Low pressure casting apparatus and method of die casting

Abstract

The application belongs to the technical field of low-pressure casting, and particularly relates to a low-pressure casting device which comprises a lower mold positioned at the top of a holding furnace, an upper mold and an internal sand core, a liquid injection port of the lower mold is communicated with a liquid lifting channel of the holding furnace, a pressure maintaining assembly is arranged at the liquid injection port of the lower mold, the pressure maintaining assembly comprises an inclined forming groove, one end of the forming groove is communicated with the liquid injection port, the other end of the forming groove is provided with a push plate and a first linear driving element, one end of the push plate is a low end, accommodating grooves are arranged on the two sides of the forming groove in the liquid injection port, and the accommodating grooves accommodate clamping plates. The application can avoid the influence of the oxide skin on the quality of the castings, the liquid injection port is blocked after the cavity is filled to realize pressure maintaining, and the backflow of the metal liquid is effectively prevented; the casting block is smoothly moved along the vertical direction of the liquid injection port, the volume shrinkage in the solidification process is effectively compensated, the compactness of the castings is improved, and the generation of shrinkage cavity and shrinkage porosity defects is reduced.

Description

Technical Field

[0001] This invention relates to the field of low-pressure casting technology, and in particular to a low-pressure casting equipment and its die-casting method. Background Technology

[0002] Low-pressure casting is an advanced anti-gravity metal forming process. Its principle involves introducing dry compressed air (typically at a pressure of 20–60 kPa) into a sealed, insulated furnace, causing molten metal to rise smoothly along riser pipes and fill the sand mold, where it solidifies under pressure. This process offers advantages such as stable mold filling and high metal utilization, making it suitable for the production of high-quality aluminum alloy and magnesium alloy castings.

[0003] However, after the casting solidifies, it needs to be cooled to sufficient strength under pressure before the pressure can be released to allow the residual molten metal to fall back into the holding furnace. This process reduces production efficiency and increases energy consumption. In the traditional method, a "neck" is set, that is, a local thinning section is designed at the connection between the casting and the gating. Although this can promote the early closure of the feeding channel during solidification and reduce the holding time, this structure is very prone to stress concentration during subsequent cleaning, which can lead to casting cracking or dimensional deviation. Furthermore, oxide scale may sometimes be present inside the injection tube, affecting the purity of the molten metal and leading to inclusion defects inside the casting. Summary of the Invention

[0004] This invention provides a low-pressure casting equipment and a die-casting method thereof, aiming to solve at least one of the above-mentioned technical problems.

[0005] This invention provides the following technical solution: On one hand, this application provides a low-pressure casting equipment, including a lower mold, an upper mold, and a sand core positioned on the top of a holding furnace. The injection port of the lower mold is connected to the liquid rising channel of the holding furnace. A pressure holding assembly is provided at the injection port of the lower mold. The pressure holding assembly includes an inclined forming groove. One end of the forming groove is connected to the injection port, and the other end of the forming groove is provided with a push plate and a first linear drive. The end of the push plate is the lower end. A receiving groove is provided on both sides of the forming groove inside the injection port. The receiving groove contains a clamping plate. A second linear drive is connected to the side of the clamping plate away from the center of the injection port.

[0006] Furthermore, a crucible is fixed inside the heat preservation furnace, and molten metal liquid is contained in the crucible. A liquid riser is fixed on the top of the heat preservation furnace. The lower end of the liquid riser extends into the crucible and contacts the molten metal liquid, while the upper end is connected to the liquid injection port of the lower mold.

[0007] Furthermore, the heat preservation furnace is connected to a pressure-increasing pipe and a pressure-reducing pipe.

[0008] Furthermore, a lifting assembly is provided on the opposite side of the injection port to the forming groove, including a slide groove, in which a lifting member slides. The lifting member is connected to a fourth linear drive member and can reciprocate within the slide groove. The slide groove and the forming groove are arranged at an angle so that the lifting member can lift the formed casting upward from the injection port when it moves.

[0009] Furthermore, the lower mold and the upper mold are provided with clamping components on their exterior, including a base and a peripheral wall. The base has a docking interface at its center for connecting with the top of the riser pipe. The peripheral wall is provided with clamping arms for clamping and fixing the sides of the lower mold and the upper mold in four directions. The clamping arms are driven by a third linear drive component and can move in a direction perpendicular to the peripheral wall.

[0010] Furthermore, it also includes a material receiving conveyor, a die-casting conveyor, and a discharge conveyor arranged in sequence. The die-casting conveyor is a movable conveyor with a liftable top, while the material receiving conveyor and the discharge conveyor are fixed conveyor platforms with fixed tops. The movable conveyor is located above the holding furnace, and a fifth linear drive component for lifting is provided at the bottom of the movable conveyor to drive the movable conveyor to lift vertically, so as to achieve precise docking and separation of the lower mold and the riser pipe.

[0011] Furthermore, the movable transmission table is provided with a sixth linear drive on the sand box travel path. The sixth linear drive is arranged to avoid the transmission roller of the movable transmission table. A stop is fixed at the output end of the sixth linear drive so that the stop can extend when the sand box travels to a designated position. The movable transmission table is provided with a seventh linear drive on both sides of the sand box travel path. The output end of the seventh linear drive is connected to a positioning pin. The positioning pin can extend and retract in the horizontal plane and is used to insert into the side positioning hole when the sand box stops.

[0012] On the other hand, this application provides a low-pressure die-casting method, comprising the following steps: Step 1: Place the sand box into the clamping assembly. The clamping arms on the periphery of the clamping assembly are pushed by the third linear drive to clamp and fix the outer wall of the sand box from four directions. Step 2: Transfer the clamping assembly containing the sand box to the incoming material transfer table, and then transport the clamping assembly to the die-casting transfer table via the incoming material transfer table; Step 3: The sixth linear drive unit extends the stop to restrict the sand box from moving forward, while the seventh linear drive units on both sides push the positioning pins to insert into the positioning holes on the side of the sand box to achieve precise positioning. Step 4: The fifth linear drive unit is activated, driving the movable transfer table to descend, so that the liquid injection port of the lower mold is precisely aligned with the top of the riser pipe; at the same time, the pressure pipe introduces inert gas into the holding furnace, so that the molten metal in the crucible is forced into the lower mold through the riser pipe; Step 5: Continuously pressurize the furnace through the pressurization pipe to inject the molten metal into the lower mold cavity at a stable pressure. The molten metal first fills the forming groove of the lower mold. The molten metal in the forming groove cools and gradually solidifies during the filling process, forming a casting block. Step Six: Then, the molten metal enters the cavity of the upper mold through the injection port until the entire cavity is filled. When the molten metal is filled and pressure needs to be maintained, the casting plug is pushed out of the forming groove to seal the injection port and prevent the molten metal from flowing back. Step 7: When the casting block is fully pushed out, the push plate blocks the groove of the forming groove. At the same time, the lifting part slides out along the slide. The lifting part pushes the casting block upward along the injection port. After moving a predetermined distance, it stops. Then the casting block is clamped by the clamping plate. Step 8: Expel the gas from the holding furnace through the pressure relief pipe, and let the molten metal inside the riser pipe flow back into the crucible; Step 9: The fifth linear drive unit drives the movable conveyor table to rise and become flush with the discharge conveyor table at the rear end, making it easier for the clamping component to be moved out; at this time, the seventh linear drive unit retracts and pulls out the positioning pin, the sixth linear drive unit retracts and retracts the stop, and the clamping component moves out along the discharge conveyor table to the designated position. Step 10: Repeat steps 1 to 9 above to achieve continuous automated low-pressure casting operation.

[0013] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit the invention.

[0014] The molten metal first enters the forming tank of the lower mold and solidifies to form a casting block. The oxide scale on the inner surface of the injection pipe is injected into the forming tank to form a casting block, thereby preventing the oxide scale from entering the cavity and affecting the casting quality.

[0015] Once the cavity is filled, the pusher plate, driven by the first linear drive, pushes out the casting plug, sealing the injection port to maintain pressure and effectively prevent the molten metal from flowing back, ensuring the internal structure of the casting is dense. At this time, the clamping plate, driven by the second linear drive, clamps the casting plug, ensuring that the casting plug remains stable and does not fall off during subsequent pressure relief.

[0016] Moving the casting plug smoothly along the vertical direction of the injection port allows for sufficient pressure transmission during the cooling and solidification of the molten metal in the mold cavity. This effectively compensates for volume shrinkage during solidification, improves the density of the casting, and reduces the occurrence of shrinkage cavities and porosity defects.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a front structural diagram of a die-casting transfer table according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the lower mold according to an embodiment of the present invention; Figure 3 for Figure 2 One of the schematic diagrams of the cross-sectional structure at point AA; Figure 4 for Figure 2 Schematic diagram of the cross-sectional structure at point AA (Part 2); Figure 5 for Figure 2 One of the schematic diagrams of the cross-sectional structure at point BB; Figure 6 for Figure 2 Schematic diagram of the cross-sectional structure at point BB (Part 2); Figure 7 This is a top view of a die-casting transfer table according to an embodiment of the present invention; Figure 8 This is a front view of the overall structure of an embodiment of the present invention.

[0019] Figure label: 1. Clamping assembly; 2. Clamping arm; 3. Upper mold; 4. Sand core; 5. Lower mold; 6. Third linear drive; 7. Die casting transfer table; 8. Pressurizing pipe; 9. Holding furnace; 10. First linear drive; 11. Crucible; 12. Pressure relief pipe; 13. Liquid riser pipe; 14. Lifting component; 15. Second linear drive; 16. Clamping plate; 17. Casting plug; 18. Push plate; 19. Forming groove; 20. Liquid injection port; 21. Sixth linear drive; 22. Discharge transfer table; 23. Seventh linear drive; 24. Positioning pin; 25. Stop; 26. Incoming material transfer table. Detailed Implementation

[0020] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0022] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0025] To better understand the purpose, function, and specific design of this invention, the invention will be described in further detail below with reference to the accompanying drawings.

[0026] like Figures 1-6 As shown, this application provides a low-pressure casting equipment, including a lower mold 5, an upper mold 3, and a sand core 4 positioned on the top of a holding furnace 9. The injection port 20 of the lower mold 5 is connected to the liquid rising channel of the holding furnace 9. A pressure holding assembly is provided at the injection port 20 of the lower mold 5. The pressure holding assembly includes an inclined forming groove 19. One end of the forming groove 19 is connected to the injection port 20, and the other end of the forming groove 19 is provided with a push plate 18 and a first linear drive 10. The push plate 18 is located at the lower end. The injection port 20 is provided with receiving grooves on both sides adjacent to the forming groove 19. The receiving grooves contain clamping plates 16. A second linear drive 15 is connected to the side of the clamping plate 16 away from the center of the injection port 20.

[0027] When the holding furnace 9 is pressurized, the molten metal is continuously transported to the injection port 20 through the riser pipe 13. The molten metal first enters the forming groove 19 of the lower mold 5 and solidifies to form the casting block 17. The oxide scale on the inner surface of the injection pipe is injected into the forming groove 19 to form the casting block 17, thereby preventing the oxide scale from entering the cavity and affecting the casting quality. When the cavity is full, the push plate 18 pushes out the casting block 17 under the action of the first linear drive 10, sealing the injection port 20 to achieve pressure holding, effectively preventing the molten metal from flowing back and ensuring the internal structure of the casting is dense. At this time, the clamping plate 16 clamps the casting block 17 under the action of the second linear drive 15 to ensure that the casting block 17 is stable and does not fall off during the subsequent pressure relief process. After the holding furnace 9 completes the pressure relief through the pressure relief pipe 12, the molten metal in the riser pipe 13 flows back to the crucible 11, thus completing a single low-pressure casting process.

[0028] For further details, please refer to... Figure 6 In this embodiment, two clamping plates 16 are provided, which are symmetrically distributed on both sides of the injection port 20, namely the first clamping plate 16 and the second clamping plate 16. The two sides are separated from the forming groove 19 and the sliding groove to ensure that no motion interference occurs. The clamping plates 16 can move towards the center of the injection port 20 under the push of the second linear drive member 15 to clamp and position the casting block 17. During the clamping and positioning process, since the casting block 17 is formed to match the cross-sectional shape of the injection port 20, the clamping plates 16 do not detach from the receiving groove and only provide sufficient clamping force on both sides of the casting block 17.

[0029] For example, the first linear drive 10 and the second linear drive 15 are electric actuators.

[0030] like Figure 1 As shown, in some embodiments, a crucible 11 is fixed inside the holding furnace 9, and molten metal liquid is contained in the crucible 11. A liquid riser pipe 13 is fixed on the top of the holding furnace 9. The lower end of the liquid riser pipe 13 extends into the crucible 11 and contacts the molten metal liquid, and the upper end is connected to the liquid injection port 20 of the lower mold 5.

[0031] The aforementioned heat preservation furnace 9 is a sealed pressure-resistant container used for heat preservation and pressure preservation. The riser pipe 13 serves as a channel for molten metal to enter the cavity of the lower mold 5 from the crucible 11. During the pressurization process, the gas pressure pushes the molten metal to rise steadily along the riser pipe 13, ensuring a smooth and controllable filling process. When the pressure is released, the pressure inside the furnace decreases, and the molten metal flows back to the crucible 11 along the riser pipe 13 under the action of gravity, realizing the recovery of residual molten metal and reducing waste.

[0032] Furthermore, a sealing structure is provided at the connection between the riser pipe 13 and the lower mold 5 to prevent gas leakage.

[0033] like Figure 1As shown, in some embodiments, the holding furnace 9 is connected to a pressure-increasing pipe 8 and a pressure-reducing pipe 12. The pressure-increasing pipe 8 is connected to an external gas source and is used to introduce inert gas into the holding furnace 9 to increase the pressure. The inert gas enters the interior of the holding furnace 9 through the pressure-increasing pipe 8, gradually increasing the pressure inside the cavity and pushing the molten metal in the crucible 11 to rise steadily along the riser pipe 13 until the molten metal fills the cavity of the lower mold 5. The pressure-reducing pipe 12 is connected to an external exhaust system and is used to release the pressure inside the holding furnace 9 after casting is completed, so that the pressure inside the furnace gradually decreases and causes the molten metal in the riser pipe 13 to flow back to the crucible 11 under the action of gravity, realizing residual liquid recovery and safe pressure release.

[0034] like Figures 2-4 As shown, in some embodiments, the injection port 20 is provided with a lifting assembly on the opposite side of the forming groove 19, including a slide groove, in which a lifting member 14 slides. The lifting member 14 is connected to a fourth linear drive member and can reciprocate in the slide groove. The slide groove and the forming groove 19 are arranged at an angle so that the lifting member 14 can lift the formed casting upward from the injection port 20 when it moves.

[0035] Driven by the fourth linear drive, the lifting component 14 rises along the chute. After its top end contacts the bottom of the casting block 17, it continuously applies a thrust, which moves the casting block 17 smoothly along the vertical direction of the injection port 20. This allows the pressure transmission to be fully maintained when the molten metal in the cavity cools and solidifies, effectively compensating for the volume shrinkage during the solidification process, improving the density of the casting, and reducing the generation of shrinkage cavities and porosity defects. The chute and the forming groove 19 are arranged at an angle to form a wedge structure, which allows the lifting component 14 to convert the oblique movement into a vertical lifting force, ensuring the stability of the lifting process and enhancing the efficiency of force transmission.

[0036] For example, the fourth linear drive can be an electric actuator or other linear drive mechanism. In this embodiment, the fourth linear drive is an electric actuator.

[0037] The lifting component 14 includes a sliding part adapted to the slide groove and a push head whose end contacts the lower side of the casting block 17. The push head is designed with an arc surface structure to increase the contact area with the casting block 17. The sliding part is a rod with a cross-sectional shape adapted to the slide groove.

[0038] Furthermore, in order to limit the stroke of the lifting member 14, the sliding part of the lifting member 14 is provided with a stroke limiting block, and a stroke limiting groove is provided in the slide groove. When the stroke limiting block moves in the slide groove, it is restricted by the two ends of the limiting groove, thereby accurately controlling the lifting range of the lifting member 14.

[0039] like Figure 1As shown, in some embodiments, the lower mold 5 and the upper mold 3 are provided with a clamping assembly 1, including a base and a peripheral wall. The base is provided with a docking interface at its center for docking with the top of the riser pipe 13. The peripheral wall is provided with a clamping arm 2 for clamping and fixing the sides of the lower mold 5 and the upper mold 3 in four directions. The clamping arm 2 is driven by a third linear drive 6 and can move in a direction perpendicular to the peripheral wall.

[0040] The clamping assembly 1 is used to position and securely clamp the lower mold 5 and the upper mold 3, ensuring mold closing accuracy and sealing. During the pressurized filling process, it effectively resists the upward expansion force generated by the molten metal, preventing mold displacement or leakage. The interface is a central through-hole structure, with the bottom coaxially connected to the top of the riser pipe 13 and the top aligned with the injection port 20 of the lower mold 5, ensuring that the molten metal is smoothly injected into the cavity under pressure. The clamping arm 2 is a plate structure adapted to the side contours of the lower mold 5 and the upper mold 3. The plate structure fits tightly against the side of the mold, enhancing clamping stability. The plate structure is also provided with a clearance groove to avoid the temperature measuring hole, lifting component 14 or other auxiliary structures on the mold.

[0041] like Figure 8 As shown, in some embodiments, the system also includes a material receiving conveyor 26, a die-casting conveyor 7, and a material discharge conveyor 22 arranged sequentially. The die-casting conveyor 7 is a movable conveyor with a liftable top, while the material receiving conveyor 26 and the material discharge conveyor 22 are fixed conveyor platforms with fixed tops. The movable conveyor is located above the holding furnace 9, and a fifth linear drive component for lifting is provided at the bottom of the movable conveyor to drive the movable conveyor to lift vertically, thereby achieving precise docking and separation between the lower mold 5 and the riser pipe 13.

[0042] The material conveying station 26 is used to smoothly transport the lower mold 5 and upper mold 3 components that have been assembled into the clamping assembly 1 to the die casting station; the die casting conveying station 7 is used to realize the die casting process, and the material discharge conveying station 22 is used to transport the castings that have completed the die casting process, together with the mold assembly, to the subsequent cooling or disassembly station to realize automated continuous production.

[0043] like Figure 1 , Figure 7 As shown, in some embodiments, the movable transmission table is provided with a sixth linear drive 21 on the sand box travel path. The sixth linear drive 21 is arranged to avoid the transmission roller of the movable transmission table. The output end of the sixth linear drive 21 is fixed with a stop 25 so that the stop 25 can extend when the sand box travels to a designated position. The movable transmission table is provided with a seventh linear drive 23 on both sides of the sand box travel path. Its output end is connected to a positioning pin 24. The positioning pin 24 can extend and retract in the horizontal plane and is used to insert into its side positioning hole when the sand box stops.

[0044] The aforementioned sixth linear drive 21, in conjunction with the stop 25, achieves axial positioning of the sand box on the movable transfer table, preventing displacement during lifting and lowering. When the sand box enters the designated position on the movable transfer table, such as when the end of the clamping assembly 1 enters the initial position of the movable transfer table, the sensor on the movable transfer table detects that the clamping assembly 1 is in place, and the sixth linear drive 21 actuates to extend the stop 25, restricting the axial (transfer direction) movement of the sand box. When the clamping assembly 1 contacts the stop 25, the sensor on the stop 25 detects the contact signal and feeds it back to the control system, confirming that the axial positioning of the sand box is complete. At the same time, the seventh linear drive 23 actuates synchronously, pushing the positioning pin 24 into the positioning hole on the side of the sand box to achieve lateral constraint, ensuring the positional accuracy and stability of the sand box during lifting and lowering, and avoiding docking deviation or equipment damage due to offset.

[0045] For example, the sixth linear actuator 21 and the seventh linear actuator 23 can be electric push rods or other linear motion devices, and the sensors can be proximity switches, photoelectric sensors or pressure sensors to achieve precise control of position detection and signal feedback.

[0046] Furthermore, the positioning holes can be set on both sides of the base along its length. The shape of the positioning holes can match the positioning pin 24. In order to improve positioning efficiency, the opening of the positioning holes can be designed as a chamfer or a flared structure to facilitate the automatic insertion of the positioning pin 24 and reduce alignment errors.

[0047] On the other hand, this application also provides a low-pressure die-casting method, comprising the following steps: Step 1: Place the sand box into the clamping assembly 1. The clamping arm 2 on the periphery of the clamping assembly 1 is pushed by the third linear drive 6 to clamp and fix the outer wall of the sand box from four directions. In order to determine whether the clamping is in place, a pressure sensor or displacement sensor can be set on the clamping arm 2 to monitor the change of resistance or the end position of the stroke in real time during the clamping process. When the end position signal is fed back to the control system, the clamping is confirmed to be completed. Step 2: The clamping assembly 1 loaded with sand box is transferred to the material transfer table 26. The clamping assembly 1 is then transported to the die casting transfer table 7 via the material transfer table 26. When the front end of the clamping assembly 1 loaded with sand box enters the initial position of the movable transfer table, the sensor detects the positioning signal of the clamping assembly 1, and the sixth linear drive 21 is activated. Step 3: The sixth linear drive 21 drives the stop 25 to extend, restricting the sand box from moving forward. When the clamping assembly 1 carrying the sand box contacts the stop 25, the sensor on the stop 25 immediately captures the contact signal and transmits it to the control system to confirm that the axial positioning of the sand box is completed. At this time, the control system controls the seventh linear drive 23 to start. The seventh linear drive 23 on both sides pushes the positioning pin 24 to insert into the positioning hole on the side of the sand box to achieve precise positioning. Step 4: After the sixth linear drive component 21 and the seventh linear drive component 23 have completed their actions, the control system controls the fifth linear drive component to start, driving the movable transmission table to descend, so that the liquid injection port 20 of the lower mold 5 is precisely aligned with the top of the liquid riser 13; after the fifth linear drive component has completed its actions, the control system controls the external air source to introduce inert gas into the holding furnace 9, so that the molten metal liquid in the crucible 11 is pressed into the lower mold 5 through the liquid riser 13; Step 5: Pressurize the heat preservation furnace 9 through the pressurizing pipe 8 to inject the molten metal into the cavity of the lower mold 5 at a stable pressure. The molten metal first fills the forming groove 19 of the lower mold 5. The molten metal in the forming groove 19 cools and gradually solidifies during the filling process to form the casting block 17. Step 6: Then, the molten metal enters the cavity of the upper mold 3 through the injection port 20 until the entire cavity is filled. When the molten metal is filled and pressure needs to be maintained, the pressure sensor monitors the pressure change inside the cavity in real time and feeds the data back to the control system. The control system controls the first linear drive component 10 to push the casting block 17 out of the forming groove 19 to block the injection port 20 and prevent the molten metal from flowing back. Step 7: When the first linear drive 10 completes its action, the casting block 17 is fully pushed out, and the push plate 18 blocks the opening of the forming groove 19. At the same time, the control system controls the fourth linear drive to activate, so that the lifting member 14 slides out along the slide groove. The lifting member 14 pushes the casting block 17 to move upward along the injection port 20. After moving a predetermined distance, it stops. The control system controls the second linear drive 15 to start, and then clamps the casting block 17 through the clamping plate 16. Step 8: The gas is discharged from the holding furnace 9 through the pressure relief pipe 12, and the molten metal inside the riser pipe 13 flows back into the crucible 11; Step 9: The fifth linear drive unit drives the movable conveyor table to rise and become flush with the discharge conveyor table 22 at the rear end, so as to facilitate the removal of the clamping component 1; at this time, the seventh linear drive unit 23 retracts and pulls out the positioning pin 24, the sixth linear drive unit 21 retracts and retracts the stop 25, and the clamping component 1 moves out along the discharge conveyor table 22 to the designated position. Step 10: Repeat steps 1 to 9 above to achieve continuous automated low-pressure casting operation.

[0048] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. In the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A low-pressure casting equipment, characterized in that, The device includes a lower mold (5), an upper mold (3), and a sand core (4) positioned on the top of the heat preservation furnace (9). The liquid injection port (20) of the lower mold (5) is connected to the liquid rising channel of the heat preservation furnace (9). A pressure holding component is provided at the liquid injection port (20) of the lower mold (5). The pressure holding component includes an inclined forming groove (19). One end of the forming groove (19) is connected to the liquid injection port (20). The other end of the forming groove (19) is provided with a push plate (18) and a first linear drive component (10). The push plate (18) is located at the lower end. A receiving groove is provided on both sides of the forming groove (19) inside the liquid injection port (20). The receiving groove contains a clamping plate (16). A second linear drive component (15) is connected to the side of the clamping plate (16) away from the center of the liquid injection port (20).

2. The low-pressure casting equipment according to claim 1, characterized in that, The heat preservation furnace (9) has a crucible (11) fixed inside, which contains molten metal liquid. A liquid riser (13) is fixed on the top of the heat preservation furnace (9). The lower end of the liquid riser (13) extends into the crucible (11) and contacts the molten metal liquid, while the upper end is connected to the liquid injection port (20) of the lower mold (5).

3. The low-pressure casting equipment according to claim 1, characterized in that, The heat preservation furnace (9) is connected to a pressure pipe (8) and a pressure relief pipe (12).

4. The low-pressure casting equipment according to claim 1, characterized in that, The injection port (20) is provided with a lifting assembly on the opposite side of the forming groove (19), including a slide groove, in which a lifting member (14) slides. The lifting member (14) is connected to a fourth linear drive member and can reciprocate in the slide groove. The slide groove and the forming groove (19) are arranged at an angle so that the lifting member (14) can lift the formed casting from the injection port (20) upward when it moves.

5. A low-pressure casting equipment according to claim 4, characterized in that, The lower mold (5) and the upper mold (3) are provided with a clamping assembly (1), including a base and a peripheral wall. The base is provided with a docking interface at the center for docking with the top of the riser pipe (13). The peripheral wall is provided with a clamping arm (2) for clamping and fixing the sides of the lower mold (5) and the upper mold (3) in four directions. The clamping arm (2) is driven by a third linear drive (6) and can move in a direction perpendicular to the peripheral wall.

6. The low-pressure casting equipment according to claim 1, characterized in that, It also includes a material receiving conveyor (26), a die casting conveyor (7), and a material discharge conveyor (22) arranged in sequence. The die casting conveyor (7) is a movable conveyor with a liftable top, while the material receiving conveyor (26) and the material discharge conveyor (22) are fixed conveyors with fixed tops. The movable conveyor is located above the heat preservation furnace (9). The bottom of the movable conveyor is provided with a fifth linear drive for lifting and lowering, which drives the movable conveyor to lift and lower in the vertical direction to achieve precise docking and separation of the lower mold (5) and the riser pipe (13).

7. A low-pressure casting equipment according to claim 6, characterized in that, The movable transmission platform is provided with a sixth linear drive (21) on the sand box travel path. The sixth linear drive (21) is arranged to avoid the transmission roller of the movable transmission platform. The output end of the sixth linear drive (21) is fixed with a stop (25) so that the stop (25) can extend when the sand box travels to a designated position. The movable transmission platform is provided with a seventh linear drive (23) on both sides of the sand box travel path. Its output end is connected to a positioning pin (24). The positioning pin (24) can move in and out in the horizontal plane and is used to insert into its side positioning hole when the sand box stops.

8. A low-pressure die-casting method, using the equipment described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Place the sand box into the clamping assembly (1), and use the clamping arms (2) on the periphery of the clamping assembly (1) to push the outer wall of the sand box from four directions to clamp and fix it. Step 2: Transfer the clamping assembly (1) loaded with sand box to the incoming material transfer table (26), and transport the clamping assembly (1) to the die casting transfer table (7) through the incoming material transfer table (26); Step 3: The sixth linear drive component (21) drives the stop component (25) to extend, restricting the sand box from moving forward. At the same time, the seventh linear drive components (23) on both sides push the positioning pin (24) to insert into the positioning hole on the side of the sand box to achieve precise positioning. Step 4: The fifth linear drive unit is activated, driving the movable transmission table to descend, so that the liquid injection port (20) of the lower mold (5) is precisely aligned with the top of the liquid riser (13); at the same time, the pressure pipe (8) introduces inert gas into the heat preservation furnace (9), so that the molten metal in the crucible (11) is pressed into the lower mold (5) through the liquid riser (13); Step 5: Pressurize the furnace (9) continuously through the pressurizing pipe (8) so that the molten metal in the crucible (11) enters the injection port (20) through the riser pipe (13). The molten metal first enters and fills the forming tank (19) connected to the injection port (20), and then enters the mold cavity through the injection port (20). During the filling process, the molten metal in the forming tank (19) cools and gradually solidifies to form a casting block (17) whose cross-sectional shape matches the cross-sectional shape of the injection port (20). Step 6: When the molten metal in the molding tank (19) forms the casting block (17) and the molten metal fills the cavity and needs to be pressure maintained, the first linear drive (10) drives the push plate (18) to move and push the casting block (17) out of the molding tank (19) to seal the injection port (20). Step 7: When the casting block (17) is fully pushed out, the push plate (18) blocks the opening of the forming groove (19). The fourth linear drive drives the lifting member (14) to move along the slide, so that the lifting member (14) pushes the casting block (17) upward along the injection port (20). After moving a predetermined distance, the second linear drive (15) drives the clamping plates (16) located on both sides of the injection port (20) to move towards the center of the injection port (20) to clamp the casting block (17). Step 8: After clamping the casting block (17) with the clamping plate (16), the gas is discharged from the holding furnace (9) through the pressure relief pipe (12), so that the molten metal in the riser pipe (13) flows back into the crucible (11); Step 9: The fifth linear drive unit drives the movable transmission table to rise and become flush with the discharge transmission table (22) at the rear end, so that the clamping component (1) can be moved out; at this time, the seventh linear drive unit (23) retracts and pulls out the positioning pin (24), the sixth linear drive unit (21) retracts and retracts the stop (25), and the clamping component (1) moves out along the discharge transmission table (22) to the designated position; Step 10: Repeat steps 1 to 9 above to achieve continuous automated low-pressure casting operation.

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