An injection mold that prevents the product from sticking to the front mold.
By combining the front mold air ejector device and the rear mold undercut insert, the problem of products sticking to the front mold during injection molding is solved, achieving balanced demolding and a high yield rate injection mold design, supporting fully automated production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGGUAN ARRK PROD DEV LTD
- Filing Date
- 2025-07-18
- Publication Date
- 2026-07-03
AI Technical Summary
During injection molding, the product tends to stick to the front mold, leading to uneven demolding, scratches, and surface damage, which affects the product's appearance quality and yield.
By employing the synergistic effect of the front mold air ejector and the rear mold undercut pins, uniform air blowing and forced demolding by the undercut pins ensure that the product adheres preferentially to the rear mold, preventing it from sticking to the front mold and avoiding deformation during the demolding process.
It achieves balanced demolding of products, avoids smudging and deformation, improves the product appearance qualification rate, and supports fully automated production.
Smart Images
Figure CN224446748U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of injection mold technology, and more specifically, to an injection mold that can prevent products from sticking to the front mold. Background Technology
[0002] Injection molds are tools used to produce plastic products. Injection molding refers to the process of injecting molten plastic into a mold cavity under high pressure using an injection molding machine. After cooling and solidification, the molded product is obtained. During injection molding, the front mold and rear mold close to form the gating system and cavity. When the mold opens, the front mold and rear mold separate to remove the plastic product. Figure 1 and Figure 2 The injection molded product 10 shown has multiple deep cavity areas in both the front and rear molds. During injection molding, it was found that the product tends to stick to the front mold. In the initial trial molding, an air ejector device was added to the front mold to assist ejection. The product could be successfully demolded during injection molding. However, due to the limited distribution area of the air ejector, the product was unbalanced when it detached from the front mold, which caused scratches to easily appear on the product surface. This not only affected the appearance quality of the product, but may also reduce the product's pass rate due to surface damage. Utility Model Content
[0003] The purpose of this utility model is to overcome the above-mentioned defects in the prior art and provide an injection mold that can achieve balanced demolding without product dragging through the synergistic effect of front mold air ejection and rear mold undercut pins, thereby improving the product qualification rate and preventing the product from sticking to the front mold.
[0004] To achieve the above objectives, this utility model provides an injection mold that prevents the product from sticking to the front mold, including a front mold mechanism and a rear mold mechanism. The front mold mechanism includes a front ejector plate, a front mold plate, a front mold core, a hot runner needle valve assembly, and an air ejector device. The rear mold mechanism includes a rear mold plate, a rear mold core, and several undercut inserts. The front mold plate is installed at the bottom of the front ejector plate, and a sprue is provided at the sprue port on the front ejector plate. The front mold core is embedded at the bottom of the front mold plate. The hot runner needle valve assembly is installed inside the front ejector plate and communicates with the sprue. The rear mold core is embedded at the top of the rear mold plate. The front mold core and the rear mold core are positioned close together. In conjunction with each other to form a mold cavity, each needle valve-type hot nozzle of the hot runner needle valve assembly passes through the front mold plate and the front mold core and extends into the mold cavity. The air ejector device includes an air blowing pipe and an air jet nozzle. Several air blowing pipes are provided and are evenly arranged inside the front mold core. The air inlet end of the air blowing pipe passes through the side wall of the front mold core and extends out from the side wall of the front mold plate. The air outlet end of each air blowing pipe is equipped with an air jet nozzle, which faces downward and corresponds to the mold cavity. The undercut pins are evenly fixedly installed on the rear mold core. The undercut end of each undercut pin passes upward through the top surface of the rear mold core and extends into the mold cavity.
[0005] Preferably, the undercut end of the undercut pin is configured as an inverted suction cup structure, and an annular gap is provided at the connection between the rod end of the undercut pin and its undercut end, so that the undercut end of the undercut pin can be inserted into the product during product injection molding.
[0006] Preferably, the hot runner needle valve assembly includes a sprue sleeve, a hot manifold, a needle valve drive cylinder, and a valve needle. The hot manifold is embedded inside the front top plate. Several needle valve drive cylinders are provided and fixedly installed on the top of the hot manifold and located inside the front top plate. The sprue sleeve is fixedly inserted downward at the inlet of the hot manifold and its inlet end is connected to the injection nozzle. The needle valve hot nozzles are fixedly installed at the bottom of the hot manifold and correspond one-to-one with each needle valve drive cylinder. Each needle valve hot nozzle extends out of the bottom of the front top plate and through the front mold plate and the front mold core into the mold cavity. Each needle valve hot nozzle has a through valve needle channel inside. One end of each valve needle is connected to the piston rod of its corresponding needle valve drive cylinder. The valve needle extends to the sprue position of the needle valve hot nozzle.
[0007] Preferably, the upper and lower end faces of the heat distribution plate are both embedded with a first heating tube and a second heating tube arranged in a meandering manner.
[0008] Preferably, the interior of the front mold core is provided with several first cooling water channels connected to the first cooling water inlet / outlet joints on the two outer side walls of the front mold plate, and the interior of the rear mold core is provided with several second cooling water channels connected to the second cooling water inlet / outlet joints on the two outer side walls of the rear mold plate.
[0009] Preferably, the rear mold mechanism further includes a rear base plate, an ejector base plate, an ejector panel, ejector pins, square irons, and limiting posts. Two square irons are provided and are installed at intervals between the top of the rear base plate and the bottom of the rear mold plate. Several ejector pins are provided and are installed on the top of the ejector base plate through the ejector panel. The upper ends of the several ejector pins can extend into the mold core assembly after the rear mold core. The limiting posts are located between the rear base plate and the rear mold core and pass through the ejector base plate and the ejector panel respectively.
[0010] Preferably, the front top plate has a first guide shaft extending longitudinally through the front template at each of its four corners, and the rear template has a guide sleeve corresponding to the first guide shaft at each of its four corners.
[0011] Preferably, the four corners of the rear base plate are respectively provided with a second guide shaft that passes longitudinally through the ejector base plate and the ejector panel, and the four corners of the rear template are respectively provided with guide channels corresponding to the second guide shaft.
[0012] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0013] This utility model features a novel structure and reasonable design. By using the air ejector device in the front mold mechanism to blow air evenly onto the product during mold opening, and combined with the evenly distributed undercut pins in the rear mold mechanism, the product can be forced to adhere to the rear mold first, preventing the product from sticking to the front mold. After the undercut pins are forcibly demolded, they deform but do not protrude from the product surface. Its operation is reliable, solving the problems of dragging and deformation caused by the unbalanced demolding of traditional molds, significantly improving the product appearance qualification rate, and enabling fully automated production. Attached Figure Description
[0014] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0015] Figure 1 This is a front structural diagram of the product provided in the background technology of this utility model;
[0016] Figure 2 This is a schematic diagram of the back structure of the product provided in the background art of this utility model;
[0017] Figure 3 This is a schematic diagram of the structure of an injection mold that can prevent products from sticking to the front mold, provided in an embodiment of this utility model;
[0018] Figure 4 This is an exploded schematic diagram of the front mold mechanism of an injection mold that can prevent products from sticking to the front mold, provided in an embodiment of this utility model.
[0019] Figure 5 This is a partial exploded schematic diagram of the front mold mechanism of the injection mold that can prevent the product from sticking to the front mold, provided in an embodiment of this utility model.
[0020] Figure 6 This is an enlarged cross-sectional view of the hot runner needle valve assembly of the injection mold that can prevent the product from sticking to the front mold, provided in an embodiment of this utility model.
[0021] Figure 7 This is an exploded schematic diagram of the rear mold core and undercut pins of an injection mold that can prevent the product from sticking to the front mold, provided by an embodiment of this utility model.
[0022] Figure 8 This is an enlarged schematic diagram of the rear mold core and undercut pins of the injection mold that can prevent the product from sticking to the front mold, as provided in this embodiment of the utility model.
[0023] Figure 9 This is an exploded schematic diagram of the rear mold mechanism of an injection mold that can prevent the product from sticking to the front mold, provided in an embodiment of this utility model.
[0024] Figure 10 This is a cross-sectional schematic diagram of the mold closing state of the injection mold provided in this embodiment of the utility model, which can prevent the product from sticking to the front mold.
[0025] Figure 11 This is an enlarged cross-sectional view of the undercut insert of the injection mold, which prevents the product from sticking to the front mold, and the product in the mold-closed state, according to an embodiment of this utility model. Detailed Implementation
[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0027] Please refer to Figure 3 , Figure 4 and Figure 9 The present invention provides an injection mold that can prevent the product from sticking to the front mold, including a front mold mechanism 1 and a rear mold mechanism 2. The front mold mechanism 1 includes a front top plate 11, a front mold plate 12, a front mold core 13, a hot runner needle valve assembly 14, and an air ejector device 15. The rear mold mechanism 2 includes a rear mold plate 21, a rear mold core 22, and several undercut inserts 23, etc. The components of this embodiment will be described in detail below with reference to the accompanying drawings.
[0028] like Figure 4 As shown, the front mold plate 12 can be installed at the bottom of the front top plate 11. The front top plate 11 has a sprue nozzle 111 at the feed port. The front mold core 13 is embedded at the bottom of the front mold plate 12. The hot runner needle valve assembly 14 is installed in the front top plate 11 and is connected to the sprue nozzle 111. The rear mold core 22 is embedded at the top of the rear mold plate 21. The front mold core 13 and the rear mold core 22 cooperate to form a mold cavity. Each needle valve type hot nozzle 144 of the hot runner needle valve assembly 14 passes through the front mold plate 12 and the front mold core 13 and extends into the mold cavity.
[0029] Specifically, the air ejector device 15 may include an air blowing pipe 151 and an air nozzle 152. Several air blowing pipes 151 are provided and are evenly arranged inside the front mold core 13. The air inlet end of the air blowing pipe 151 passes through the side wall of the front mold core 13 and extends out from the side wall of the front template 12. An air inlet connector 120 is provided on the side wall of the front template 12 corresponding to each air blowing pipe. An air nozzle 152 is installed at the air outlet end of each air blowing pipe 151 and faces downwards corresponding to the mold cavity.
[0030] During implementation, each jet nozzle 152 is aligned with the top of the product 10. When the mold is opened, an external air supply device, such as a commercially available air compressor, can supply air through the air pipe 151 and spray gas onto the product through each jet nozzle 142 to prevent the product 10 and the front mold core 13 from generating a vacuum at the molding area, reduce the possibility of vacuum adsorption, and reduce the problem of smudging caused by the adhesion between the jet nozzle 152 and the product 10.
[0031] Preferably, the four corners of the front top plate 11 are provided with a first guide shaft 17 that passes longitudinally through the front template 12, and the four corners of the rear template 21 are provided with guide sleeves 211 corresponding to the first guide shaft 17.
[0032] The first guide shaft 17 cooperates with the guide sleeve 211 of the rear template 21 to ensure accurate positioning when the front mold mechanism and the rear mold mechanism are closed, thereby improving the mold closing accuracy.
[0033] like Figure 5 and Figure 6 As shown, the hot runner needle valve assembly 14 may include a sprue sleeve 141, a hot manifold 142, a needle valve drive cylinder 143, and a valve needle 1441. The hot manifold 142 is embedded inside the front top plate 11. Several needle valve drive cylinders 143 are provided and fixedly installed on the top of the hot manifold 142 and located inside the front top plate 11. The downward fixed insertion of the sprue sleeve 141 is placed at the inlet of the hot manifold 142 and its inlet end is connected to the glue inlet nozzle 111. The needle valve hot nozzles 1441 are respectively fixed. Installed at the bottom of the hot runner plate 142 and corresponding to each needle valve drive cylinder 143, each needle valve hot nozzle 144 extends out of the bottom of the front top plate 11 and through the front mold plate 12 and the front mold core 13 into the mold cavity. Each needle valve hot nozzle 144 has a through valve needle 1441 channel inside. One end of each valve needle 1441 is connected to the piston rod of its corresponding needle valve drive cylinder 143. The extension of the valve needle 1441 reaches the gate position of the needle valve hot nozzle 144.
[0034] In order to maintain a uniform temperature of the plastic melt, the upper and lower end faces of the heat distribution plate 142 can be embedded with a first heating tube 1421 and a second heating tube 1422 arranged in a meandering manner.
[0035] Among them, the hot runner needle valve assembly 14 controls the timing and flow rate of molten adhesive injected into the mold cavity, precisely controls the opening and closing of the gate, reduces waste and prevents drooling.
[0036] like Figure 7 As shown, the undercut pins 23 can be evenly fixedly installed on the rear mold core 22. The undercut end 231 of each undercut pin 23 passes upward through the through hole 221 opened on the top surface of the rear mold core 22 and extends into the mold cavity.
[0037] like Figure 8 As shown, the undercut end 231 of the undercut pin 23 can be configured as an inverted suction cup structure. An annular gap 230 is provided at the connection between the rod end of the undercut pin 23 and its undercut end 231. The undercut end 231 of the undercut pin 23 can be inserted into the product during product injection molding.
[0038] In this embodiment, the annular gap 230 provides space for the deformation of the undercut end 231 of the undercut pin 23 during demolding. When the mold is opened, the undercut end 231 will undergo a certain deformation as it is inserted into the product. The annular gap can accommodate this deformation, avoiding excessive compression or damage to the inside of the product when the undercut end deforms. At the same time, it ensures that the undercut will not protrude from the product surface after forced demolding, ensuring the appearance and structural quality of the product and providing a guarantee for the realization of fully automated production.
[0039] like Figure 9 As shown, the rear mold mechanism 2 may also include a rear base plate 251, an ejector base plate 261, an ejector panel 262, ejector pins 263, square iron 271, and a limiting post 281. Two square iron pieces are provided and are installed at intervals between the top of the rear base plate 251 and the bottom of the rear mold plate 21. Several ejector pins 263 are provided and are installed on the top of the ejector base plate 261 through the ejector panel 262. The upper ends of the several ejector pins 263 can extend into the mold core assembly after the rear mold core 22. The limiting post 281 is located between the rear base plate 251 and the rear mold core 22 and passes through the ejector base plate 261 and the ejector panel 262 respectively.
[0040] Furthermore, at the four corners of the rear base plate 251, a second guide shaft 291 can be provided vertically through the ejector base plate 261 and the ejector panel 262, and at the four corners of the rear template 21, a guide channel 212 corresponding to the second guide shaft 291 is provided.
[0041] The second guide shaft 291 cooperates with the guide hole 212 of the rear template 21 to ensure the accuracy of the movement of components such as the ejector base plate 261 and the ejector panel 262, and to ensure that the ejector 263 ejects smoothly and reliably.
[0042] To accelerate cooling and molding, the interior of the front mold core 13 may be provided with several first cooling water channels 16 connected to the first cooling water inlet / outlet joints on the two outer side walls of the front mold plate 12, and the interior of the rear mold core 22 may be provided with several second cooling water channels 24 connected to the second cooling water inlet / outlet joints on the two outer side walls of the rear mold plate 21.
[0043] The working principle of this utility model is as follows:
[0044] During injection molding, the molten plastic enters through the sprue 111, and is diverted by the sprue sleeve 141 and the hot runner manifold 142 of the hot runner needle valve assembly 14 to each needle valve hot nozzle 144. Under the control of the needle valve drive cylinder 143, the valve needle 1441 opens and enters the mold cavity for injection molding. After injection molding, the first cooling water channel 16 of the front mold core 13 and the second cooling water channel 24 of the rear mold core 22 cool the mold cavity, causing the molten plastic to solidify into the product 10. Simultaneously, the insert pins 2 are snapped back into place. The undercut end 231 of 3 combines with the melt during the molding process of product 10; when the mold is opened, the front mold mechanism 1 and the rear mold mechanism 2 are separated, the air blowing pipe 151 of the air ejector device 15 is connected to the external air supply device and blows air evenly to product 10 through the air nozzle 152, and each undercut insert 23 forces product 10 to attach to the rear mold first to prevent it from sticking to the front mold. Finally, the ejector pin 263 pushes product 10 out of the rear mold core 22 under the action of the ejector pin base plate 261 and the ejector pin panel 262.
[0045] In summary, this utility model uses the air ejector device of the front mold mechanism to blow air evenly onto the product during mold opening. At the same time, combined with the evenly distributed undercut pins in the rear mold mechanism, it can force the product to adhere to the rear mold first, preventing the product from sticking to the front mold. After the undercut pins are forcibly demolded, they deform but do not protrude from the product surface. Its operation is reliable, and it solves the problems of dragging and deformation caused by the unbalanced demolding of traditional molds. It significantly improves the product appearance qualification rate and can realize fully automated production.
[0046] The above embodiments are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present utility model shall be considered equivalent substitutions and shall be included within the protection scope of the present utility model.
Claims
1. An injection mold that prevents the product from sticking to the front mold, characterized in that: The system includes a front mold mechanism and a rear mold mechanism. The front mold mechanism includes a front top plate, a front mold plate, a front mold core, a hot runner needle valve assembly, and an air ejector. The rear mold mechanism includes a rear mold plate, a rear mold core, and several undercut inserts. The front mold plate is installed at the bottom of the front top plate, and a sprue nozzle is provided at the sprue port on the front top plate. The front mold core is embedded at the bottom of the front mold plate. The hot runner needle valve assembly is installed inside the front top plate and communicates with the sprue nozzle. The rear mold core is embedded at the top of the rear mold plate. The front mold core and the rear mold core cooperate to form a mold cavity. The hot runner needle valve... Each needle valve-type hot nozzle of the component passes through the front mold plate and the front mold core and extends into the mold cavity. The air ejector device includes an air blowing pipe and an air jet nozzle. Several air blowing pipes are provided and are evenly arranged inside the front mold core. The air inlet end of the air blowing pipe passes through the side wall of the front mold core and extends out from the side wall of the front mold plate. The air outlet end of each air blowing pipe is equipped with an air jet nozzle, which faces downward and corresponds to the mold cavity. The undercut pins are evenly fixed on the rear mold core. The undercut end of each undercut pin passes upward through the top surface of the rear mold core and extends into the mold cavity.
2. The injection mold capable of preventing product sticking to a front mold according to claim 1, characterized by: The inverted end of the inverted pin is configured as an inverted suction cup structure. An annular gap is provided at the connection between the rod end of the inverted pin and its inverted end. The inverted end of the inverted pin can be inserted into the product during product injection molding.
3. The injection mold capable of preventing product sticking to a front mold according to claim 1, characterized by: The hot runner needle valve assembly includes a sprue sleeve, a hot manifold, a needle valve drive cylinder, and a valve needle. The hot manifold is embedded inside the front top plate. Several needle valve drive cylinders are provided and fixedly installed on the top of the hot manifold and located inside the front top plate. The sprue sleeve is fixedly inserted downwards into the inlet of the hot manifold and its inlet end is connected to the injection nozzle. The needle valve hot nozzles are fixedly installed at the bottom of the hot manifold and correspond one-to-one with each needle valve drive cylinder. Each needle valve hot nozzle extends out of the bottom of the front top plate and through the front mold plate and the front mold core into the mold cavity. Each needle valve hot nozzle has a through valve needle channel inside. One end of each valve needle is connected to the piston rod of its corresponding needle valve drive cylinder. The valve needle extends to the sprue position of the needle valve hot nozzle.
4. The injection mold capable of preventing product sticking to a front mold according to claim 3, characterized by: The upper and lower end faces of the heat distribution plate are both embedded with a first heating tube and a second heating tube arranged in a meandering manner.
5. The injection mold capable of preventing product sticking to a front mold according to claim 1, characterized by: The interior of the front mold core is provided with several first cooling water channels connected to the first cooling water inlet and outlet joints on the two outer side walls of the front mold plate, and the interior of the rear mold core is provided with several second cooling water channels connected to the second cooling water inlet and outlet joints on the two outer side walls of the rear mold plate.
6. The injection mold capable of preventing product sticking to a front mold according to claim 1, characterized by: The rear mold mechanism also includes a rear base plate, an ejector base plate, an ejector panel, ejector pins, square irons, and limiting posts. Two square irons are provided and are installed at intervals between the top of the rear base plate and the bottom of the rear mold plate. Several ejector pins are provided and are installed on the top of the ejector base plate through the ejector panel. The upper ends of the ejector pins can extend into the mold core assembly. The limiting posts are located between the rear base plate and the rear mold core and pass through the ejector base plate and the ejector panel respectively.
7. The injection mold capable of preventing product sticking to a front mold according to claim 1, characterized by: The front top plate has a first guide shaft that extends longitudinally through the front template at each of its four corners, and the rear template has a guide sleeve corresponding to the first guide shaft at each of its four corners.
8. The injection mold capable of preventing product sticking to a front mold according to claim 6, characterized by: The four corners of the rear base plate are respectively provided with a second guide shaft that passes longitudinally through the ejector base plate and the ejector panel, and the four corners of the rear template are respectively provided with guide channels corresponding to the second guide shaft.