Multi-loop integrated control high-pressure vacuum die casting system and method

Abstract

The invention discloses a multi-loop integrated control high-pressure vacuum die-casting system and method, and relates to the technical field of die-casting. The multi-loop integrated control high-pressure vacuum die-casting system comprises a die, a feeding mechanism, a soup feeding mechanism and a plurality of vacuum devices; the core solves the sealing problem of key parts by arranging'vacuum sealing belts': a closed sealing groove is formed in a mold closing interface of a movable mold and a static mold to form a first vacuum sealing belt, a second vacuum sealing belt is formed in a gap between a pouring tank and a pouring port, and a third vacuum sealing belt is formed in a gap between an injection punch and a pressure chamber; the liquid feeding mechanism gradually extracts molten metal through negative pressure of a vacuum device, and quantitative control is achieved. The system further integrates a filter, a pressure sensor, a control valve and a blowback cleaning function, and is used for monitoring and purifying the pipeline and the die cavity. Through multi-loop cooperative control and targeted sealing design, the sealing performance of the die cavity and the pressure chamber is remarkably improved, the high-vacuum die-casting requirement is met, the defects of casting air holes, oxidation and the like are reduced, and meanwhile the die-casting efficiency and the product quality stability are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vacuum die casting equipment, in particular to a high-pressure vacuum die casting system and method with multi-loop integrated control. BACKGROUND

[0002] High-vacuum die casting technology is a key means to improve the quality of die castings. By reducing the gas content inside the mold cavity and pressure chamber, it can effectively reduce defects such as porosity and shrinkage in castings, significantly improve the mechanical properties and sealing performance of castings, and is widely used in fields such as automobiles and aerospace that require high precision of parts.

[0003] However, the existing high-vacuum die casting system still has shortcomings in terms of sealing, for example: (1) There are tiny gaps at the joint interface of the moving and stationary dies, which can easily allow external gas to enter the mold cavity and destroy the vacuum environment; (2) The mating gap between the pressure chamber and the moving plunger affects the sealing of the pressure chamber and the shooting speed of the plunger; (3) There is a mating gap between the pouring pot and the gating mechanism, which not only allows air to enter the pressure chamber and contaminate the metal liquid, but also reduces the vacuum pumping efficiency, making it difficult to meet the extreme vacuum requirement of high-precision castings.

[0004] In addition, traditional sealing methods rely heavily on mechanical pressure or single sealing elements, which are greatly affected by machining precision and assembly errors, have poor sealing stability, and are difficult to work in coordination with the vacuum pumping system, restricting the further development of high-vacuum die casting technology.

[0005] The existing technology patent CN115301915A discloses a double-loop closed-loop vacuum balancing system, which solves the gap problem between the moving and stationary dies and the mating gap problem between the plunger and the pressure chamber using a sealing groove. However, for the sealing of the gating, the balancing system has a sealing leakage problem at the gating when the metal liquid is poured into the pressure chamber, which can easily allow external air to enter the pressure chamber and oxidize the metal liquid, thereby affecting the quality of the die casting product. In addition, the mating gap at the gating also affects the vacuum pumping efficiency of the pressure chamber and the mold cavity, making it difficult to ensure that the vacuum degree in the mold cavity meets the set requirements at the set time point, which makes it difficult to accurately control the key parameters of the vacuum die casting process and affects the die casting quality.

[0006] Therefore, it is necessary to provide a new high-pressure vacuum die casting system and method with multi-loop integrated control to solve the above technical problems. SUMMARY

[0007] The main objective of this invention is to provide a high-pressure vacuum die-casting system and method with multi-loop integrated control. By utilizing a vacuum sealing strip to simultaneously seal the fitting gaps at the mold cavity, the gate, and the punch and pressure chamber, the sealing performance of the internal cavities of the entire die-casting system is improved. Combined with a high-precision quantitative feeding mechanism, a high-precision, high-vacuum, and high-efficiency vacuum die-casting process is achieved, thereby improving die-casting quality and efficiency.

[0008] This invention achieves the above objective through the following technical solution: a multi-loop integrated control high-pressure vacuum die-casting system, comprising: The mold includes a moving mold and a stationary mold that together enclose and form a mold cavity, and a sealing groove that is set on the mold closing interface and surrounds the cut surface of the mold cavity. The feeding mechanism includes a pressure chamber communicating with the mold cavity, an injection punch reciprocatingly disposed in the pressure chamber and injecting the metal in the pressure chamber into the mold cavity, a vacuum port communicating with the pressure chamber, and a pouring port. The soup dispensing mechanism includes a multi-axis robot, a pouring tank located at the end of the multi-axis robot and having a liquid outlet at its bottom, a stopper head movably disposed within the pouring tank and used to seal the liquid outlet, a drive unit for driving the stopper head to move up and down, and a second vacuum device communicating with the interior of the pouring tank; the bottom of the pouring tank is inserted into the pouring port to dispense soup. The first vacuum device includes a negative pressure energy storage tank, a first vacuum pump connected to the negative pressure energy storage tank, a first vacuum extraction pipeline, a second vacuum extraction pipeline, a third vacuum extraction pipeline, and a fourth vacuum extraction pipeline. The first vacuum device evacuates the sealing groove through the first vacuum extraction pipeline to form a first vacuum sealing band, evacuates the mating gap between the pouring port and the pouring tank through the second vacuum extraction pipeline to form a second vacuum sealing band, evacuates the mold cavity through the third vacuum extraction pipeline, and evacuates the pressure chamber through the fourth vacuum extraction pipeline.

[0009] Furthermore, it also includes a third vacuum device and a fifth vacuum line, wherein the third vacuum device evacuates the fitting gap between the injection punch and the inner wall of the pressure chamber via the fifth vacuum line.

[0010] Furthermore, one end of the fifth vacuum line passes through the interior of the injection punch and extends to the outer peripheral surface of the injection punch, while the other end is connected to the third vacuum device; a third control valve is provided on the fifth vacuum line to control its opening or closing.

[0011] Furthermore, one end of the first vacuuming pipeline is connected to the sealing groove and the other end is connected to the first vacuum pump; a first control valve and a first pressure sensor are provided on the first vacuuming pipeline.

[0012] Furthermore, one end of the second vacuum pipeline is connected to the pouring port and the other end is connected to the first vacuum pump; a second control valve and a second pressure sensor are provided on the second vacuum pipeline.

[0013] Furthermore, a first vacuum valve is provided at one end of the third vacuum pipeline near the mold cavity to block the vacuum port on the inner wall surface of the mold cavity; the third vacuum pipeline is provided with a first filter, a third pressure sensor, a second filter, and a fourth control valve.

[0014] Furthermore, a first branch line extends from the third vacuum line between the third pressure sensor and the second filter, and the other end of the first branch line is connected to a first positive pressure energy storage tank. A fifth control valve is provided on the first branch line to control its opening and closing. A fourth pressure sensor is provided downstream of the branch port of the first branch line on the third vacuum line.

[0015] Furthermore, a second vacuum valve is provided at the vacuum port to seal the vacuum port; one end of the fourth vacuum pipeline is connected to the vacuum port, and the other end is connected to the negative pressure energy storage tank; a fifth pressure sensor, a third filter, and a sixth control valve are provided on the fourth vacuum pipeline.

[0016] Furthermore, a second branch pipe is provided on the fourth vacuum pipeline between the fifth pressure sensor and the third filter, and the other end of the second branch pipe is connected to a second positive pressure energy storage tank; a seventh control valve is provided on the second branch pipe to control its opening and closing; a sixth pressure sensor is provided on the fourth vacuum pipeline downstream of the branch port of the second branch pipe.

[0017] Furthermore, the second vacuum device includes a second vacuum pump connected to the interior of the casting tank via a second pipeline; a ninth control valve and an eighth pressure sensor are provided on the second pipeline.

[0018] Furthermore, the soup-feeding mechanism also includes a third positive pressure energy storage tank connected to the interior of the pouring tank via a first pipeline; an eighth control valve and a seventh pressure sensor are installed on the first pipeline.

[0019] Furthermore, the gas stored in the third positive pressure energy storage tank is oxygen.

[0020] Furthermore, the molten metal feeding mechanism also includes a level sensor for monitoring the liquid level of the molten metal in the pouring tank.

[0021] Another object of the present invention is to provide a die-casting method based on a high-pressure vacuum die-casting system with multi-loop integrated control as described above, which includes the following steps: S1. Preparation of the soup-feeding mechanism: The stopper head is in the open state, the multi-axis robot drives the casting tank to move into the furnace, and the liquid outlet is extended below the liquid surface; S2. Soup dispensing mechanism: The second vacuum device is activated to perform a vacuuming operation inside the pouring tank at a set speed until the pressure inside the pouring tank reaches the first set pressure P1, at which point the vacuuming stops. During this process, the molten metal is gradually drawn into the pouring tank, and the amount of molten metal drawn reaches the set volume when the vacuuming stops. The drive unit drives the pressure plug head to seal the liquid outlet, and the multi-axis robot drives the pouring tank to move to the pouring port. S3. Pressure adjustment inside the casting tank: The process requires the pressure chamber to be evacuated to the second set pressure P2. If the first set pressure P1 is greater than the second set pressure P2, there is no need to adjust the pressure inside the casting tank. If the first set pressure P1 is less than the second set pressure P2, gas is injected into the casting tank to adjust the pressure inside the casting tank to be greater than or equal to the second set pressure P2. S4. Preparation of the liquid: During the execution of S1~S3, the mold is closed; the outlet of the pouring tank is inserted into the pouring port; the first vacuum device evacuates the sealing groove through the first vacuum line to form the first vacuum sealing strip; the second vacuum line evacuates the gap between the pouring port and the pouring tank to form the second vacuum sealing strip; the third vacuum device evacuates the gap between the injection punch and the pressure chamber through the fifth vacuum line to form the third vacuum sealing strip; the vacuum port is in the closed state. S5. Vacuuming of mold cavity and pressure chamber: The first vacuum device evacuates the mold cavity through the third vacuuming pipeline and simultaneously evacuates the pressure chamber through the fourth vacuuming pipeline until the pressure inside the two chambers reaches the second set pressure P2 and then stops evacuating. S6. Pouring: The driving component drives the pressure plug head to move upward, opening the outlet. The molten metal in the pouring tank enters the pressure chamber through the pouring port under its own weight. S7. Die Casting: After the molten metal is released, the injection punch moves to efficiently push the molten metal in the pressure chamber into the mold cavity, completing the die casting.

[0022] Furthermore, in step S3, gas is injected into the casting tank to adjust the internal pressure of the casting tank to be greater than or equal to the second set pressure P2, including: If the first set pressure P1 is less than the second set pressure P2, then it is determined whether the first set pressure P1 is less than or equal to the third set pressure P3. If it is less, gas is directly injected into the casting tank to adjust the pressure inside the casting tank to be greater than or equal to the second set pressure P2. Otherwise, the second vacuum device continues to evacuate the inside of the casting tank until the third set pressure P3 is reached, and then gas is injected into the casting tank to adjust the pressure inside the casting tank to be greater than or equal to the second set pressure P2.

[0023] Compared with the prior art, the beneficial effects of the multi-loop integrated control high-pressure vacuum die-casting system and method of the present invention are as follows: (1) Significantly improve sealing performance and vacuum stability: By setting “first, second and third vacuum sealing strips” at the mold closing interface between the moving mold and the stationary mold, the gap between the pouring tank and the pouring gate, and the gap between the injection punch and the pressure chamber, the leakage problem of key parts of die casting is specifically solved; among them, the third vacuum sealing strip is equipped with a separate vacuum device, which effectively avoids pressure interference between circuits, ensures the reliability of dynamic sealing, and enables the mold cavity and pressure chamber to maintain a stable high vacuum, greatly reducing gas entrapment during the filling process of molten metal, and reducing defects such as porosity and oxide inclusions in the casting; (2) Improve the accuracy of molten metal feeding and the quality of molten metal: The molten metal feeding mechanism adopts a progressive negative pressure vacuum extraction method, combined with real-time monitoring by pressure sensors and Boyle's law to accurately control the amount of molten metal, avoiding the problem of molten metal churning and air entrapment caused by traditional strong vacuum extraction; the pressure of the casting tank is adjusted by the third positive pressure energy storage tank, which solves the problem of molten metal feeding caused by pressure difference. In particular, pure oxygen is used for pressure adjustment, which not only improves the efficiency of molten metal feeding by utilizing the pressure difference, but also eliminates the casting void defects caused by nitrogen residue through the trace reaction between oxygen and molten metal, thus ensuring the quality of molten metal from the source. (3) Enhanced system stability and ease of maintenance: Multi-stage filters (particle filters, dust filters) are installed in the pipeline to effectively intercept impurities, protect core components such as vacuum pumps, and extend equipment life; integrated backflushing cleaning function (using positive pressure storage tank to purge pipelines, mold cavities, and casting tanks) to remove residual impurities in a timely manner, avoid pipeline blockage, and ensure long-term stability of vacuum efficiency; coordinated control of multiple pressure sensors and control valves enables real-time monitoring and precise regulation of pressure in each circuit, improving the reliability of system operation; (4) Improve die casting efficiency and product quality stability: The multi-loop integrated control design enables each process (such as taking soup, closing the mold, and vacuuming) to be carried out in parallel or in an orderly manner, shortening the single cycle time; through the synergy of improving sealing performance, optimizing soup feeding accuracy, and controlling impurities, the defects such as porosity, shrinkage, and oxidation of castings are significantly reduced, improving the mechanical properties and appearance quality of the products, and the quality stability is stronger in mass production, making it suitable for the large-scale manufacturing of high-precision die casting products.

[0024] In summary, this invention comprehensively improves the quality, efficiency, and stability of high-pressure vacuum die casting through innovative sealing design, precise vacuum control, and convenient maintenance mechanisms, making it suitable for the large-scale production of high-precision metal parts. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the system piping connection according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the connection structure of the die-casting mold, the feeding mechanism, and the first vacuum device in an embodiment of the present invention; Figure 3 This is a schematic diagram of the connection structure between the injection punch and the third vacuum device in an embodiment of the present invention; Figure 4 This is a schematic diagram of the soup dispensing mechanism in an embodiment of the present invention. Figure 5 This is a schematic diagram of the soup-feeding mechanism in an embodiment of the present invention during soup dispensing; The numbers in the diagram represent: 100 - High-pressure vacuum die-casting system with multi-loop integrated control; 200 - Furnace; 1-Mold, 11-Mold cavity, 12-Sealing groove; 2-Feeding mechanism, 21-Pressure chamber, 22-Injection punch, 23-Vacuum port, 24-Gating port; 3-Soup dispensing mechanism, 31-Multi-axis robot, 32-Pouring tank, 321-Outlet, 322-Cavity, 323-Straight cylinder, 324-Conical part, 33-Plug head, 34-Drive component, 35-Second vacuum device, 351-Second pipeline, 352-Second vacuum pump, 353-Ninth control valve, 354-Eighth pressure sensor, 36-Mounting bracket, 37-First pipeline, 371-Eighth control valve, 372-Seventh pressure sensor, 38-Third positive pressure storage tank, 39-Level sensor; 4-First vacuum device, 41-Negative pressure storage tank, 42-First vacuum pump, 43-First vacuuming pipeline, 431-First control valve, 432-First pressure sensor, 44-Second vacuuming pipeline, 441-Second control valve, 442-Second pressure sensor, 45-Third vacuuming pipeline, 451-First vacuum valve, 452-First filter, 453-Third pressure sensor, 454-Second filter, 455-Fourth control valve, 456-First branch pipeline, 457-First positive pressure storage tank, 458-Fifth control valve, 459-Fourth pressure sensor, 46-Second vacuum valve, 47-Fourth vacuuming pipeline, 471-Fifth pressure sensor, 472-Third filter, 473-Sixth control valve, 474-Second branch pipeline, 475-Second positive pressure storage tank, 476-Seventh control valve, 477-Sixth pressure sensor; 5-Fifth vacuum line; 51-Third control valve; 6-Third vacuum device. Detailed Implementation

[0026] Example 1: Please refer to Figures 1-5 This embodiment is a high-pressure vacuum die-casting system 100 with multi-loop integrated control, which includes a mold 1, a feeding mechanism 2, a pouring mechanism 3, and a first vacuum device 4; the mold 1 includes a moving mold and a stationary mold, which together form a mold cavity 11; the feeding mechanism 2 includes a pressure chamber 21 communicating with the mold cavity 11, an injection punch 22 reciprocatingly disposed in the pressure chamber 21 and injecting the metal in the pressure chamber 21 into the mold cavity 11, a vacuum port 23 communicating with the pressure chamber 21, and a pouring port 24; the pouring mechanism 3 includes a multi-axis The system includes a robot 31, a casting tank 32 located at the end of the multi-axis robot 31 and having a liquid outlet 321 at its bottom, a stopper head 33 movably disposed inside the casting tank 32 and used to block the liquid outlet 321, a drive unit 34 that drives the stopper head 33 to move up and down, and a second vacuum device 35 communicating with the inside of the casting tank 32; the first vacuum device 4 includes a negative pressure energy storage tank 41 and a first vacuum pump 42 communicating with the negative pressure energy storage tank 41; the first vacuum device 4 is connected to the mold cavity 11, the vacuum port 23 and the casting port 24.

[0027] To improve the sealing performance of the die-casting system's internal mold cavity 11 and pressure chamber 21 to meet higher vacuum die-casting requirements, this embodiment utilizes a "vacuum sealing strip" to seal three gaps: the joint gap on the inner wall surface of the mold cavity 11, the fit gap between the inner wall surface of the pouring port 24 and the pouring mechanism 3, and the fit gap between the injection punch 22 and the pressure chamber 21. Specifically: First, the mold cavity 11 is formed by the moving mold and the stationary mold. However, after the moving mold and the stationary mold are closed, some gaps are inevitable. In order to seal these gaps, this embodiment provides a closed sealing groove 12 on the interface between the moving mold and the stationary mold. The sealing groove 12 surrounds the cross-sectional area of ​​the mold cavity 11 on this interface. The sealing groove 12 is connected to the first vacuum device 4, specifically to the first vacuum pump 42 through the first vacuum pumping pipeline 43, and a first control valve 431 and a first pressure sensor 432 are provided on the connecting pipeline. The first control valve 431 is used to control the opening and closing of the first vacuum pumping pipeline 43; the first pressure sensor 432 is used to monitor the pressure in the sealing groove 12. By evacuating the sealing groove 12 through the first vacuum pump 42, a closed negative pressure loop is formed in the sealing groove 12, forming a "first vacuum sealing band", thereby sealing the gap between the interface between the moving mold and the stationary mold.

[0028] Secondly, to achieve high-precision die casting, this embodiment employs a molten metal feeding mechanism 3 capable of precise quantity control. The pouring vessel 32 in the feeding mechanism 3 extracts a fixed amount of molten metal from the furnace and moves it to the pouring port 24, partially extending into the interior of the pouring port 24. Therefore, a gap exists between the pouring vessel 32 and the inner wall surface of the pouring port 24. This gap poses a risk of molten metal entering the pressure chamber 21 and oxidizing it, and also compromises the sealing of the pressure chamber 21, affecting the efficiency and effectiveness of vacuuming inside the pressure chamber 21. To address this technical problem, the first vacuum device 4 in this embodiment further includes several second vacuuming pipes 44 connected to the pouring port 24. At least two second vacuuming pipes 44 are provided, and the connection openings between each second vacuuming pipe 44 and the pouring port 24 are distributed circumferentially along the inner wall of the pouring port 24. Preferably, the connection ports of each second vacuum line 44 to the pouring port 24 are evenly distributed circumferentially along the inner wall of the pouring port 24 to ensure the balance of the negative pressure environment between the pouring tank and the pouring port 24. One end of the second vacuum line 44 is connected to the pouring port 24 and the other end is connected to the first vacuum device 4, specifically connected to the first vacuum pump 42 in the first vacuum device 4. The second vacuum line 44 is equipped with a second control valve 441 and a second pressure sensor 442. The second control valve 441 is used to control the opening and closing of the second vacuum line 44; the second pressure sensor 442 is used to monitor the pressure in the second vacuum line 44, that is, to reflect the pressure in the gap space between the inner wall surface of the pouring tank 32 and the pouring port 24. The first vacuum pump 42 evacuates the gap between the inner wall of the casting tank 32 and the inner wall of the casting port 24 through the second vacuum pipe 44, forming an annular negative pressure chamber in the annular gap between the casting tank and the inner wall of the casting port 24, thus forming a "second vacuum sealing zone". This seals the gap between the casting tank and the inner wall of the casting port 24, effectively preventing the molten metal from being oxidized and improving the sealing of the pressure chamber 21 inside the vacuum die casting machine, ensuring the effective pushing of the injection punch 22 to pour the molten metal into the pressure chamber 21.

[0029] Finally, a gap exists between the injection punch 22 and the inner wall surface of the pressure chamber 21, affecting the sealing performance of the pressure chamber 21. To solve this technical problem, this embodiment also includes a fifth vacuum line 5. One end of the fifth vacuum line 5 passes through the interior of the injection punch 22 and extends to the outer peripheral surface of the injection punch 22, thereby connecting the gap space between the injection punch 22 and the inner wall of the pressure chamber 21. The other end is connected to a third vacuum device 6. A third control valve 51 is provided on the fifth vacuum line 5 to control its opening or closing. By using the third vacuum device 6 to perform a vacuuming operation on the gap space between the injection punch 22 and the pressure chamber 21 via the fifth vacuum line 5, an annular negative pressure cavity is formed between the injection punch 22 and the pressure chamber 21, i.e., a "third vacuum sealing zone" is formed, thus achieving the sealing of the gap between the injection punch 22 and the inner wall of the pressure chamber 21.

[0030] To further ensure the effective implementation of the "vacuum sealing band" structure between the moving mold and the stationary mold, and between the casting tank and the sprue 24, the width of the sealing groove 12 is 5~10mm, and the surface roughness Ra≤1.6μm; the gap width between the sprue 24 and the outer peripheral surface of the casting tank is 5~10mm, and the surface roughness Ra of the inner wall surface of the sprue 24 is ≤1.6μm; the gap width between the injection punch 22 and the pressure chamber 21 is 5~10mm, and the surface roughness Ra of the injection punch 22 and the pressure chamber 21 working together is ≤1.6μm; through gap control and surface roughness design, the basic conditions are provided for realizing the "first vacuum sealing band" at the interface between the moving mold and the stationary mold, the "second vacuum sealing band" between the casting tank and the sprue, and the "third vacuum sealing band" between the injection punch 22 and the pressure chamber 21.

[0031] In this embodiment, the "first vacuum sealing strip" and the "second vacuum sealing strip" share the same first vacuum device 4 for integrated control, while the "third vacuum sealing strip" is configured with a separate third vacuum device 6 for separate control, so as to avoid pressure interference between the various circuits.

[0032] To achieve vacuum die casting, the first vacuum device 4 in this embodiment further includes several third vacuum lines 45 connected to the mold cavity 11. One end of each third vacuum line 45 is connected to the mold cavity 11 and the other end is connected to a negative pressure storage tank 41. The mold cavity 11 is efficiently vacuumed through the negative pressure storage tank 41 via the third vacuum lines 45. A first vacuum valve 451 is provided at one end of the third vacuum line 45 near the mold cavity 11. The first vacuum valve 451 quickly and efficiently seals the vacuum port on the inner wall surface of the mold cavity 11.

[0033] The third vacuum line 45 is also equipped with a first filter 452, a third pressure sensor 453, a second filter 454, and a fourth control valve 455. The first filter 452 is a particulate filter, the second filter 454 is a dust filter, the third pressure sensor 453 is used to monitor the pressure inside the mold cavity 11, and the fourth control valve 455 is used to control the opening and closing of the third vacuum line 45. During the die casting process, the gas inside the mold cavity 11 may contain impurities such as metal particles, oxide scale, and molding sand. By setting the first filter 452, larger particulate impurities can be effectively intercepted, preventing them from entering the first vacuum pump 42 in the first vacuum device 4, avoiding wear, blockage, or damage to the internal parts of the first vacuum pump 42, thereby ensuring the normal operation and service life of the first vacuum pump 42. At the same time, the first filter 452 can also reduce the burden on the subsequent dust filter (i.e., the second filter 454), improving the stability and reliability of the entire vacuum system.

[0034] During die casting, after the moving mold and stationary mold open, the product is removed from the mold cavity 11. Then, the moving mold and stationary mold close again for the next die casting cycle. However, some impurities may remain inside the mold cavity 11 after the moving mold and stationary mold close, which seriously affects the die casting quality of the next product. To solve this problem, a backflushing cleaning function is also configured on the third vacuum line 45. Specifically, a first branch line 456 extends from the third vacuum line 45 between the third pressure sensor 453 and the second filter 454. The other end of the first branch line 456 is connected to the first positive pressure energy storage tank 457. A fifth control valve 458 is installed on the first branch line 456 to control its opening and closing. A fourth pressure sensor 459 is installed downstream of the branch port of the first branch line 456 on the third vacuum line 45.

[0035] After vacuuming, the first positive pressure energy storage tank 457 can be used for "pipeline cleaning": When it is necessary to clean the trace amounts of gas or impurities remaining in the third vacuum pipeline 45 and the mold cavity 11, the fifth control valve 458 on the first branch pipeline 456 can be opened, and the positive pressure gas (such as compressed air) of the first positive pressure energy storage tank 457 can be used to back-purge the third vacuum pipeline 45. When the mold 1 is in the open state, the residual material is blown into the mold cavity 11 and discharged to avoid the residual impurities affecting the efficiency of the next vacuuming.

[0036] A second vacuum valve 46 is installed at the vacuum port 23 to seal the vacuum port 23. The vacuum port 23 is connected to the negative pressure energy storage tank 41 through a fourth vacuum pipeline 47. The fourth vacuum pipeline 47 is equipped with a fifth pressure sensor 471, a third filter 472, and a sixth control valve 473. The fifth pressure sensor 471 is used to monitor the pressure in the pressure chamber 21; the third filter 472 is a dust filter to intercept dust carried out from the pressure chamber 21 during vacuuming in the fourth vacuum pipeline 47; and the sixth control valve 473 is used to control the opening and closing of the fourth vacuum pipeline 47. To prevent impurities from remaining on the inner wall surface of the fourth vacuum line 47 and the vacuum port 23, thus affecting the efficiency of the next vacuuming operation, this embodiment also includes a backflushing cleaning function on the fourth vacuum line 47. A second branch line 474 extends from the fourth vacuum line 47 between the fifth pressure sensor 471 and the third filter 472. The second branch line 474 is connected to the second positive pressure energy storage tank 475, and a seventh control valve 476 is installed on the second branch line 474 to control its opening and closing. A sixth pressure sensor 477 is also installed downstream of the branch port of the second branch line 474 on the fourth vacuum line 47 to monitor the pressure inside the fourth vacuum line 47.

[0037] When it is necessary to clean the trace amounts of gas or impurities remaining in the fourth vacuum line 47 and vacuum port 23, the seventh control valve 476 on the second branch line 474 can be opened, and the positive pressure gas (such as compressed air) of the second positive pressure energy storage tank 475 can be used to back purge the fourth vacuum line 47 and vacuum port 23, blowing the residual material into the pressure chamber 21. It can be discharged through the opening at one end of the pressure chamber 21 or through the pouring port 24, so as to avoid the residual impurities affecting the efficiency of the next vacuuming.

[0038] In the molten metal feeding mechanism 3, the moving end of the multi-axis robot 31 is fixedly mounted with a mounting bracket 36, and the pouring tank 32 is mounted at the bottom of the mounting bracket 36. The pouring tank 32 has a cavity 322 inside, and the second vacuum device 35 is used to evacuate the cavity 322 and use negative pressure to draw in the molten metal.

[0039] In this embodiment, the multi-axis robot 31 is used to drive the casting tank 32 to move between the furnace 200 and the pouring port 24; the mounting bracket 36 is used to fix the casting tank 32 and the driving component 34; the casting tank 32 serves as a container for carrying molten metal; the stopper head 33 is used to seal the outlet 321 at the bottom of the casting tank 32. On the one hand, before drawing in molten metal, the stopper head 33 seals the casting tank 32 so that the second vacuum device 35 acts on the cavity 322 to remove the air inside the cavity 322, so that a negative pressure environment with a certain degree of vacuum is formed inside the cavity 322; on the other hand, after the casting tank 32 draws in molten metal and during the process of transferring to the pouring port 24, the stopper head 33 seals the casting tank 32 to effectively prevent molten metal from leaking out of the casting tank 32.

[0040] To improve the sealing performance of the casting tank 32 and the pouring port 24, the bottom of the casting tank 32 has a straight cylindrical portion 323 with a uniform diameter. The bottom of the straight cylindrical portion 323 forms a liquid outlet 321. The top of the straight cylindrical portion 323 is adjacent to a tapered portion 324 with a gradually decreasing diameter. The bottom end of the tapered portion 324 is adjacent to the straight cylindrical portion 323, and its diameter decreases towards the straight cylindrical portion 323. The tapered portion 324 and the straight cylindrical portion 323 together form the liquid outlet connection portion of the casting tank 32. Through the structural design of the tapered portion 324 and the straight cylindrical portion 323, the shape of the pouring port 24 is also designed to conform to the shape of the tapered portion 324 and the straight cylindrical portion 323, so that the gap between the outer periphery of the liquid outlet connection portion and the inner wall of the pouring port 24 can be effectively controlled within the range of 5~10mm.

[0041] The shape of the pressure plug head 33 is designed to conform to the inner wall of the liquid outlet connection part, thereby improving the sealing performance.

[0042] Because the vacuum pressure values ​​inside the pressure chamber 21 and mold cavity 11 vary depending on the die-casting process, there will be a pressure value inside the pressure chamber 21 after vacuuming, denoted as the second set pressure P2. After the molten metal is drawn from the casting tank 32 by the pouring mechanism 3, there will also be a set pressure value inside, denoted as the first set pressure P1. The first set pressure P1 and the second set pressure P2 cannot be exactly equal; in most cases, there will be a pressure difference between them. If the first set pressure P1 is lower than the second set pressure P2, the pouring speed of the casting tank 32 will become very slow when pouring molten metal into the casting port 24. If the pressure difference is too large, the molten metal in the casting tank 32 may not even be able to enter the pressure chamber 21, resulting in pouring failure. Therefore, to solve this technical problem, this embodiment also includes a pressure regulating module in the soup dispensing mechanism 3 to regulate the internal pressure of the pouring tank 32. Specifically, the soup dispensing mechanism 3 also includes a third positive pressure energy storage tank 38 connected to the cavity 322 via a first pipeline 37; an eighth control valve 371 and a seventh pressure sensor 372 are installed on the first pipeline 37. The eighth control valve 371 controls the opening and closing of the first pipeline 37; the seventh pressure sensor 372 monitors the pressure inside the first pipeline 37 and inside the pouring tank 32 connected to the first pipeline 37 in real time. When the pressure value after a certain amount of molten metal is drawn from the casting tank 32 is less than the pressure value after vacuuming the pressure chamber 21, the eighth control valve 371 can be opened. The positive pressure gas stored in the third positive pressure energy storage tank 38 is released into the casting tank 32, increasing the pressure inside the casting tank 32 to be higher than or equal to the pressure value after vacuuming the pressure chamber 21. This allows the molten metal to enter the pressure chamber 21 quickly and efficiently under its own weight or pressure during the pouring process. This effectively solves the technical problem of low pouring efficiency or pouring failure caused by the pressure inside the casting tank 32 being lower than the pressure inside the pressure chamber 21. At the same time, the pressure difference between the pressure inside the casting tank 32 and the pressure inside the pressure chamber 21 can be used to improve the pouring efficiency.

[0043] Furthermore, after a certain amount of molten metal is extracted from the casting tank 32, there will still be some space above the casting tank 32. This space will contain some residual air, which is approximately 80% nitrogen. Although the total amount of residual nitrogen inside the casting tank 32 is small under low pressure, nitrogen is an inert gas. When the casting tank 32 is connected to the pouring port 24 for molten metal injection, the nitrogen inside the casting tank 32 will also enter the pressure chamber 21. When the injection punch 22 is working, the nitrogen will be pushed into the mold cavity 11 along with the molten metal. Since this nitrogen cannot react with the molten metal, it remains inside the mold cavity 11 and is enveloped by the molten metal. This can easily form defects such as voids and pores inside the die-cast product, seriously affecting the quality of the die-cast product. To solve this technical problem, in this embodiment, the gas stored in the third positive pressure energy storage tank 38 is preferably a gas that can react with the molten metal, preferably pure oxygen. The total volume of the casting tank 32 is not very large, typically 10L. After a certain amount of molten metal is extracted, the remaining space is even smaller. Furthermore, the internal pressure of the casting tank 32 is very low when the molten metal is being poured, for example, 200~500mbar. In such a low-pressure environment and small space, the oxygen content is even lower. After being pushed into the pressure chamber 21, this very small amount of oxygen will react with the molten metal. For example, oxygen reacts with molten aluminum to produce aluminum dioxide. The reaction products may adhere to the inner wall of the pressure chamber 21 or enter the mold cavity 11 along with the molten metal. These small amounts of products will not have a significant impact on the quality of the die-cast product. Compared to the voids and porosity defects caused by nitrogen in the die-cast product, they can be ignored.

[0044] The second vacuum device 35 includes a second vacuum pump 352 connected to the cavity 322 via a second pipeline 351; a ninth control valve 353 and an eighth pressure sensor 354 are installed on the second pipeline 351. The ninth control valve 353 controls the opening and closing of the second pipeline 351; the eighth pressure sensor 354 monitors the pressure inside the second pipeline 351 in real time, and also reflects the pressure inside the casting tank 32 connected to the second pipeline 351.

[0045] In this embodiment, since the second vacuum device 35 operates on the high-temperature casting tank 32, the second vacuum pump 352 is a high-temperature resistant vacuum pump. The materials of the first pipeline 37 and the second pipeline 351 are also preferably high-temperature resistant materials.

[0046] In this embodiment, the pressure value inside the casting tank 32 is monitored by the eighth pressure sensor 354. Based on the physical relationship between gas pressure and liquid volume, combined with the fluidity of the molten metal and the pressure balance characteristics of the confined space, precise control of the amount of molten metal drawn from the casting tank 32 can be achieved. Specifically, the process of molten metal entering the casting tank 32 can be regarded as: the pressure difference between the external pressure and the negative pressure inside the tank pushes the molten aluminum upward until the gas pressure above the liquid surface inside the tank reaches equilibrium with the weight of the molten metal and the pressure at the liquid surface. According to the principles of fluid mechanics, when the volume of the casting tank 32 is fixed, the increase in the volume of molten metal will compress the volume of the remaining gas inside the tank, resulting in an increase in pressure inside the casting tank 32 (according to Boyle's Law: at a certain temperature, gas pressure is inversely proportional to volume), and the pressure difference decreases accordingly. Therefore, the change in the pressure difference can directly reflect the change in the volume of molten metal. When the external atmospheric pressure P0 remains constant, the change in pressure inside the casting tank 32 is ΔP. ​​By presetting the target ΔP (corresponding to the target molten metal volume), the timing of stopping the vacuum pump 352 can be controlled.

[0047] In this embodiment, when drawing molten metal from the casting tank 32, the second vacuum pump 352 is used to gradually create a vacuum to extract the molten metal, instead of directly creating a vacuum chamber with a large negative pressure value inside the casting tank 32 before using this powerful negative pressure chamber to extract the molten metal from the furnace. If a large negative pressure chamber is created inside the casting tank 32 beforehand, when the casting tank 32 is inserted below the surface of the molten metal in the furnace, the surface of the molten metal will experience strong bubbling and agitation at the moment the stopper head 33 opens. This could easily bring gas from the casting tank 32 into the furnace, affecting the accurate and quantitative extraction of molten metal by the casting tank 32.

[0048] In this embodiment, the soup-feeding mechanism 3 also includes a level sensor 39 for monitoring the liquid level of the molten metal inside the pouring tank 32. When the second vacuum pump 352 evacuates the pouring tank 32 to achieve quantitative extraction of the molten metal, on the one hand, the eighth pressure sensor 354 monitors whether the pressure inside the pouring tank 32 reaches the first set pressure P1; on the other hand, the level sensor 39 monitors whether the molten metal inside the pouring tank 32 has reached the set height, achieving closed-loop feedback and ensuring the reliability and effectiveness of quantitative extraction of the molten metal. Furthermore, when the pouring tank 32 is connected to the pouring port 24 for soup feeding, the level sensor 39 monitors the change in the liquid level of the molten metal inside the pouring tank 32, effectively providing feedback on whether the molten metal has been released from the pouring tank 32, thus monitoring whether the soup feeding process is reliably and effectively carried out.

[0049] This embodiment also provides a die-casting method for a high-pressure vacuum die-casting system with multi-loop integrated control, which includes the following steps: S1. Preparation for taking soup: In the initial state, the stopper head 33 is in the open state, the multi-axis robot 31 drives the casting tank 32 to move into the furnace 200, and extends the liquid outlet 321 into the liquid surface; S2, Taking the soup: The second vacuum device 5 starts to evacuate, the eighth control valve 371 closes, the ninth control valve 353 opens, the second vacuum pump 352 starts, and evacuates the inside of the casting tank 32 at a set speed until the eighth pressure sensor 354 detects that the pressure value inside the casting tank 32 reaches the first set pressure P1, and then stops evacuating. During this process, the molten metal is gradually drawn into the casting tank 32, and the amount of molten metal drawn reaches the set volume when the evacuation stops; the driving component 34 drives the pressure plug head 33 to seal the liquid outlet 321, and the multi-axis robot 31 drives the casting tank 32 to move to the pouring port 24; P1 can be calculated using the following formula: , Where ρ is the density of the molten metal; g is the acceleration due to gravity (approximately 9.8 m / s²); h is the height of the molten metal in the casting vessel, which can be calculated from the cross-sectional area of ​​the casting vessel and the volume of molten metal to be drawn; V0 is the total volume of the casting vessel; V1 is the volume of molten metal to be drawn; and P0 is the pressure value in the casting vessel before vacuuming, which is equal to the external atmospheric pressure. S3. Pressure Adjustment Inside Casting Tank 32: The process requires that the vacuum inside the pressure chamber 21 reach the second set pressure P2 (e.g., 200~500 mbar). If the first set pressure P1 is greater than the second set pressure P2, there is no need to adjust the pressure inside the casting tank 32. If the first set pressure P1 is less than the second set pressure P2, it is determined whether the first set pressure P1 is less than or equal to the third set pressure P3 (e.g., 10~50 mbar). If it is less, the ninth control valve 353 is closed, the eighth control valve 371 is opened, and gas is injected into the casting tank 32 through the third positive pressure energy storage tank 38 to adjust the pressure inside the casting tank 32 to be greater than or equal to the second set pressure P2. Otherwise, the second vacuum pump 352 continues to evacuate the inside of the casting tank 32 until the third set pressure P3 is reached. Then, the ninth control valve 353 is closed, the eighth control valve 371 is opened, and gas is injected into the casting tank 32 through the third positive pressure energy storage tank 38 to adjust the pressure inside the casting tank 32 to be greater than or equal to the second set pressure P2. In step S3, when it is necessary to adjust the internal pressure of the casting tank 32, this embodiment sets a gas replacement pressure threshold—the third set pressure P3. If the pressure after the casting tank 32 extracts a certain amount of liquid metal (the first set pressure P1) is lower than or equal to this pressure threshold, it indicates that the nitrogen content in the remaining space inside the casting tank 32 is extremely low and can be ignored. In this case, oxygen is directly injected into the casting tank 32 through the third positive pressure energy storage tank 38 to achieve pressure regulation. If the pressure after the casting tank 32 extracts a certain amount of liquid metal (the first set pressure P1) is higher than this pressure threshold, it is considered that the nitrogen content in the remaining space inside the casting tank 32 is within the range that can cause product defects. Oxygen filling and pressure regulation cannot be carried out directly. The gas in the remaining space inside the casting tank 32 needs to be extracted to the pressure threshold before oxygen filling and pressure regulation can be carried out to achieve the purpose of strictly controlling the nitrogen content in the casting tank 32. S4. Preparation of the liquid: During the execution of S1~S3, the mold 1 completes the mold closing; the liquid outlet 321 of the pouring tank 32 is inserted into the pouring port 24; the first vacuum device 4 evacuates the sealing groove 12 through the first vacuum pipe 43 to form a first vacuum sealing strip; the second vacuum pipe 44 evacuates the gap space between the pouring port 24 and the pouring tank 32 to form a second vacuum sealing strip; the third vacuum device 6 evacuates the gap space between the injection punch 22 and the pressure chamber 21 through the fifth vacuum pipe 5 to form a third vacuum sealing strip; the second vacuum valve 46 at the vacuum port 23 is in the closed state, sealing the vacuum port 23. At this time, the mold cavity 11 and the pressure chamber 21 inside the vacuum system are completely sealed. S5. Vacuuming of the mold cavity and pressure chamber: The first vacuum device 4 evacuates the mold cavity 11 via the third vacuum line 45, and simultaneously evacuates the pressure chamber 21 via the fourth vacuum line 47. Both chambers are evacuated simultaneously until the internal pressure reaches the second set pressure P2, at which point the vacuuming stops. The third set pressure P1 can be monitored by the third pressure sensor 453 (monitoring the pressure inside the mold cavity 11) and the fifth pressure sensor 471 (monitoring the pressure inside the pressure chamber 21), respectively. The second set pressure P2 is equivalent to the value of the second set pressure P2, meaning the pressure inside the casting tank 32 is equivalent to the pressure inside the mold cavity 11 and the pressure chamber 21. This ensures that the molten metal is in a sealed vacuum environment during casting, improving die-casting efficiency and significantly enhancing the quality of the die-cast products. This effectively solves the problem of poor product quality caused by oxidation of the molten metal upon contact with external air. The second set pressure P2 is set according to process requirements. S6. Pouring: The driving component 34 drives the pressure plug head 33 to move upward, opening the outlet 321. Under its own weight, the molten metal in the pouring tank 32 enters the pressure chamber 21 through the pouring port 24. Since the pressure in the pouring tank 32 is equivalent to the pressure in the pressure chamber 21, the pressure in the entire die-casting system will not change significantly after the molten metal is transferred from the pouring tank 32 to the pressure chamber 21, and will not affect the subsequent die-casting. S7. Die casting: After the molten metal is released, the injection punch 22 moves to efficiently push the molten metal in the pressure chamber 21 into the mold cavity 11 to complete the die casting. S8. Unloading: Mold 1 is opened and the product is taken out. The back-blowing cleaning function module on the third vacuum line 45 and the fourth vacuum line 47 is activated to back-blow the third vacuum line 45 and the fourth vacuum line 47 to remove impurities in the mold cavity 11 and the vacuum port 23. At the same time, the multi-axis robot 31 drives the casting tank 32 to move back into the furnace 200 for the next extraction. During the movement, the second vacuum device 35 also activates the back-blowing function, using the third positive pressure energy storage tank 38 and the first line 37 to blow the inside of the casting tank 32 to remove impurities.

[0050] For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of this invention, and these all fall within the protection scope of this invention.

Claims

1. A high-pressure vacuum die-casting system with multi-loop integrated control, characterized in that: It includes: The mold includes a moving mold and a stationary mold that together enclose and form a mold cavity, and a sealing groove that is set on the mold closing interface and surrounds the cut surface of the mold cavity. The feeding mechanism includes a pressure chamber communicating with the mold cavity, an injection punch reciprocatingly disposed in the pressure chamber and injecting the metal in the pressure chamber into the mold cavity, a vacuum port communicating with the pressure chamber, and a pouring port. The soup dispensing mechanism includes a multi-axis robot, a pouring tank located at the end of the multi-axis robot and having a liquid outlet at its bottom, a stopper head movably disposed within the pouring tank and used to seal the liquid outlet, a drive unit for driving the stopper head to move up and down, and a second vacuum device communicating with the interior of the pouring tank; the bottom of the pouring tank is inserted into the pouring port to dispense soup. The first vacuum device includes a negative pressure energy storage tank, a first vacuum pump connected to the negative pressure energy storage tank, a first vacuum extraction pipeline, a second vacuum extraction pipeline, a third vacuum extraction pipeline, and a fourth vacuum extraction pipeline. The first vacuum device evacuates the sealing groove through the first vacuum extraction pipeline to form a first vacuum sealing band, evacuates the mating gap between the pouring port and the pouring tank through the second vacuum extraction pipeline to form a second vacuum sealing band, evacuates the mold cavity through the third vacuum extraction pipeline, and evacuates the pressure chamber through the fourth vacuum extraction pipeline.

2. The high-pressure vacuum die-casting system with multi-loop integrated control as described in claim 1, characterized in that: It also includes a third vacuum device and a fifth vacuum line, wherein the third vacuum device evacuates the fitting gap between the injection punch and the inner wall of the pressure chamber via the fifth vacuum line.

3. The high-pressure vacuum die-casting system with multi-loop integrated control as described in claim 2, characterized in that: One end of the fifth vacuum line passes through the interior of the injection punch and extends to the outer peripheral surface of the injection punch, while the other end is connected to the third vacuum device; a third control valve is provided on the fifth vacuum line to control its opening or closing.

4. The high-pressure vacuum die-casting system with multi-loop integrated control as described in claim 1, characterized in that: One end of the first vacuuming pipeline is connected to the sealing groove and the other end is connected to the first vacuum pump; a first control valve and a first pressure sensor are provided on the first vacuuming pipeline.

5. The high-pressure vacuum die-casting system with multi-loop integrated control as described in claim 1, characterized in that: One end of the second vacuum pipeline is connected to the pouring port and the other end is connected to the first vacuum pump; a second control valve and a second pressure sensor are provided on the second vacuum pipeline.

6. The high-pressure vacuum die-casting system with multi-loop integrated control as described in claim 1, characterized in that: A first vacuum valve is provided at one end of the third vacuum pipeline near the mold cavity to block the vacuum port on the inner wall surface of the mold cavity; the third vacuum pipeline is provided with a first filter, a third pressure sensor, a second filter and a fourth control valve.

7. The high-pressure vacuum die-casting system with multi-loop integrated control as described in claim 6, characterized in that: A first branch line extends from the third vacuum line between the third pressure sensor and the second filter. The other end of the first branch line is connected to a first positive pressure energy storage tank. A fifth control valve is installed on the first branch line to control its opening and closing. A fourth pressure sensor is installed downstream of the branch port of the first branch line on the third vacuum line.

8. The high-pressure vacuum die-casting system with multi-loop integrated control as described in claim 1, characterized in that: A second vacuum valve is provided at the vacuum port to seal the vacuum port; one end of the fourth vacuum pipeline is connected to the vacuum port and the other end is connected to the negative pressure energy storage tank; a fifth pressure sensor, a third filter and a sixth control valve are provided on the fourth vacuum pipeline.

9. The high-pressure vacuum die-casting system with multi-loop integrated control as described in claim 8, characterized in that: A second branch line extends from the fourth vacuum line between the fifth pressure sensor and the third filter, and the other end of the second branch line is connected to a second positive pressure energy storage tank; a seventh control valve is provided on the second branch line to control its opening and closing; a sixth pressure sensor is provided on the fourth vacuum line downstream of the branch line outlet.

10. The high-pressure vacuum die-casting system with multi-loop integrated control as described in claim 1, characterized in that: The second vacuum device includes a second vacuum pump connected to the interior of the casting tank via a second pipeline; a ninth control valve and an eighth pressure sensor are installed on the second pipeline.

11. The high-pressure vacuum die-casting system with multi-loop integrated control as described in claim 1, characterized in that: The soup dispensing mechanism also includes a third positive pressure energy storage tank that is connected to the inside of the pouring tank through a first pipeline; an eighth control valve and a seventh pressure sensor are installed on the first pipeline.

12. The high-pressure vacuum die-casting system with multi-loop integrated control as described in claim 11, characterized in that: The gas stored in the third positive pressure energy storage tank is oxygen.

13. The high-pressure vacuum die-casting system with multi-loop integrated control as described in claim 1, characterized in that: The molten metal feeding mechanism also includes a level sensor for monitoring the liquid level of the molten metal in the pouring tank.

14. A die-casting method, characterized in that: The high-pressure vacuum die-casting system based on the multi-loop integrated control as described in any one of claims 2 to 13 includes the following steps: S1. Preparation of the soup-feeding mechanism: The stopper head is in the open state, the multi-axis robot drives the casting tank to move into the furnace, and the liquid outlet is extended below the liquid surface; S2. Soup dispensing mechanism: The second vacuum device is activated to perform a vacuuming operation inside the pouring tank at a set speed until the pressure inside the pouring tank reaches the first set pressure P1, at which point the vacuuming stops. During this process, the molten metal is gradually drawn into the pouring tank, and the amount of molten metal drawn reaches the set volume when the vacuuming stops. The drive unit drives the pressure plug head to seal the liquid outlet, and the multi-axis robot drives the pouring tank to move to the pouring port. S3. Pressure adjustment inside the casting tank: The process requires the pressure chamber to be evacuated to the second set pressure P2. If the first set pressure P1 is greater than the second set pressure P2, there is no need to adjust the pressure inside the casting tank. If the first set pressure P1 is less than the second set pressure P2, gas is injected into the casting tank to adjust the pressure inside the casting tank to be greater than or equal to the second set pressure P2. S4. Preparation of the liquid: During the execution of S1~S3, the mold is closed; the outlet of the pouring tank is inserted into the pouring port; the first vacuum device evacuates the sealing groove through the first vacuum line to form the first vacuum sealing strip; the second vacuum line evacuates the gap between the pouring port and the pouring tank to form the second vacuum sealing strip; the third vacuum device evacuates the gap between the injection punch and the pressure chamber through the fifth vacuum line to form the third vacuum sealing strip; the vacuum port is in the closed state. S5. Vacuuming of mold cavity and pressure chamber: The first vacuum device evacuates the mold cavity through the third vacuuming pipeline and simultaneously evacuates the pressure chamber through the fourth vacuuming pipeline until the pressure inside the two chambers reaches the second set pressure P2 and then stops evacuating. S6. Pouring: The driving component drives the pressure plug head to move upward, opening the outlet, and the molten metal in the pouring tank enters the pressure chamber through the pouring port; S7. Die Casting: After the molten metal is released, the injection punch moves to efficiently push the molten metal in the pressure chamber into the mold cavity, completing the die casting.

15. The die-casting method as described in claim 14, characterized in that: In step S3, gas is injected into the casting tank to adjust the internal pressure of the casting tank to be greater than or equal to the second set pressure P2, including: If the first set pressure P1 is less than the second set pressure P2, then it is determined whether the first set pressure P1 is less than or equal to the third set pressure P3. If it is less, gas is directly injected into the casting tank to adjust the pressure inside the casting tank to be greater than or equal to the second set pressure P2. Otherwise, the second vacuum device continues to evacuate the inside of the casting tank until the third set pressure P3 is reached, and then gas is injected into the casting tank to adjust the pressure inside the casting tank to be greater than or equal to the second set pressure P2.

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