Injection mold

Abstract

The invention discloses an injection mold, and relates to the technical field of injection molds, the injection mold comprises a lower mold frame, an upper mold frame, a male mold and a female mold, the male mold and the female mold are each internally provided with a plurality of cooling liquid flow channels, the cooling liquid flow channels are independently arranged, and the cooling liquid flow channels are distributed in a net shape and evenly distributed on the periphery of a forming mold cavity; a water supply waterway system and a backflow waterway system are arranged on each of the upper mold frame and the lower mold frame; the water supply waterway system and the backflow waterway system on the upper mold frame are respectively communicated with each cooling liquid runner on the female mold; and the water supply waterway system and the backflow waterway system on the lower mold frame are respectively connected with the cooling liquid runners on the male mold. According to the cooling device, the product can be uniformly and quickly cooled, the conditions of warping, sink marks and the like of the product are avoided, and the production period is effectively shortened.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of injection molds, in particular to an injection mold. BACKGROUND

[0002] At present, an injection mold mainly comprises a lower mold frame, an upper mold frame, a male mold arranged on the lower mold frame, a female mold arranged on the upper mold frame, a hot runner system and a cooling system, the male mold and the female mold cooperatively form a molding cavity, the female mold is provided with a plurality of injection holes in communication with the molding cavity, and injection molding of a product is realized by pouring injection material into the molding cavity through the injection holes. During the injection molding process, the hot runner system continuously heats the injection material to ensure that the injection material is in a molten state, so as to facilitate smooth filling of the mold cavity. The cooling system pours cooling water into cooling water channels in the male mold and the female mold, and utilizes heat conduction of the male mold and the female mold to cool and cool down the molded product, so that the product can be quickly shaped.

[0003] However, the existing cooling system is difficult to effectively cater to complex product shells, and the flowability of the cooling liquid is poor, which leads to inconsistent cooling speeds of various parts of the product during the cooling process, and uneven cooling occurs. Such uneven cooling easily causes quality problems such as product warping and shrinkage marks, and seriously affects the appearance and performance of the product. At the same time, due to the poor cooling effect, the production cycle of the product is also correspondingly prolonged, which reduces the production efficiency and increases the production cost. SUMMARY

[0004] In view of the problems in the prior art, the application provides an injection mold.

[0005] The injection mold provided by the application adopts the following technical scheme: The injection mold comprises a lower mold frame, an upper mold frame, a male mold and a female mold, the inside of the male mold and the female mold is respectively provided with a plurality of cooling liquid channels, each of the cooling liquid channels is independently arranged, each of the cooling liquid channels is arranged in a mesh shape and is uniformly distributed on the periphery of the molding cavity; the upper mold frame and the lower mold frame are respectively provided with a water supply waterway system and a backflow waterway system, the water supply waterway system and the backflow waterway system on the upper mold frame are respectively in communication with each of the cooling liquid channels on the female mold; the water supply waterway system and the backflow waterway system on the lower mold frame are respectively in communication with each of the cooling liquid channels on the male mold.

[0006] Optionally, the top of the female mold and along the periphery of each injection hole are respectively provided with a partition groove.

[0007] Optionally, the water supply pipeline system on the upper die frame also respectively communicates with each of the partition grooves, the female die is provided with a plurality of water outlet channels, the water outlet channels correspond to the partition grooves one by one, and the water outlet channels communicate with the partition grooves at positions close to the bottom, and the backflow pipeline system on the upper die frame respectively communicates with each of the water outlet channels on the female die.

[0008] Optionally, the side wall of the partition groove close to the injection port is provided with a plurality of heat conduction ports communicating with the injection port, each of the heat conduction ports is distributed along the circumference of the injection port, and each of the heat conduction ports is fixedly provided with a heat conduction block.

[0009] Optionally, the female die is provided with an exhaust hole communicating with the forming cavity, and the upper die frame is provided with a vacuum air pipeline system, and the vacuum air pipeline system communicates with the exhaust hole.

[0010] Optionally, the exhaust hole is provided with a plurality of exhaust holes, and the diameter of the exhaust hole is controlled to be between 0.8-1mm.

[0011] Optionally, the vacuum air pipeline system includes a negative pressure cavity arranged at the top end of the female die, an exhaust groove arranged on the upper die frame for communicating with the negative pressure cavity, and an air path channel arranged on the upper die frame and communicating with the exhaust groove, each of the exhaust holes communicates with the negative pressure cavity, and the bottom wall of the upper die frame is provided with an annular sealing groove along the circumference of the exhaust groove, and a sealing ring is fixedly arranged in the annular sealing groove.

[0012] Optionally, a pneumatic piston block is slidably arranged in the negative pressure cavity, a plurality of needle stops are fixedly arranged on the bottom wall of the pneumatic piston block, the needle stops correspond to the exhaust holes one by one, the needle stops slide through the corresponding exhaust holes, and are used to close the corresponding exhaust holes, the upper die frame is provided with a driving member for driving the pneumatic piston block to slide, the side wall of each of the exhaust holes is provided with a side flow channel, and each of the side flow channels communicates with the negative pressure cavity, and the pneumatic piston block is provided with a vent.

[0013] Optionally, a gas blocking plug is slidably arranged in the vent, the gas blocking plug is matched with the vent, the gas blocking plug is hollow, a baffle is fixedly arranged at the bottom end of the gas blocking plug and used to abut against the bottom wall of the pneumatic piston block, a vent hole is arranged on the side wall of the gas blocking plug, the pneumatic piston block is provided with an elastic member for driving the baffle to slide towards the bottom wall of the pneumatic piston block, a top cylinder is fixedly arranged in the exhaust groove, the top cylinder communicates with the air path channel, and the top cylinder is used to abut against the gas blocking plug and push the gas blocking plug to slide away from the pneumatic piston block.

[0014] Optionally, the outer side wall of the bottom end of the top cylinder is provided with an insertion inclined surface along the circumference of the top cylinder, and the inner side wall of the top end of the gas blocking plug is provided with an insertion groove matched with the insertion inclined surface along the circumference of the gas blocking plug.

[0015] To sum up, the present application includes at least one of the following beneficial technical effects: 1. The present application sets multiple cooling liquid channels in the inner part of the male and female molds, which are independent of each other and arranged in a mesh shape and uniformly distributed in the periphery of the molding cavity. The water supply and return water channel systems on the upper and lower mold frames are matched to make the cooling liquid better fit the complex product shape and ensure the flowability of the cooling liquid, achieving uniform and rapid cooling of the product, avoiding warping, shrinkage and other situations, and effectively shortening the production cycle.

[0016] 2. Since the hot runner system needs to continuously heat the injection material during the injection molding process, the heat generated by the hot runner system will be directly transmitted to the female mold during the heating process, making it difficult to achieve efficient cooling of the temperature in the area of the female mold that directly contacts the hot runner system when the product is cooled after injection molding, resulting in a longer demolding time. By setting a partition groove along the periphery of each injection hole at the top of the female mold, the heat conduction path can be effectively blocked, reducing the impact of heat on the female mold during injection molding, which is beneficial for cooling in the later stage.

[0017] 3. When cooling and shaping the product, the cooling liquid can flow into the partition groove through the water supply channel system on the upper mold frame and then flow back to the return water channel system on the upper mold frame through the water outlet channel that communicates with the bottom of the partition groove. The flow of cooling liquid in the partition groove can further improve the cooling effect around the injection hole, reduce product warping and shrinkage, and shorten the production cycle.

[0018] 4. By opening multiple heat-conducting ports in the side wall of the partition groove near the injection port and fixedly arranging heat-conducting blocks in the heat-conducting ports, the heat around the injection port can be effectively conducted into the cooling liquid in the partition groove, enhancing the cooling effect at the position of the injection port.

[0019] 5. By setting an exhaust hole on the female mold that communicates with the molding cavity and a vacuum airway system on the upper mold frame that communicates with the exhaust hole, the air in the molding cavity can be exhausted before injection molding, forming a negative pressure, which can effectively avoid defects such as weld marks, bubbles, and concave printing on the molded product due to poor exhaust.

[0020] 6. The pneumatic piston block is arranged in the negative pressure chamber, and the needle stopper of the bottom wall of the pneumatic piston block can block the exhaust hole. During the injection molding process, the driving member drives the pneumatic piston block to slide, so that the needle stopper blocks the corresponding exhaust hole, which can prevent the injection material from entering the exhaust hole and causing the exhaust hole to be blocked. When exhaust is needed, the driving member drives the pneumatic piston block to slide upwards, so that the side flow channel communicates with the corresponding exhaust hole, and then the air vent provided on the pneumatic piston block provides a channel for gas flow. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1It is a whole structure schematic diagram of the embodiment of the present application; Figure 2 It is a whole structure sectional view of the embodiment of the present application; Figure 3 It is a structure schematic diagram of the embodiment of the present application for expressing a female mold; Figure 4 It is a partial structure sectional view of the embodiment of the present application, mainly for expressing a structure sectional view of a partition groove position; Figure 5 It is a partial structure schematic diagram of the embodiment of the present application, mainly for expressing a structure sectional view of an exhaust hole position.

[0022] The figure mark explanation: 100, a forming mold cavity; 101, a cooling liquid flow channel; 102, a water supply channel; 103, a backflow channel; 1, a lower mold frame; 2, an upper mold frame; 21, an exhaust groove; 22, an air path channel; 23, a sealing ring; 24, a driving piece; 25, a top cylinder; 3, a male mold; 4, a female mold; 41, an injection hole; 42, a partition groove; 421, a heat conduction port; 422, a heat conduction block; 43, a water outlet channel; 44, an exhaust hole; 441, a side flow channel; 45, a negative pressure cavity; 46, a pneumatic piston block; 461, a needle stop; 462, a vent; 463, an elastic piece; 47, a gas blocking plug; 471, a baffle; 472, a vent hole; 5, a hot runner system. DETAILED DESCRIPTION

[0023] The following will be combined with the accompanying Figure 1 - the accompanying Figure 5 , the technical solutions in the embodiments of the present application are clearly and completely described, and the described embodiments are only possible technical implementations of the present application, not all possible implementations. Those skilled in the art can certainly combine the embodiments of the present application without creative labor to obtain other embodiments, and these embodiments are also within the protection scope of the present application.

[0024] The inventor of the present application finds that the existing cooling system is difficult to effectively cater to the complex product shell, and the flowability of the cooling liquid is poor, which leads to inconsistent cooling speed of each part of the product in the cooling process, and uneven cooling occurs. This uneven cooling easily causes product warping, shrinkage marks and other quality problems, seriously affecting the appearance and performance of the product. At the same time, due to the poor cooling effect, the production cycle of the product is also correspondingly prolonged, which reduces the production efficiency and increases the production cost. Therefore, the present application discloses an injection mold, mainly adopting the following scheme: The embodiment of the present application discloses an injection mold. Referring to Figure 1 and Figure 2, including a lower die frame 1, an upper die frame 2, a male die 3, a female die 4 and a hot runner system 5, wherein the upper die frame 2 is slidingly arranged on the lower die frame 1 in the vertical direction, the lower die frame 1 and the upper die frame 2 cooperate with each other to provide support and installation basis for the male die 3 and the female die 4, the male die 3 is fixedly installed on the top of the lower die frame 1, the female die 4 is fixedly installed on the bottom of the upper die frame 2, the male die 3 and the female die 4 cooperate with each other to form a molding cavity 100 for injection molding of products, the top of the female die 4 is provided with a plurality of injection holes 41 communicating with the molding cavity 100, the hot runner system 5 communicates with each injection hole 41 respectively, and is used for continuously heating the injection material during injection molding to ensure that the injection material is in a molten state, thereby facilitating smooth filling of the cavity.

[0025] With reference to Figure 2 and Figure 3 , specifically, a plurality of cooling liquid flow channels 101 are arranged in the interiors of the male die 3 and the female die 4, the cooling liquid flow channels 101 are independently arranged, are arranged in a mesh shape, and are uniformly distributed on the periphery of the molding cavity 100 according to the shape of the molding cavity 100. Through this arrangement, the cooling liquid can better conform to the complex product shape, thereby more uniformly cooling the molding cavity 100, avoiding cooling dead angles, and avoiding product warping, shrinkage and the like. The independent arrangement of each cooling liquid flow channel 101 can ensure the flowability of the cooling liquid, improve the cooling effect, and effectively shorten the product cooling cycle.

[0026] With reference to Figure 1 , the upper die frame 2 and the lower die frame 1 are both provided with a water supply system and a backflow system, the water supply system and the backflow system on the upper die frame 2 respectively communicate with each cooling liquid flow channel 101 on the female die 4, and the water supply system and the backflow system on the lower die frame 1 respectively communicate with each cooling liquid flow channel 101 on the male die 3. Specifically, the water supply system includes a plurality of independently arranged water supply channels 102, the backflow system includes a plurality of independently arranged backflow channels 103, each cooling liquid flow channel 101 on the male die 3 corresponds to one water supply channel 102 and one backflow channel 103 on the lower die frame 1 respectively, and communicates with the corresponding water supply channel 102 and backflow channel 103. Each cooling liquid flow channel 101 on the female die 4 corresponds to one water supply channel 102 and one backflow channel 103 on the upper die frame 2 respectively, and communicates with the corresponding water supply channel 102 and backflow channel 103. The cooling liquid flow channel 101 and the water supply channel 102 and the backflow channel 103 are all sealingly connected to prevent leakage of the cooling liquid. The water supply system and the backflow system are connected to an external cooling liquid circulation system during use of the mold to realize circulation of the cooling liquid.

[0027] With reference to Figure 3 and Figure 4The top of the female mold 4 and the periphery of each injection hole 41 are respectively provided with a partition groove 42. The partition groove 42 is formed on the female mold 4 by machining, and has an arc-shaped groove or a ring-shaped groove, which can effectively cut off the heat conduction path and reduce the influence of heat on the female mold 4 during injection molding. Each partition groove 42 corresponds to a water supply channel 102 and a backflow channel 103 on the upper mold frame 2, and the partition groove 42 is in communication with the corresponding water supply channel 102; the female mold 4 is also provided with a plurality of water outlet channels 43, which correspond one-to-one to the partition grooves 42 and are in communication with the positions close to the bottom of the partition grooves 42, the water outlet channels 43 are in communication with the corresponding backflow channels 103, and the water outlet channels 43 and the backflow channels 103 are connected in a sealed manner. Through this arrangement, the cooling liquid can flow in the partition groove 42, further improving the cooling effect around the injection hole 41.

[0028] With reference to Figure 4 The side wall of the partition groove 42 close to the injection port is provided with a plurality of heat conduction ports 421, which are formed on the side wall of the partition groove 42 by milling, and have a circular or square shape. Each heat conduction port 421 is distributed along the circumference of the injection port, and each heat conduction port 421 is fixedly provided with a heat conduction block 422. The heat conduction block 422 is made of a high-thermal-conductivity metal material, such as a copper block or an aluminum block, which can effectively conduct the heat around the injection port to the cooling liquid in the partition groove 42, enhancing the cooling effect at the position of the injection port. The heat conduction block 422 is fixed in the heat conduction port 421 by welding or bonding, ensuring good heat conduction performance.

[0029] With reference to Figure 5 The female mold 4 is provided with a plurality of exhaust holes 44, which are formed on the female mold 4 by drilling, and have a diameter of 0.8-1mm. The upper mold frame 2 is provided with a vacuum air path system, which is in communication with each exhaust hole 44. Before injection molding, the air in the molding cavity 100 is discharged to form a negative pressure, which can effectively avoid defects such as weld marks, bubbles, and concave printing on the molded product due to poor exhaust. The setting position of the exhaust hole 44 is carefully designed to cover the entire molding cavity 100, ensuring the exhaust effect.

[0030] With reference to Figure 5, specifically, the vacuum air system includes a negative pressure cavity 45 arranged at the top end of the female mold 4, an exhaust groove 21 arranged on the upper mold frame 2 for communicating with the negative pressure cavity 45, and an air passage 22 arranged on the upper mold frame 2 and communicated with the exhaust groove 21. The negative pressure cavity 45 is formed by casting or machining, and each exhaust hole 44 is communicated with the negative pressure cavity 45. The exhaust groove 21 is formed on the upper mold frame 2 by milling. The bottom wall of the upper mold frame 2 is provided with an annular sealing groove along the circumference of the exhaust groove 21, and a sealing ring 23 is fixedly arranged in the annular sealing groove. The sealing ring 23 is made of rubber material and has good sealing performance, which can prevent gas leakage.

[0031] Referring to Figure 5 , the negative pressure cavity 45 is slidably provided with a pneumatic piston block 46, which is made of metal material and has a shape matched with the negative pressure cavity 45, and can freely slide in the negative pressure cavity 45. The bottom wall of the pneumatic piston block 46 is fixedly provided with a needle stopper 461, which is made of metal rod material and has a diameter matched with the exhaust hole 44. The needle stopper 461 corresponds to the exhaust hole 44 one by one, and is slidably arranged in the corresponding exhaust hole 44 and used for closing the corresponding exhaust hole 44. The upper mold frame 2 is provided with a driving member 24 for driving the pneumatic piston block 46 to slide, which can be a pneumatic cylinder or an electric push rod, etc., and can accurately control the sliding of the pneumatic piston block 46.

[0032] Referring to Figure 5 , the side wall of each exhaust hole 44 is provided with a side flow passage 441, and each side flow passage 441 is communicated with the negative pressure cavity 45, and the pneumatic piston block 46 is provided with an air vent 462. In the injection molding process, the pneumatic piston block 46 is driven to slide by the driving member 24, so that the needle stopper 461 closes the corresponding exhaust hole 44 respectively, which can avoid the injection material entering the exhaust hole 44 and causing the exhaust hole 44 to be blocked; when exhaust is needed, the pneumatic piston block 46 is driven to slide upward by the driving member 24, so that the side flow passage 441 is communicated with the corresponding exhaust hole 44, and the air vent 462 arranged on the pneumatic piston block 46 is used for providing a passage for gas flow.

[0033] Referring to Figure 5The air baffle 47 is slidably arranged in the air vent 462, is made of metal material, is matched with the air vent 462 in shape, and can freely slide in the air vent 462. The air baffle 47 is hollow, is fixedly provided with a baffle plate 471 at the bottom end, and is integrally formed with the air baffle 47. The baffle plate 471 is used for abutting against the bottom wall of the pneumatic piston block 46, and the top of the baffle plate 471 is provided with a sealing gasket made of rubber. An air vent hole 472 is formed in the side wall of the air baffle 47 in a drilling manner, and the diameter of the air vent hole 472 is designed according to the gas flow. The pneumatic piston block 46 is fixedly provided with a guide rod at the bottom wall, the baffle plate 471 is slidably arranged on the guide rod, and the bottom end of the guide rod is fixedly provided with a limiting block. The pneumatic piston block 46 is provided with an elastic element 463, which can be a spring. The spring is arranged on the guide rod, and the two ends of the spring abut against the limiting block and the baffle plate 471 respectively, and is used for driving the baffle plate 471 to slide towards the bottom wall of the pneumatic piston block 46.

[0034] With reference to Figure 5 The top cylinder 25 is fixedly arranged in the exhaust groove 21, is made of metal pipe material, is communicated with the gas passage 22, and is provided with an insertion inclined surface on the outer side wall of the bottom end along the circumferential direction of the top cylinder 25. The inner side wall of the top end of the air baffle 47 is provided with an insertion groove matched with the insertion inclined surface along the circumferential direction of the air baffle 47. When the top cylinder 25 abuts against the air baffle 47, the air baffle 47 is driven to slide away from the pneumatic piston block 46 through the cooperation of the insertion inclined surface and the insertion groove, so that the upper and lower sides of the pneumatic piston block 46 are communicated through the air vent hole 472 on the air baffle 47.

[0035] When the product is injection molded, the driving element 24 drives the pneumatic piston block 46 to slide downwards, so that the stop pin 461 closes the corresponding exhaust hole 44, the air baffle 47 is separated from the top cylinder 25, and the baffle plate 471 on the air baffle 47 abuts against the bottom end of the pneumatic piston block 46 under the elastic force of the elastic element 463, so as to close the space below the pneumatic piston block 46, thereby avoiding the gas leakage. When the exhaust is needed, the pneumatic piston block 46 slides upwards, the top cylinder 25 abuts against the air baffle 47, and the air baffle 47 is driven to slide on the pneumatic piston block 46, so that the space above and below the pneumatic piston block 46 is communicated, and a gas flow channel is formed.

[0036] The implementation principle of the injection mold embodiment of the present application is that: the injection mold realizes efficient injection molding of the product through the synergistic effect of the mesh cooling liquid runner 101, the multi-waterway system, the partition groove 42, the heat conduction block 422, the vacuum air path system and other structures. The mesh cooling liquid runner 101 and the multi-waterway system ensure the uniform flow and efficient cooling of the cooling liquid, improve the cooling speed and uniformity of the product, and reduce quality problems such as warping and shrinkage marks. The partition groove 42 and the heat conduction block 422 enhance the cooling effect around the injection hole 41, further improving the product quality. The vacuum air path system prevents the injection material from blocking the exhaust hole 44 through exhaust, avoiding defects such as weld marks and bubbles on the product. These improvements improve the injection quality and production efficiency of the product, reduce production costs, and make significant improvements and contributions to existing injection mold technology.

[0037] The above are preferred embodiments of the present application, but do not limit the protection scope of the present application, therefore: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. An injection mold, comprising a lower mold base (1), an upper mold base (2), a male mold (3), and a female mold (4), characterized in that: The male mold (3) and female mold (4) are each provided with multiple coolant channels (101). Each coolant channel (101) is independently provided and arranged in a mesh pattern, and is evenly distributed around the molding cavity (100). Both the upper mold frame (2) and the lower mold frame (1) are equipped with a water supply system and a return water system. The water supply system and the return water system on the upper mold frame (2) are respectively connected to the coolant channels (101) on the female mold (4); the water supply system and the return water system on the lower mold frame (1) are respectively connected to the coolant channels (101) on the male mold (3).

2. The injection mold according to claim 1, characterized in that: The top of the master mold (4) and along the periphery of each injection hole (41) are respectively provided with partition grooves (42).

3. The injection mold according to claim 2, characterized in that: The water supply system on the upper mold frame (2) is also connected to each of the partition grooves (42). The mother mold (4) is provided with multiple water outlet channels (43). The water outlet channels (43) correspond one-to-one with the partition grooves (42), and the water outlet channels (43) are connected to the partition grooves (42) near the bottom. The return water system on the upper mold frame (2) is connected to each water outlet channel (43) on the mother mold (4).

4. The injection mold according to claim 3, characterized in that: The partition groove (42) has multiple heat-conducting ports (421) connected to the injection port on the side wall near the injection port. Each heat-conducting port (421) is distributed circumferentially along the injection port, and each heat-conducting port (421) is fixedly provided with a heat-conducting block (422).

5. The injection mold according to claim 1, characterized in that: The master mold (4) is provided with an exhaust hole (44) that communicates with the molding cavity (100), and the upper mold frame (2) is provided with a vacuum air passage system that communicates with the exhaust hole (44).

6. The injection mold according to claim 5, characterized in that: The exhaust port (44) is provided in multiple ways, and the diameter of the exhaust port (44) is controlled between 0.8-1mm.

7. An injection mold according to claim 6, characterized in that: The vacuum air path system includes a negative pressure chamber (45) set at the top of the mother mold (4), an exhaust groove (21) set on the upper mold frame (2) for connecting the negative pressure chamber (45), and an air passage (22) set on the upper mold frame (2) and connected to the exhaust groove (21). Each of the exhaust holes (44) is connected to the negative pressure chamber (45). The bottom wall of the upper mold frame (2) is provided with an annular sealing groove along the circumference of the exhaust groove (21), and a sealing ring (23) is fixedly set in the annular sealing groove.

8. An injection mold according to claim 7, characterized in that: A pneumatic piston block (46) is slidably disposed in the negative pressure chamber (45). A plurality of stop pins (461) are fixedly disposed on the bottom wall of the pneumatic piston block (46). The stop pins (461) correspond one-to-one with the exhaust holes (44). The stop pins (461) are slidably disposed in the corresponding exhaust holes (44) and are used to close the corresponding exhaust holes (44). The upper mold frame (2) is provided with a driving member (24) for driving the pneumatic piston block (46) to slide. The side wall of each exhaust hole (44) is provided with a side flow channel (441), and each side flow channel (441) is connected to the negative pressure chamber (45). A vent (462) is opened on the pneumatic piston block (46).

9. An injection mold according to claim 8, characterized in that: An air-blocking plug (47) is slidably inserted into the vent (462). The air-blocking plug (47) is adapted to the vent (462). The air-blocking plug (47) is hollow. A baffle (471) is fixedly installed at the bottom end of the air-blocking plug (47) and is used to abut against the bottom wall of the pneumatic piston block (46). A vent hole (472) is opened on the side wall of the air-blocking plug (47). An elastic element (463) is provided on the pneumatic piston block (46) to drive the baffle (471) to slide closer to the bottom wall of the pneumatic piston block (46). A top cylinder (25) is fixedly installed in the exhaust groove (21). The top cylinder (25) is connected to the air passage (22). The top cylinder (25) is used to abut against the air-blocking plug (47) and push the air-blocking plug (47) to slide away from the pneumatic piston block (46).

10. An injection mold according to claim 9, characterized in that: The outer side wall at the bottom of the top cylinder (25) is provided with an insertion slope along the circumference of the top cylinder (25), and the inner side wall at the top of the air baffle (47) is provided with an insertion groove adapted to the insertion slope along the circumference of the air baffle (47).

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