Four-stage sealing mechanism of ultrahigh vacuum mold

Abstract

The application discloses a four-stage sealing mechanism of an ultrahigh vacuum mold, relates to the technical field of metal die casting and molds, and comprises a front mold plate, the inner side surface of the front mold plate is provided with a front mold core, the mechanism is arranged in a concentric and coaxial four-layer annular sealing mode from inside to outside and from a mold cavity to a mold outer frame, each stage of sealing is formed into a negative pressure buffer interlayer in a radial layered and spaced mode along the mold cavity, and the four-stage sealing is formed into a negative pressure buffer interlayer in a layered mode. The four-stage sealing mechanism of the ultrahigh vacuum mold is designed in a four-stage concentric and coaxial sealing structure, the sealing space is separated layer by layer from the inner side of the mold cavity to the outer side, each stage of sealing independently bears the air leakage blocking effect, even if slight air leakage occurs in a certain layer of sealing, the negative pressure buffer interlayer in the middle can block air from continuously penetrating into the mold cavity, and the high vacuum degree inside the mold cavity can be stably maintained.

Description

Technical Field

[0001] This invention relates to the field of metal die casting and mold technology, specifically to a four-stage sealing mechanism for an ultra-high vacuum mold. Background Technology

[0002] Die casting is widely used in automotive parts manufacturing due to its high production efficiency and good forming accuracy. With the development of integrated die casting for new energy vehicles, the requirements for density, mechanical properties, airtightness, heat treatment and weldability of large aluminum alloy castings such as body structural parts and battery trays have significantly increased. Traditional die casting processes can no longer meet production needs. Although conventional vacuum die casting molds can reduce porosity defects, they still have obvious shortcomings when applied to castings that require brazing: poor sealing effect of mold parting surfaces, ejector pins, slides and other parts, easy air leakage, low vacuum degree of cavity and insufficient stability, unreasonable exhaust channel design, slow air extraction speed, easy blockage by molten metal during filling, difficulty in quickly exhausting gas from the cavity, poor matching between vacuum system and filling rhythm, and the problem of air entrapment is still prominent.

[0003] In the prior art, Chinese Patent No. CN220387847U discloses a combined fully sealed vacuum mold structure, including an upper mold and a lower mold. The upper mold is a moving mold, and the lower mold is a fixed mold. The upper mold and the lower mold are respectively provided with a first molding chamber and a second molding chamber, which form a molding cavity. The upper mold and the lower mold form an exhaust channel, which is connected to the molding cavity. The exhaust channel includes a first groove in the lower mold and a second groove and a third groove spaced apart in the upper mold. The lower mold is provided with a discharge channel connected to the first groove. The rear end of the first groove and the third groove form a closed channel connected to the discharge channel. The diameter of the second groove is smaller than the diameter of the closed channel, which can generate a more stable negative pressure during vacuum adsorption, ensuring the airtightness of the molding cavity. Through the reasonable arrangement of the exhaust channel, the vacuum of the mold is effectively guaranteed, thereby ensuring the quality of the cast product.

[0004] Chinese Patent CN219648667U discloses a fixed-point vacuum mold for aluminum castings, comprising a fixed mold base and a moving mold base. A fixed mold core is installed on the inner wall of the fixed mold base, and a material inlet is provided on the fixed mold base. A moving mold core is installed on the inner wall of the moving mold base, and a support column is fixed on the outer wall of the moving mold base. The moving mold base is fixed to a moving part inside the die-casting machine by the support column. A hydraulic cylinder is installed on the outer wall of the moving mold base, and a push rod is fixed to the end of the piston rod of the hydraulic cylinder. The push rod slides through the inner and outer walls of the moving mold base. A through hole is provided on the moving mold core directly opposite the push rod. The end of the push rod is fixed to the end of the piston rod of the hydraulic cylinder. The front end of the push rod has a material ejection part, which is fitted into the through hole. A sealing ring is fitted on the push rod. An air outlet is provided on the outer wall of the moving mold base, and an exhaust groove is also provided on the moving mold base, which effectively ensures that the interior of the formed aluminum casting is dense and improves the product yield.

[0005] The aforementioned devices use single-stage or two-stage sealing structures to seal the cavity during use, only sealing the parting surface or a single assembly gap. They do not provide full-area sealing for leakage gaps at multiple locations such as the gate, slider, and tie rod. Outside air can still seep into the cavity through multiple scattered gaps, making it impossible to achieve a highly stable vacuum environment. At the same time, the sealing structure does not form a negative pressure buffer layer in layers, making it impossible to create a transitional negative pressure between each level of sealing. The single-stage seal needs to withstand a large pressure difference, making it difficult to maintain a long-term stable ultra-high vacuum state in the cavity. Summary of the Invention

[0006] The purpose of this invention is to provide a four-stage sealing mechanism for ultra-high vacuum molds, so as to solve the problem that the single-stage or two-stage sealing structures proposed in the background art can only seal a single gap, resulting in poor sealing effect.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a four-stage sealing mechanism for an ultra-high vacuum mold, comprising a front template, a front mold core disposed on the inner side of the front template, a rear mold frame disposed on the bottom surface of the front template, a square iron disposed on the bottom surface of the rear mold frame, a base plate fixedly mounted on the bottom surface of the square iron, a positioning wedge disposed on the bottom surface of the front template, a trapezoidal sealing groove formed on the bottom surface of the front template, and a rear mold core disposed on the inner side of the rear mold frame, wherein the front mold core and the rear mold core are sealed and fitted together; the mechanism comprises four concentric and coaxial annular seals arranged sequentially from the inside out, from the cavity to the outer frame of the mold, and is divided into four stages of sealing from the innermost gate to the outermost mold frame, with each stage of sealing forming a negative layer at intervals along the radial direction of the cavity. The pressure buffer interlayer consists of a four-stage gate end seal, a three-stage slider vent seal, a first-stage cavity seal, and a second-stage mold frame layer seal. The four-stage seals form a negative pressure buffer interlayer. The four-stage gate end seal includes a gate sleeve and a gate sealing groove. The gate sleeve has a gate sealing groove on its inner wall and an axially through-type vacuum extraction hole inside the gate sleeve. The first-stage cavity seal includes a front mold core, a front mold core sealing groove, a rear mold core, and a rear mold core U-shaped sealing groove. The front mold core has a front mold core sealing groove on its outer periphery and a front mold core U-shaped sealing groove on its bottom surface. The rear mold core has a rear mold core U-shaped sealing groove on its outer periphery. Each sealing groove is fitted with a high-temperature resistant sealing strip. The joints of the sealing strips are beveled at an angle and seamlessly bonded with high-temperature resistant adhesive.

[0008] Furthermore, the three-stage slider venting seal includes a slider seat, a slider seat trapezoidal sealing groove, an venting block, and an venting block trapezoidal sealing groove. The slider seat has a slider seat trapezoidal sealing groove on its outer ring, and the venting block has an venting block trapezoidal sealing groove on its outer periphery. The two-stage mold frame layered seal includes a rear mold frame, a rear mold frame U-shaped sealing groove, a square iron, a square iron contact surface, a base plate, and a base plate U-shaped sealing groove. The bottom surface of the rear mold frame has a rear mold frame U-shaped sealing groove, the upper and lower contact surfaces of the square iron are both provided with square iron contact surfaces, the top surface of the base plate has a base plate U-shaped sealing groove, and the inner side of the base plate has a rear template tie rod sleeve groove.

[0009] Furthermore, the front mold core sealing groove, the slider seat trapezoidal sealing groove, the vent block trapezoidal sealing groove, and the gate sealing groove are all trapezoidal groove structures, while the rear mold frame U-shaped sealing groove, the bottom plate U-shaped sealing groove, and the square iron contact surface are U-shaped groove structures.

[0010] Furthermore, the rear mold frame, square iron, and base plate of the secondary mold frame layered sealing are vertically stacked from top to bottom, and the sealing grooves of the three are completely aligned on the same axis. The multi-layer U-groove surrounds and forms a vertical annular buffer cavity, which is located radially outside the primary and tertiary seals, completely enclosing the cavity seal.

[0011] Furthermore, the three-stage slider vent seal is radially arranged between the first-stage cavity seal and the second-stage mold base seal. The slider seat and vent block are located in the parting surface area on the side of the front mold core. Their annular sealing grooves fit together when the front and rear molds are closed, sealing the slider, vent block and the mold core side seam.

[0012] Furthermore, the sprue sleeve axially penetrates the front mold plate and the front mold core, the sprue sealing groove is tightly attached to the feed end face of the cavity, and the vacuum extraction hole is opened along the axis of the sprue sleeve, directly connecting to the inside of the die-casting cavity.

[0013] Furthermore, the tie rod sleeve groove is arranged in annular seal on the inner side of the base plate to seal the outer peripheral assembly gap formed by the tie rod passing through the plate.

[0014] Furthermore, the inner side of the front mold core is provided with a wedge groove. After the front mold core and the rear mold core parting surface are closed, the first-level cavity sealing grooves are completely aligned and fit together in a ring on the same plane. The third-level slider seal and the first-level cavity seal are at the same parting height and are radially offset by a certain distance. The segmented sealing design without breaks uniformly blocks the infiltration of external air throughout the entire area.

[0015] Furthermore, the fourth, first, and third level seals are arranged radially from the inside to the outside on the same horizontal parting surface, and the second level mold frame seal is a vertical multi-layer annular seal, which vertically wraps three layers of horizontal seals, forming an inner and outer enclosed layout in space.

[0016] Furthermore, the sealant is made of fluororubber that is resistant to high temperature and aluminum liquid corrosion. After the sealant strip is embedded in the groove, an axial pre-compression amount is reserved. After the mold is closed, the sealant strip completely fits the sealing surface without any segmented air leakage gaps.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] (1) Through the design of a four-level concentric and coaxial nested sealing structure, the sealing space is separated from the inside to the outside of the cavity layer by layer. Each level of sealing independently undertakes the function of preventing leakage. Even if a certain layer of sealing leaks slightly, the negative pressure buffer layer in the middle can prevent air from continuing to seep into the cavity, which can stably maintain the high vacuum inside the cavity and effectively solve the problem of rapid decrease in cavity vacuum after leakage of traditional single-level sealing.

[0019] (2) By vertically wrapping the secondary mold base seal on the outside, all assembly gaps at the cavity and slider are completely covered inside, sealing the air leakage gaps that are easily overlooked, such as the ejector pin hole, tie rod hole, and mold base mating surface, achieving a dead-angle-free seal at all assembly positions of the mold, and greatly reducing the probability of external air seeping into the cavity.

[0020] (3) The vacuum evacuation hole directly connects to the inside of the cavity. With the step-by-step venting of the layered buffer jacket, the gas inside the cavity can be quickly discharged during the vacuuming stage, which improves the vacuuming rate. At the same time, the evacuation position avoids the filling channel of the venting block, which prevents the molten metal from blocking the evacuation hole too early. This ensures that the vacuuming process can continue until the filling is completed, which is more conducive to purging the gas inside the cavity and improving the internal quality of the casting. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the cross-sectional structure of the front mold core of the present invention;

[0023] Figure 3 This is a schematic diagram of the three-dimensional structure of the rear mold frame of the present invention;

[0024] Figure 4 This is a schematic diagram of the three-dimensional structure of the sprue sleeve of the present invention;

[0025] Figure 5 This is a schematic diagram of the three-dimensional structure of the rear mold core of the present invention;

[0026] Figure 6 This is a schematic diagram of the three-dimensional structure of the square iron of the present invention;

[0027] Figure 7 This is a schematic diagram of the three-dimensional structure of the base plate of the present invention;

[0028] Figure 8This is a three-dimensional structural diagram of the U-shaped sealing groove of the rear mold frame of the present invention;

[0029] Figure 9 This is a three-dimensional structural diagram of the trapezoidal sealing groove of the slider seat of the present invention;

[0030] Figure 10 This is a schematic diagram of the three-dimensional structure of the trapezoidal sealing groove of the present invention.

[0031] In the diagram: 1. Front template; 2. Front mold core; 3. Rear mold frame; 4. Rear mold core; 5. Square iron; 6. Base plate; 7. Positioning wedge; 8. Trapezoidal sealing groove of front template; 9. Wedge groove; 10. Sealing groove of front mold core; 11. U-shaped sealing groove of front mold core; 12. U-shaped sealing groove of rear mold core; 13. U-shaped sealing groove of rear mold frame; 14. U-shaped sealing groove of base plate; 15. Square iron mating surface; 16. Tie rod sleeve groove; 17. Slider seat; 18. Trapezoidal sealing groove of slider seat; 19. Vent block; 20. Trapezoidal sealing groove of vent block; 21. Sprue sleeve; 22. Sprue sealing groove. Detailed Implementation

[0032] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1: Please refer to Figure 1 - Figure 2The present invention provides the following technical solution: a four-stage sealing mechanism for an ultra-high vacuum mold, comprising a front template 1, a front mold core 2 disposed on the inner side of the front template 1, a rear mold frame 3 disposed on the bottom surface of the front template 1, a square iron 5 disposed on the bottom surface of the rear mold frame 3, a base plate 6 fixedly installed on the bottom surface of the square iron 5, a positioning wedge 7 disposed on the bottom surface of the front template 1, a trapezoidal sealing groove 8 formed on the bottom surface of the front template 1, and a rear mold core 4 disposed on the inner side of the rear mold frame 3, wherein the front mold core 2 and the rear mold core 4 are sealed and fitted together; the mechanism consists of four concentric and coaxial annular seals arranged sequentially from the inside out, from the cavity to the outer frame of the mold, and is divided into four stages of sealing from the innermost gate to the outermost mold frame, with each stage of sealing forming a negative pressure buffer layer at intervals along the radial direction of the cavity, which are respectively four stages. The system includes a gate end seal, a three-stage slider vent seal, a first-stage cavity seal, a second-stage mold base layer seal, and a fourth-stage seal layer forming a negative pressure buffer layer. The fourth-stage gate end seal includes a gate sleeve 21 and a gate sealing groove 22. The gate sleeve 21 has a gate sealing groove 22 on its inner wall and an axially through-type vacuum extraction hole inside the gate sleeve 21. The first-stage cavity seal includes a front mold core 2, a front mold core sealing groove 10, a rear mold core 4, and a rear mold core U-shaped sealing groove 12. The front mold core 2 has a front mold core sealing groove 10 on its outer periphery and a front mold core U-shaped sealing groove 11 on its bottom surface. The rear mold core 4 has a rear mold core U-shaped sealing groove 12 on its outer periphery. Each sealing groove is fitted with a high-temperature resistant sealing strip. The joint of the sealing strip is cut at a 45° angle and seamlessly bonded with high-temperature resistant adhesive.

[0034] Through the layered nested layout of the four-level seal, a multi-level negative pressure buffer layer can be formed. Each layer of seal can block the infiltration of external air. Even if a slight leak occurs in a certain outer layer of seal, the remaining inner seal can still maintain the vacuum degree inside the cavity, effectively improving the stability of the vacuum seal. This solves the problem that if a local leak occurs in the traditional single-ring seal, the vacuum degree of the cavity will not meet the standard. The four-level gate seal directly opens a vacuum channel at the axis of the gate sleeve 21. The evacuation path is short and will not be blocked by molten metal in advance. It can quickly reduce the air pressure inside the cavity, with higher evacuation efficiency, and is more suitable for the rapid vacuuming needs of large-size cavities.

[0035] Example 2: Based on Example 1, the problem of poor sealing effect of existing molds is solved. Please refer to Example 2. Figure 2 - Figure 5The paper also discloses a trapezoidal sealing groove 20 for an exhaust block, the specific structure of which is as follows: The three-stage slider exhaust seal includes a slider seat 17, a trapezoidal sealing groove 18 for the slider seat, an exhaust block 19, and a trapezoidal sealing groove 20 for the exhaust block. The outer ring of the slider seat 17 is provided with a trapezoidal sealing groove 18 for the slider seat, and the outer periphery of the exhaust block 19 is provided with a trapezoidal sealing groove 20 for the exhaust block. The two-stage mold frame layered seal includes a rear mold frame 3, a rear mold frame U-shaped sealing groove 13, a square iron 5, a square iron contact surface 15, a base plate 6, and a base plate U-shaped sealing groove 14. The bottom surface of the rear mold frame 3 is provided with a rear mold frame U-shaped sealing groove 13. The upper and lower contact surfaces of the square iron 5 are both provided with square iron contact surfaces 15. The top surface of the base plate 6 is provided with a base plate U-shaped sealing groove 14. The inner side of the base plate 6 is provided with a rear template tie rod sleeve groove 16. The front mold core sealing groove 10 and the slider... The trapezoidal sealing groove 18, the venting block trapezoidal sealing groove 20, and the gate sealing groove 22 are all trapezoidal groove structures. The rear mold frame U-shaped sealing groove 13, the bottom plate U-shaped sealing groove 14, and the square iron contact surface 15 are U-shaped groove structures. The rear mold frame 3, square iron 5, and bottom plate 6 of the secondary mold frame layered sealing are vertically stacked from top to bottom. The sealing grooves of the three are completely aligned and coaxial. The multi-layer U-grooves enclose and form a vertical annular buffer cavity. The overall position is on the radial outside of the first-level and third-level sealing, completely enclosing the cavity seal. The third-level slider venting seal is radially arranged between the first-level cavity seal and the second-level mold frame seal. The slider seat 17 and the venting block 19 are located in the parting surface area on the side of the front mold core 2. Their annular sealing grooves fit together when the front and rear molds are closed, sealing the slider, venting block 19 and the mold core side seam.

[0036] After mold closing, the vacuum system begins to evacuate air from the cavity along the vacuum extraction hole on the axis of the sprue bushing 21. The four-stage sprue end seal first blocks the assembly gap between the sprue bushing 21 and the sprue channel to prevent air from seeping in from the feed end. Then, the first-stage cavity seal fits circumferentially around the outer periphery of the front mold core 2 and the rear mold core 4, sealing the main gap of the parting surface and sealing the entire cavity inside. For the lateral assembly gap between the side slider seat 17, the vent block 19 and the mold core, the third-stage slider vent seal, located outside the first-stage cavity seal, completes the overall sealing to prevent air from seeping in from the slider movement gap. The outermost second-stage mold base is layered. The sealing structure forms a vertical multi-layer annular seal along the mating surfaces of the rear mold frame 3, square iron 5, and base plate 6, which encloses the first three horizontal seals and further seals the air leakage channels in the stacking gaps of the mold frame layers. The negative pressure buffer layer formed between the seals at each level can gradually reduce the air pressure gradient. Even if there is a slight air leakage in the outer seal, the inner seal can still maintain the high vacuum required by the cavity. Finally, the cavity can obtain a stable and higher vacuum, effectively reducing air entrapment defects in the aluminum alloy filling process, improving the density and mechanical properties of the casting, and meeting the high performance requirements of large integrated aluminum alloy die castings for new energy vehicles.

[0037] Example 3: Based on Example 1, the problem of low vacuum degree in existing molds is solved. Please refer to Example 3. Figure 3 - Figure 10 The sprue sleeve 21 was also disclosed, with the following specific structure: the sprue sleeve 21 axially penetrates the front mold plate 1 and the front mold core 2; the sprue sealing groove 22 is tightly attached to the cavity feed end face; the vacuum extraction hole is opened along the axis of the sprue sleeve 21, directly connecting to the inside of the die-casting cavity; the tie rod sleeve groove 16 is arranged in annular seal on the inner side of the base plate 6, sealing the outer peripheral assembly gap formed by the tie rod passing through the plate; the inner side of the front mold core 2 is provided with a wedge groove 9; the first-level cavity sealing grooves corresponding to the parting surfaces of the front mold core 2 and the rear mold core 4 are completely aligned after mold closing, and are annularly fitted on the same plane; the three-level slider seal... The seal and the primary cavity seal are at the same parting height, radially offset by a certain distance, with a segmented sealing design without breaks, uniformly blocking the infiltration of external air throughout the entire area. The fourth, first, and third level seals are arranged radially from the inside out on the same horizontal parting surface. The secondary mold frame seal is a vertical multi-layered annular seal, vertically wrapping three layers of horizontal seals, forming an inner and outer enclosed layout in space. The sealant is made of high-temperature resistant and aluminum liquid corrosion fluororubber material. After the rubber strip is embedded in the groove, an axial pre-compression amount is reserved. After the mold is closed, the rubber strip completely fits the sealing surface, with no segmented air leakage gaps.

[0038] This layered sealing layout, with its inner and outer enclosures, can fully cover and seal all assembly and movement gaps in the mold, eliminating blind spots. The uniform groove structure also facilitates manufacturing and reduces the complexity of mold processing. The pre-compression design allows the sealing strip to fully adhere to the sealing surface after mold closing. Combined with the 45° beveled seamless joint, it effectively avoids segmented air leakage. The fluororubber material can withstand the high temperatures of the die-casting process for a long time, has good resistance to aluminum corrosion, and has a longer service life. This reduces the frequency of mold maintenance and seal replacement, and improves production efficiency.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" 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. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A four-stage sealing mechanism for an ultra-high vacuum mold, comprising a front template (1), wherein a front mold core (2) is provided on the inner side of the front template (1), characterized in that: The bottom surface of the front template (1) is provided with a rear template frame (3), the bottom surface of the rear template frame (3) is provided with a square iron (5), the bottom surface of the square iron (5) is fixedly installed with a base plate (6), the bottom surface of the front template (1) is provided with a positioning wedge (7), the bottom surface of the front template (1) is provided with a front template trapezoidal sealing groove (8), the inner side of the rear template frame (3) is provided with a rear mold core (4), and the front mold core (2) and the rear mold core (4) are sealed and fitted together; The mechanism consists of four concentric and coaxial annular seals arranged from the inside out, from the cavity to the outer frame of the mold. From the innermost gate to the outermost mold frame, it is divided into four levels of seals. Each level of seal forms a negative pressure buffer layer along the radial direction of the cavity. These are the fourth level gate end seal, the third level slider vent seal, the first level cavity seal, and the second level mold frame layered seal. The four levels of seals form a negative pressure buffer layer. The four-stage gate end seal includes a gate sleeve (21) and a gate sealing groove (22). The gate sleeve (21) has a gate sealing groove (22) on its inner wall and a through-type vacuum extraction hole in the axial direction. The first-stage cavity seal includes a front mold core (2), a front mold core sealing groove (10), a rear mold core (4), and a rear mold core U-shaped sealing groove (12). The front mold core (2) has a front mold core sealing groove (10) on its outer periphery and a front mold core U-shaped sealing groove (11) on its bottom surface. The rear mold core (4) has a rear mold core U-shaped sealing groove (12) on its outer periphery. Each sealing groove is fitted with a high-temperature resistant sealing strip. The joint of the sealing strip is cut at 45° and seamlessly bonded with high-temperature resistant adhesive.

2. The four-stage sealing mechanism for an ultra-high vacuum mold according to claim 1, characterized in that: The three-stage slider venting seal includes a slider seat (17), a slider seat trapezoidal sealing groove (18), an venting block (19), and an venting block trapezoidal sealing groove (20). The slider seat (17) is provided with a slider seat trapezoidal sealing groove (18) on its outer ring. The venting block (19) is provided with an venting block trapezoidal sealing groove (20) on its outer periphery. The two-stage mold frame layered seal includes a rear mold frame (3), a rear mold frame U-shaped sealing groove (13), a square iron (5), a square iron contact surface (15), a base plate (6), and a base plate U-shaped sealing groove (14). The rear mold frame (3) is provided with a rear mold frame U-shaped sealing groove (13) on its bottom surface. The square iron (5) is provided with a square iron contact surface (15) on both its upper and lower contact surfaces. The base plate (6) is provided with a base plate U-shaped sealing groove (14) on its top surface. The base plate (6) is provided with a rear template tie rod sleeve groove (16) on its inner side surface.

3. The four-stage sealing mechanism for an ultra-high vacuum mold according to claim 1, characterized in that: The front mold core sealing groove (10), the slider seat trapezoidal sealing groove (18), the vent block trapezoidal sealing groove (20), and the gate sealing groove (22) are all trapezoidal groove structures. The rear mold frame U-shaped sealing groove (13), the bottom plate U-shaped sealing groove (14), and the square iron contact surface (15) are U-shaped groove structures.

4. The four-stage sealing mechanism for an ultra-high vacuum mold according to claim 1, characterized in that: The rear mold frame (3), square iron (5), and bottom plate (6) of the secondary mold frame layered sealing are vertically stacked from top to bottom. The sealing grooves of the three are completely aligned on the same axis. The multi-layer U-groove surrounds and forms a vertical annular buffer cavity. The overall position is on the radial outside of the primary and tertiary seals, completely enclosing the cavity seal.

5. The four-stage sealing mechanism for an ultra-high vacuum mold according to claim 1, characterized in that: The three-stage slider vent seal is radially arranged between the first-stage cavity seal and the second-stage mold frame seal. The slider seat (17) and the vent block (19) are located in the parting surface area on the side of the front mold core (2). Their annular sealing grooves fit together when the front and rear molds are closed, sealing the slider, vent block and the mold core side seam.

6. The four-stage sealing mechanism for an ultra-high vacuum mold according to claim 1, characterized in that: The sprue sleeve (21) axially penetrates the front template (1) and the front mold core (2), the sprue sealing groove (22) is tightly attached to the feed end face of the cavity, and the vacuum extraction hole is opened along the axis of the sprue sleeve (21) and directly connects to the inside of the die-casting cavity.

7. The four-stage sealing mechanism for an ultra-high vacuum mold according to claim 2, characterized in that: The tie rod sleeve groove (16) is arranged in annular seal on the inner side of the base plate (6) to seal the outer peripheral assembly gap formed by the tie rod passing through the plate.

8. The four-stage sealing mechanism for an ultra-high vacuum mold according to claim 1, characterized in that: The inner side of the front mold core (2) is provided with a wedge groove (9). The first-level cavity sealing grooves corresponding to the parting surfaces of the front mold core (2) and the rear mold core (4) are completely aligned after mold closing, and are circumferentially fitted on the same plane. The third-level slider seal and the first-level cavity seal are at the same parting height, and are radially offset by a distance. The segmented sealing design without breaks is uniformly blocked from the infiltration of external air throughout the entire area.

9. The four-stage sealing mechanism for an ultra-high vacuum mold according to claim 1, characterized in that: The fourth, first, and third level seals are arranged radially from the inside to the outside on the same horizontal parting surface. The second level mold frame seal is a vertical multi-layer annular seal, which vertically wraps three layers of horizontal seals, forming an inner and outer enclosed layout in space.

10. The four-stage sealing mechanism for an ultra-high vacuum mold according to claim 1, characterized in that: The sealant is made of fluororubber that is resistant to high temperature and aluminum liquid corrosion. After the sealant strip is embedded in the groove, an axial pre-compression amount is reserved. After the mold is closed, the sealant strip completely fits the sealing surface without any segmented air leakage gaps.

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