Vacuum die casting system and vacuum die casting method

Abstract

According to the vacuum die-casting method, a telescopic mechanism is arranged on one side of a movable die, a sliding groove is formed in the die assembly face of the movable die, the inner end of the sliding groove extends in the direction of a movable die core, the middle of the sliding groove and an inner pouring gate are arranged in a crossed mode, and a sliding block is arranged in the sliding groove in a sliding fit mode; the second exhaust grooves and the pouring gate grooves are formed in the sliding block at intervals, the cavity is vacuumized before the injection punch is pushed at a low speed and slow injection is carried out, air in the pressure chamber is exhausted in the slow injection process, in this way, when molten metal is rapidly injected, no air exists in the cavity, the cavity is in a high-vacuum state, and the forming quality of a die casting can be effectively guaranteed. And after the telescopic mechanism is controlled to drive the sliding block to move at different moments, the ingate and the exhaust channel are opened or blocked, so that it can be effectively guaranteed that the exhaust channel is unblocked and the ingate is blocked in the slow injection process, and it can be effectively guaranteed that the exhaust channel is blocked and the ingate is opened in the fast injection process, and molten metal can be rapidly filled in.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of die casting, in particular to a vacuum die casting system and a vacuum die casting method. BACKGROUND

[0002] In traditional die casting, the high-speed injected metal liquid will roll in the air and release agent volatile gas in the cavity, forming pores or oxidation inclusions, affecting the quality of the casting. The vacuum die casting uses a vacuum system to extract the air in the die casting mold cavity before and during the filling process, so that a certain degree of vacuum (usually 10-100 mbar or lower) is formed in the cavity. When the metal liquid fills the mold in a vacuum environment, the flow is more stable due to the reduced gas resistance, and can more completely fill complex thin-walled structures, significantly reducing air entrainment and porosity defects.

[0003] The vacuum die casting system mainly includes a die casting machine, a die casting mold, a vacuum pump, a hydraulic vacuum valve, and a vacuum valve controller. The die casting machine is provided with a fixed mold plate, a movable mold plate, a pressure chamber, a pressure rod, a pressure injection punch, and a pouring gate. The die casting mold includes a fixed mold block and a movable mold block. The fixed mold block is installed on the fixed mold plate of the horizontal die casting machine, and the movable mold block is installed on the movable mold plate of the horizontal die casting machine. The fixed mold block and the movable mold block are respectively provided with mold cores. The fixed mold block is provided with an inner runner, and the movable mold block is provided with an ejection device. The fixed mold block and the movable mold block form an inner pouring cavity, a cavity, and an exhaust passage after clamping. The inner runner is connected to the pressure chamber through the pouring bush, and the pressure injection punch is arranged in the pressure chamber. Before the metal liquid fills the cavity from the pressure chamber, the air in the cavity and the pressure chamber is extracted, and the extraction process is as follows: the vacuum valve is opened, and under the action of the vacuum pump, the air in the cavity and the pressure chamber enters the vacuum tank through the exhaust passage, so that a vacuum-like environment is formed in the cavity and the pressure chamber. However, during the vacuum extraction process, when the vacuum valve is opened, the pressure in the cavity is about 1000 mbar (atmospheric pressure), and the pressure in the vacuum tank is about 50 mbar. At this time, the pressure difference is as high as about 950 mbar, and the flowing metal liquid in the pressure chamber is easily rolled into the mold cavity in advance, affecting the product forming quality. SUMMARY

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a vacuum die casting system and a vacuum die casting method, which solves the problem that the metal liquid easily enters the mold cavity in advance during the vacuum extraction process in the prior art, resulting in unqualified products.

[0005] To solve the above technical problems, the present application adopts the following technical solutions:

[0006] A vacuum die-casting system includes a fixed mold, a moving mold, a sprue sleeve, a pressure chamber, an injection punch, and a vacuum pump. The moving mold is separable from or can be closed relative to the fixed mold. A moving mold core is embedded in the center of the moving mold, and a fixed mold core is embedded in the center of the fixed mold. When the moving mold and the fixed mold are closed, a cavity is formed between the moving mold core and the fixed mold core, and an ingate is provided on the cavity. The ingate is connected to the pressure chamber through the sprue sleeve, and the injection punch is located in the pressure chamber. The ingate is located on the moving mold core. A groove is provided on the closing surface of the moving mold, with its inner end extending towards the moving mold core and its middle part intersecting the ingate. A slider is slidably fitted in the groove, and the side end of the slider is connected to a telescopic mechanism, which can be driven by the telescopic mechanism. Under the influence of the sliding mechanism, the slide moves and positions itself along the length of the slide. A first vent is provided on the moving mold core, with one end connected to the slide. A second vent is provided on the slide block, and a sprue groove is provided on one side of the second vent. When the slide block moves towards the moving mold core under the drive of the telescopic mechanism, and the first and second vents are connected, the sprue groove and the ingate are misaligned, and the slide block blocks the middle of the ingate, placing the system in a vacuum state. When the slide block moves outwards under the drive of the telescopic mechanism, and the sprue groove corresponds to the ingate, the second vent is misaligned with the first vent, and the sprue groove and the middle of the ingate are connected, placing the system in a hydraulic injection filling state. In this way, by setting a telescopic mechanism on one side of the moving mold's parting surface and installing a slider on the parting surface, before evacuating the cavity, the telescopic mechanism can move the slider inward, aligning the venting groove on the slider with the venting groove on the moving mold core. After moving, the portion of the slider placed in the groove will be positioned in the middle of the ingate, blocking it. This ensures that after the moving and fixed molds are closed, the portion connecting the cavity and the pressure chamber is separated and blocked by the slider, forming a sealed space relative to the pressure chamber. When evacuating the cavity, this allows it to quickly reach a vacuum state. Simultaneously, the slider's obstruction effectively prevents molten metal from being sucked into the pressure chamber during evacuation and prematurely entering the mold cavity. While the ingate is blocked by the slider, the second venting groove on the slider corresponds to the first venting groove on the moving mold core. This allows air from the pressure chamber to be discharged through the venting channel formed by the second and first venting grooves during slow injection by the injection punch. In addition, a sprue groove is provided on the slider. This sprue groove has the same shape and size as the middle section of the ingate. After the cavity reaches a vacuum state, the slider can be moved outward by the telescopic mechanism until the sprue groove aligns with the ingate, thus connecting the space between the pressure chamber and the cavity. At this point, the injection punch is activated to inject molten metal, which can then enter the cavity through the channel formed by the sprue groove and the ingate, completing the die casting. The slider is easy to manufacture and can move within the groove. Different working conditions correspond to different positions, which can meet the needs of different stages of die casting. Moreover, the overall structure requires minimal modification and is easy to manufacture.

[0007] Furthermore, the telescopic mechanism includes a hydraulic cylinder, which is fixed to the outside of the slide groove by a bracket. The piston rod of the hydraulic cylinder extends into the slide groove and connects with the outer end of the slider. In this way, the telescopic mechanism uses a hydraulic cylinder structure to achieve telescopic movement. The piston rod of the hydraulic cylinder is connected to the slider, so the slider can be moved by controlling the extension and retraction of the piston rod, and the overall structure operates smoothly.

[0008] Furthermore, the hydraulic cylinder is fixedly mounted on the moving mold via a hydraulic cylinder bracket located on the moving mold side. A slide block is fixed on the side of the slider near the hydraulic cylinder, and the slide block is fixedly connected to the piston rod via a connector. In this way, the hydraulic cylinder and the moving mold are fixed together by the hydraulic cylinder bracket, resulting in smoother operation. The connector between the slider and the piston rod facilitates the connection between the plate and the rod.

[0009] Furthermore, the slide groove consists of a first groove on the mating surface of the moving mold and a second groove on the moving mold core. The width of the first groove is greater than the width of the second groove. On each opposite side of the first groove, there is a guide strip with its end extending out of the moving mold and fixedly connected to the cylinder bracket. The distance between the two guide strips is equal to the width of the second groove. The connector slides between the two guide strips. Thus, the slide groove is formed by two sections joined together. The end on the moving mold core is mainly used for assembling the slider, and the end on the moving mold is mainly used for assembling the slide block, connector, and accommodating the piston rod of the cylinder. The guide strips are longer than the first groove and extend out of the moving mold, enabling them to support and fix the cylinder bracket and guide the sliding of the slider and slide block, ensuring smooth slider movement.

[0010] Furthermore, the inner end of the first venting channel is bent downwards, forming an L-shape. The second venting channel consists of an upper connecting section, a lower corresponding section, and a transverse connecting section connecting the upper connecting section and the lower corresponding section. The upper connecting section corresponds to the end of the bent portion of the first venting channel, and the lower corresponding section corresponds to the ingate. Thus, both the first and second venting channels are curved, effectively increasing the venting path throughout the injection process. The ingate corresponds to the end of the second venting channel, allowing air in the pressure chamber to be discharged through the ingate, the second venting channel, and the first venting channel during slow injection.

[0011] A vacuum die-casting method for a vacuum die-casting system includes the following steps: S1, preparing a molten metal and a vacuum die-casting system according to design requirements, wherein the vacuum die-casting system is as described above; S2, activating the telescopic mechanism in the vacuum die-casting system to move the slider towards the moving mold core, so that the second venting groove on the slider is connected to the first venting groove on the moving mold core, at which point the slider blocks the ingate; S3, starting the die-casting machine to move the moving mold towards the fixed mold and then closing the mold, forming a sealed cavity between the moving mold core and the fixed mold core; S4, starting the vacuum pump to extract the air from the cavity, achieving the process requirements. The vacuum degree is determined; S5, molten metal is injected into the pressure chamber through the pouring port on the pressure chamber, and the injection punch is advanced at a low speed. The injection punch pushes the molten metal towards the ingate, and the air in the pressure chamber is discharged sequentially through the second venting groove and the first venting groove; S6, when the molten metal reaches the ingate, the telescopic mechanism controls the slider to move towards the hydraulic cylinder until the sprue groove on the slider corresponds to the ingate, and the second venting groove is misaligned with the first venting groove. After the first venting groove is blocked by the slider, the injection punch is advanced rapidly, and the molten metal quickly fills the cavity; S7, after holding the pressure for a set time, the molten metal is allowed to cool and solidify. In this way, the cavity is evacuated before the slow injection by advancing the injection punch at a low speed, and the air in the pressure chamber is discharged during the slow injection process. Thus, when the molten metal is injected quickly, there is no air in the cavity, and it is in a high vacuum state, which can effectively ensure the molding quality of the die casting. By controlling the telescopic mechanism to move the slider at different times, the ingate and venting channels are opened or blocked. This effectively ensures that the venting channel is unobstructed during slow injection, while the ingate is blocked. During fast injection, the venting channel is blocked, and the ingate is opened, allowing molten metal to fill quickly. Compared to traditional die casting, this process extends the vacuum time, increases the vacuum level in the mold cavity, and effectively ensures the molding quality of the die-cast parts.

[0012] Furthermore, the vacuum pump is connected to the mold cavity via an exhaust pipe, and a vacuum valve is installed on the exhaust pipe. Thus, by installing the vacuum valve, the size of the vacuum passage can be controlled by opening and closing the vacuum valve.

[0013] Furthermore, a hydraulic cylinder control system is installed on the cylinder. This system can control the cylinder to retract within a set time after the cylinder initially extends. In this way, the cylinder determines the retraction timing by setting a time interval, which is simpler to set compared to using sensors. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the installation structure of the vacuum die-casting system in the embodiment;

[0015] Figure 2 This is a schematic diagram of the installation structure of the fixed mold, slider, and telescopic mechanism in the vacuum die-casting system of the embodiment;

[0016] Figure 3 This is a schematic diagram of the three-dimensional installation structure of the fixed mold, slider, and telescopic mechanism in the embodiment. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0018] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, the terms "horizontal," "vertical," etc., do not indicate that the component is required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] like Figure 1As shown, the existing vacuum die-casting system mainly includes a die-casting mold, a vacuum pump, a hydraulic vacuum valve, and a vacuum valve controller. The die-casting machine is equipped with a fixed mold plate, a moving mold plate, an injection chamber, an injection rod, an injection punch, and a sprue. The die-casting mold includes a fixed module and a moving module. The fixed module is installed on the fixed mold plate of the horizontal die-casting machine, and the moving module is installed on the moving mold plate of the horizontal die-casting machine. A mold core is installed inside each of the fixed and moving modules. The fixed module has an ingate, and the moving module has an ejector device. After the fixed and moving modules are closed, an ingate cavity, a mold cavity, and an venting channel are formed. When using this die-casting system, because the ingate is always connected to the mold cavity, during vacuuming and slow injection, some molten metal is easily drawn into the mold cavity, affecting the quality of the die-cast parts.

[0020] Example 1

[0021] To solve the above problems, the vacuum die-casting system provided in this embodiment (such as...) Figures 1-3(As shown), it includes a fixed mold 1, a moving mold 2, a sprue bushing, a pressure chamber 3, an injection punch 4, and a vacuum pump 7. The moving mold 2 can be separated or closed relative to the fixed mold 1. A moving mold core 21 is embedded in the middle of the moving mold 2, and a fixed mold core is embedded in the middle of the fixed mold 1. When the moving mold 2 and the fixed mold 1 are closed, a cavity 5 is formed between the moving mold core 21 and the fixed mold core, and an inner sprue 23 is provided on the cavity 5. The inner sprue 23 is connected to the pressure chamber 3 through the sprue bushing, and the injection punch 4 is located in the pressure chamber 3. The inner sprue 23 is located on the moving mold core 21. A groove is provided on the mold closing surface of the moving mold 2, with its inner end extending towards the moving mold core 21 and its middle part intersecting with the inner sprue 23. A slider 9 is slidably fitted in the groove. The side end of the slider 9 is connected to a telescopic mechanism 8, and it can slide under the drive of the telescopic mechanism 8. The groove moves and is positioned along its length; a first venting groove 22 is provided on the moving mold core 21, with one end connected to the slide groove, and a second venting groove 91 is provided on the slider 9. A sprue groove 92 is provided on one side of the second venting groove 91; when the slider 9 moves towards the moving mold core 21 under the drive of the telescopic mechanism 8, and the first venting groove 22 and the second venting groove 91 are correspondingly connected, the sprue groove 92 and the inner sprue 23 are misaligned, and the slider 9 blocks the middle of the inner sprue 23, and the system is in a vacuum state of the cavity 5; when the slider 9 moves towards the outside of the moving mold 2 under the drive of the telescopic mechanism 8, and the sprue groove 92 corresponds to the inner sprue 23, the second venting groove 91 and the first venting groove 22 are misaligned, and the sprue groove 92 and the middle of the inner sprue 23 are correspondingly connected, and the system is in a metal hydraulic injection filling state. In this way, after setting the telescopic mechanism 8 on one side of the mold closing surface of the moving mold 2 and setting the slider 9 on the mold closing surface, before evacuating the cavity 5, the telescopic mechanism 8 can drive the slider 9 to move inward, so that the venting groove on the slider 9 corresponds to the venting groove on the moving mold core 21. At this time, after the slider 9 moves, the part placed in the groove will be placed in the middle of the inner sprue 23, blocking the inner sprue 23. After the moving mold 2 and the fixed mold 1 are closed, the part connecting the cavity 5 and the pressure chamber 3 is separated and blocked by the slider 9. The slider 9 and the cavity 5 form a sealed space relative to the pressure chamber 3. At this time, when evacuating the cavity 5, the cavity 5 can quickly reach a vacuum state. At the same time, due to the blocking of the slider 9, the molten metal in the pressure chamber 3 can be effectively prevented from being sucked in during evacuation and entering the mold cavity 5 in advance. While the middle part of the inner runner 23 is blocked by the slider 9, the second exhaust groove 91 provided on the slider 9 corresponds to the first exhaust groove 22 provided on the moving mold core 21. When the injection punch 4 performs slow injection, the air in the pressure chamber 3 can be discharged through the exhaust channel formed by the second exhaust groove 91 and the first exhaust groove 22.In addition, a sprue groove 92 is provided on the slider 9. The sprue groove 92 has the same shape and size as the middle section of the ingate 23. After the cavity 5 reaches a vacuum state, the slider 9 can be moved outward by the telescopic mechanism 8 until the sprue groove 92 corresponds to the ingate 23. This will connect the space between the pressure chamber 3 and the cavity 5. At this time, the injection punch 4 is activated to inject molten metal. The molten metal can then enter the cavity 5 through the channel formed by the sprue groove 92 and the ingate 23, completing the die casting. The slider 9 is easy to process and can move within the groove. When it moves to different positions, the corresponding working conditions are different, which can meet the needs of different stages of die casting. Moreover, the overall structure requires little modification and is easy to process.

[0022] The telescopic mechanism 8 used in this embodiment includes a hydraulic cylinder 81. The hydraulic cylinder 81 is fixed to the outside of the slide groove by a bracket 85, and the piston rod 811 of the hydraulic cylinder 81 extends into the slide groove and connects with the outer end of the slider 9. In this way, the telescopic mechanism 8 uses the hydraulic cylinder 81 structure to achieve telescopic movement. The piston rod 811 of the hydraulic cylinder 81 is connected to the slider 9, so the slider 9 can be moved by controlling the extension and retraction of the piston rod 811, and the overall structure operates smoothly.

[0023] Furthermore, the hydraulic cylinder 81 is fixedly mounted on the moving mold 2 via a hydraulic cylinder 81 bracket 85 located on the side of the moving mold 2. A slide block 83 is fixed on the side of the slider 9 near the hydraulic cylinder 81, and the slide block 83 is fixedly connected to the piston rod 811 via a connector 82. In this way, the hydraulic cylinder 81 is fixed to the moving mold 2 via the hydraulic cylinder 81 bracket 85, resulting in smoother operation. The slider 9 and the piston rod 811 are connected via the connector 82, facilitating the connection between the plate and the rod.

[0024] Furthermore, the slide groove is composed of a first groove on the mating surface of the moving mold 2 and a second groove on the moving mold core 21. The width of the first groove is greater than the width of the second groove. On both opposite sides of the first groove, there is a guide strip 84 with its end extending out of the moving mold 2 and fixedly connected to the cylinder 81 bracket 85. The distance between the two guide strips 84 is equal to the width of the second groove. The connector 82 is slidably fitted between the two guide strips 84. Thus, the slide groove is formed by two sections joined together. One end on the moving mold core 21 is mainly used for assembling the slider 9, and the other end on the moving mold 2 is mainly used for assembling the slide block 83, the connector 82, and accommodating the piston rod 811 of the cylinder 81. The guide strip 84 is longer than the first groove, with its end extending out of the moving mold 2, and can be used to support and fix the cylinder 81 bracket 85, and guide the sliding of the slider 9 and the slide block 83, ensuring smooth sliding of the slider 9.

[0025] In this embodiment, the depth of the sprue is greater than the depth of the ingate 23, and the depth of the sprue groove 92 is the same as the depth of the ingate 23, with the same shape and size as the middle part of the ingate 23. For ease of installation and fixation, the outer end of the slider 9 corresponds to the shape of the slide block 83, is rectangular, and is fixed by fasteners. The end of the connector 82 facing the piston rod 811 is cylindrical, and the end corresponding to the slide block 83 is cubic, and is fixedly connected to the slide block 83. The end of the piston rod 811 extends into the cylinder of the connector 82 and is locked and fixed by a connector.

[0026] Furthermore, the inner end of the first venting groove 22 is bent downwards, forming an L-shape. The second venting groove 91 consists of an upper connecting section, a lower corresponding section, and a transverse connecting section connecting the upper connecting section and the lower corresponding section. The upper connecting section corresponds to the end of the bent portion of the first venting groove 22, and the lower corresponding section corresponds to the ingate 23. Thus, both the first venting groove 22 and the second venting groove 91 are curved, effectively increasing the venting path during the injection process. The ingate 23 corresponds to the end of the second venting groove 91, allowing air in the pressure chamber 3 to be discharged through the ingate 23, the second venting groove 91, and the first venting groove 22 during slow injection.

[0027] Example 2

[0028] This embodiment provides a vacuum die casting method for a vacuum die casting system, including the following steps: S1, preparing the molten metal and vacuum die casting system according to design requirements, the vacuum die casting system as described above; S2, activating the telescopic mechanism 8 in the vacuum die casting system, driving the slider 9 to move towards the core of the moving mold 2, so that the second venting groove 91 on the slider 9 is connected to the first venting groove 22 on the moving mold core 21, at which time the slider 9 blocks the inner sprue 23; S3, starting the die casting machine to move the moving mold 2 towards the fixed mold 1 and then closing the mold, forming a sealed cavity 5 between the moving mold core 21 and the fixed mold core; S4, starting the vacuum pump 7 to extract the air from the cavity 5 to achieve the process requirements. S5, the molten metal is injected into the pressure chamber 3 through the pouring port on the pressure chamber 3, and the injection punch 4 is advanced at a low speed. The injection punch 4 pushes the molten metal towards the ingate, and the air in the pressure chamber 3 is discharged through the second venting groove 91 and the first venting groove 22 in sequence; S6, when the molten metal reaches the ingate 23, the telescopic mechanism 8 controls the slider 9 to move towards the oil cylinder 81 until the sprue groove 92 on the slider 9 corresponds to the ingate 23, and the second venting groove 91 and the first venting groove 22 are misaligned. After the first venting groove 22 is blocked by the slider 9, the injection punch 4 is advanced quickly, and the molten metal quickly fills the cavity 5; S7, after the pressure is held for a set time, the molten metal is cooled and solidified. In this way, the cavity 5 is evacuated before the slow injection by advancing the injection punch 4 at low speed, and the air in the pressure chamber 3 is expelled during the slow injection process. This ensures that the cavity 5 is completely air-free and in a high vacuum state during the fast injection of molten metal, effectively guaranteeing the molding quality of the die-cast part. Furthermore, by controlling the telescopic mechanism 8 to move the slider 9 at different times, the ingate 23 and venting channel are opened or blocked. This effectively ensures that the venting channel is unobstructed during the slow injection process, while the ingate 23 is blocked. During the fast injection process, the venting channel is blocked, and the ingate 23 is opened, allowing for rapid filling of the molten metal. Compared to traditional die casting, this process extends the vacuum time, increases the vacuum level of the cavity 5, and effectively guarantees the molding quality of the die-cast part.

[0029] Furthermore, the vacuum pump 7 is connected to the cavity 5 via an exhaust pipe, and a vacuum valve is installed on the exhaust pipe. Thus, by installing the vacuum valve, the size of the vacuum passage can be controlled by opening and closing the vacuum valve.

[0030] Furthermore, a control system for the hydraulic cylinder 81 is installed on the cylinder 81. This control system can control the cylinder 81 to retract within a set time after the cylinder 81 initially extends. In this way, the cylinder 81 determines the retraction timing by setting a time interval, which is simpler to set compared to using a sensor.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A vacuum die-casting system, comprising a fixed mold, a moving mold, a sprue bushing, a pressure chamber, an injection punch, and a vacuum pump, wherein the moving mold is separable from or can be closed relative to the fixed mold, a moving mold core is embedded in the middle of the moving mold, and a fixed mold core is embedded in the middle of the fixed mold; when the moving mold and the fixed mold are closed, a cavity is formed between the moving mold core and the fixed mold core, and an inner sprue is provided on the cavity; the inner sprue is connected to the pressure chamber through the sprue bushing, and the injection punch is disposed in the pressure chamber; characterized in that… The ingate is located on the moving mold core. A groove is provided on the moving mold's mating surface, extending inwards towards the moving mold core and intersecting the ingate in the middle. A slider slides within the groove, its side end connected to a telescopic mechanism, allowing it to move and be positioned along the length of the groove under the action of the telescopic mechanism. A first vent is located on the moving mold core, one end of which communicates with the groove. A second vent is located on the slider, and a sprue groove is located on one side of the second vent. When the slider moves towards the moving mold core under the drive of the telescopic mechanism, and the first and second vents are correspondingly connected, the sprue groove and the ingate are misaligned, and the slider blocks the middle of the ingate, putting the system in a vacuum state. When the slider moves outwards under the drive of the telescopic mechanism, and the sprue groove corresponds to the ingate, the second vent is misaligned with the first vent, and the sprue groove and the middle of the ingate are correspondingly connected, putting the system in a hydraulic injection filling state.

2. The vacuum die-casting system according to claim 1, characterized in that, The telescopic mechanism includes a hydraulic cylinder, which is fixed to the outside of the slide groove by a bracket, and the piston rod of the hydraulic cylinder extends into the slide groove and is connected to the outer end of the slider.

3. The vacuum die-casting system and method according to claim 2, characterized in that, The hydraulic cylinder is fixedly mounted on the moving mold by a hydraulic cylinder bracket located on the moving mold side. A slide block is fixed on the side of the slider near the hydraulic cylinder, and the slide block and the piston rod are fixedly connected by a connector.

4. The vacuum die-casting system according to claim 3, characterized in that, The slide groove consists of a first groove on the moving mold mating surface and a second groove on the moving mold core. The width of the first groove is greater than the width of the second groove. On each of the two opposite sides of the first groove, there is a guide strip with one end extending out of the moving mold and fixedly connected to the oil cylinder bracket. The distance between the two guide strips is equal to the width of the second groove. The connector is slidably fitted between the two guide strips.

5. The vacuum die-casting system according to claim 1, 2, 3, or 4, characterized in that, The inner end of the first venting groove is bent downwards to form an L shape. The second venting groove consists of an upper connecting section, a lower corresponding section, and a transverse connecting section connecting the upper connecting section and the lower corresponding section. The upper connecting section is used to correspond to the end of the bent part of the first venting groove, and the lower corresponding section is used to correspond to the inner gating.

6. A vacuum die-casting method for a vacuum die-casting system, characterized in that, The process includes the following steps: S1, preparing the molten metal and vacuum die-casting system according to design requirements, wherein the vacuum die-casting system is as described in any one of claims 1-5; S2, activating the telescopic mechanism in the vacuum die-casting system to move the slider towards the moving mold core, so that the second venting groove on the slider is connected to the first venting groove on the moving mold core, at which point the slider blocks the ingate; S3, starting the die-casting machine to move the moving mold towards the fixed mold and then closing the mold, forming a sealed cavity between the moving mold core and the fixed mold core; S4, starting the vacuum pump to extract the air from the cavity, achieving the required vacuum level. S5, the molten metal is injected into the pressure chamber through the pouring port on the pressure chamber, and the injection punch is advanced at a low speed. The injection punch pushes the molten metal towards the ingate, and the air in the pressure chamber is discharged through the second venting groove and the first venting groove in sequence; S6, when the molten metal reaches the ingate, the telescopic mechanism controls the slider to move towards the oil cylinder until the sprue groove on the slider corresponds to the ingate, and the second venting groove is misaligned with the first venting groove. After the first venting groove is blocked by the slider, the injection punch is advanced quickly, and the molten metal quickly fills the cavity; S7, after holding the pressure for a set time, the molten metal is allowed to cool and solidify.

7. The vacuum die-casting method of the vacuum die-casting system according to claim 6, characterized in that, The vacuum pump is connected to the mold cavity through an exhaust pipe, and a vacuum valve is installed on the exhaust pipe.

8. The vacuum die-casting method of the vacuum die-casting system according to claim 6, characterized in that, A hydraulic cylinder control system is installed on the hydraulic cylinder. The hydraulic cylinder control system can control the hydraulic cylinder to retract within a set time after the hydraulic cylinder is first started to extend.

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