensured, the consistency and stability of the printing quality are improved, and the 3D printing quality is improved. And the yield of products is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy powder production, and in particular to a method and equipment for producing aluminum alloy powder for a metal 3D printer. Background Art

[0002] With the rapid development of the manufacturing industry, 3D printing technology, as an emerging additive manufacturing process, is gradually changing the traditional production model. 3D printers can build complex-shaped solid parts by stacking materials layer by layer based on three-dimensional model data, without the need for mold manufacturing, cutting and other processes in traditional processing technology, which greatly shortens the product development cycle and reduces production costs. It also has unique advantages in personalized customization and complex structural parts manufacturing. Among the many 3D printing materials, metal materials have attracted much attention due to their good mechanical properties and wide application fields. Among them, aluminum alloys have become one of the commonly used materials in the field of metal 3D printing due to their low density, high strength, good corrosion resistance and good processing performance. They are widely used in aerospace, automobile manufacturing, medical equipment and other high-end manufacturing fields.

[0003] However, there are many shortcomings in the existing production methods of aluminum alloy powder for 3D printers. In the smelting process, it is usually difficult to accurately control the smelting temperature, resulting in uneven alloy composition, which will directly affect the stability of the mechanical properties of 3D printed parts, making it easy for the printed parts to have problems such as insufficient local strength or stress concentration during use. In addition, the traditional screening process is not effective for aluminum alloy powder, which is easy to agglomerate. The screen is easily blocked and the screening efficiency is low. It is difficult to obtain aluminum alloy powder with precise and uniform particle size, which cannot meet the increasingly stringent requirements of metal 3D printing for high-quality aluminum alloy powder. Therefore, it is necessary to propose a method and equipment for producing aluminum alloy powder for metal 3D printers to solve the problems in the prior art. Summary of the invention

[0004] The purpose of the present invention is to make up for the shortcomings of the prior art and provide a method and equipment for producing aluminum alloy powder for a metal 3D printer. It can accurately control the melting temperature and high vacuum environment to ensure that the alloy elements are fully and evenly integrated, reduce oxidation and the introduction of impurities, thereby significantly improving the mechanical properties stability and corrosion resistance of 3D printed parts. Ultrasonic vibration screening equipment and technology are used, and the efficient screening process can obtain aluminum alloy powder with precise and uniform particle size.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for producing aluminum alloy powder for a metal 3D printer and equipment thereof, the method comprising the following steps:

[0006] Raw material pretreatment and precise proportioning: Strictly screen aluminum and various alloy element raw materials, remove surface impurities, oxides and other foreign matter, use spectrometer to ensure that the purity of each raw material reaches more than 99.5%, and configure the proportion of each alloy element to form a raw material formula based on the comprehensive requirements of the target aluminum alloy powder in terms of strength, toughness, corrosion resistance and printability. Among them, the alloy elements include but are not limited to magnesium, silicon, copper, zinc, and manganese. Each element has a specific content range under different performance requirements. When preparing high-strength and high-corrosion-resistant aluminum alloy powder, the magnesium content is 2%-5%, the silicon content is 0.5%-1.5%, the copper content is 1%-3%, the zinc content is 0.2%-0.8%, and the manganese content is 0.1%-0.5%;

[0007] Vacuum induction melting: put the prepared raw materials into a vacuum induction furnace with an efficient thermal insulation layer and a precise temperature control system. First, evacuate the furnace to a high vacuum degree below 1×10-3Pa, remove air, moisture and other volatile impurities in the furnace, and use a multi-stage gradient heating method. Initially, the temperature is raised to 500℃ at a rate of 50℃ / min. Keep it at this temperature for 30-60 minutes to soften the raw materials and heat them evenly. Then, the temperature is raised to the target melting range of 750℃-900℃ at a rate of 30℃ / min. During the melting process, the melt is stirred at a speed of 100-500r / min by an electromagnetic stirring device. The temperature is monitored and adjusted in real time by the high-precision temperature sensor and intelligent control system in the furnace to control the temperature fluctuation within ±5℃.

[0008] High-pressure inert gas atomization powder making: After smelting, the aluminum alloy melt is introduced into the atomization chamber through a guide tube with a flow regulating valve and a temperature monitoring device at the bottom. A high-pressure inert gas atomization system is used. Before atomization, the air pressure in the atomization chamber is adjusted to a positive pressure state of 0.5-1.0MPa. The high-pressure gas valve is opened to allow the inert gas to impact the aluminum alloy melt flow at a high speed of 2.5MPa-5MPa. Through the supersonic annular atomization nozzle, the inert gas and the melt flow form an angle of 30°-60° for high-speed interaction, breaking the melt into tiny droplets. During the atomization process, the inert gas is continuously added to the atomization chamber at a flow rate of 10-30L / min. The atomized powder particles fall into the cooling collection bucket below under the action of gravity and airflow;

[0009] Ultrasonic vibration screening and post-processing: The aluminum alloy powder in the cooling collection barrel is transported to the ultrasonic vibration screening equipment to drive the screen assembly to work. The screen assembly uses three layers of screens with different apertures and anti-adhesion coating on the surface, the upper layer is 100-200 mesh, the middle layer is 200-300 mesh, and the lower layer is 300-500 mesh. Under the action of ultrasonic vibration and gravity, the aluminum alloy powder passes through each layer of screen in turn for graded screening. The screened aluminum alloy powder is vacuum packaged. The packaging material is an aluminum foil composite bag with a thickness of 0.05-0.15mm. The inner layer of the composite bag is a polyethylene material with a thickness of 0.03-0.08mm.

[0010] Furthermore, when preparing high-toughness aluminum alloy powder, the raw material formula adjusts the magnesium content to 3%-6%, the silicon content to 0.3%-1%, the copper content to 0.5%-2%, the zinc content to 0.5%-1.2%, the manganese content to 0.1%-0.5%, and 0.05%-0.2% of titanium is added.

[0011] Furthermore, during the vacuum induction melting process, when the pressure fluctuation in the furnace exceeds ±10% of the set threshold, the pressure balancing device is automatically started for adjustment. The pressure balancing device maintains the pressure in the furnace stable by adjusting the opening of the intake valve and the exhaust valve, and the response time of the intake valve and the exhaust valve is within 2-5 seconds.

[0012] Furthermore, during the high-pressure inert gas atomization powder making process, the inner core structure of the supersonic annular atomizing nozzle has an adjustment range of 0-5mm, and is dynamically optimized according to the viscosity and flow rate of the aluminum alloy melt to ensure the consistency of the atomization effect. The atomizing chamber is provided with an observation window and an internal lighting device, and the observation window is made of a transparent ceramic material that is resistant to high pressure, high temperature and anti-atomization.

[0013] Furthermore, during the vacuum packaging process, the aluminum foil composite bag is subjected to ultraviolet sterilization treatment before packaging, and the sterilization time is 10-30 minutes to kill the microorganisms on the surface of the packaging material to ensure the microbial safety of the powder during storage and transportation. A humidity sensor is set in the packaging room. When the humidity exceeds 30%, the dehumidification device is started to control the humidity below 20%.

[0014] A kind of aluminum alloy powder production equipment for metal 3D printer, the equipment is an ultrasonic vibration screening equipment used for the production method described in claim 1, the equipment comprises an equipment housing and an ultrasonic generator, a sealing cover is installed on the top of the equipment housing, a feed port is arranged on the top of the sealing cover, two screen frames are arranged inside the equipment housing, two guide grooves are provided on the inner wall of the equipment housing, guide blocks are installed on the outer surfaces of the two screen frames, and the guide blocks are slidably connected to the inner walls of the guide grooves, two groups of limit grooves are provided on the inner wall of the equipment housing, two limit assemblies are installed on the inner walls of the two screen frames, a screen is installed on the inner wall of the screen frame, a group of transducers are installed on the bottom surfaces of the two screen frames, the outer surfaces of the two screen frames are fixedly connected with a discharge pipe, and the discharge pipe extends to the outside of the equipment housing at one end away from the screen frame.

[0015] Furthermore, the limiting assembly includes a square frame fixedly embedded in the inner wall of the screen frame, the inner wall of the square frame is slidably connected with a connecting plate, the outer surface of the connecting plate is installed with a limiting plate, and one end of the limiting plate away from the connecting plate is clamped with the inner wall of the limiting groove.

[0016] Furthermore, a spring is installed between the connecting plate and the inner wall of the frame, a pull rod is installed on the outer surface of the connecting plate, and a pull ring is installed at one end of the pull rod away from the connecting plate.

[0017] Furthermore, the ultrasonic generator has an automatic power adjustment function, and automatically adjusts the ultrasonic power between 100-500W according to the load condition of the screen, and the screen and the screen frame are sealed with a sealing strip.

[0018] Compared with the prior art, the aluminum alloy powder production method and equipment for metal 3D printer have the following beneficial effects:

[0019] The present invention solves the problems of uneven composition and low purity of aluminum alloy in the existing process through precise raw material pretreatment and proportioning combined with vacuum induction melting technology. The precisely controlled melting temperature and high vacuum environment can ensure that the alloy elements are fully and evenly integrated, reduce oxidation and the introduction of impurities, thereby improving the mechanical properties stability and corrosion resistance of 3D printed parts. The efficient screening process using ultrasonic vibration screening equipment can obtain aluminum alloy powder with precise and uniform particle size, ensuring the fluidity and powder spreading uniformity of the powder during 3D printing, improving the consistency and stability of printing quality, and improving the product yield.

[0020] Other advantages, objectives and features of the present invention will be set forth in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be taught from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 It is a schematic diagram of the three-dimensional structure of the ultrasonic vibration screening equipment;

[0023] Figure 2 It is a schematic diagram of the connection structure between the equipment housing and the screen frame;

[0024] Figure 3 It is a three-dimensional structural schematic diagram of the screen frame;

[0025] Figure 4 It is a schematic diagram of the three-dimensional structure of the limiting component;

[0026] Figure 5 Schematic diagram of the internal structure of the box.

[0027] In the figure: 1. Equipment housing; 2. Ultrasonic generator; 3. Sealing cover; 4. Feed inlet; 5. Screen frame; 6. Guide groove; 7. Guide block; 8. Limiting groove; 9. Limiting assembly; 901. Frame; 902. Connecting plate; 903. Limiting plate; 904. Spring; 905. Pull rod; 906. Pull ring; 10. Screen; 11. Transducer; 12. Discharge pipe. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1

[0030] Aluminum and various alloy element raw materials are strictly screened to remove surface impurities, oxides and other foreign matter. Spectrometer is used to ensure that the purity of aluminum raw materials reaches 99.7%, the purity of magnesium is 99.8%, the purity of silicon is 99.6%, the purity of copper is 99.5%, etc. The purity of each raw material is above 99.5%.

[0031] According to the performance requirements of the target aluminum alloy powder in terms of high strength and good corrosion resistance, professional material performance simulation software is used to accurately calculate and configure the proportions of each alloy element, with the magnesium content set to 3%, the silicon content to 1%, the copper content to 2%, the zinc content to 0.5%, and the manganese content to 0.3%, to form a raw material formula.

[0032] Put the prepared raw materials into a vacuum induction furnace with a high-efficiency heat insulation layer and a precise temperature control system. First, evacuate the furnace to 8×10 -4 The high vacuum degree of Pa was set, and a multi-stage gradient heating method was adopted. The temperature was initially raised to 500°C at a rate of 50°C / min, and kept at this temperature for 40 minutes to allow the raw materials to be initially softened and heated evenly, and then the temperature was raised to the target melting range of 800°C at a rate of 30°C / min.

[0033] During the smelting process, the melt was stirred at a speed of 300 r / min using an electromagnetic stirring device, and the furnace circulation purification system was turned on at 8m 3 / h flow rate circulation purifies the furnace atmosphere to ensure that all components are fully and evenly mixed to form a uniform aluminum alloy melt. The temperature is monitored and adjusted in real time through the high-precision temperature sensor and intelligent control system in the furnace, and the temperature fluctuation is controlled within ±3°C. The key parameters such as melting temperature, pressure, stirring speed, etc. are recorded every 10 minutes to form a melting process data log.

[0034] After smelting, the aluminum alloy melt is introduced into the atomization chamber through a guide tube with a flow regulating valve and a temperature monitoring device at the bottom. A high-pressure argon atomization system is used. Before atomization, the air pressure in the atomization chamber is adjusted to a positive pressure state of 0.8MPa. The high-pressure gas valve is opened to allow argon gas to impact the aluminum alloy melt flow at a high speed at a pressure of 3.5MPa. Through a specially designed supersonic annular atomization nozzle (the inner core structure is adjusted to 2mm), the argon gas and the melt flow form a 45° high-speed interaction, breaking the melt into tiny droplets.

[0035] During the atomization process, argon is continuously added to the atomization chamber at a flow rate of 20L / min to maintain an inert atmosphere inside and ensure that the droplets are not oxidized or contaminated during the solidification process. The atomized powder particles fall into the cooling collection barrel below under the action of gravity and airflow. The cooling collection barrel adopts a circulating water cooling system to control the temperature in the barrel at 80°C. A spiral guide plate is installed in the barrel to make the powder particles spiral downward in the barrel, prolong the cooling time, accelerate the solidification of the powder particles and prevent the particles from agglomerating. At the same time, an electrostatic eliminator is installed between the atomization chamber and the cooling collection barrel to eliminate the static electricity generated by the powder particles during the atomization process and avoid powder agglomeration and pipeline blockage caused by electrostatic adsorption.

[0036] The aluminum alloy powder in the cooling collection barrel is transported to the ultrasonic vibration screening equipment. The ultrasonic generator of the equipment generates a high-frequency vibration signal of 30kHz to drive the vibration screen assembly. The vibration screen assembly adopts three layers of stainless steel screens with different apertures and polytetrafluoroethylene anti-adhesion coating on the surface, with an upper layer of 150 mesh, a middle layer of 250 mesh, and a lower layer of 400 mesh. Under the action of ultrasonic vibration and gravity, the aluminum alloy powder is graded and screened through each layer of screen in turn. During the screening process, the speed of the vibration motor is controlled at 1200r / min and the inclination angle of the screen is adjusted at 10° to optimize the screening efficiency. The upper screen retains larger particle impurities and agglomerates, the middle screen further screens out the main powder products with moderate particle size, and the lower screen collects finer powder particles, which can be deployed and used according to the requirements of subsequent 3D printing processes.

[0037] The sieved aluminum alloy powder is vacuum packaged. The vacuum degree in the packaging room is controlled at 5×10-3Pa. The packaging material is an aluminum foil composite bag with a thickness of 0.1mm. The inner layer of the composite bag is a polyethylene material with a thickness of 0.05mm. Before packaging, the powder is tested for metal foreign matter using a high-precision metal detector with a detection sensitivity of 0.1mm. 3 The above ensures that there is no metal foreign matter mixed in the packaged powder, and after packaging, each bag of powder is marked with a QR code, which contains detailed information such as the powder's batch number, production date, ingredient ratio, particle size distribution, etc., for traceability and quality control.

[0038] Embodiment 2

[0039] First, aluminum and alloy element raw materials are screened and processed comprehensively and meticulously. Advanced physical separation technologies, such as magnetic separation and flotation, are used to remove trace ferromagnetic impurities and other impurity particles with large density differences that may exist in aluminum raw materials. For alloy element raw materials such as magnesium, silicon, copper, zinc, manganese, and titanium, a combination of chemical purification and refining is used to further improve their purity, so that the purity of aluminum raw materials reaches 99.6%, the purity of magnesium elements is increased to 99.7%, the purity of silicon elements reaches 99.5%, the purity of copper elements is 99.5%, the purity of zinc elements is 99.6%, the purity of manganese elements is 99.5%, and the purity of titanium elements is 99.4%. The purity of each raw material is significantly higher than the standard requirement of 99.5%.

[0040] In the precise proportioning stage, based on the comprehensive performance requirements of high toughness and a certain strength of the target aluminum alloy powder, multiple rounds of calculations and analyses are carried out with the help of professional and high-precision material performance simulation software. The software fully considers the interaction, diffusion mechanism and synergistic effect of each alloy element in the aluminum alloy crystal structure on the final performance. After repeated simulations and optimizations, the magnesium content is determined to be 4%, the silicon content is 0.6%, the copper content is 1.5%, the zinc content is 0.8%, the manganese content is 0.2%, and 0.1% of titanium is added to form the most suitable raw material formula. This formula can maximize the toughness index while ensuring a certain strength of the aluminum alloy, such as the elongation at break can be increased to 15%-20%, and the yield strength is maintained between 200-250MPa, which meets the stringent requirements of specific high-end manufacturing fields for aluminum alloy materials.

[0041] The carefully prepared raw materials are carefully placed in a vacuum induction furnace with an excellent and efficient heat insulation layer and an ultra-precise temperature control system. Before the smelting starts, the furnace body is deeply vacuumed using highly sensitive vacuum detection equipment until the vacuum degree in the furnace reaches 9×10 -4 The extremely high level of Pa. This high vacuum environment can effectively remove the air, moisture and other volatile impurities that may remain in the furnace, and prevent the oxidation reaction and air absorption of the raw materials during the smelting process from the source, laying a solid foundation for the purity and stability of the subsequent smelting process.

[0042] A carefully designed multi-stage gradient heating program is used. In the initial stage, the furnace temperature is quickly raised to 500°C at a stable rate of 50°C / min. At this critical temperature node, the temperature is accurately maintained for 30 minutes. This heat preservation process can fully soften the raw materials and achieve initial uniform heating, ensuring that the components begin to have gentle and orderly physical and chemical interactions.

[0043] Subsequently, the temperature was steadily raised to the target melting range of 780°C at a more finely controlled rate of 30°C / min. During the entire melting process, the melt was continuously and evenly stirred at a moderate speed of 200r / min using an advanced electromagnetic stirring device. At the same time, the efficient circulation purification system in the furnace was turned on and its flow rate was set to 6m 3 / h, the atmosphere in the furnace is circulated and purified in real time. The high-precision temperature sensor in the furnace works closely with the intelligent and advanced control system to continuously monitor and accurately adjust the melting temperature in real time, strictly control the temperature fluctuation within a very small range of ±4°C, and, at a predetermined time interval, comprehensively record key parameters such as temperature, pressure, stirring speed, etc. during the melting process every 10 minutes to form a detailed and complete melting process data log, which provides rich and reliable data support for subsequent quality traceability and process optimization.

[0044] When the smelting process is successfully completed, the aluminum alloy melt is smoothly and accurately introduced into the atomization chamber through a guide tube equipped with a high-precision flow control valve and a high-sensitivity temperature monitoring device at the bottom under strict flow control and temperature monitoring. Before the atomization operation is started, the advanced air pressure regulation system is used to accurately adjust the air pressure in the atomization chamber to a standard positive pressure state of 0.7MPa, creating a stable and suitable air pressure environment for the subsequent atomization process.

[0045] High-pressure argon is used as the atomization power source. After the high-pressure gas valve is opened, the argon gas impacts the aluminum alloy melt flow at a precise high-speed pressure of 3 MPa. Through the specially designed supersonic annular atomizing nozzle with a flexibly adjustable inner core structure (the inner core is adjusted to 1.5 mm this time), the argon gas and the melt flow form a precise 40° high-speed interaction angle, thereby efficiently breaking the melt into tiny and uniform droplets. During the atomization process, argon gas is continuously replenished to the atomization chamber through an automated gas supply system, and the replenishment flow rate is stably controlled at 15L / min, ensuring that a stable and pure inert atmosphere is always maintained in the atomization chamber, effectively preventing the droplets from oxidation or other contamination during the solidification process.

[0046] Under the synergistic effect of gravity and airflow, the atomized powder particles fall orderly into the carefully designed cooling collection barrel below. The cooling collection barrel adopts an advanced circulating water cooling system to accurately control the temperature in the barrel at 70°C, and a spiral guide plate is cleverly arranged in the barrel. This unique design allows the powder particles to slowly settle along the spiral descending path in the barrel, significantly extending the cooling time, effectively accelerating the solidification process of the powder particles, and effectively preventing the agglomeration of particles. In addition, a static elimination device is scientifically arranged between the atomization chamber and the cooling collection barrel, which can promptly eliminate the electrostatic charge generated by the powder particles during the atomization process due to high-speed friction and other factors, and completely avoid adverse problems such as powder agglomeration and pipeline blockage caused by electrostatic adsorption, thereby ensuring the efficiency and stability of the entire atomization powder making process.

[0047] The aluminum alloy powder in the cooling collection barrel is smoothly transported to the ultrasonic vibration screening equipment through a closed and efficient conveying system. The core component of the equipment, the ultrasonic generator, can generate a stable and accurate 25kHz high-frequency vibration signal to drive the vibration screen assembly to work efficiently. The vibration screen assembly uses three layers of carefully customized stainless steel screens with different apertures and the surface is evenly coated with high-quality polytetrafluoroethylene anti-adhesion coating. The aperture of the upper screen corresponds to 120 mesh, the middle layer is 220 mesh, and the lower layer is 350 mesh. Driven by the powerful depolymerization effect of ultrasonic vibration and the coordinated drive of gravity, the aluminum alloy powder passes through each layer of the screen in order for fine classification and screening.

[0048] During the screening process, the intelligent control system accurately controls the speed of the vibration motor at 1000r / min, and reasonably adjusts the inclination angle of the screen at 8° to optimize the screening efficiency and effect. The upper screen can accurately intercept larger particle impurities and agglomerates, and the middle screen further screens out the main powder products with moderate particle size and good uniformity. The lower screen is responsible for collecting finer powder particles. These powders of different particle size levels can be flexibly allocated and used according to the diverse needs of subsequent 3D printing processes.

[0049] The screened aluminum alloy powder immediately enters the vacuum packaging process. A high-power vacuum pump is used to evacuate the packaging room, and the vacuum degree is strictly controlled at a high standard level of 8×10-3Pa. The packaging material is a high-quality aluminum foil composite bag, in which the thickness of the aluminum foil is 0.08mm, which has good barrier properties and can effectively block the erosion of the powder by external moisture, oxygen, etc. The inner layer of the composite bag is polyethylene material with a thickness of 0.04mm, which plays a role in buffering and protecting the powder.

[0050] Before packaging, the powder is thoroughly and carefully inspected for metal foreign bodies using highly sensitive metal foreign body detection equipment, with a detection sensitivity of up to 0.1mm. 3 The above ensures that there are no tiny metal foreign objects mixed in the packaged powder, ensuring the purity and quality stability of the powder. After packaging, advanced QR code identification technology is used to uniquely identify each bag of powder. The QR code comprehensively covers the powder's batch number, production date, precise ingredient ratio, detailed particle size distribution and other key information, so as to achieve convenient and efficient traceability and strict quality control throughout the product life cycle, providing solid and reliable quality assurance for downstream 3D printing applications.

[0051] Comparative Example

[0052] In the raw material pretreatment stage, only a simple and rough selection process was carried out, and no advanced impurity removal technology and precise purity detection methods were used. For aluminum and alloy element raw materials, only the appearance was roughly checked and their availability was judged based on experience, without in-depth analysis of their internal impurity content and actual purity. In the mixing stage, there was no scientific calculation and precise simulation analysis, but the proportion of each alloy element was roughly estimated according to past experience. For example, magnesium was about 3.5%, silicon was about 0.8%, copper was about 1.8%, etc. This extensive mixing method could not guarantee the uniform distribution and optimal proportion of each alloy element in the aluminum alloy system, which laid a serious hidden danger for the instability of subsequent product quality.

[0053] An ordinary resistance furnace is used for smelting operation. The resistance furnace lacks an effective atmosphere control device and cannot be vacuumed during the smelting process. Smelting can only be carried out in an ordinary air environment. Since the air contains a large amount of oxygen, moisture and other impurity gases, during the high-temperature smelting process, the aluminum alloy raw materials are very likely to undergo oxidation reactions with these gases to generate various oxide inclusions, which seriously reduce the purity and quality of the aluminum alloy. In addition, the heating rate of the resistance furnace is extremely unstable, fluctuating greatly between about 60-80℃ / min. This unstable heating process will cause uneven heating of the raw materials, further aggravating the component segregation phenomenon.

[0054] In addition, the smelting equipment is not equipped with an electromagnetic stirring device and only relies on occasional simple manual stirring, which is unable to achieve uniform mixing and sufficient reaction of the melt. In terms of temperature control, due to the lack of a high-precision temperature monitoring and control system, the temperature fluctuates greatly, at around ±15°C. This makes it impossible for the aluminum alloy to reach the ideal melting temperature and holding time during the smelting process, resulting in uneven alloy structure and increased crystal structure defects, which seriously affects the final performance of the aluminum alloy powder.

[0055] A simple gas atomization device is used for atomization operation. The device has a simple structure and a single function. The atomization gas pressure is not adjustable, and is a fixed pressure of about 2 MPa. It cannot be flexibly adjusted according to the characteristics of the aluminum alloy melt and the atomization requirements. The atomization nozzle is of ordinary design, without special structural optimization and airflow control functions, which makes the atomization effect extremely poor, and the generated powder particles are seriously uneven in size, low in sphericity, and a large amount of powder presents an irregular shape. During the atomization process, due to the lack of inert gas protection and air pressure control measures, the air in the atomization chamber is very easy to contact with the high-temperature powder particles, resulting in rapid oxidation of the powder and the formation of an oxide film, which not only reduces the purity of the powder, but also affects the fluidity and sinterability of the powder. Moreover, the atomization device is not equipped with a special cooling collection barrel. The powder falls directly into an ordinary container after atomization. Due to the lack of effective cooling and anti-agglomeration measures, the powder agglomeration phenomenon is very serious, forming a large number of large particle agglomerates, which cannot meet the requirements of 3D printing for powder particle size and uniformity.

[0056] An ordinary vibrating screen is used for screening operation. The vibrating screen relies only on mechanical vibration for screening without ultrasonic vibration assistance. During the screening process, due to the strong adhesion between aluminum alloy powder particles, it is difficult for ordinary vibrating screens to overcome this adhesion, resulting in easy clogging of the screen, extremely low screening efficiency, and the inability to effectively classify the powder according to the particle size requirements. The obtained powder particle size distribution range is extremely wide, which cannot meet the strict requirements of metal 3D printing for powder particle size uniformity. In the packaging process, ordinary plastic bags are used for packaging without any vacuum treatment and metal foreign body detection. Ordinary plastic bags have poor barrier properties and cannot prevent the erosion of powder by external moisture, oxygen, etc., which easily causes the powder to become damp and oxidized. Moreover, due to the lack of metal foreign body detection, the packaged powder may be mixed with foreign matter such as metal debris, which will damage the printing equipment during the 3D printing process and affect the printing quality. After packaging, no product information is marked, making it difficult to achieve product traceability and quality control, which brings great difficulties to product quality assurance and after-sales service.

[0057]

[0058] It can be clearly and intuitively seen from the above detailed comparison table that the present invention adopts advanced, precise and scientific processes and equipment in each key link such as raw material processing, smelting, atomization, screening and packaging, and comprehensively guarantees the high quality characteristics of aluminum alloy powder. Whether in terms of raw material purity, smelting temperature control accuracy, atomization effect, powder particle size uniformity or packaging quality, it shows excellent performance, which can fully meet the strict requirements of metal 3D printing for high-quality aluminum alloy powder, and provide reliable material guarantee for the high-end manufacturing field. The comparative example adopts extensive and simple production processes and equipment, and has serious defects and deficiencies in each link, resulting in the aluminum alloy powder produced being far lower in quality and performance than the present invention, and cannot be applied to metal 3D printing processes with high requirements on powder quality, highlighting the significant advantages and innovative value of the present invention in the field of aluminum alloy powder production.

[0059] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the same elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for producing aluminum alloy powder for a metal 3D printer, characterized in that: The method comprises the following steps: Raw material pretreatment and precise proportioning: Strictly screen aluminum and various alloy element raw materials, remove surface impurities, oxides and other foreign matter, use spectrometer to ensure that the purity of each raw material reaches more than 99.5%, and configure the proportion of each alloy element to form a raw material formula based on the comprehensive requirements of the target aluminum alloy powder in terms of strength, toughness, corrosion resistance and printability. Among them, the alloy elements include but are not limited to magnesium, silicon, copper, zinc, and manganese. Each element has a specific content range under different performance requirements. When preparing high-strength and high-corrosion-resistant aluminum alloy powder, the magnesium content is 2%-5%, the silicon content is 0.5%-1.5%, the copper content is 1%-3%, the zinc content is 0.2%-0.8%, and the manganese content is 0.1%-0.5%; Vacuum induction melting: put the prepared raw materials into a vacuum induction furnace with an efficient thermal insulation layer and a precise temperature control system. First, evacuate the furnace to a high vacuum degree below 1×10-3Pa, remove air, moisture and other volatile impurities in the furnace, and use a multi-stage gradient heating method. Initially, the temperature is raised to 500℃ at a rate of 50℃ / min. Keep it at this temperature for 30-60 minutes to soften the raw materials and heat them evenly. Then, the temperature is raised to the target melting range of 750℃-900℃ at a rate of 30℃ / min. During the melting process, the melt is stirred at a speed of 100-500r / min by an electromagnetic stirring device. The temperature is monitored and adjusted in real time by the high-precision temperature sensor and intelligent control system in the furnace to control the temperature fluctuation within ±5℃. High-pressure inert gas atomization powder making: After smelting, the aluminum alloy melt is introduced into the atomization chamber through a guide tube with a flow regulating valve and a temperature monitoring device at the bottom. A high-pressure inert gas atomization system is used. Before atomization, the air pressure in the atomization chamber is adjusted to a positive pressure state of 0.5-1.0MPa. The high-pressure gas valve is opened to allow the inert gas to impact the aluminum alloy melt flow at a high speed of 2.5MPa-5MPa. Through the supersonic annular atomization nozzle, the inert gas and the melt flow form an angle of 30°-60° for high-speed interaction, breaking the melt into tiny droplets. During the atomization process, the inert gas is continuously added to the atomization chamber at a flow rate of 10-30L / min. The atomized powder particles fall into the cooling collection bucket below under the action of gravity and airflow; Ultrasonic vibration screening and post-processing: The aluminum alloy powder in the cooling collection barrel is transported to the ultrasonic vibration screening equipment to drive the screen assembly to work. The screen assembly uses three layers of screens with different apertures and anti-adhesion coating on the surface, the upper layer is 100-200 mesh, the middle layer is 200-300 mesh, and the lower layer is 300-500 mesh. Under the action of ultrasonic vibration and gravity, the aluminum alloy powder passes through each layer of screen in turn for graded screening. The screened aluminum alloy powder is vacuum packaged. The packaging material is an aluminum foil composite bag with a thickness of 0.05-0.15mm. The inner layer of the composite bag is a polyethylene material with a thickness of 0.03-0.08mm.

2. The method for producing aluminum alloy powder for a metal 3D printer according to claim 1, characterized in that: When preparing high-toughness aluminum alloy powder, the raw material formula adjusts the magnesium content to 3%-6%, reduces the silicon content to 0.3%-1%, the copper content to 0.5%-2%, increases the zinc content to 0.5%-1.2%, maintains the manganese content at 0.1%-0.5%, and adds 0.05%-0.2% of titanium.

3. The method for producing aluminum alloy powder for a metal 3D printer according to claim 1, characterized in that: During the vacuum induction melting process, when the pressure fluctuation in the furnace exceeds ±10% of the set threshold, the pressure balancing device is automatically started for adjustment. The pressure balancing device maintains the pressure in the furnace stable by adjusting the opening of the intake valve and the exhaust valve, and the response time of the intake valve and the exhaust valve is within 2-5 seconds.

4. The method for producing aluminum alloy powder for a metal 3D printer according to claim 1, characterized in that: During the high-pressure inert gas atomization powder making process, the inner core structure of the supersonic annular atomizing nozzle is adjusted in the range of 0-5 mm, and is dynamically optimized according to the viscosity and flow rate of the aluminum alloy melt to ensure the consistency of the atomization effect. The atomizing chamber is provided with an observation window and an internal lighting device, and the observation window is made of a transparent ceramic material that is resistant to high pressure, high temperature and anti-atomization.

5. The method for producing aluminum alloy powder for a metal 3D printer according to claim 1, characterized in that: During the vacuum packaging process, the aluminum foil composite bag is sterilized by ultraviolet light before packaging for 10-30 minutes to kill microorganisms on the surface of the packaging material, thereby ensuring the microbial safety of the powder during storage and transportation. A humidity sensor is arranged in the packaging room, and when the humidity exceeds 30%, the dehumidification device is started to control the humidity below 20%.

6. A device for producing aluminum alloy powder for a metal 3D printer, characterized in that: The device is an ultrasonic vibration screening device used in the production method of claim 1, comprising a device housing (1) and an ultrasonic generator (2), a sealing cover (3) is installed at the top of the device housing (1), a feed port (4) is arranged at the top of the sealing cover (3), two screen frames (5) are arranged inside the device housing (1), two guide grooves (6) are provided on the inner wall of the device housing (1), guide blocks (7) are installed on the outer surfaces of the two screen frames (5), and the guide blocks (7) are provided with a plurality of guide grooves (6). ) is slidably connected to the inner wall of the guide groove (6), the inner wall of the device housing (1) is provided with two groups of limit grooves (8), the inner walls of the two screen frames (5) are each installed with two limit assemblies (9), the inner walls of the two screen frames (5) are each installed with a screen (10), the bottom surfaces of the two screen frames (5) are each installed with a group of transducers (11), the outer surfaces of the two screen frames (5) are each fixedly connected with a discharge pipe (12), and the discharge pipe (12) extends to the outside of the device housing (1) at one end away from the screen frame (5).

7. The aluminum alloy powder production equipment for a metal 3D printer according to claim 6, characterized in that: The limiting assembly (9) comprises a square frame (901) fixedly embedded in the inner wall of the screen frame (5); the inner wall of the square frame (901) is slidably connected with a connecting plate (902); a limiting plate (903) is installed on the outer surface of the connecting plate (902); and one end of the limiting plate (903) away from the connecting plate (902) is snap-fitted to the inner wall of the limiting groove (8).

8. The aluminum alloy powder production equipment for metal 3D printer according to claim 7, characterized in that: A spring (904) is installed between the connecting plate (902) and the inner wall of the frame (901), a pull rod (905) is installed on the outer surface of the connecting plate (902), and a pull ring (906) is installed at one end of the pull rod (905) away from the connecting plate (902).

9. The aluminum alloy powder production equipment for a metal 3D printer according to claim 6, characterized in that: The ultrasonic generator (2) has an automatic power adjustment function and automatically adjusts the ultrasonic power between 100-500W according to the load condition of the screen (10). The screen (10) and the screen frame (5) are sealed with a sealing strip.

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