Plastic injection mold with exhaust structure

Abstract

The utility model relates to the technical field of plastic manufacturing, in particular to a plastic injection mold with an exhaust structure, which comprises a lower mold and a lower mold, a mold cavity is arranged in the middle of the lower mold, an injection molding pipe is arranged in the middle of the upper mold, and exhaust pipes which are symmetrically distributed are arranged in the upper mold. And an ejector pin is slidably arranged in each exhaust pipe, and a semicircular vent groove is formed in the side face of the lower end of each ejector pin. According to the device, the slidable ejector pin is arranged in the exhaust pipe to achieve the efficient automatic exhaust function, when the internal pressure of the mold cavity is increased, the ejector pin can move upwards under the action of air pressure, the semicircular vent groove is exposed and is in butt joint with the exhaust pipe, and therefore gas in the mold cavity is rapidly exhausted; the ejector pin can automatically reset under the action of the first spring, the ventilation channel is closed, the automatic exhaust process can be completed under the condition that no additional operation steps are added, and manual intervention is not needed.

Description

Technical Field

[0001] This utility model relates to the field of plastic manufacturing technology, and in particular to a plastic injection mold with a venting structure. Background Technology

[0002] In modern industrial production, injection molding is a key process widely used in various industries such as automobiles, electronic devices, and packaging materials. This technology involves injecting heated and molten plastic material into a precisely designed mold cavity, and then cooling and solidifying it to form a product with a specific shape and size. However, during the injection molding process, air or other gases may be present inside the mold cavity. If these gases cannot be expelled in time, it will lead to a series of quality problems, such as bubbles, surface defects, and incomplete filling. These problems not only affect the appearance quality of the final product, but may also weaken its physical properties, such as strength and durability, thereby reducing product quality. Therefore, the venting design of injection molds is crucial for improving product quality.

[0003] Patent CN215661612U discloses a novel ejector pin venting structure for plastic molds. According to the design of this patent, after the lower mold and upper mold are combined to form a cavity, the vent outlet is opened by manually unscrewing the threaded post of each ejector pin assembly. This allows the gas in the cavity to enter the venting hood through the air hole and flow to the outside of the lower mold through the air channel, achieving the function of venting while injection molding. When the cavity is filled with molten plastic, injection is stopped and the injection port is sealed. Then, the threaded post is screwed onto the inner wall of the hollow ejector pin to seal the cavity and prevent dust. Although the above patent provides an effective venting solution, it has inconveniences in practical applications. When gas is generated during mold closing and cooling, the venting components need to be manually opened and closed, which increases the complexity and time cost of manual operation and is also prone to human error.

[0004] Therefore, there is an urgent need to provide a plastic injection mold with an automatic venting structure. Utility Model Content

[0005] To overcome the shortcomings of existing patents that require manual opening and closing of the venting components when gas is generated during mold closing and cooling, which increases the complexity and time cost of manual operation and is prone to human error, this utility model provides a plastic injection mold with an automatic venting structure.

[0006] The technical solution of this utility model is as follows: a plastic injection mold with a venting structure, including a lower mold and an upper mold, wherein a mold cavity is provided in the middle of the lower mold, an injection tube is provided in the middle of the upper mold, symmetrically distributed venting pipes are provided inside the upper mold, an ejector pin is slidably provided inside each venting pipe, a semi-circular venting groove is provided on the lower side of the ejector pin, a sealing cap is provided at the top of the ejector pin, and a first spring is connected between the ejector pin and the venting pipe.

[0007] In one embodiment, fixing plates are provided on both sides of the upper mold.

[0008] In one embodiment, the lower mold has a built-in cooling pipe that surrounds the mold cavity. In addition, one end of the cooling pipe is interference-fitted with a water supply pipe, and a rubber sealing ring is fitted at the connection between the water supply pipe and the cooling pipe.

[0009] In one embodiment, the upper mold is fixedly connected to symmetrically distributed guide rods, each guide rod is slidably provided with a movable plate, one end of the movable plate is fixedly connected to a push rod, the push rod moves through the upper mold, and each guide rod is fitted with a second spring, the two ends of the second spring being connected to the movable plate and the upper mold respectively.

[0010] In one embodiment, a handle is provided at the other end of the movable plate.

[0011] In one embodiment, the other end of the cooling pipe is fitted with a threaded connector.

[0012] Compared with the prior art, the present invention has the following advantages: 1. The device is equipped with a sliding ejector pin in the exhaust pipe to achieve efficient automatic exhaust function. When the pressure inside the mold cavity increases, the ejector pin will move upward under the action of air pressure, so that the semi-circular venting groove is exposed and connected to the exhaust pipe, thereby quickly exhausting the gas in the mold cavity. As the gas is exhausted, the ejector pin will automatically reset under the action of the first spring and close the venting channel. The automatic exhaust process can be completed without adding extra operation steps and without manual intervention.

[0013] 2. By circulating the coolant in the cooling pipe, the lower mold can be effectively cooled, thereby accelerating the curing process of the plastic parts. This not only shortens the production cycle of a single product, but also improves the overall production efficiency.

[0014] 3. The demolding action can be easily completed by holding the handle and pulling the moving plate downward, avoiding the problem of the molded plastic part sticking to the upper mold, simplifying the demolding process and reducing the difficulty of manual operation. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0016] Figure 2 This is a three-dimensional sectional view of the lower mold, upper mold, and exhaust pipe components of this utility model.

[0017] Figure 3 This is an exploded view of the lower mold and the upper mold of this utility model.

[0018] Figure 4 This is a three-dimensional sectional view of the exhaust pipe, ejector pin, and sealing cap of this utility model.

[0019] Figure 5 This is a three-dimensional sectional view of the lower mold, cooling pipe, and water supply pipe components of this utility model.

[0020] Figure 6 This is a three-dimensional sectional view of the components of this utility model, including the cooling pipe, water supply pipe, and rubber sealing ring.

[0021] Figure 7 This is a three-dimensional sectional view of the lower mold, upper mold, and movable plate components of this utility model.

[0022] Figure 8 This is a three-dimensional sectional view of the movable plate, push rod, and guide rod of this utility model.

[0023] The markings in the diagram are as follows: 1-lower mold, 2-mold cavity, 3-upper mold, 4-injection pipe, 5-vent pipe, 6-ejector pin, 7-sealing cap, 8-first spring, 9-fixed plate, 10-cooling pipe, 11-water supply pipe, 12-rubber sealing ring, 13-moving plate, 14-push rod, 15-guide rod, 16-second spring, 17-handle, 18-threaded connector. Detailed Implementation

[0024] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0025] Example 1: Please refer to Figures 1-4A plastic injection mold with a venting structure includes a lower mold 1 and an upper mold 3. The lower mold 1 has a cavity 2 in the middle for molding plastic products. The upper mold 3 has an injection tube 4 in the middle for injecting liquid plastic into the cavity 2. The upper mold 3 has symmetrically distributed venting pipes 5 inside. Each venting pipe 5 has a sliding ejector pin 6 inside. The lower side of the ejector pin 6 has a semi-circular venting groove. The top of the ejector pin 6 has a sealing cap 7 for sealing the venting pipe 5. A first spring 8 connects the ejector pin 6 and the venting pipe 5 to support the ejector pin 6 and allow it to move freely within the venting pipe 5. The upper mold 3 has fixing plates 9 on both the left and right sides, providing two fixing points for easy installation of the upper mold 3 on a machine.

[0026] When the lower mold 1 and the upper mold 3 are closed, the ejector pin 6 is in its natural reset position. The semi-circular vent groove is tightly surrounded by the inner wall of the lower end of the exhaust pipe 5, forming a sealed state and preventing any substance from passing through. When the injection tube 4 injects liquid plastic into the mold cavity 2, the air in the mold cavity 2 is compressed and the pressure gradually increases. As the air pressure increases, the ejector pin 6 is pushed upward. The upward push of the ejector pin 6 overcomes the elastic force of the first spring 8 and drives the sealing cover 7 to move upward, opening the exhaust pipe 5. At the same time, the semi-circular vent groove is gradually exposed and forms a gap with the inner wall of the exhaust pipe 5, allowing the air in the mold cavity 2 to enter the exhaust pipe 5 through the gap and be discharged outside the mold, thus completing the automatic venting. When the air in the mold cavity 2 is completely discharged, the air pressure drops and there is no longer enough force to push the ejector pin 6 to slide upward. The elastic force of the first spring 8 causes the ejector pin 6 to reset downward and return to the initial position. As the ejector pin 6 resets, the sealing cover 7 covers and seals the exhaust pipe 5, and the semi-circular vent groove is blocked by the exhaust pipe 5 again.

[0027] Example 2: Based on Example 1, please refer to... Figure 5 and Figure 6 The lower mold 1 has two cooling pipes 10 built in, which are arranged around the mold cavity 2. In addition, one end of the cooling pipe 10 is interference-connected to a water supply pipe 11 for connecting to an external coolant supply system. A rubber sealing ring 12 is fitted at the connection between the water supply pipe 11 and the cooling pipe 10 to ensure the sealing of the connection. The other end of the cooling pipe 10 is equipped with a threaded connector 18 for connecting to a circulation device or a drainage device to facilitate the recovery or discharge of coolant.

[0028] After the pressing and molding process is completed, the cooling process begins. Coolant flows into the cooling pipe 10 through the water supply pipe 11 and flows along the cooling pipe 10 to effectively cool the lower mold 1, thereby accelerating the curing and molding of the plastic part. The cooled liquid that has absorbed heat then flows out from the other end of the cooling pipe 10 and is connected to the circulation device through the threaded joint 18 so that the coolant can be recooled and reused.

[0029] Please see Figure 7 and Figure 8 The upper mold 3 is fixedly connected with symmetrically distributed guide rods 15. Each guide rod 15 is slidably provided with a movable plate 13. One end of the movable plate 13 is fixedly connected to a push rod 14. The push rod 14 moves through the upper mold 3 to perform material pushing operation. Each guide rod 15 is fitted with a second spring 16. The two ends of the second spring 16 are respectively connected to the movable plate 13 and the upper mold 3 to provide a return spring force for the push rod 14. The other end of the movable plate 13 is provided with a handle 17, which provides a convenient operating point for the operator to manually control the up and down movement of the movable plate 13.

[0030] After the lower mold 1 separates from the upper mold 3, in order to prevent the molded plastic part from sticking to the upper mold 3, the operator can pull the moving plate 13 downward by holding the handle 17, which will cause the push rod 14 to move downward to perform the pushing action. After demolding is completed, the handle 17 is released, and the moving plate 13 and the push rod 14 will automatically reset under the action of the second spring 16, ready for the next cycle.

[0031] It should be understood that the above description is for illustrative purposes only and is not intended to limit the present invention. Those skilled in the art will understand that variations of the present invention will be included within the scope of the claims herein.

Claims

1. A plastic injection mold with a venting structure, comprising a lower mold (1) and an upper mold (3), wherein the lower mold (1) has a cavity (2) in the middle position, and the upper mold (3) has an injection tube (4) in the middle position, characterized in that: The upper mold (3) is provided with symmetrically distributed exhaust pipes (5), and each exhaust pipe (5) is provided with a sliding ejector pin (6). The lower side of the ejector pin (6) is provided with a semi-circular ventilation groove, and the top of the ejector pin (6) is provided with a sealing cap (7). A first spring (8) is connected between the ejector pin (6) and the exhaust pipe (5).

2. A plastic injection mold with a venting structure as described in claim 1, characterized in that: The upper mold (3) is provided with fixing plates (9) on both sides.

3. A plastic injection mold with a venting structure as described in claim 2, characterized in that: The lower mold (1) has a built-in cooling pipe (10) which surrounds the mold cavity (2). In addition, one end of the cooling pipe (10) is interference-connected to a water supply pipe (11), and a rubber sealing ring (12) is fitted at the connection between the water supply pipe (11) and the cooling pipe (10).

4. A plastic injection mold with a venting structure as described in claim 3, characterized in that: The upper mold (3) is fixedly connected with symmetrically distributed guide rods (15). Each guide rod (15) is slidably provided with a movable plate (13). One end of the movable plate (13) is fixedly connected with a push rod (14). The push rod (14) moves through the upper mold (3). Each guide rod (15) is fitted with a second spring (16). The two ends of the second spring (16) are respectively connected to the movable plate (13) and the upper mold (3).

5. A plastic injection mold with a venting structure as described in claim 4, characterized in that: A handle (17) is provided at the other end of the movable plate (13).

6. A plastic injection mold with a venting structure as described in claim 5, characterized in that: The other end of the cooling pipe (10) is fitted with a threaded connector (18).

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