Injection mold

Abstract

The invention relates to the technical field of injection molding, in particular to an injection mold which comprises a front mold plate, a front mold core, a rear mold plate, a rear mold core, a rear mold slide seat, a stripper plate, an upper fixing plate, an ejector plate and a sprue needle which are connected with the ejector plate and the rear mold core respectively, and the sprue needle is provided with a sprue demolding part; the upper fixing plate is provided with a main runner, the stripper plate, the front mold plate, the front mold core and the rear mold slide seat are provided with branch runners, the rear mold core is provided with a sprue, the main runner, the branch runners and the sprue are communicated, the sprue is divided into a needle connecting part, a true water gap part and a false water gap part, and the true water gap part and the false water gap part are communicated with each other. And the true nozzle part and the false nozzle part are symmetrically arranged relative to the needle connecting part in a balanced manner. By means of the pouring gate demolding part, the contact area between the pouring gate needle and the material head is reduced, the phenomenon of bouncing off is not prone to occurring, the gravity center of the material head is balanced and the phenomenon of bouncing off is not prone to occurring due to the fact that the real water gap part and the fake water gap part are symmetrically arranged in a balanced mode.

Description

Technical Field

[0001] This invention belongs to the field of injection molding technology, and specifically relates to an injection mold. Background Technology

[0002] In injection molding production, submarine gates are widely used because they can automatically cut off the gate. Their ejection principle is based on the force of the ejector pins, which cause the sprue formed by the submarine gate to yield and deform, forcibly ejecting it from the mold cavity.

[0003] Currently, the main method for cleaning sprue heads is to use ejector pins to eject them, relying on either automatic dropping after ejection or gripping by a robotic arm. The automatic dropping method has the drawback of the sprue head being bounced away due to elastic deformation after ejection. However, the complex structure of the mold cavity means the sprue head may become stuck inside. If it is not removed promptly before mold closing, it can easily cause a mold-breaking accident, damaging the precision and expensive mold cavity. Therefore, with the increasing level of industrial automation, using robotic arms for positioning and gripping at fixed stations has become the mainstream solution. This solution requires the sprue head to remain stably in a preset position after ejection, but it faces a core contradiction: if the force of the sprue head on the ejector pin is too small, it is prone to falling; if the force is too large, the robotic arm cannot grip it effectively.

[0004] Publication No.: CN218660209U, Patent Name: Injection Molding Head. This injection molding head includes a sprue body with a push rod formed on it. The end of the push rod has multiple spaced-apart baffles, which together form a ejector pin cavity. The core purpose of this design is that the ejector pin extends into the cavity to push the sprue head, and is positioned by the cooperation of the baffles and the ejector pin. Simultaneously, the gaps between the baffles reduce the wrapping force of the cooled sprue head on the ejector pin, thus facilitating subsequent gripping by the robotic arm. However, the following problems exist: First, while the cavity design at the baffles reduces the wrapping force of the sprue head on the ejector pin, the uniform distribution of the cavities excessively weakens the guiding and positioning effect of the ejector pin on the sprue head, resulting in an excessively weakened constraint force. Second, this design does not consider the balance of the sprue head's center of gravity; the center of gravity does not coincide with the ejector pin.

[0005] Based on these two issues, the following situations may occur: First, during the process of leaving the mold cavity, the part of the sprue close to the product cavity will accumulate elastic potential energy. If the force applied to the sprue by the mold is greater than the constraint force between the ejector pin and the sprue before the sprue has completely left the mold cavity, the sprue and the ejector pin will separate and tilt to a certain extent. After the sprue has completely left the mold cavity, the force generated by the release of elastic potential energy will be greater than the constraint force between the ejector pin and the sprue, which will cause the sprue to bounce off.

[0006] Secondly, if the sprue remains on the ejector pin after leaving the mold cavity, the torque generated by the imbalance of the center of gravity will cause the softer sprue to deflect and deform under a larger constraint force, and under a smaller constraint force, it will cause the softer sprue to deflect and rotate relative to the ejector pin, thus affecting the accuracy of the robot's gripping. Summary of the Invention

[0007] The purpose of this application is to provide an injection mold to solve the technical problems existing in the prior art.

[0008] To achieve the above objectives, the technical solution adopted in this application is: to provide an injection mold, comprising: The front template has a front mold core. The rear template is equipped with a rear mold core and a rear mold slide seat; A stripper plate is provided on the front side of the front template. An upper fixing plate is disposed on the front side of the stripper plate; Ejector plate, disposed on the rear side of the rear template; The sprue pin is connected to the ejector plate and the rear mold core respectively. The end of the sprue pin inserted into the rear mold core is tapered and narrows towards the front mold plate to form a sprue demolding part. The upper fixed plate is provided with a main runner, the stripper plate, the front template, the front mold core, and the rear mold slide seat are provided with branch runners, the rear mold core is provided with a gate, the main runner, the branch runners, and the gate are connected, the gate is divided into a connecting pin section, a true gate section, and a false gate section, the connecting pin section is connected to the cavity where the gate pin is located, the true gate section is connected to the product cavity, and the true gate section and the false gate section are symmetrically and balanced relative to the connecting pin section.

[0009] Optionally, the end of the gate pin inserted into the rear mold core also has an anti-rotation limiting part, the anti-rotation limiting part is located on the side of the gate demolding part away from the gate, the peripheral outer wall of the anti-rotation limiting part is used to connect with the sprue head, and the non-circular arc outer wall of the anti-rotation limiting part is connected with the sprue head.

[0010] Optionally, the outer wall of the anti-rotation limiting part has a material connecting surface and a cavity-adhering surface. The material connecting surface is used to connect with the material head, and the cavity-adhering surface is used to abut against the inner wall of the chamber where the gate needle is located.

[0011] Optionally, the angle between the real sprue and the connecting needle is greater than the angle between the fake sprue and the connecting needle.

[0012] Optionally, the length of the real gate portion along the axial direction of the gate needle is the same as the length of the fake gate portion along the axial direction of the gate needle.

[0013] Optionally, the true water inlet portion is narrowed in the direction away from the connecting needle portion.

[0014] Optionally, the gate further includes a supplementary connecting cavity that connects the true gate portion and the product cavity, wherein the end of the supplementary connecting cavity that is away from the true gate portion extends toward the front mold plate.

[0015] Optionally, the ejector plate is connected to a sprue riser, which slides through the rear mold core, and the outer wall of the sprue riser forms a product cavity and a portion of the inner wall of the supplementary connecting cavity.

[0016] Optionally, the rear mold core includes a rear mold core and a rear mold insert. The rear mold core is used for the gate and is fixedly mounted on the rear mold plate. The rear mold insert is fixedly inserted into the rear mold core to form a ribbed cavity in the rear mold core. The rear mold insert is provided with an ejector pin guide hole. The ejector plate is connected to an insert ejector pin, and the insert ejector pin slides through the ejector pin guide hole.

[0017] Optionally, the ejector plate is provided with a lower fixing plate on the side away from the rear mold plate. The lower fixing plate is fixedly installed and is provided with a hole-forming insert. The hole-forming insert slides through the rear mold core. The ejector plate is provided with a hole-removing guide sleeve. The hole-removing guide sleeve is slidably sleeved on the hole-forming insert and slides through the rear mold core.

[0018] The beneficial effects of the injection mold provided in this application are as follows: Compared with the prior art, this application solves the following problems: First, by using the gate demolding part, the contact area between the gate pin and the sprue is reduced, but the constraint force of the gate pin on the sprue is not excessively weakened. Therefore, the sprue is less likely to tilt or deviate uncontrollably when it is not completely separated from the mold cavity, so it is less likely to bounce off at the moment of subsequent separation. At the same time, the conical gate demolding part makes the force generated by the cooling and shrinkage of the sprue mainly transform into the tendency of the sprue to loosen along the axial direction of the gate pin, ensuring the convenience of the robot's gripping. Second, due to the symmetrical balance between the real gate and the fake gate, the center of gravity of the sprue is balanced, so the sprue is less likely to deviate, deform or rotate, which will not affect the gripping accuracy of the robot, and it is even less likely to bounce off at the moment of separation from the mold cavity. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, 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 application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the three-dimensional structure of an embodiment of this application. Figure 1 ; Figure 2 For the embodiments of this application along Figure 1 Cross-sectional view of AA Figure 2 ; Figure 3 This is a schematic diagram of the flow channel structure in an embodiment of this application. Figure 3 ; Figure 4 This is a schematic diagram of the force applied to the feed head in an embodiment of this application. Figure 4 ; Figure 5 This is a schematic diagram of the three-dimensional structure of the gate pin in an embodiment of this application. Figure 5 ; Figure 6 This is a schematic diagram illustrating the mating of the rear mold core and the rear template in an embodiment of this application. Figure 6 ; Figure 7 This is a schematic diagram illustrating the fit between the hole-removing guide sleeve and the hole-forming insert in an embodiment of this application. Figure 7 ; Figure 8 Examples of this application Figure 7 Magnification of a portion of point A Figure 8 .

[0021] The following are the labeling elements in the figure: 1. Front mold plate; 11. Front mold core; 2. Rear mold plate; 21. Rear mold core; 211. Rear mold core; 212. Rear mold insert; 2121. Ejector pin guide hole; 213. Rib cavity; 214. Insert ejector pin; 22. Rear mold slide seat; 3. Stripper plate; 4. Upper fixing plate; 5. Ejector plate; 51. Sprue angled ejector; 52. Hole guide sleeve; 6. Sprue pin; 61. Sprue demolding part; 62. Anti-rotation limiting part; 621. Connecting surface; 622. Cavity surface; 7. Main runner; 71. Sub-runner; 72. Sprue; 721. Connecting pin part; 722. True sprue part; 723. False sprue part; 724. Supplementary connecting cavity part; 8. Lower fixing plate; 81. Hole insert. Detailed Implementation

[0022] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0023] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0024] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] The following is combined with Figures 1 to 8 This application describes an injection mold provided in an embodiment. like Figures 1 to 3 As shown, specifically, the injection mold includes a front mold plate 1, a rear mold plate 2, a stripper plate 3, an upper fixing plate 4, an ejector plate 5, and a sprue pin 6. The front mold plate 1 is provided with a front mold core 11, which is fixedly located on the side of the front mold plate 1 closest to the rear mold plate 2, i.e., the lower side of the front mold plate 1 in the figure. The rear mold plate 2 is provided with a rear mold core 21 and a rear mold slide seat 22. The rear mold core 21 is fixedly located, while the rear mold slide seat 22 is slidably located, allowing it to close or move away from the front mold core 11 and the rear mold core 21. The stripper plate 3 is located on the front side of the front mold plate 1, which is the side of the front mold plate 1 furthest from the rear mold plate. On one side of the mold plate 2, the stripper plate 3 can be close to or away from the front mold plate 1; the upper fixing plate 4 is set on the front side of the stripper plate 3, the front side is the side of the stripper plate 3 away from the front mold plate 1, and the upper fixing plate 4 can also be close to or away from the stripper plate 3; the ejector plate 5 is located on the rear side of the rear mold plate 2, the rear side is the side of the rear mold plate 2 away from the front mold plate 1, and the ejector plate 5 can be close to or away from the rear mold plate 2; the sprue pin 6 is connected to the ejector plate 5 and the rear mold core 21 respectively, and the sprue pin 6 is inserted into the end of the rear mold core 21 in a tapered shape that narrows towards the front mold plate 1 to form a sprue demolding part 61, thus forming the mold-related solid structure.

[0026] The mold also involves a gating system. Specifically, the upper fixed plate 4 is provided with a main runner 7, the stripper plate 3, the front template 1, the front mold core 11, and the rear mold slide seat 22 are provided with runners 71, and the rear mold core 21 is provided with a gate 72. The main runner 7 connects the two sides of the upper fixed plate 4 that are close to and away from the stripper plate 3. One end of the runner 71 connects to the side surface of the stripper plate 3 that is close to the upper fixed plate 4, and the other end connects to the side surface of the rear mold slide seat 22 that abuts against the rear mold core 21. One end of the gate 72 connects to the side surface of the rear mold core 21 that abuts against the rear mold slide seat 22, and the other end connects to the product cavity. Therefore, the main runner 7, the runner 71, and the gate 72 can be connected.

[0027] In this embodiment, a submarine gate 72 is used, a method often applied in multi-cavity molds, where one mold can process multiple products. Therefore, a runner 71 is provided. The main runner 7, the runner 71, and the gate 72 are connected to form a complete flow path from the injection molding machine to the product cavity, ensuring that the melt can continuously and stably fill every corner of the product cavity.

[0028] Meanwhile, the gate 72 is further divided into a connecting needle section 721, a true gate section 722, and a false gate section 723. The connecting needle section 721 connects to the chamber where the gate needle 6 is located, and the true gate section 722 connects to the product cavity. The true gate section 722 and the false gate section 723 are symmetrically and balanced relative to the connecting needle section 721. The symmetrical and balanced arrangement does not mean that the geometry of the sprue head between the true gate section 722 and the false gate section 723 is exactly the same, but rather that the sprue head is located in two parts of the true gate section 722 and the false gate section 723, and the center of gravity of these two parts is located at the connecting needle section 721, so as to achieve the balance of the center of gravity of the sprue head.

[0029] It should be noted that during mold opening, the portion of the sprue located at the main runner 7 and the branch runner 71 will separate from the portion located at the gate 72. The portion located at the main runner 7 and the branch runner 71 will form a mesh structure. Furthermore, during the mold opening process, the portion of the sprue located at the main runner 7 and the branch runner 71 will not undergo yielding deformation, so there will be no issues such as ejection or displacement. Therefore, the sprue mentioned in this application refers only to the portion located in the gate 72, and for ease of description, the term "sprue" will be used directly in the following description.

[0030] Considering that the sprue needs to move stably along the demolding path during the ejection process by the sprue pin 6 in order to avoid it flying away due to uneven force at the moment of ejection, the sprue pin 6 has a sprue demolding part 61 in this embodiment. During the ejection process, no matter which circumferential direction the sprue deflects, it will be subjected to the reverse force of the conical surface to ensure that the sprue moves stably along the demolding path. In addition, the ejected sprue will shrink towards the center during the natural cooling process. Since the contact surface between the sprue and the sprue demolding part 61 is conical, the shrinkage force generated by the cooling deformation of the contact surface will be converted into a component of displacement along the axis of the sprue pin 6.

[0031] In this embodiment, the taper of the gate demolding part 61 is 15°. This angle value is the optimal solution based on a comprehensive consideration of the friction characteristics, shrinkage behavior and ejection mechanics of various plastics. It is especially suitable for commonly used engineering plastics such as ABS and PC. If the taper of the gate demolding part 61 is too large, the contact area between the gate demolding part 61 and the sprue will be reduced, resulting in a decrease in the wrapping force. If the taper is too small, the contact area with the sprue will be increased, resulting in an increase in the wrapping force, making it impossible for the sprue to detach from the gate demolding part 61 properly.

[0032] Because the sprue head formed at gate 72, if only the true gate portion 722 is present, the center of gravity of the sprue head will be significantly deviated from the axis of the gate pin 6. Since the ejected sprue head is not fully cooled, the shifted center of gravity will cause the incompletely cooled sprue head to rotate around the axis of the gate pin 6, affecting the gripper's ability to hold it. Furthermore, during the ejection process, the true gate is prone to elastic deformation; that is, the true gate portion 722 will release elastic force the instant it detaches from gate 72, which could potentially cause the entire sprue head to be ejected. Therefore, in this embodiment, a false gate portion 723 is provided. The false gate portion 723 and the true gate portion 722 are symmetrically positioned relative to the connecting pin portion 721 and are of balanced mass. The false gate portion 723 ensures that the center of gravity of the ejected sprue head remains at the axis of the gate pin 6, preventing the incompletely cooled sprue head from rotating around the axis of the gate pin 6.

[0033] In summary, firstly, by using the gate ejection section 61, the contact area between the gate pin 6 and the sprue is reduced without excessively weakening the constraint force of the gate pin 6 on the sprue. Therefore, the sprue is less likely to tilt or deviate uncontrollably when it is not completely detached from the mold cavity, and is less likely to bounce off at the moment of detachment. At the same time, the conical gate ejection section 61 transforms the force generated by the cooling and shrinkage of the sprue into a tendency for the sprue to loosen along the axial direction of the gate pin 6, ensuring the convenience of the robot's gripping. Secondly, due to the symmetrical balance between the true gate section 722 and the false gate section 723, the center of gravity of the sprue is balanced, so the sprue is less likely to deviate, deform, or rotate, which will not affect the subsequent gripping accuracy of the robot, and is less likely to bounce off at the moment of detachment from the mold cavity.

[0034] It is important to note that when the mold is opened, the sprue is in a state that is somewhat soft and has a certain degree of toughness. However, the ratio of softness to toughness is determined by the cooling efficiency. If the softness ratio is higher, the aforementioned factors will cause the sprue to deviate and deform after leaving the mold cavity, and will also cause the sprue to deviate and rotate relative to the gate pin 6. If the hardness ratio is higher, the aforementioned bounce-off situation will occur.

[0035] like Figure 4 As shown in the attached figure, A is the ejection direction of the gate pin 6, B is the direction of the force applied to the feed head by the mold when the feed head accumulates elastic potential energy, and C is the direction of the torque generated by the feed head due to the imbalance of the center of gravity.

[0036] In summary, this application adopts a combination of a symmetrical arrangement of the gate demolding part 61, the true gate part 722, and the false gate part 723. This is intended to adapt to most types of sprues, that is, to adapt to various soft-hard ratios, so that the sprue will not bounce off after the mold is opened, and the relative posture of the sprue and the gate pin 6 will not change too much, so that the robot can grasp it. Moreover, this grasping is relatively convenient and does not require a lot of force to pull the sprue off the gate pin 6.

[0037] like Figure 2 and Figure 4 As shown, considering that the gate ejection section 61 is conical, the ejected sprue head may rotate around the axis of the gate pin 6 when subjected to external force, affecting the subsequent gripping by the robot. Based on this, the end of the gate pin 6 inserted into the rear mold core 21 also has an anti-rotation limiting section 62. The anti-rotation limiting section 62 is located on the side of the gate ejection section 61 away from the gate 72. The peripheral outer wall of the anti-rotation limiting section 62 is used to connect with the sprue head. The non-circular arc outer wall of the anti-rotation limiting section 62 is connected with the sprue head. Specifically, from the cross-section of the anti-rotation limiting section 62 perpendicular to the axis of the gate pin 6, there must be at least one straight line along the perimeter of the cross-section to limit the rotation of the sprue head around the axis of the gate pin 6, ensuring that the posture of the sprue head is unique each time the robot grips it.

[0038] If the sprue head completely covers the outer periphery of the anti-rotation limiting part 62, the excessive contact area between the anti-rotation limiting part 62 and the sprue head may lead to excessive wrapping force on the anti-rotation limiting part 62 after cooling, making it difficult for the robot arm to grip it. To resolve this issue, the outer periphery of the anti-rotation limiting part 62 has a connecting surface 621 and a cavity-adhering surface 622. The connecting surface 621 is used to connect with the sprue head, and the cavity-adhering surface 622 is used to abut against the inner wall of the chamber where the gate needle 6 is located. The connecting surface 621 serves the aforementioned function of preventing the sprue head from rotating, while the cavity-adhering surface 622 reduces the contact area between the anti-rotation limiting part 62 and the sprue head, making it easier for the robot arm to grip the sprue head.

[0039] In another embodiment of this application, the internal space of the mold is usually very compact, and the position and angle of the real sprue 722 are determined by the product design and the injection requirements, and are often unchangeable. The dummy sprue 723 serves as a cavity to balance the center of gravity of the sprue head. If the included angle between the dummy sprue 723 and the connecting pin 721 is equal to or greater than the included angle between the real sprue 722 and the connecting pin 721, the volume of the rear mold core 21 needs to be larger to accommodate the dummy sprue 723. This not only increases production costs but also encroaches on the space layout within the mold.

[0040] Based on this, the following settings are adopted: the angle between the true sprue 722 and the connecting needle 721 is greater than the angle between the dummy sprue 723 and the connecting needle 721. Although, intuitively, the volume of the dummy sprue 723 is smaller than that of the true sprue 722, during casting, after the molten plastic enters the connecting needle 721, part flows to the true sprue 722 and part flows to the dummy sprue 723. However, the dummy sprue 723 will be filled more quickly. After the product cavity is filled, the density of the sprue at the dummy sprue 723 is greater than that at the true sprue 722. Therefore, the center of gravity is balanced by the density difference, which can also improve the utilization rate of the internal space of the mold and reduce the production cost.

[0041] In another embodiment of this application, considering that the true sprue 722 and the dummy sprue 723 release elastic force the instant the sprue is ejected from the mold core 21, if the released elastic forces are not synchronized or asymmetrical, they will form impact torques in opposite directions, causing the sprue to twist, vibrate, or even bounce off the mold core 21 the instant it is ejected. Based on this, the following configuration is made: the length of the true sprue 722 along the axial direction of the sprue pin 6 is the same as the length of the dummy sprue 723 along the axial direction of the sprue pin 6. By ensuring that the two sprue sections have the same axial length, their elastic deformation and energy storage state during the ejection process tend to be synchronized. When the sprue leaves the mold core 21, the elastic potential energy stored in the true sprue 722 and the dummy sprue 723 is released at the same instant and on the same axis. Because they are symmetrically arranged relative to the gate pin 6, the elastic forces generated by the two are in opposite directions, which cancels out and neutralizes the two opposite torques, eliminating the phenomenon that the sprue bounces away due to uneven release of internal stress when it leaves the mold core 21.

[0042] In another embodiment of this application, the true gate portion 722 serves as a channel connecting the product cavity. If the cross-section of the true gate portion along the melt flow direction is equal, it will lead to melt pressure loss. For high-viscosity materials such as PC and POM, this can easily cause defects such as insufficient filling and air bubbles in the product cavity. To reduce melt pressure loss, the true gate portion 722 is configured to narrow away from the connecting needle portion 721. A larger cross-section is retained on the side of the true gate portion 722 near the connecting needle portion 721 to ensure sufficient melt inlet flow. The cross-section gradually narrows along the melt flow direction, forming a stable pressure boosting effect and solving the problem of insufficient filling of high-viscosity materials.

[0043] In another embodiment of this application, for products with high appearance requirements, placing the gate 72 on the outer surface would leave marks such as protrusions and depressions, greatly affecting aesthetics. Furthermore, in this embodiment, the product cavity is relatively deep. Therefore, it is necessary to connect the gate 72 to the inner side of the product, i.e., the non-outer surface. Accordingly, the gate 72 includes a supplementary connecting cavity portion 724 that connects the true gate portion 722 to the product cavity. The supplementary connecting cavity portion 724 extends towards the front mold plate 1 from the end away from the true gate portion 722, and the supplementary connecting cavity portion 724 extends in a straight line. In other embodiments, if the inner cavity of the product is shallow, the true gate portion 722 can also be curved (horn-shaped) and directly connected to the product cavity.

[0044] The connecting section 724 connects to the inner wall of the product, making the gate 72 mark less noticeable and ensuring a perfect product appearance. Furthermore, since the gate 72 is connected to the inner wall, it is generally easier to remove and trim it later. In contrast, removing the gate from the outer surface of the product requires consideration of the impact on surface quality, making the process more difficult.

[0045] In summary, the aforementioned optimizations regarding gate 72 include: the setting of the anti-rotation limiting part 62, the setting of the connecting surface 621 and the cavity surface 622, the included angle relationship and axial length relationship between the true gate part 722 and the false gate part 723, the shape of the true gate part 722, and the setting of the supplementary connecting cavity part 724. These optimized structures are usually used in combination to improve the overall performance of the mold. The overall performance of the mold should be viewed from two dimensions: one is the quality of the product produced by the mold, and the other is the ease of removing the product and the sprue during frequent use of the mold. Therefore, the aforementioned optimizations regarding gate 72 are used in combination from these two dimensions.

[0046] Since the aforementioned supplementary connecting cavity 724 is included, the location of the sprue head in the supplementary connecting cavity 724 also needs to be considered during product demolding. Therefore, the following configuration is adopted: the ejector plate 5 is connected to a sprue angled ejector 51, which slides through the rear mold core 21. The outer wall of the sprue angled ejector 51 forms part of the product cavity and a portion of the inner wall of the supplementary connecting cavity 724. During mold opening, the sprue angled ejector 51 moves away from the portion of the sprue head located in the supplementary connecting cavity 724. Thus, during the process of ejecting the product from the rear mold core 21, the sprue angled ejector 51 and the product will be offset relative to the mold opening direction, releasing the adhesion between the sprue angled ejector 51 and the product. Simultaneously, the sprue angled ejector 51 also moves away from the portion of the sprue head located in the supplementary connecting cavity 724, further releasing the adhesion between the sprue angled ejector 51 and the sprue head, thereby facilitating the subsequent removal of the product from the mold.

[0047] Since the gate screw 51 also separates the two parts of the sprue head located between the supplementary cavity 724 and the true gate 722, in order to achieve a smoother separation, the part of the gate screw 51 that mates with the supplementary cavity 724 will have a groove to provide more sufficient upward force so as to more smoothly separate the two parts of the sprue head located between the supplementary cavity 724 and the true gate 722.

[0048] After the final mold opening action is completed, on the sprue pin 6, the sprue head is located in the connecting pin part 721, the dummy sprue part 723, and the real sprue part 722. On the product, there is also a part of the sprue head located in the supplementary connecting cavity part 724. In order to facilitate the removal of the part of the sprue head located in the supplementary connecting cavity part 724 on the product, the connection between the supplementary connecting cavity part 724 and the product cavity will gradually narrow, so as to facilitate the subsequent removal of the remaining sprue head on the product.

[0049] like Figure 6 As shown, in another embodiment of this application, in order to improve the structural rigidity and bending resistance of the product, most products are provided with reinforcing ribs. Since the reinforcing ribs are thin plates, it is difficult to directly form the cavity where the reinforcing ribs are located on the rear mold core 21. In addition, the contact area between the reinforcing ribs and the rear mold core 21 is large. If the reinforcing ribs are forcibly ejected during demolding, the root of the reinforcing ribs may be broken. Based on this, the following configuration is provided: the rear mold core 21 includes a rear mold core 211 and a rear mold insert 212. The rear mold core 211 is provided with a gate 72 and is fixedly set on the rear mold plate 2. The rear mold insert 212 is fixedly inserted into the rear mold core 211, which will form a rib cavity 213 in the rear mold core 211. The cavity formed by the reinforcing ribs is formed by embedding the rear mold insert 212 into the rear mold core 211, which greatly reduces the difficulty of forming the cavity where the reinforcing ribs are located.

[0050] Meanwhile, the rear mold insert 212 is provided with an ejector guide hole 2121, and the ejector plate 5 is connected with an insert ejector pin 214. The insert ejector pin 214 slides through the ejector guide hole 2121 to directly eject the part of the product near the reinforcing rib, so as to promote demolding at the reinforcing rib. Since it acts directly near the reinforcing rib, it is less likely that other parts will demold first and the reinforcing rib will demold later, resulting in the reinforcing rib being torn off.

[0051] like Figure 7 and Figure 8 As shown, in another embodiment of this application, since the ejected product gradually cools down and tightly wraps around the molded part after cooling, for deeper holes in the product, if a regular ejector pin is used for ejection, the contact area between the ejector pin and the hole is large, and the hole exerts a strong wrapping force on the ejector pin after cooling, making it difficult for the robot to grip the product. Therefore, it is necessary to reduce the wrapping force while ensuring that the hole is ejected. The following configuration is provided: a lower fixing plate 8 is provided on the side of the ejector plate 5 away from the rear mold plate 2. The lower fixing plate 8 is fixedly set and is provided with a hole-forming insert 81, which slides through the rear mold core 21; the ejector plate 5 is provided with a hole-removing guide sleeve 52, which slides on the hole-forming insert 81 and slides through the rear mold core 21. The hole-forming pin 81 is fixedly mounted on the lower fixed plate 8. The end of the hole-forming pin 81 away from the lower fixed plate 8 is wrapped by the product, forming the inner wall of the product's hole. The hole-removing guide sleeve 52 is slidably sleeved on the hole-forming pin 81, with its end face away from the lower fixed plate 8 abutting against the product. In summary, during the ejection process, the hole-forming pin 81 remains stationary, while the hole-removing guide sleeve 52 slides out with the ejector plate 5. The hole-forming pin 81 eventually separates from the inner wall of the product's hole, avoiding the problem of excessive wrapping force after the product cools down, making it impossible to clamp.

[0052] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An injection mold, characterized in that, include: The front template (1) is provided with a front mold core (11); The rear template (2) is provided with a rear mold core (21) and a rear mold slide seat (22); A stripper plate (3) is disposed on the front side of the front template (1); The upper fixing plate (4) is disposed on the front side of the stripping plate (3); Ejector plate (5) is disposed on the rear side of the rear template (2); The sprue pin (6) is connected to the ejector plate (5) and the rear mold core (21) respectively. The end of the sprue pin (6) inserted into the rear mold core (21) is tapered and narrows towards the front mold plate (1) to form a sprue demolding part (61). The upper fixed plate (4) is provided with a main runner (7), the stripper plate (3), the front template (1), the front mold core (11) and the rear mold slide seat (22) are provided with a runner (71), the rear mold core (21) is provided with a gate (72), the main runner (7), the runner (71) and the gate (72) are connected, the gate (72) is divided into a connecting pin part (721), a true gate part (722) and a false gate part (723), the connecting pin part (721) is connected to the cavity where the gate pin (6) is located, the true gate part (722) is connected to the product cavity, and the true gate part (722) and the false gate part (723) are symmetrically and balanced relative to the connecting pin part (721).

2. The injection mold as described in claim 1, characterized in that: The sprue pin (6) is inserted into the end of the rear mold core (21) and also has an anti-rotation limiting part (62). The anti-rotation limiting part (62) is located on the side of the sprue demolding part (61) away from the sprue (72). The peripheral outer wall of the anti-rotation limiting part (62) is used to connect with the sprue head. The non-circular arc outer wall of the anti-rotation limiting part (62) is connected with the sprue head.

3. The injection mold as described in claim 2, characterized in that: The outer wall of the anti-rotation limiting part (62) has a material connecting surface (621) and a cavity-attaching surface (622). The material connecting surface (621) is used to connect with the material head, and the cavity-attaching surface (622) is used to abut against the inner wall of the chamber where the gate needle (6) is located.

4. The injection mold as described in claim 1, characterized in that: The angle between the true sprue (722) and the connecting needle (721) is greater than the angle between the false sprue (723) and the connecting needle (721).

5. An injection mold as described in claim 1, characterized in that: The length of the true gate (722) along the axial direction of the gate needle (6) is the same as the length of the false gate (723) along the axial direction of the gate needle (6).

6. The injection mold as described in claim 1, characterized in that: The true water inlet (722) is narrowed in the direction away from the connecting needle (721).

7. The injection mold as described in claim 1, characterized in that: The gate (72) also includes a supplementary connecting cavity (724) that connects the true gate (722) and the product cavity. The supplementary connecting cavity (724) extends from the end away from the true gate (722) toward the front template (1).

8. An injection mold as described in claim 7, characterized in that: The ejector plate (5) is connected to a sprue riser (51), which slides through the rear mold core (21). The outer wall of the sprue riser (51) forms the product cavity and part of the inner wall of the supplementary connecting cavity (724).

9. An injection mold as described in claim 1, characterized in that: The rear mold core (21) includes a rear mold core (211) and a rear mold insert (212). The rear mold core (211) is provided for the gate (72) and is fixedly mounted on the rear mold plate (2). The rear mold insert (212) is fixedly inserted into the rear mold core (211) to form a rib cavity (213) in the rear mold core (21). The rear mold insert (212) is provided with an ejector guide hole (2121). The ejector plate (5) is connected to an insert ejector pin (214), which slides through the ejector guide hole (2121).

10. An injection mold as described in claim 1, characterized in that: The ejector plate (5) is provided with a lower fixing plate (8) on the side away from the rear mold plate (2). The lower fixing plate (8) is fixedly installed and is provided with a hole-forming insert. The hole-forming insert slides through the rear mold core (21). The ejector plate (5) is provided with a hole-removing guide sleeve (52). The hole-removing guide sleeve (52) slides on the hole-forming insert and slides through the rear mold core (21).

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