Mold for injection molding product
By designing the cavity gate as a bottom-side injection gate and combining it with runners and vents, the appearance and bubble problems in gel injection molding were solved, improving product quality and yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-03
- Publication Date
- 2026-03-31
AI Technical Summary
Existing gel injection molding processes suffer from problems such as rough surface, obvious wrinkles or CD patterns, and numerous small air bubbles, which affect the airtightness and functional stability of light distribution network products.
The cavity gate is optimized to be located on the ground side of the injection cavity. The ground side injection method is adopted. Combined with the design of injection runner and vent hole, it ensures that the melt enters the cavity smoothly and exhausts the air, avoiding appearance defects and bubble formation caused by the cooling of cold material.
It effectively improves the appearance quality of gel injection molded products, reduces CD lines and wrinkles, lowers the frequency of internal air bubbles, and increases product yield to over 85%.
Smart Images
Figure CN224060332U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of injection mold technology, and in particular to a mold for injection molded products. Background Technology
[0002] Injection molded products, such as gels, are typically produced by injection molding using a mold, followed by ejection from the mold after cooling, thus obtaining the injection molded product.
[0003] After injection molding, gel exhibits strong toughness and a hardness as low as 3-5 Shore A, providing excellent sealing and waterproofing after extrusion. It also maintains stable performance under both high and low temperature conditions, meeting the needs of various complex scenarios. Furthermore, in terms of chemical stability, this type of product is unaffected by acids, alkalis, solvents, or other environmental factors, exhibiting extremely high chemical stability. This allows it to maintain its performance even in harsh chemical environments. Therefore, its application in the Optical Distribution Network (ODN) industry is becoming increasingly widespread. For example, in fiber optic splice boxes, gel products serve as a sealing structure, providing excellent sealing and waterproofing after extrusion.
[0004] In injection molding, the distinction between the top and bottom sides is based on the mold's placement on the injection molding machine. When the mold is mounted, the upper side is the top side, and the lower side is the bottom side. The side where the operator works is called the operating side, and the other side, the side away from the operator, is called the non-operating side or the side away from the operator. Currently used molds, when performing gel injection molding, are operated from the operator's right side. Specifically, for example... Figure 1 and Figure 2 As shown, the existing mold includes a front mold core and a rear mold core. The front mold core has an interconnected melt injection port and a cavity gate. The molten gel fluid (referred to as melt) is injected into the cavity from the operator's right side through the melt injection port and the cavity gate. Since the cavity gate is located in the middle of the injection molded product, at the beginning of injection, the melt at the front end of the gate will fall onto the lower rear side wall or bottom of the cavity under the action of gravity and cool first. It cannot fuse well with the melt injected later, resulting in quality problems such as rough appearance, wrinkles, or obvious CD patterns. At the same time, the melt will fall during injection, and the gas in the cavity is easily trapped and difficult to escape, resulting in more small air bubbles inside the molded product.
[0005] It is evident that current gel injection molding processes exhibit quality issues such as rough surfaces, wrinkles, or noticeable CD patterns, and are prone to the formation of dense small air bubbles internally, resulting in a yield rate of only around 55%. These quality problems affect the airtightness of the entire optical distribution network, ultimately determining whether the product malfunctions. Summary of the Invention
[0006] This application provides a mold for injection molded products to solve the quality problems existing in gel injection molding in related technologies.
[0007] This application provides a mold for injection molding products, comprising:
[0008] Preform kernel;
[0009] A rear mold core, which docks with the front mold core to form an injection cavity between the rear mold core and the front mold core;
[0010] The injection runner is connected to the injection cavity, and the cavity gate formed by the connection between the injection runner and the injection cavity is located on the ground side of the injection cavity. The mold is also provided with a first vent hole connected to the injection cavity.
[0011] In this application, the cavity gate is optimized so that it is located on the ground side of the injection cavity. That is, when the mold is placed on the injection molding machine, the cavity gate is on the ground side of the mold. Compared with the prior art where the melt falls, in this application, the melt enters from the ground side during actual injection and then enters the injection cavity. The melt gradually accumulates layer by layer, which can effectively expel the air in the injection cavity and makes it less likely for bubbles to appear after the product is formed.
[0012] By using side injection, the area around the mold cavity gate is filled with melt from the beginning. The melt adheres tightly to the surface of the injection cavity. After the melt around the mold cavity gate cools and solidifies, it is less likely to form CD marks when more melt is injected. This effectively improves quality problems such as rough appearance, wrinkles, or obvious CD marks.
[0013] In some embodiments, the cavity gate is connected to the sidewall of the injection runner;
[0014] Along the flow direction of the melt in the injection runner, the end of the injection runner located downstream of the cavity gate is the first end, and the portion of the injection runner located between the cavity gate and the first end forms a cold slug well.
[0015] In some embodiments, the mold is further provided with a second vent hole communicating with the cold sluice well.
[0016] In some embodiments, the mold is further provided with a melt injection port, which is connected to the side wall of the injection runner;
[0017] Along the flow direction of the melt in the injection runner, the end upstream of the melt injection port of the injection runner is the second end, and the portion of the injection runner between the melt injection port and the second end forms a cold slug well.
[0018] In some embodiments, the mold is further provided with a second vent hole communicating with the cold sluice well.
[0019] In some embodiments, the second vent hole is disposed on the rear mold core;
[0020] And / or, the second vent is provided on the front mold core.
[0021] In some embodiments, a first groove is formed on the rear mold core to form the injection runner;
[0022] Alternatively, a second groove may be provided on the front mold core to form the injection flow channel;
[0023] Alternatively, a first groove is provided on the rear mold core, and a second groove is provided on the front mold core, with the first groove and the second groove engaging to form the injection flow channel.
[0024] In some embodiments, the mold is further provided with a melt injection port, which is connected to the injection runner and is located on the rear mold core or on the front mold core.
[0025] In some embodiments, the cross-section of the cavity gate gradually increases along the flow direction of the melt in the cavity gate.
[0026] In some embodiments, the rear mold core is provided with ejector pin holes for mounting ejector pins.
[0027] The beneficial effects of the technical solution provided in this application include:
[0028] In this application, the cavity gate is optimized so that it is located on the ground side of the injection cavity. That is, when the mold is placed on the injection molding machine, the cavity gate is on the ground side of the mold. Compared with the prior art where the melt falls, in this application, the melt enters from the ground side during actual injection and then enters the injection cavity. The melt gradually accumulates layer by layer, which can effectively expel the air in the injection cavity and makes it less likely for bubbles to appear after the product is formed.
[0029] By using side injection, the area around the mold cavity gate is filled with melt from the beginning. The melt adheres tightly to the surface of the injection cavity. After the melt around the mold cavity gate cools and solidifies, it is less likely to form CD marks when more melt is injected. This effectively improves quality problems such as rough appearance, wrinkles, or obvious CD marks. Attached Figure Description
[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.
[0031] Figure 1 This is a schematic diagram of a mold in the prior art;
[0032] Figure 2 This is a schematic diagram of the rear mold core in the prior art;
[0033] Figure 3 A schematic diagram of the mold provided in the embodiments of this application;
[0034] Figure 4 A schematic diagram of the front mold core provided in the embodiments of this application;
[0035] Figure 5 A schematic diagram of the rear mold core provided in an embodiment of this application;
[0036] Figure 6 This is a schematic diagram of the rear mold core provided in an embodiment of this application.
[0037] In the diagram: 1. Front mold core; 2. Rear mold core; 3. Injection cavity; 4. Injection runner; 5. Cavity gate; 6. Cold slug well; 7. Second vent; 8. Melt inlet; 9. Ejector pin hole; 10. Injection molded product. Detailed Implementation
[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0039] See Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, this application provides a mold for injection molding products, which includes a front mold core 1, a rear mold core 2, and an injection runner 4. The rear mold core 2 is connected to the front mold core 1 to form an injection cavity 3 between the rear mold core 2 and the front mold core 1. After the injection cavity 3 is filled with melt and cooled, an injection molded product 10, such as a gel product, can be formed. The injection runner 4 is connected to the injection cavity 3, and the cavity gate 5 formed by the connection between the injection runner 4 and the injection cavity 3 is located on the ground side of the injection cavity 3. The mold is also provided with a first vent hole that is connected to the injection cavity 3.
[0040] In this application, the cavity gate 5 is optimized so that it is located on the ground side of the injection cavity 3. That is, when the mold is placed on the injection molding machine, the cavity gate 5 is on the ground side of the mold. Compared with the prior art where the melt falls, in this application, the melt enters from the ground side during actual injection and then enters the injection cavity 3. The melt gradually accumulates layer by layer upwards (low-pressure and low-speed process conditions can be used during injection), which can effectively expel air from the injection cavity 3 and makes it less likely for air bubbles to appear after the product is formed.
[0041] By using side injection, the area around the mold cavity gate is filled with melt from the beginning. The melt adheres tightly to the surface of the injection cavity. After the melt around the mold cavity gate cools and solidifies, it is less likely to form CD marks when more melt is injected. This effectively improves quality problems such as rough appearance, wrinkles, or obvious CD marks.
[0042] When the melt flows within the injection runner 4, the melt at the front end tends to cool first, forming cold material. This cold material entering the injection cavity 3 can easily cause surface defects. To solve this problem, see [link to relevant documentation]. Figure 5 As shown, along the flow direction of the melt in the injection runner 4 (indicated by the dashed arrow), the injection runner 4 has two ends, namely a first end and a second end. The first end is located downstream of the second end. The cavity gate 5 is connected to the side wall of the injection runner 4, not to the end. Along the flow direction of the melt in the injection runner 4, the end of the injection runner 4 located downstream of the cavity gate 5 is the first end. The portion of the injection runner 4 between the cavity gate 5 and the first end forms a cold slug well 6. The function of the cold slug well 6 is to collect the cold material at the front end during the melt flow process, preventing the cold material from entering the injection cavity and causing appearance problems.
[0043] Furthermore, since the injection runner 4 is filled with gas before injection, this gas is pushed into the injection cavity 3 during the melt flow. When cold material is collected in the cold slug well 6, if it is not discharged in time, it will reduce the effectiveness of the cold slug well 6 in collecting cold material because it occupies the space of the cold slug well 6. To solve this problem, see [link to relevant documentation]. Figure 5As shown, the mold is also provided with a second vent 7 that communicates with the cold material well 6, through which gas is discharged in a timely manner.
[0044] Combination Figure 4 and Figure 5 As shown, the mold is also provided with a melt injection port 8, which is connected to the side wall of the injection runner 4; along the flow direction of the melt in the injection runner 4, the end of the injection runner 4 located upstream of the melt injection port is the second end, and the part of the injection runner 4 located between the melt injection port 8 and the second end forms a cold slug well 6. The mold is also provided with a second vent 7 connected to the cold slug well 6.
[0045] It is understood that the second vent hole 7 can be provided on the rear mold core 2, the second vent hole 7 can also be provided on the front mold core 1, or the second vent hole 7 can be provided on both the rear mold core 2 and the front mold core 1.
[0046] Similarly, the first vent hole can be provided on the rear mold core 2, or on the front mold core 1, or both the rear mold core 2 and the front mold core 1 can be provided with the first vent hole.
[0047] Since the vent is for venting air, both the first vent and the second vent 7 can be designed with very small diameters so that air can pass through easily while the melt cannot. For example, the diameter can be as small as 0.015 mm.
[0048] Of course, the first and second vent holes 7 mentioned above can be grooves dug directly on the mold, with a groove depth of only 0.015mm.
[0049] In this application, the injection runner 4 can be formed in various ways. For example, as an example, a first groove is provided on the rear mold core 2 to form the injection runner 4; or, a second groove is provided on the front mold core 1 to form the injection runner 4; or, a first groove is provided on the rear mold core 2, a second groove is provided on the front mold core 1, and the first groove and the second groove are connected to form the injection runner 4.
[0050] The shape of the injection runner 4 can vary greatly. For example, as an example, it can be selected as... Figure 5 The shape can be U-shaped, C-shaped, or straight, etc.
[0051] In this application, the mold is further provided with a melt injection port 8, which is connected to the injection channel 4. The melt injection port 8 can be formed in various ways. For example, the melt injection port 8 is located on the rear mold core 2, or the melt injection port 8 is located on the front mold core 1.
[0052] In this application, the cross-section of the cavity gate 5 gradually increases along the flow direction of the melt in the cavity gate 5. That is, the size of the cavity gate 5 gradually increases from the injection runner 4 side towards the injection cavity 3 side, so that the cavity gate 5 is like a trumpet. The advantage of this design is that it facilitates the entry of the melt into the cavity and reduces the injection pressure.
[0053] See Figure 5 As shown, the rear mold core 2 is provided with ejector pin holes 9 for mounting ejector pins. After the product is molded, the ejection system located on the back operating side of the injection molding machine ejects the product out of the injection cavity 3 through the ejector pins.
[0054] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and 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, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.
[0055] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0056] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A mold for injection-molding a product, characterized in that, It comprises: a front half (1); a back half (2) which is butted against the front half (1) to form an injection molding cavity (3) between the back half (2) and the front half (1); an injection flow channel (4) which is in communication with the injection molding cavity (3), and a cavity gate (5) formed by the connection of the injection flow channel (4) and the injection molding cavity (3) is located at the land side of the injection molding cavity (3), and the mold is further provided with a first vent hole which is in communication with the injection molding cavity (3).
2. The mold for injection molding products according to claim 1, wherein: the cavity gate (5) is in communication with the side wall of the injection flow channel (4); along the flow direction of the melt in the injection flow channel (4), one end of the two ends of the injection flow channel (4) which is downstream of the cavity gate (5) is a first end, and the part of the injection flow channel (4) between the cavity gate (5) and the first end forms a cold well (6).
3. The mold for injection molding products according to claim 2, wherein: the mold is further provided with a second vent hole (7) which is in communication with the cold well (6).
4. The mold for injection molding products according to claim 1, wherein: the mold is further provided with a melt inlet (8) which is in communication with the side wall of the injection flow channel (4); along the flow direction of the melt in the injection flow channel (4), one end of the two ends of the injection flow channel (4) which is upstream of the melt inlet (8) is a second end, and the part of the injection flow channel (4) between the melt inlet (8) and the second end forms a cold well (6).
5. The mold for injection molding products according to claim 4, wherein: the mold is further provided with a second vent hole (7) which is in communication with the cold well (6).
6. The mold for injection molding products according to claim 3 or 5, wherein: the second vent hole (7) is provided on the back half (2); and / or, the second vent hole (7) is provided on the front half (1).
7. The mold for injection molding products according to claim 1, wherein: a first groove is provided on the back half (2) to form the injection flow channel (4); or, a second groove is provided on the front half (1) to form the injection flow channel (4); or, a first groove is provided on the back half (2) and a second groove is provided on the front half (1), and the first groove and the second groove are butted against each other to form the injection flow channel (4).
8. The mold for injection molding products according to claim 1, wherein: the mold is further provided with a melt inlet (8) which is in communication with the injection flow channel (4), and the melt inlet (8) is located on the back half (2) or the melt inlet (8) is located on the front half (1).
9. The mold for injection molding products according to claim 1, wherein: The cross section of the cavity gate (5) increases gradually along the flow direction of the melt in the cavity gate (5).
10. The mold for injection-molded products according to claim 1, characterized in that: The back mold core (2) is provided with a knockout pin hole (9) for mounting a knockout pin.