Multi-point underfeed wire insert injection mold

Abstract

The application discloses a multi-point lower feeding type small part injection mold, and relates to the technical field of mold injection, which comprises a lower mold group, a multi-point injection mechanism is arranged below the lower mold group, the multi-point injection mechanism is used for dynamically conveying injection liquid, the multi-point injection mechanism comprises a liquid conveying pipeline arranged below the lower mold group, branch pipelines are uniformly and communicatively connected above the liquid conveying pipeline, a pressure cylinder is mounted on the side wall of the liquid conveying pipeline, a driving module is mounted in the pressure cylinder, a guide bin is mounted on the output shaft end of the driving cylinder in the driving module, a movable plate is mounted on the side wall of the guide bin, when the injection liquid is discharged, under the joint action of gravity and self-flow inertia, the injection liquid can more smoothly flow along the inclined pipeline and the mold cavity, for some parts with deep recesses or complex curved surfaces, the inclined design enables the injection liquid to naturally flow into and fill, avoids defects such as material shortage and cavity caused by poor flow of the injection liquid, and thus improves the forming quality and integrity of products.

Description

Technical Field

[0001] This invention relates to the field of mold injection technology, specifically to a multi-point bottom-feed thin-part injection mold. Background Technology

[0002] Multi-point injection molds for thin parts are molds used to produce thin plastic products. They are characterized by injecting molten plastic into the mold cavity through multiple discharge points to achieve more uniform filling and better product quality.

[0003] However, existing technologies still have the following drawbacks in practical applications:

[0004] 1. Compared with existing multi-point feeding thin-part injection molds, although multiple feed ports are set, the flow channel design of each feed port is often relatively simple. When feeding material from one point to multiple points, the molten plastic flows through flow channels of different lengths and different numbers of bends to reach the feed port. Due to the different flow channel resistance, it is difficult to ensure that the flow rate and velocity of the molten plastic at each feed port are consistent. Moreover, during the injection process, as the cavity is gradually filled, the pressure distribution inside the cavity changes continuously, further interfering with the balanced entry of molten plastic at each feed port. Uneven feeding results in differences in the amount of plastic filling in different parts of the thin part, leading to uneven product wall thickness. For example, on a plastic curved shell, some areas have excessively thick walls, increasing material costs and affecting the product appearance, while some areas have excessively thin walls, reducing product strength and making it easy to break during subsequent use.

[0005] Furthermore, the molten plastic flows relatively smoothly into the mold cavity from multiple inlets. During the filling process, the flow of the molten plastic is relatively uniform and regular, which cannot create strong disturbances to the air inside the mold cavity. As the molten plastic is pushed forward, the air is easily trapped inside and difficult to expel from the mold cavity. Moreover, if the speed of the molten plastic is stable during the flow process, the gas inside cannot escape from the molten plastic by means of fluctuations, and gradually accumulates to form hollows or bubbles. Hollows and bubbles will weaken the structural strength of the product, making the bubble or hollow part a weak point when subjected to external force, which is prone to cracking and deformation. In some products with high requirements for air tightness, the presence of bubbles can also cause the product to leak air and become unusable.

[0006] In existing injection molds, the mold tubes are often placed horizontally. For multi-point injection molding of curved plastic shells, horizontal tubes are not conducive to the natural flow of molten plastic in the cavity. When the molten plastic flows in horizontal tubes, it needs to overcome a large amount of friction. After entering the cavity, without the assistance of gravity, it is difficult to fill quickly and evenly along the shape of the curved shell. When the temperature of the molten plastic decreases and its viscosity increases, poor flow or even blockage will occur in the bends or narrow parts of the horizontal tubes. Once blocked, not only will production be interrupted, but a lot of time will also be spent cleaning the tubes, reducing production efficiency and increasing production costs.

[0007] 3. The existing mold injection pipe is located at the top. After injection is completed, the residual injection liquid in the pipe will not flow back naturally under the action of gravity, but will remain in the pipe. When the injection molding machine works again, this residual injection liquid may have cooled and solidified, blocking the main outlet or the inside of the pipe, affecting the normal delivery of new injection liquid. To solve the blockage problem, the pipe needs to be cleaned frequently, which not only increases the labor intensity of workers, but also leads to product quality problems due to incomplete cleaning, such as impurities mixed in the product.

[0008] Furthermore, when the injection pipe is at the top, the mold is connected to the injection pipe during the mold opening process. The direction in which the mold falls is restricted by the pipe, which increases the complexity of mold opening. When removing the mold, the operator needs to carefully avoid the injection pipe above. The operating space is limited, and the difficulty of removing the mold increases. This not only reduces the efficiency of mold opening and removal, but also easily damages the mold or product during the operation, affecting the continuity of production and the yield rate of the product.

[0009] Therefore, in view of this, the present invention proposes a multi-point bottom-feed thin-part injection mold to make up for and improve the deficiencies of the prior art. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention provides a multi-point bottom-feed thin-part injection mold, thereby resolving the technical issues raised in the background section.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a multi-point bottom-feed thin-part injection mold for injection molding multiple injection mold shells, including a lower mold assembly, wherein a multi-point injection mechanism is provided below the lower mold assembly, and the multi-point injection mechanism is used for dynamically conveying injection liquid.

[0012] Furthermore, the multi-point injection molding mechanism includes a liquid delivery pipe disposed below the lower module, with branch pipes evenly connected above the liquid delivery pipe, a pressure cylinder installed on the side wall of the liquid delivery pipe, and a drive module installed inside the pressure cylinder. The drive module works with the liquid delivery pipe to provide injection liquid to the equipment in a pulse manner, and the liquid delivery pipe works with the branch pipes to deliver injection liquid to the equipment in an inclined manner.

[0013] Furthermore, an upper module is installed above the lower module, and multiple injection mold shells are formed after the lower module and the upper module are assembled. The drive module includes a drive cylinder, and a guide chamber is installed outside the output shaft end of the drive cylinder. A movable plate is installed on the side wall of the guide chamber.

[0014] Furthermore, the drive module also includes a cam, a pressing shaft, and a return spring. The cam is driven to rotate by an external motor, the pressing shaft is located on the rotation path of the cam, and the return spring is sleeved on the outer wall of the pressing shaft.

[0015] Furthermore, the lower module, the upper module, and the infusion pipeline are all installed at an angle, and the infusion pipeline is located below the upper module and the lower module, using a bottom injection molding method.

[0016] By adopting the above technical solution, the backflow of residual injection molding liquid is prevented, and the residual injection molding liquid is prevented from cooling and solidifying in the pipeline, thus avoiding blockage.

[0017] Furthermore, the infusion pipeline is designed to be inclined, with one end higher than the horizontal plane and one end lower than the horizontal plane, and the starting position of the infusion pipeline is located at the end higher than the horizontal plane.

[0018] By adopting the above technical solution, gravity is utilized to make gravity the natural driving force for the flow of molten plastic during the injection molding process.

[0019] Furthermore, an assembly ring cylinder is installed inside the infusion pipeline, and the inside of the infusion pipeline is evenly provided with sliding grooves. Protrusions are fixedly connected to the outer wall of the assembly ring cylinder at the positions corresponding to the sliding grooves. The infusion pipeline and the assembly ring cylinder are slidably connected through the sliding grooves and the protrusions.

[0020] By adopting the above technical solution, the assembled ring can be easily removed from the infusion pipeline, and the assembled ring can be cleaned separately.

[0021] Furthermore, each of the branch pipes is equipped with a pressure valve, which is initially in a closed state. A limit adjustment frame is installed on the outside of each branch pipe. The limit adjustment frame has a telescopic structure and is slidably connected to the lower module.

[0022] By adopting the above technical solution, the limit adjustment frame is adjusted to a telescopic state and fitted to the outside of the lower module.

[0023] Furthermore, the pressure cylinder is kept in communication with the infusion pipeline, and a one-way valve is installed inside the pressure cylinder near the end of the infusion pipeline, which is initially in a closed state.

[0024] By adopting the above technical solution, the backflow of the injection liquid in the infusion pipeline into the pressure cylinder is prevented.

[0025] Furthermore, an assembly piece is installed on the side wall of the output end of the drive cylinder in the drive module, and the output end of the drive cylinder in the drive module is slidably connected to the guide chamber through the assembly piece.

[0026] Furthermore, a telescopic shaft is fixedly connected to the side wall of the movable plate, and a spring is sleeved on the outer wall of the telescopic shaft. The two ends of the spring are fixedly connected to the movable plate and the assembly piece, respectively.

[0027] By adopting the above technical solution, an additional instantaneous acceleration force is provided to the active plate, thereby enhancing the pulse intensity.

[0028] Furthermore, the movable plate is located at the center of the pressure cylinder, and the inner wall of the pressure cylinder corresponding to the position of the movable plate is frosted.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] (1) For injection molding of curved shells made of plastic, this device introduces a liquid delivery pipe and a branch pipe. The two are combined to form a multi-point overall pipe. The output end of the branch pipe corresponds to the injection mold shell. The output end of the branch pipe is slightly higher than the injection mold shell. Furthermore, the lower mold, upper mold and liquid delivery pipe are installed in an inclined manner. At the same time, the overall pipe formed by the liquid delivery pipe and the branch pipe is located below the lower mold. Therefore, when the injection liquid is discharged, under the combined action of gravity and its own flow inertia, it can flow more smoothly along the inclined pipe and mold cavity, reducing flow resistance and dead angles. For example, for some parts with deep concavity or complex curved surfaces, the inclined design allows the injection liquid to flow in and fill naturally, avoiding defects such as material shortage and voids caused by poor flow of injection liquid, thereby improving the molding quality and integrity of the product.

[0031] In multi-point injection molding, uniform flow of injection fluid is crucial. The inclined design allows the injection fluid to be distributed and flow more evenly in each branch pipe. Due to gravity, the injection fluid will automatically flow to lower places, thus forming a relatively consistent pressure and flow rate at each branch output end. This helps to ensure that the injection fluid supply and filling speed at each injection point are similar, reducing problems such as inconsistent product wall thickness and surface quality differences caused by uneven injection at each point, and improving the overall quality and consistency of the product.

[0032] This device features an assembly ring installed inside the infusion pipeline. Since the assembly ring can be easily removed from the pipeline, it can be cleaned separately during equipment maintenance and cleaning to remove residual injection liquid and impurities adhering to its surface. This prevents the accumulation of residual substances in the pipeline, thus preventing blockage and affecting the flow of injection liquid, ensuring the smooth progress of the injection process. Furthermore, after removing the assembly ring, a comprehensive inspection can be conducted to promptly identify any potential wear or damage, and to perform appropriate repairs or replacements.

[0033] (2) More importantly, this device uses multiple structural components such as pressure cylinder and drive module to achieve intermittent power supply during the process of conveying injection liquid, so that the injection liquid is conveyed in a slow-fast-slow-fast pulse mode. First, the pulse flow can make the injection liquid shake, effectively breaking the state of air accumulation. When the injection liquid flows quickly, the impact force generated can disperse the originally accumulated air into small bubbles. The slow flow stage provides time for the small bubbles to escape, preventing them from re-aggregating into large bubbles or hollows, thus improving the density and quality of the product.

[0034] Secondly, for the injection molding of curved and thin-walled products in this device, the injection liquid will encounter greater resistance during the flow process. The pulsed power supply can apply additional rapid thrust when the injection liquid flows slowly, helping it overcome the resistance and reach all parts of the mold smoothly, ensuring the complete molding of the product.

[0035] (3) In actual use, the injection pipe is placed under the mold and the starting material feeding point is installed at the higher end, which cleverly utilizes the effect of gravity. During the injection process, gravity becomes the natural force that drives the flow of plastic liquid, reducing the dependence on additional power equipment (such as high pressure pumps). This not only reduces equipment costs and energy consumption, but also simplifies the structure of the injection system.

[0036] Furthermore, in the bottom injection molding method, after the first stage of injection molding is completed, the residual injection liquid will naturally flow back under the action of gravity, thereby avoiding the blockage problem caused by the residual injection liquid cooling and solidifying in the pipeline. Compared with the traditional top injection molding method, the residual injection liquid is easy to accumulate at the outlet and gradually form hard lumps over time. However, the backflow of bottom injection molding in this device can ensure that the residual injection liquid flows back to the infusion pipeline, thereby ensuring the smooth flow of the injection process, reducing the number of shutdowns for cleaning, and improving injection efficiency.

[0037] Meanwhile, installing the injection pipe below the mold provides more space for mold opening and removal operations. Compared to the traditional top injection method, where the injection pipe is located above the mold and restricts the range of mold opening and removal operations, the bottom injection method of this device eliminates the obstruction of the pipe above the mold. Operators can perform mold opening and removal operations more freely, improving the convenience and safety of operation. The larger operating space and more convenient operation method also reduce the risk of product damage during mold opening and removal, making it easier for operators to remove products and improving the product yield. Attached Figure Description

[0038] Figure 1 This is a front-view three-dimensional structural schematic diagram of the present invention;

[0039] Figure 2This is a schematic diagram of the internal three-dimensional structure of the lower module of the present invention;

[0040] Figure 3 This is a three-dimensional structural diagram of the multi-point injection molding mechanism of the present invention;

[0041] Figure 4 This is a schematic diagram of the three-dimensional structure of the limit adjustment frame of the present invention;

[0042] Figure 5 For the present invention Figure 4 A magnified three-dimensional structural diagram of a portion of point A in the middle;

[0043] Figure 6 This is a schematic diagram of the exploded structure of the infusion pipeline and the assembled ring cylinder of the present invention;

[0044] Figure 7 This is a schematic diagram of the three-dimensional structure of the pressure cylinder of the present invention;

[0045] Figure 8 This is a schematic diagram of the internal three-dimensional structure of the pressure cylinder of the present invention;

[0046] Figure 9 This is a schematic diagram of the internal three-dimensional structure of the guide compartment of the present invention;

[0047] Figure 10 This is a three-dimensional structural diagram of the spring in the compressed state of the present invention;

[0048] Figure 11 This is a schematic diagram of the cam structure of the present invention.

[0049] The diagram is labeled as follows: 1. Upper module; 11. Lower module; 12. Injection mold shell; 2. Multi-point injection molding mechanism; 21. Infusion pipeline; 22. Assembly ring cylinder; 23. Branch pipeline; 24. Pressure valve; 25. Limit adjustment frame; 26. Pressure cylinder; 27. Check valve; 28. Drive module; 29. ​​Assembly piece; 210. Guide chamber; 211. Movable plate; 212. Telescopic shaft; 213. Spring. Detailed Implementation

[0050] 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0051] It should be noted that the structure and working principle of the above-mentioned upper module 1, lower module 11, injection mold shell 12 and other components are existing technologies and will not be described in detail here.

[0052] Example 1: Please refer to Figure 1 - Figure 10 As shown, a multi-point bottom-feed thin-part injection mold is used to perform injection molding on multiple injection mold shells 12. It includes a lower mold assembly 11, and a multi-point injection mechanism 2 is provided below the lower mold assembly 11. The multi-point injection mechanism 2 is used to dynamically deliver injection liquid.

[0053] It should be noted that the upper module 1 is installed above the lower module 11, and after the lower module 11 and the upper module 1 are assembled, multiple injection mold shells 12 are formed.

[0054] Please refer to Figure 1 - Figure 10 As shown, the multi-point injection molding mechanism 2 includes an infusion pipe 21 located below the lower module 11. Branch pipes 23 are evenly connected above the infusion pipe 21. A pressure cylinder 26 is installed on the side wall of the infusion pipe 21. A drive module 28 is installed inside the pressure cylinder 26. The drive module 28 works with the infusion pipe 21 to provide injection liquid to the equipment in a pulse manner. The infusion pipe 21 works with the branch pipes 23 to deliver injection liquid to the equipment in an inclined manner. An upper module 1 is installed above the lower module 11. After the lower module 11 and the upper module 1 are assembled, multiple injection mold shells 12 are formed. The drive module 28 includes a drive cylinder, and a guide chamber 210 is installed outside the output shaft end of the drive cylinder. A movable plate 211 is installed on the side wall of the guide chamber 210.

[0055] It should be noted that the lower module 11, upper module 1, and infusion pipe 21 are all installed at an angle, and the infusion pipe 21 is located below the upper module 1 and lower module 11. Injection molding is performed from below. Due to its angled design, the infusion pipe 21 has a high end above the horizontal plane and a low end below the horizontal plane. The initial material feeding position of the infusion pipe 21 is located at the end above the horizontal plane. An assembly ring cylinder 22 is installed inside the infusion pipe 21, and grooves are evenly distributed inside the infusion pipe 21. The outer wall of the assembly ring cylinder 22 corresponds to the grooves. Each position is fixedly connected with a protrusion. The infusion pipeline 21 and the assembly ring cylinder 22 are slidably connected to the protrusion through a sliding groove. Each branch pipeline 23 is equipped with a pressure valve 24, which is initially closed. A limit adjustment frame 25 is installed on the outside of the branch pipeline 23. The limit adjustment frame 25 has a telescopic structure and is slidably connected to the lower module 11. The pressure cylinder 26 is kept in communication with the infusion pipeline 21, and a one-way valve 27 is installed inside the pressure cylinder 26 near the end of the infusion pipeline 21. The one-way valve 27 is initially closed.

[0056] Specifically, the lower module 11, upper module 1, and infusion pipeline 21 are all installed at an angle, with the infusion pipeline 21 located entirely below the upper module 1 and lower module 11. The infusion pipeline 21 has a high end above the horizontal plane and a low end below the horizontal plane, with the initial material conveying position at the high end. At this time, the pressure valve 24 inside the branch pipeline 23 is initially in the closed state, and the limit adjustment bracket 25 is adjusted to its telescopic state and fitted to the outside of the lower module 11.

[0057] When the injection molding liquid is input from the high end of the infusion pipe 21, due to the inclination of the infusion pipe 21, the injection molding liquid naturally flows to the low end under the action of gravity. Due to gravity and its own flow inertia, the injection molding liquid is distributed and flows in each branch pipe 23. Under the action of gravity, the injection molding liquid forms a relatively uniform pressure and flow rate at the output end of each branch pipe 23. Since the infusion pipe 21 and the branch pipes 23 form a whole pipe, and the output end of the branch pipe 23 is slightly higher than the injection mold shell 12 and corresponds to it one by one, when the injection molding liquid reaches the branch pipe 23, the pressure valve 24 turns to the open state under the action of the injection molding liquid pressure difference, and flows into the injection mold shell 12 from the output end of the branch pipe 23. When the injection molding liquid flows into the mold shell, it generates pressure on the inner wall of the mold shell. The mold shell is subjected to the impact force of the injection molding liquid and the support force of its own structure, and is filled in the mold cavity. Due to the inclined design, the injection molding liquid can fill all parts of the mold shell more smoothly, especially the deep concave or complex curved surfaces.

[0058] During subsequent equipment maintenance and cleaning, the assembly ring 22 can be pulled and removed from the infusion pipeline 21 by utilizing the sliding connection between the protrusion and the slide groove. After removal, the assembly ring 22 can be cleaned separately to remove residual injection liquid and impurities on the surface for continued use. The limit adjustment bracket 25 can be extended and adjusted as needed during the injection molding process and fitted to the outside of the lower mold 11 to ensure the stability of each component during the injection molding process and ensure that the injection liquid can flow accurately into the injection mold shell 12.

[0059] Example 2: Based on Example 1, please refer to... Figure 1 - Figure 10 As shown, an assembly piece 29 is installed on the side wall of the output end of the drive cylinder in the drive module 28. The output end of the drive cylinder in the drive module 28 is slidably connected to the guide chamber 210 through the assembly piece 29. A telescopic shaft 212 is fixedly connected to the side wall of the movable plate 211. A spring 213 is sleeved on the outer wall of the telescopic shaft 212. The two ends of the spring 213 are fixedly connected to the movable plate 211 and the assembly piece 29, respectively. The movable plate 211 is located at the center position inside the pressure cylinder 26, and the inner wall of the pressure cylinder 26 corresponding to the position of the movable plate 211 is frosted.

[0060] Specifically, in the initial state, the movable plate 211 is located at the center of the pressure cylinder 26, the drive module 28 is not activated, the spring 213 is in a naturally extended state, and the position of the movable plate 211 is relatively stable.

[0061] Subsequently, the drive module 28 is activated. As the output shaft of the drive cylinder extends, the telescopic shaft 212 gradually moves towards the movable plate 211, and the spring 213 is gradually compressed during this process. Because the inner wall of the pressure cylinder 26 is frosted, the friction is relatively high. Therefore, during the compression of the spring 213, the compressive force is gradually absorbed by the spring 213 and the telescopic shaft 212. The compressive force on the movable plate 211 is relatively small, and with the effect of the frosted inner wall, the movable plate 211 remains stationary. Figure 10 As shown, when the telescopic shaft 212 cannot be compressed, the output end of the drive cylinder continues to move. At this time, the movable plate 211 is directly subjected to the squeezing force of the output shaft and begins to move towards the one-way valve 27. The movement of the movable plate 211 causes the space in the pressure cylinder 26 near the end of the infusion pipeline 21 to gradually decrease, which in turn causes the internal pressure of this pipeline to gradually increase. When the pressure in the pressure cylinder 26 increases to a level sufficient to overcome the opening pressure of the one-way valve 27, the one-way valve 27 changes from the initial closed state to the open state. As the one-way valve 27 opens, the space between the one-way valve 27 and the movable plate 211 is no longer sealed. Therefore, the compressed spring 213 releases its elastic force at the same time as the one-way valve 27 opens, and gives the movable plate 211 an additional instantaneous acceleration force, thereby enhancing the pulse force. This causes the pressure in the pressure cylinder 26 to be transmitted to the inside of the infusion pipeline 21, thereby accelerating the flow of the injection molding liquid.

[0062] After the drive cylinder completes one pushing stroke, it begins its return stroke. The output end moves in the opposite direction along the guide chamber 210. As the output end returns, the assembly piece 29 pulls the spring 213, which gradually returns to a stretched state. At the same time, the telescopic shaft 212 also moves back to its original state. When the telescopic shaft 212 returns to its original state, the pulling force of the drive cylinder's output end acts directly on the movable plate 211. The movable plate 211 also gradually moves back to its initial position within the pressure cylinder 26. During the movement of the movable plate 211, the space near the infusion pipeline 21 within the pressure cylinder 26 gradually increases, and the pressure decreases. When the pressure within the pressure cylinder 26 decreases below the closing pressure of the one-way valve 27, the one-way valve 27 returns to its initial closed state to prevent the injection liquid in the infusion pipeline 21 from flowing back into the pressure cylinder 26. The one-way valve 27 then returns to its compressed state until the pressure within the pressure cylinder 26 rises back to the opening pressure.

[0063] The drive cylinder in the drive module 28 continuously repeats the above-mentioned cycle of starting, pushing, and returning, causing the movable plate 211 to move back and forth in the pressure cylinder 26. The pressure in the pressure cylinder 26 also periodically increases and decreases, thereby realizing the intermittent pulse-like pushing of the injection molding liquid in the infusion pipeline 21, ensuring that the injection molding liquid flows in a slow-fast-slow-fast manner to meet the requirements of the injection molding process. It should be noted that the above-mentioned increase in slowness is the injection molding liquid flowing at normal speed, only slower than after acceleration.

[0064] Example 3: Based on Example 2, please refer to... Figure 1 - Figure 11 As shown, in relation to the use of the drive module 28 and other components mentioned in Embodiment 2, the drive motor in the drive module 28 can also be replaced by the coordinated movement of the cam, the compression shaft and the return spring.

[0065] Specifically, the cam is driven to rotate by an external motor, and the extrusion shaft is located on the rotation path of the cam. One end of the shaft is fixedly connected to the assembly piece 29, and a return spring is sleeved on the outer wall of the extrusion shaft. In the initial state, the movable plate 211 is located at the center of the pressure cylinder 26, the return spring is in the natural state, the extrusion shaft and the cam are not in contact and are in a staggered state, and the position of the movable plate 211 is relatively stable.

[0066] When the external motor starts and drives the cam to rotate, the rotation path of the cam causes it to gradually approach and squeeze the extrusion shaft. As the cam rotates, the extrusion shaft moves towards the movable plate 211 under the squeezing action of the cam. During this process, the return spring is compressed. When the cam rotates, it gradually squeezes the extrusion shaft, causing the extrusion shaft to move towards the movable plate 211 and compress the return spring. This process is equivalent to the extension of the cylinder output shaft to compress the spring 213 in embodiment 2. The squeezing force is absorbed by the return spring and the extrusion shaft, so the movable plate 211 remains stationary. When the extrusion shaft can no longer be compressed, the squeezing force generated by the continuous rotation of the cam acts directly on the movable plate 211 through the extrusion shaft and the assembly piece, pushing the movable plate 211 to move towards the one-way valve 27. Subsequent processes, including the opening of the one-way valve 27, the release of the return spring to increase the pulse force, and the acceleration of the flow of the injection molding liquid, are all equivalent to the method described in embodiment 2.

[0067] This new implementation method, which utilizes the cooperation between the cam, the compression shaft, and the return spring, has a relatively simple and compact structure, and the parts are easy to process and assemble. It uses the periodic rotation of the cam to achieve stable pulse drive, and the motion process is highly regular. The pulse characteristics can be flexibly changed by adjusting the cam profile curve. The return spring assists in energy transfer and reset, reduces mechanical rigid collisions, reduces wear, and improves the durability and reliability of the system. Furthermore, the external motor drive facilitates integration with automated control systems.

[0068] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-point underfeed fine part injection mold for injection molding a plurality of injection mold shells (12), comprising a lower mold set (11), characterized in that: The lower mold group (11) is provided below a multi-point injection mechanism (2) for dynamically conveying injection liquid; The multi-point injection mechanism (2) comprises a liquid conveying pipeline (21) arranged below the lower mold group (11), the upper part of the liquid conveying pipeline (21) is uniformly communicated with branch pipelines (23), the side wall of the liquid conveying pipeline (21) is provided with a pressure cylinder (26), the inside of the pressure cylinder (26) is provided with a driving module (28), the driving module (28) and the liquid conveying pipeline (21) cooperatively provide injection liquid for the device in a pulse mode, and the liquid conveying pipeline (21) and the branch pipelines (23) cooperatively convey injection liquid for the device in an inclined mode. The upper part of the lower mold group (11) is provided with an upper mold group (1), a plurality of injection mold shells (12) are formed after the assembly of the lower mold group (11) and the upper mold group (1), the driving module (28) comprises a driving cylinder, and the outer part of the output shaft end of the driving cylinder is provided with a guide bin (210), and the side wall of the guide bin (210) is provided with a movable plate (211). The driving module (28) further comprises a cam, a pressing shaft and a return spring, the cam is driven to rotate by an external motor, the pressing shaft is located on the rotating path of the cam, and the outer wall of the pressing shaft is sleeved with the return spring. The lower mold group (11), the upper mold group (1) and the liquid conveying pipeline (21) are all arranged in an inclined mode, the liquid conveying pipeline (21) is located below the upper mold group (1) and the lower mold group (11) as a whole, the liquid conveying pipeline (21) is designed to be inclined, has a high end higher than the horizontal plane and a low end lower than the horizontal plane, and the starting liquid conveying position of the liquid conveying pipeline (21) is located at the high end higher than the horizontal plane.

2. A multi-point underfeed tubular part injection mold according to claim 1, characterized in that: The inside of the liquid conveying pipeline (21) is provided with an assembly ring cylinder (22), the inside of the liquid conveying pipeline (21) is uniformly provided with a sliding groove, the outer wall of the assembly ring cylinder (22) is fixedly connected with a protruding block at the position corresponding to the sliding groove, and the liquid conveying pipeline (21) and the assembly ring cylinder (22) are slidably connected through the sliding groove and the protruding block.

3. A multi-point underfeed wire insertion injection mold according to claim 1, wherein: The inside of the branch pipeline (23) is provided with a pressure valve (24), the pressure valve (24) is initially in a closed state, the outside of the branch pipeline (23) is provided with a limiting adjusting frame (25), the limiting adjusting frame (25) is in an extension structure, and the limiting adjusting frame (25) is slidably connected with the lower mold group (11).

4. A multi-point underfeed wire insertion injection mold according to claim 1, wherein: The pressure cylinder (26) is in communication with the liquid conveying pipeline (21), and the inside of the pressure cylinder (26) near one end of the liquid conveying pipeline (21) is provided with a one-way valve (27), and the one-way valve (27) is initially in a closed state.

5. A multi-point underfeed wire insertion injection mold according to claim 1, wherein: The output end side wall of the driving cylinder in the driving module (28) is provided with an assembly piece (29), and the output end of the driving cylinder in the driving module (28) is slidably connected with the guide bin (210) through the assembly piece (29).

6. A multi-point underfeed wire insertion injection mold according to claim 1, wherein: The side wall of the movable plate (211) is fixedly connected with an extension shaft (212), the outer wall of the extension shaft (212) is sleeved with a spring (213), and the two ends of the spring (213) are fixedly connected with the movable plate (211) and the assembling sheet (29) respectively.

7. A multi-point underfeed wire insertion injection mold according to claim 1, wherein: The movable plate (211) is located at the central position inside the pressure cylinder (26), and the inner wall of the pressure cylinder (26) is frosted at the position corresponding to the movable plate (211).

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