An injection mold for secondary injection based on a built-in valve

Abstract

This utility model relates to the field of injection mold technology, and in particular to an injection mold based on a built-in valve for secondary injection molding. It includes an upper mold body and a lower mold body that cooperate with each other. At least one mold core assembly is provided between the upper and lower mold bodies. The mold core assembly includes an upper mold core installed at the lower end of the upper mold body and a lower mold core installed on the lower mold body. After mold closing, at least one set of interconnected first and second mold cavities are formed between the upper and lower mold cores. The second mold cavity is provided with a valve insert, and a power component for pushing the valve insert is installed on the lower mold body. The valve insert isolates or connects the first and second mold cavities through the drive of the power component. Through the linkage design of the built-in valve insert and the power component, the traditional two-color injection mold structure requiring two sets of upper molds for switching is eliminated, eliminating the need for upper mold switching operations and fundamentally avoiding positioning deviations caused by upper mold switching.

Description

Technical Field

[0001] This utility model relates to the field of injection mold technology, and in particular to an injection mold based on a built-in valve to achieve secondary injection. Background Technology

[0002] In the manufacturing of plastic products, injection molding is one of the most widely used processing techniques. Its core involves injecting molten plastic material into a mold cavity through the cooperation of an injection mold and an injection molding machine. After cooling and solidification, it forms a product of a predetermined shape. As market demands for the functionality, performance, and aesthetic diversity of plastic products continue to increase, more and more products are required to be molded in one piece using plastic materials of different colors, compositions, or hardnesses. These products not only meet the needs of complex usage scenarios but also reduce subsequent assembly processes and improve production efficiency. Therefore, they are widely used in fields such as electronic device housings, automotive parts, and everyday consumer goods. For example, in cable chain plates, the plate itself is made of rigid plastic, while the elastic buffer structure formed on the plate is made of a relatively elastic plastic material. This can be achieved by changing the pressure of the two materials when they are injected into the mold.

[0003] To meet the aforementioned requirement of integrated molding of multiple materials, existing technologies commonly employ two-color injection molding machines for production. The core structure of this type of equipment is designed with two independent upper mold structures and a shared lower mold structure, with each upper mold corresponding to a different injection molding material. The specific processing flow is as follows: First, the first upper mold is precisely aligned with the lower mold, forming an injection mold cavity suitable for the first material. The first plastic material is injected into this cavity using the injection molding machine. After the material cools and solidifies to form the product base, the mold switching mechanism is activated to separate the first upper mold from the lower mold. Then, the second upper mold is moved to the position where it aligns with the lower mold and precisely closes. At this point, the second upper mold and the already formed product base form an injection mold cavity suitable for the second material. Plastic material is injected again, and after cooling and solidification, a two-material integrated overmolded product is finally formed.

[0004] However, the existing two-color injection molding technology still has significant defects and shortcomings in practical applications. On the one hand, due to the need to switch the upper mold between the two injection molding processes, the switching involves the movement and positioning of the upper mold and a secondary mold closing with the lower mold. Even with a high-precision guiding mechanism, it is difficult to completely avoid positioning deviations between the upper and lower molds, which leads to a decrease in the dimensional accuracy of the injection mold cavity for the second material. This ultimately affects the molding accuracy of the overmolded product, especially for precision plastic products with high dimensional accuracy requirements. On the other hand, the design of two independent upper molds not only increases the design complexity of the mold but also requires the separate manufacture of two sets of upper molds, significantly increasing the mold manufacturing cost. At the same time, the storage and maintenance of the two sets of upper molds further increases the overall cost in the production process, which is not conducive to improving the cost-effectiveness of product production. Therefore, how to optimize the mold structure for multi-material integrated injection molding and reduce mold costs while ensuring product molding accuracy has become an urgent technical problem to be solved in this field. Utility Model Content

[0005] To overcome the shortcomings mentioned above, this utility model aims to provide a technical solution that can solve the above problems.

[0006] An injection mold for secondary injection based on a built-in valve includes an upper mold body and a lower mold body that cooperate with each other. At least one mold core assembly is disposed between the upper mold body and the lower mold body. The mold core assembly includes an upper mold core installed at the lower end of the upper mold body and a lower mold core installed on the lower mold body. After the mold is closed, at least one set of first mold cavity and second mold cavity that are interconnected are formed between the upper mold core and the lower mold core. The second mold cavity is provided with a valve insert, and a power component for pushing the valve insert is installed on the lower mold body. The valve insert isolates or connects the first mold cavity and the second mold cavity through the drive of the power component. It also includes a gating system integrated in the upper mold body and the mold core assembly. The gating system is provided with a first gate and a second gate. The first gate is connected to the first mold cavity, and the second gate is connected to the second mold cavity. When the first mold cavity and the second mold cavity are isolated by a valve insert, the second gate is blocked by the valve insert.

[0007] Preferably, the power component includes a fixedly mounted power cylinder and a long rod connected to the piston end of the power cylinder. The long rod is guided and slidably fitted with the mold core assembly. An inclined portion is formed on the long rod. The valve insert is provided with a groove that mates with the inclined portion. The power component drives the long rod, causing the inclined portion to push the valve insert through the groove, thereby causing the valve insert to isolate or connect the first mold cavity and the second mold cavity.

[0008] Preferably, the power cylinder is fixedly installed on the lower mold body, and the lower mold body is provided with a long groove that matches the long rod. The long rod slides in conjunction with the long groove, and the long rod abuts against the lower end of the lower mold core. The lower end of the valve insert is connected to a connecting part that extends to the bottom of the lower mold core, and the long groove is provided on the connecting part.

[0009] Preferably, an even number of interconnected first and second mold cavities are formed between the upper mold core and the lower mold core, and an even number of valve inserts and inclined parts are provided accordingly, wherein the even number of inclined parts are evenly distributed on both sides of the long rod.

[0010] Preferably, the second mold cavity includes an isolation zone and a connecting zone, the valve insert is configured to cover the connecting zone, and the second gate is located in the connecting zone.

[0011] Preferably, the upper mold body is provided with a panel, a casting plate fixed to the lower end of the panel, and an upper template fixed to the lower end of the casting plate. The gating system also includes a first hot nozzle, a second hot nozzle, and two hot runner plates. The two hot runner plates are integrated in the casting plate. The upper hot runner plate and the lower hot runner plate have non-overlapping parts on the vertical projection plane. The upper hot runner plate is connected to the first hot nozzle through the non-overlapping part. The first hot nozzle is connected to the first gate. The lower hot runner plate is connected to the second hot nozzle through the non-overlapping part. The second hot nozzle is connected to the second gate.

[0012] Preferably, the gating system further includes a connecting sleeve and a first gating sleeve. The first gating sleeve is disposed on the panel and is connected to the upper hot runner plate. The two hot runner plates are connected to each other through the connecting sleeve.

[0013] Preferably, the gating system further includes a first gating sleeve and a second gating sleeve. The first gating sleeve is disposed on the panel and is connected to the upper hot runner plate. The second gating sleeve is disposed on the side of the gating plate and is connected to the lower hot runner plate.

[0014] Preferably, an even number of mold core assemblies are provided, and the even number of mold core assemblies are symmetrically distributed between the upper mold body and the lower mold body.

[0015] Preferably, the lower mold body includes a base plate, a square plate mounted on the base plate, a lower template mounted on the square plate, and an ejection mechanism that is guided and movably connected to the lower template. The lower template and the base plate form a receiving space through the square plate, and the ejection mechanism is arranged in the receiving space.

[0016] Compared with the prior art, the beneficial effects of this utility model are: By integrating the valve insert with the power components, the traditional two-color injection mold structure, which requires switching between two upper molds, is eliminated. On the one hand, the upper mold switching operation is eliminated, fundamentally avoiding positioning deviations caused by upper mold switching. At the same time, the valve insert can precisely control the opening and closing of the mold cavity and the gate, ensuring the positioning accuracy and material filling accuracy of the first and second mold cavities, significantly improving the dimensional consistency and molding quality of multi-material integrated molded products. On the other hand, only a single upper mold body, lower mold body, and integrated gating system are required, eliminating the design, processing, and maintenance costs of additional upper molds, greatly reducing the overall manufacturing cost and comprehensive production cost of the mold. At the same time, the injection molding process is simplified, the production cycle is shortened, and production efficiency is improved.

[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the disassembled structure of this utility model; Figure 3 This is a schematic diagram of the disassembled structure of one type of upper mold body in this utility model; Figure 4 This is a schematic diagram of the disassembled structure of another type of upper mold body in this utility model; Figure 5 This is a schematic diagram of the disassembled structure of the mold core assembly in this utility model; Figure 6 This is a schematic diagram of the power component in this utility model; Figure 7 This is a schematic diagram of the structure of the lower mold core in this utility model; Figure 8 This is a utility model Figure 7 A schematic diagram of the structure at point A in the middle.

[0020] The reference numerals and names in the figure are as follows: Upper mold body 10, panel 11, gating plate 12, upper template 13, lower mold body 20, long groove 21, base plate 22, square plate 23, lower template 24, ejection mechanism 25, mold core assembly 30, upper mold core 31, lower mold core 32, first mold cavity 33, second mold cavity 34, isolation area 341, connecting area 342, valve insert 35, inclined groove 351, 352, power component 36, power cylinder 361, long rod 362, inclined part 363, first gate 41, second gate 42, first hot nozzle 43, second hot nozzle 44, connecting sleeve 45, first gate sleeve 46, hot runner plate 47, second gate sleeve 48. Detailed Implementation

[0021] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] Please see Figure 1-8 In this embodiment of the present invention, an injection mold for secondary injection based on a built-in valve includes an upper mold body 10 and a lower mold body 20 that cooperate with each other. At least one mold core assembly 30 is provided between the upper mold body 10 and the lower mold body 20. The mold core assembly 30 includes an upper mold core 31 installed at the lower end of the upper mold body 10 and a lower mold core 32 installed on the lower mold body 20. After the mold is closed, at least one set of first mold cavities 33 and second mold cavities 34 that are interconnected are formed between the upper mold core 31 and the lower mold core 32. The second mold cavity 34 is provided with a valve insert 35, and a power component 36 for pushing the valve insert 35 is installed on the lower mold body 20. The valve insert 35 isolates or connects the first mold cavity 33 and the second mold cavity 34 through the drive of the power component 36. It also includes a gating system integrated in the upper mold body 10 and the mold core assembly 30. The gating system is provided with a first gate 41 and a second gate 42. The first gate 41 is connected to the first mold cavity 33, and the second gate 42 is connected to the second mold cavity 34. When the first mold cavity 33 and the second mold cavity 34 are isolated by the valve insert 35, the second gate 42 is blocked by the valve insert 35.

[0023] This injection mold, through a single upper mold body 10, lower mold body 20, and built-in valve insert 35, achieves a two-stage injection molding operation. Specifically, after mold closing, the upper mold core 31 and lower mold core 32 enclose each other to form a first mold cavity 33 and a second mold cavity 34 that are interconnected. The power component 36 drives the valve insert 35 to move, isolating the first mold cavity 33 from the second mold cavity 34. Simultaneously, the valve insert 35 blocks the second gate 42. Molten plastic is injected into the first mold cavity 33 through the first gate 41 of the gating system, and then cools and solidifies. The first material forms the product base. After the first material is formed, the power component 36 drives the valve insert 35 to reset, releasing the isolation between the first mold cavity 33 and the second mold cavity 34. At the same time, the blocked second gate 42 is opened, and the second molten plastic is injected into the second mold cavity 34 through the second gate 42 of the gating system and combines with the formed product base. After cooling and solidification, the two materials are integrated into an injection mold. The whole process does not require switching the upper mold. The linkage control of the mold cavity opening and closing and the gate opening and closing is achieved only by the movement of the valve insert 35.

[0024] Taking the chain link body of a silent cable chain described in utility model patent announcement number CN210770033U as an example, since the chain link body is provided with cantilever and elastic column, the cantilever and elastic column can generate an elastic buffering and shock absorption effect between two adjacent chain links. Through the mold cavity structure of this technical solution, the pressure of the molding material injected into the chain link body itself is controlled to be different from the molding material injected into the cantilever and elastic column itself. That is, the molding material injected into the chain link body is injected through the first gate 41 and a material with higher hardness is used, so that the chain link body itself has high hardness after molding. The molding material injected into the cantilever and elastic column is injected through the second gate 42 and a material with a certain degree of elasticity is used, so that the cantilever and elastic column have a greater degree of elasticity after molding. This allows for more precise control of material consumption in the cable chain, thereby improving the performance of the chain link body and making more effective use of consumables to a certain extent.

[0025] Therefore, this technical solution, through the linkage design of the built-in valve insert 35 and the power component 36, eliminates the traditional structure of two sets of upper molds that require switching between two two-color injection molds. On the one hand, there is no need to perform upper mold switching operations, which fundamentally avoids positioning deviations caused by upper mold switching. At the same time, the valve insert 35 can accurately control the opening and closing of the mold cavity and the gate, ensuring the positioning accuracy and material filling accuracy of the first mold cavity 33 and the second mold cavity 34, and significantly improving the dimensional consistency and molding quality of multi-material integrated molded products. On the other hand, only a single set of upper mold body 10, lower mold body 20 and integrated gating system are required, eliminating the design, processing and maintenance costs of additional upper molds, greatly reducing the overall manufacturing cost and comprehensive production cost of the mold, while simplifying the injection molding process, shortening the production cycle and improving production efficiency.

[0026] Please see Figure 5-6 Based on the above technical solution, the power component 36 is further proposed to include a fixedly installed power cylinder 361 and a long rod 362 connected to the piston end of the power cylinder 361. The long rod 362 is guided and slidably engaged with the mold core assembly 30. An inclined portion 363 is formed on the long rod 362. The valve insert 35 is provided with a groove 351 that engages with the inclined portion 363. The power component 36 drives the long rod 362, causing the inclined portion 363 to push the valve insert 35 through the groove 351, thereby driving the valve insert 35 to isolate or connect the first mold cavity 33 and the second mold cavity 34. The structure design achieves motion conversion by driving a long rod 362 with an inclined part 363 via a power cylinder 361, which works in conjunction with the inclined groove 351 of the valve insert 35. This structure utilizes the sliding engagement between the inclined part 363 and the inclined groove 351 to convert the lateral reciprocating motion output by the power cylinder 361 into the longitudinal reciprocating motion of the valve insert 35. This eliminates the need for a complex transmission mechanism to achieve the isolation or connection between the first mold cavity 33 and the second mold cavity 34, as well as the sealing or opening of the second gate 42. This simplifies the power transmission structure inside the mold and reduces the assembly difficulty and failure rate of the mold.

[0027] Please see Figure 1-2 and Figure 5-6 Based on the above technical solution, it is further proposed that the power cylinder 361 is fixedly installed on the lower mold body 20, and the lower mold body 20 is provided with a long groove 21 matching the long rod 362. The long rod 362 slides with the long groove 21, and the long rod 362 abuts against the lower end of the lower mold core 32. The lower end of the valve insert 35 is connected to a connecting part 352 extending below the lower mold core 32, and the long groove 21 is opened on the connecting part 352. The fixed connection between the power cylinder 361 and the lower mold body 20 ensures the stability of the power output and avoids the impact of the displacement of the drive components on the transmission accuracy. The sliding fit between the long rod 362 and the long groove 21 of the lower mold body 20, as well as the abutment design with the lower end of the lower mold core 32, provides double guidance and limit for the linear movement of the long rod 362, effectively preventing the long rod 362 from deflecting during its movement and ensuring the precise docking of the inclined part 363 and the inclined groove 351 of the valve insert 35. At the same time, the long groove 21 is directly opened in the connecting part 352 of the valve insert 35, eliminating the need for additional transmission connecting parts, simplifying the internal structure of the mold, and reducing the assembly difficulty and parts wear rate. In addition, the entire power transmission component is integrated into the lower mold body 20, which is compatible with the driveless structure design of the upper mold body 10, further enhancing the low-cost advantage of a single upper mold. This layout also facilitates the later inspection and replacement of the power component 36, the long rod 362, and the valve insert 35, improving the maintenance convenience and service life of the mold. Please see Figure 5-6Based on the above technical solution, it is further proposed that an even number of interconnected first mold cavities 33 and second mold cavities 34 are formed between the upper mold core 31 and the lower mold core 32, and an even number of valve inserts 35 and inclined portions 363 are correspondingly provided, wherein the even number of inclined portions 363 are evenly distributed on both sides of the long rod 362. The evenly distributed inclined portions 363 on both sides of the long rod 362 can synchronously drive the even number of valve inserts 35 to complete the actions of mold cavity isolation or connection and gate sealing or opening through the inclined grooves 351 of the corresponding valve inserts 35, ensuring the consistency of injection molding processes of multiple mold cavities and greatly improving the product output efficiency of a single injection molding; at the same time, the symmetrical distribution of the inclined portions 363 can cleverly balance the force on the long rod 362, avoiding the problem of the long rod 362 being skewed or stuck due to unilateral force, further improving the stability of power transmission and the action accuracy of valve inserts 35, and effectively ensuring the consistency of molding quality of multiple products.

[0028] Please see Figure 7-8 Based on the above technical solution, it is further proposed that the second mold cavity 34 includes an isolation area 341 and a connecting area 342, the valve insert 35 is configured to cover the connecting area 342, and the second gate 42 is located in the connecting area 342. By dividing the second mold cavity 34 into an isolation zone 341 and a connecting zone 342, and limiting the functional area of ​​the second gate 42 and the valve insert 35 to the connecting zone 342, the molding accuracy and process controllability of multi-material injection molding are further improved. Specifically, the valve insert 35 only needs to cover or avoid the connecting zone 342 to achieve the isolation and connection between the first mold cavity 33 and the second mold cavity, without the need to completely block the second mold cavity 34. This shortens the movement stroke of the valve insert 35, reduces the driving load of the power component 36, and reduces the frictional loss between the valve insert 35 and the inner wall of the mold cavity, thus extending the service life of the mold. The design of setting the second gate 42 in the connecting zone 342 allows the valve insert 35 to accurately block the second gate 42 while isolating the mold cavity, avoiding the risk of the first material flowing into the second mold cavity 34 or overflowing from the second gate 42 during injection molding, and ensuring clear molding boundaries between the two materials.

[0029] Please see Figure 1-4 Based on the above technical solution, it is further proposed that the upper mold body 10 is provided with a panel 11, a casting plate 12 fixed at the lower end of the panel 11, and an upper template 13 fixed at the lower end of the casting plate 12.

[0030] like Figure 4As shown, in one embodiment, the gating system includes a first hot nozzle 43, a second hot nozzle 44, a connecting sleeve 45, a first gate sleeve 46, and two hot runner plates 47. The two hot runner plates 47 are integrated within the gating plate 12. The upper hot runner plate 47 and the lower hot runner plate 47 have non-overlapping portions on the vertical projection plane. The upper hot runner plate 47 is connected to the first hot nozzle 43 through the non-overlapping portion, and the first hot nozzle 43 is connected to the first gate 41. The lower hot runner plate 47 is connected to the second hot nozzle 44 through the non-overlapping portion, and the second hot nozzle 44 is connected to the second gate 42. The first gate sleeve 46 is disposed on the panel 11 and is connected to the upper hot runner plate 47. The two hot runner plates 47 are connected through the connecting sleeve 45. By using a differentiated size layout for the double-layer hot runner plates 47, the upper hot runner plate 47 is connected to the first hot nozzle 43 separately using the non-overlapping portion of its vertical projection, while the lower hot runner plate 47 is independently connected to the second hot nozzle 44. This achieves complete isolation of the flow channels for the two materials, reduces the horizontal space occupied by the gating system, and improves the structural compactness of the upper mold body 10. The direct connection between the first gate sleeve 46 and the upper hot runner plate 47, and the connection between the double-layer hot runner plates 47 through the connecting sleeve 45, ensures a stable flow of molten plastic. The pressure transmission, combined with the precise docking of the first hot nozzle 43, the second hot nozzle 44 and the corresponding gate, further improves the uniformity and stability of material filling. At the same time, the gating system is integrated into the gating plate 12, which is highly compatible with the layered structure of the upper mold body 10. It is easy to adjust the temperature control parameters of the hot runner plate 47 according to different material properties, which reduces the maintenance difficulty of the gating system and eliminates the need for additional runner switching mechanisms. This is highly consistent with the low-cost design concept of a single upper mold, taking into account both molding accuracy and production economy.

[0031] like Figure 3As shown, in another embodiment, the gating system includes a first hot nozzle 43, a second hot nozzle 44, a first gate sleeve 46, a second gate sleeve 48, and two hot runner plates 47. The two hot runner plates 47 are integrated within the gating plate 12. The upper hot runner plate 47 and the lower hot runner plate 47 have non-overlapping portions on the vertical projection plane. The upper hot runner plate 47 is connected to the first hot nozzle 43 through the non-overlapping portion, and the first hot nozzle 43 is connected to the first gate 41. The lower hot runner plate 47 is connected to the second hot nozzle 44 through the non-overlapping portion, and the second hot nozzle 44 is connected to the second gate 42. The first gate sleeve 46 is disposed on the panel 11 and is connected to the upper hot runner plate 47. The second gate sleeve 48 is disposed on the side of the gating plate 12 and is connected to the lower hot runner plate 47. By using the differentiated size layout of the double-layer hot runner plates 47, the upper hot runner plate 47 is connected to the first hot nozzle 43 separately using the non-overlapping part of the vertical projection, and the lower hot runner plate 47 is independently connected to the second hot nozzle 44, thus achieving complete isolation of the flow channels of the two materials, compressing the space occupied by the gating system in the horizontal direction, and improving the structural compactness of the upper mold body 10; the direct docking of the first sprue sleeve 46 with the upper hot runner plate 47 and the direct connection of the second sprue sleeve 48 with the lower hot runner plate 47 from the side of the gating plate 13 enable the injection of two different materials.

[0032] Please see Figure 2 Based on the above technical solution, it is further proposed that an even number of mold core assemblies 30 be provided, symmetrically distributed between the upper mold body 10 and the lower mold body 20. By symmetrically distributing an even number of mold core assemblies 30 between the upper mold body 10 and the lower mold body 20, the overall compactness of the mold can be further improved, and the power cylinder 361 can be fixed to the side of the lower mold body 20, thereby further enhancing both the overall structural compactness and product molding efficiency.

[0033] Please see Figure 1-2 Based on the above technical solution, the lower mold body 20 is further proposed to include a base plate 22, a square plate 23 mounted on the base plate 22, a lower mold plate 24 mounted on the square plate 23, and an ejection mechanism 25 that is guided and movably connected to the lower mold plate 24. A receiving space is formed between the lower mold plate 24 and the base plate 22 through the square plate 23, and the ejection mechanism 25 is arranged in this receiving space. The square plate 23 creates an independent receiving space between the lower mold plate 24 and the base plate 22, allowing the ejection mechanism 25 to be integrated entirely within this space. This avoids interference between the ejection mechanism 25 and transmission components such as the power component 36 and the long rod 362, ensuring the stability of the operation of each component. Simultaneously, the ejection mechanism 25 is guided and movably connected to the lower mold plate 24, enabling precise ejection of the product after molding, avoiding problems such as sticking and deformation during demolding, and improving the demolding quality of the product.

[0034] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention.

Claims

1. An injection mold for realizing overmolding based on a built-in valve, characterized in that, The mold includes an upper mold body (10) and a lower mold body (20) that cooperate with each other. At least one mold core assembly (30) is provided between the upper mold body (10) and the lower mold body (20). The mold core assembly (30) includes an upper mold core (31) installed at the lower end of the upper mold body (10) and a lower mold core (32) installed on the lower mold body (20). After the mold is closed, at least one set of first mold cavity (33) and second mold cavity (34) that are interconnected are formed between the upper mold core (31) and the lower mold core (32). The second mold cavity (34) is provided with a valve insert (35), and a power component (36) for pushing the valve insert (35) is installed on the lower mold body (20). The valve insert (35) isolates or connects the first mold cavity (33) and the second mold cavity (34) by the drive of the power component (36). It also includes a gating system integrated in the upper mold body (10) and the mold core assembly (30). The gating system is provided with a first gate (41) and a second gate (42). The first gate (41) is connected to the first mold cavity (33), and the second gate (42) is connected to the second mold cavity (34). When the first mold cavity (33) and the second mold cavity (34) are isolated by the valve insert (35), the second gate (42) is blocked by the valve insert (35).

2. The injection mold for realizing secondary injection based on built-in valve according to claim 1, characterized in that, The power component (36) includes a fixedly mounted power cylinder (361) and a long rod (362) connected to the piston end of the power cylinder (361). The long rod (362) is guided and slidably engaged with the mold core assembly (30). An inclined portion (363) is formed on the long rod (362). The valve insert (35) is provided with a groove (351) that engages with the inclined portion (363). The power component (36) drives the long rod (362) so that the inclined portion (363) pushes the valve insert (35) through the groove (351), thereby driving the valve insert (35) to isolate or connect the first mold cavity (33) and the second mold cavity (34).

3. The injection mold for secondary injection based on a built-in valve according to claim 2, characterized in that, The power cylinder (361) is fixedly installed on the lower mold body (20), and the lower mold body (20) is provided with a long groove (21) matching the long rod (362). The long rod (362) slides with the long groove (21), and the long rod (362) abuts against the lower end of the lower mold core (32). The lower end of the valve insert (35) is connected to a connecting part (352) extending below the lower mold core (32), and the long groove (21) is opened on the connecting part (352).

4. The injection mold for secondary injection based on a built-in valve according to claim 2, characterized in that, An even number of interconnected first mold cavities (33) and second mold cavities (34) are formed between the upper mold core (31) and the lower mold core (32), and an even number of valve inserts (35) and inclined parts (363) are provided respectively, wherein the even number of inclined parts (363) are evenly distributed on both sides of the long rod (362).

5. The injection mold for secondary injection based on a built-in valve according to claim 1, characterized in that, The second mold cavity (34) includes an isolation area (341) and a connecting area (342), the valve insert (35) is configured to cover the connecting area (342), and the second gate (42) is located in the connecting area (342).

6. The injection mold for secondary injection based on a built-in valve according to claim 1, characterized in that, The upper mold body (10) is provided with a panel (11), a casting plate (12) fixed at the lower end of the panel (11), and an upper template (13) fixed at the lower end of the casting plate (12). The gating system also includes a first hot nozzle (43), a second hot nozzle (44), and two hot runner plates (47). The two hot runner plates (47) are integrated in the casting plate (12). The upper hot runner plate (47) and the lower hot runner plate (47) have non-overlapping parts on the vertical projection plane. The upper hot runner plate (47) is connected to the first hot nozzle (43) through the non-overlapping part. The first hot nozzle (43) is connected to the first gate (41). The lower hot runner plate (47) is connected to the second hot nozzle (44) through the non-overlapping part. The second hot nozzle (44) is connected to the second gate (42).

7. An injection mold for secondary injection based on a built-in valve according to claim 6, characterized in that, The gating system also includes a connecting sleeve (45) and a first gating sleeve (46). The first gating sleeve (46) is set on the panel (11). The first gating sleeve (46) is connected to the upper hot runner plate (47). The two hot runner plates (47) are connected through the connecting sleeve (45).

8. An injection mold for secondary injection based on a built-in valve according to claim 6, characterized in that, The gating system also includes a first gating sleeve (46) and a second gating sleeve (48). The first gating sleeve (46) is disposed on the panel (11) and is connected to the upper hot runner plate (47). The second gating sleeve (48) is disposed on the side of the gating plate (12) and is connected to the lower hot runner plate (47).

9. An injection mold for secondary injection based on a built-in valve according to claim 3, characterized in that, An even number of mold core assemblies (30) are provided, and the even number of mold core assemblies (30) are symmetrically distributed between the upper mold body (10) and the lower mold body (20).

10. An injection mold for secondary injection based on a built-in valve according to claim 1, characterized in that, The lower mold body (20) includes a base plate (22), a square plate (23) mounted on the base plate (22), a lower template (24) mounted on the square plate (23), and an ejection mechanism (25) that is guided and connected to the lower template (24). The lower template (24) and the base plate (22) form a receiving space through the square plate (23), and the ejection mechanism (25) is arranged in the receiving space.

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