Small cavity shell mold with one mold and multiple cavities

Abstract

The utility model relates to injection mold technical field discloses a small empty open shell mold of one mould multi -cavity, including upper die seat, upper die fixed plate, lower die seat and lower die fixed plate, its setting has a set of hot runner system and a set of independent cooling system. Hot runner system includes the hot runner board that a plurality of needle valve nozzle hot runner is equipped inside, and each needle valve nozzle hot runner is communicated with an upper shell cavity and a lower shell cavity through first and second hot runner intercepting valve inserts respectively, and is controlled by hot runner control assembly to be on-off controlled. Independent cooling system includes a plurality of independent cooling water circuit, and each circuit provides independent temperature control for a group of upper and lower shell cavity area. The utility model discloses the above structure, the feeding and temperature of each cavity are controlled in cooperation, solve the technical problem that multi -cavity injection product size consistency is poor, cannot interchange, ensure that the upper and lower shell parts of output can be high-precision interchange at will, and product quality and production stability are high.

Description

Technical Field

[0001] This utility model relates to the field of injection mold technology, and in particular to a small-cavity shell mold with multiple cavities. Background Technology

[0002] Miniature circuit breakers, often simply called small circuit breakers, are terminal protection electrical devices widely used in building electrical systems. Their housings, as key structures supporting and protecting internal components, are typically mass-produced from engineering plastics using injection molding. To improve production efficiency and reduce unit costs, the industry commonly employs multi-cavity mold technology, where multiple cavities are set within a single mold, allowing multiple housing components to be produced simultaneously in a single injection molding cycle.

[0003] In the assembly process of small circuit breakers, their outer shell is usually formed by the interlocking of an upper shell and a lower shell. For automated assembly lines, if any upper shell can be perfectly matched and interchanged with any lower shell, it will greatly improve assembly efficiency and product qualification rate. However, this places extremely stringent requirements on the dimensional accuracy and consistency of the injection-molded upper and lower shell components.

[0004] In existing multi-cavity injection molding technology, ensuring consistent dimensional accuracy of parts produced from all cavities presents a significant challenge. Firstly, after molten plastic flows from the injection molding machine nozzle into the mold, it is distributed to each cavity via a complex runner system. Slight differences in runner length and resistance at different locations lead to variations in filling pressure, speed, and holding pressure, resulting in inconsistent shrinkage rates in the parts. Secondly, mold temperature has a decisive impact on the final molded dimensions and deformation of the plastic. Achieving absolute temperature uniformity across all cavity areas on a large mold plate is extremely difficult. Localized temperature differences directly cause varying cooling rates in the parts, resulting in dimensional deviations.

[0005] Therefore, when producing multi-cavity products with high precision and interchangeability requirements, existing technologies generally face the core technical challenge of poor product dimensional consistency and inability to stably achieve arbitrary interchangeability due to the inability to balance the injection molding process parameters and cooling conditions of each cavity.

[0006] Therefore, this utility model proposes a multi-cavity small-opening shell mold to overcome the shortcomings of the prior art. Utility Model Content

[0007] In view of the problems in the existing technology of small open shell molds with multiple cavities, it is difficult to accurately control the feed amount and mold temperature of each cavity during multi-cavity injection molding, resulting in poor product dimensional consistency and inability to meet high-precision interchangeability requirements. The present invention aims to provide a small open shell mold with multiple cavities with an improved structure that can effectively solve the above problems.

[0008] This utility model provides a small open shell mold with multiple cavities, including: an upper mold base, an upper mold fixing plate, a lower mold base, a lower mold fixing plate; as well as a hot runner system and an independent cooling system.

[0009] The hot runner system consists of a main runner bushing fixedly connected to the inlet end of the upper mold base, and a hot runner plate fixed between the upper mold fixing plate and the upper mold base. The hot runner plate is provided with multiple needle valve hot runners. These needle valve hot runners are connected to the main runner bushing through runner branch interfaces. Each needle valve hot runner is connected to the upper shell cavity and the lower shell cavity of the mold through a first hot runner shut-off valve insert and a second hot runner shut-off valve insert, respectively, and the whole system is controlled by a hot runner control component.

[0010] Furthermore, the independent cooling system consists of multiple independent cooling water circuits, each of which is arranged around an upper shell cavity and a lower shell cavity. Through this structural combination, independent and precise control of multi-cavity products in the two key stages of feeding and cooling is achieved.

[0011] Preferably, a small open-circuit shell core insert for molding the internal structure of the small open-circuit shell is fixedly installed on the lower mold fixing plate by a core insert fixing block.

[0012] Preferably, the mold further includes guide pillars, guide sleeves, and positioning pins. The guide pillars are vertically fixed to the lower mold base, and the guide sleeves are opened on the upper mold base and correspond to the position of the guide pillars. A sliding fit is formed between the guide pillars and the guide sleeves. The positioning pins are inserted between the upper mold base and the lower mold base.

[0013] Preferably, the mold further includes fixing screws, lower mold support columns, and mold opening limit pins. The fixing screws pass through the upper mold base and the upper mold fixing plate and fasten them together. The two ends of the lower mold support column abut against the lower mold base and the lower mold fixing plate, respectively. The mold opening limit pins are installed on the upper mold base or the lower mold base.

[0014] Preferably, the mold further includes an ejection system, which includes an ejector rod, a push rod, a guide rod, a reset rod, and a spring post. One end of the ejector rod is connected to the push rod via a transmission mechanism. The push rod slides under the guidance of the guide rod. The reset rod drives the ejection system to reset under the action of the mold closing force. The spring post provides elastic assistance for the reset action of the reset rod.

[0015] Preferably, the mold further includes a panel, which is fixedly connected to the side of the upper mold base away from the lower mold base.

[0016] Preferably, the hot runner system further includes a hot runner component fixing plate and a hot runner insert rotation positioning component. The hot runner component fixing plate is used to stabilize the relevant components of the hot runner plate, and the hot runner insert rotation positioning component is used to ensure the accurate positioning of the first and second hot runner shut-off valve inserts.

[0017] Preferably, the sealing surface and the mutual friction surface in contact with the molten material in the upper mold fixing plate and the lower mold fixing plate are made of 8407 steel, and a chromium nitride coating is provided on the sealing surface and the mutual friction surface.

[0018] This utility model has the following beneficial effects:

[0019] 1. In this utility model, by setting up a needle valve type hot runner system and cooperating with an independent cooling water circuit, the problem of the inability to independently and accurately control the feeding and temperature of each cavity during multi-cavity injection molding is solved, resulting in poor product size consistency and severe deformation. This achieves precise control of the molding process of each product, thereby ensuring that the upper and lower shells produced by the eight cavities can be interchanged with high precision.

[0020] 2. In this utility model, by using high-temperature resistant and high-strength mold steel on the key friction surfaces and sealing surfaces of the mold, and adding a chromium nitride wear-resistant coating, the problem of easy wear and high-temperature insertion damage on the key process surfaces of existing molds during long-term injection molding of high-wear and high-temperature materials such as glass fiber is solved. This achieves a significant enhancement of the mold's high-temperature resistance and friction resistance, extends the service life of the mold under high load and high-temperature conditions, and ensures long-term stable production. Attached Figure Description

[0021] Figure 1 This is a three-dimensional schematic diagram of a multi-cavity small-opening shell mold proposed in this utility model;

[0022] Figure 2 This is a schematic diagram of the fixing screws for a multi-cavity small-opening outer shell mold proposed in this utility model;

[0023] Figure 3 This is a schematic diagram of the upper mold base of the multi-cavity small-opening shell mold proposed in this utility model.

[0024] Legend:

[0025] 1. Panel; 2. Upper mold base; 3. Upper mold fixing plate; 4. Hot runner plate; 5. Lower mold fixing plate; 6. Lower mold base; 7. Main runner bushing; 8. Runner branch interface; 9. Hot runner control component; 10. Hot runner component fixing plate; 11. Hot runner insert rotation positioning component; 12. First hot runner shut-off valve insert; 13. Second hot runner shut-off valve insert; 14. Guide post; 15. Guide sleeve; 16. Fixing screw; 17. Positioning pin; 18. Lower mold support post; 19. Mold opening limit pin; 20. Small open-end shell core insert; 21. Core insert fixing block; 22. Ejector rod; 23. Ejector rod; 24. Guide rod; 25. Reset rod; 26. Spring post. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions in 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 a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0027] Example:

[0028] Please refer to Figures 1 to 3 This utility model provides a small-cavity shell mold with multiple cavities, which aims to solve the problem in the prior art that the inability to independently and accurately control the temperature and materials of multiple cavities leads to poor product size consistency and the inability to meet arbitrary interchange requirements.

[0029] like Figure 1 As shown, the multi-cavity small-hole shell mold includes an upper mold base 2, an upper mold fixing plate 3 fixedly connected to the upper mold base 2, and a lower mold base 6 that can be opened and closed and fitted to the upper mold base 2. The lower mold fixing plate 5 is fixedly connected to the lower mold base 6. The upper mold fixing plate 3 and the lower mold fixing plate 5 together define multiple upper shell cavities for molding the upper shell of the small-hole shell and multiple lower shell cavities for molding the lower shell of the small-hole shell. The core innovation of this mold is that it includes a set of precisely fitted hot runner system and an independent cooling system.

[0030] The hot runner system is disclosed in detail as follows: It includes a main runner bushing 7 fixedly connected to the inlet end of the upper mold base 2, and a hot runner plate 4 fixed between the upper mold fixing plate 3 and the upper mold base 2. The hot runner plate 4 is provided with multiple needle valve hot runners. These needle valve hot runners are connected to the main runner bushing 7 through the runner branch interface 8. In order to achieve precise control of each cavity, each needle valve hot runner is connected to an upper shell cavity and a lower shell cavity respectively through a first hot runner shut-off valve insert 12 and a second hot runner shut-off valve insert 13. The on / off action of all the first hot runner shut-off valve inserts 12 and the second hot runner shut-off valve inserts 13 is electrically connected and uniformly coordinated and controlled by a hot runner control component 9.

[0031] The independent cooling system is disclosed in detail as follows: The system includes multiple independent cooling water circuits. Its key structure is that each cooling water circuit is set around an upper shell cavity and a lower shell cavity, thereby forming multiple mutually isolated temperature control units.

[0032] To solve the above-mentioned technical problems, the core of the technical solution of this embodiment lies in the structural design of the product molding area, especially the high-precision and high-stability splicing and fixing structure formed between the small open shell core insert 20 and the lower mold fixing plate 5 through the core insert fixing block 21.

[0033] Please refer to the following carefully. Figure 1 and Figure 3 The core molding structure will be described in detail below:

[0034] The lower mold fixing plate 5 serves as the core support platform on the lower mold side. Multiple small-hole shell core inserts 20, used to complete the predetermined internal structure of the small-hole shell, are fixedly mounted on its upper surface via core insert fixing blocks 21. These small-hole shell core inserts 20 are protruding structures precisely machined according to the internal contour of the small-hole shell. The core insert fixing blocks 21 are block-shaped parts with corresponding mounting grooves, used to firmly clamp and position the small-hole shell core inserts 20. In the assembled state, the base of the small-hole shell core insert 20 is embedded in the core insert fixing block 21, and then the core insert fixing block 21 is used to fix the entire assembly to the lower mold fixing plate 5. This interlocking connection method ensures the accuracy of the positional relationship between the various core inserts and facilitates the assembly of individual core inserts. Each core insert is processed, repaired, or replaced. When the mold is closed, each small open-end shell core insert 20 will be precisely inserted into the corresponding upper shell cavity or lower shell cavity on the upper mold fixing plate 3. The gap formed between its outer surface and the inner wall of the cavity is the product space for the molten material to be filled and solidified. This structure ensures that all small open-end upper and lower shells produced in the end have a high degree of consistency in wall thickness and dimensional accuracy. In order to cope with the wear of the mold when PA6+20%GF material is produced at high temperature, the upper mold fixing plate 3 and the lower mold fixing plate 5, which constitute the sealing surface and the mutual friction surface, as well as the small open-end shell core insert 20 that directly contacts the molten material, are all made of 8407 steel and further coated with a layer of chromium nitride.

[0035] Based on the above embodiments, the present invention may further include the following preferred technical solutions:

[0036] As a preferred embodiment, to ensure precise alignment during the opening and closing of the upper and lower molds, the mold is provided with guide pillars 14, guide sleeves 15, and positioning pins 17. The guide pillars 14 are vertically fixed to the lower mold base 6, and the guide sleeves 15 are opened on the upper mold base 2 and correspond to the position of the guide pillars 14. The guide pillars 14 and guide sleeves 15 form a sliding fit, and the positioning pins 17 are inserted between the upper mold base 2 and the lower mold base 6 to achieve the final precise positioning of the mold closing.

[0037] As another preferred embodiment, in order to enhance the overall rigidity of the mold and ensure operational safety, the mold also includes fixing screws 16, lower mold support columns 18, and mold opening limit pins 19. The fixing screws 16 pass through the upper mold base 2 and the upper mold fixing plate 3, firmly connecting the two together. The two ends of the lower mold support column 18 abut against the lower mold base 6 and the lower mold fixing plate 5 respectively, to support the lower mold structure and prevent it from deforming under injection pressure. The mold opening limit pins 19 are installed on the upper mold base 2 or the lower mold base 6 to limit the maximum mold opening stroke of the mold.

[0038] Furthermore, the mold is equipped with a complete ejection system, which includes an ejector rod 22, an ejector pin 23, a guide rod 24, a reset rod 25, and a spring column 26. One end of the ejector rod 22 is connected to the ejector pin 23 for transmission. The ejection action of the ejector pin 23 is kept smooth by the guide rod 24. The reset rod 25 drives the entire ejection system to return to the initial position under the action of the mold closing force. The spring column 26 provides elastic assistance for the reset action of the reset rod 25.

[0039] In addition, to facilitate the installation and connection of the entire mold with the injection molding machine, the mold also includes a panel 1, which is fixedly connected to the side of the upper mold base 2 away from the lower mold base 6.

[0040] To further ensure the operational stability of the hot runner system, the hot runner system also includes a hot runner component fixing plate 10 and a hot runner insert rotation positioning component 11. The hot runner component fixing plate 10 abuts against and limits the position of relevant components inside the hot runner plate 4. The hot runner insert rotation positioning component 11 cooperates with the body of the first hot runner shut-off valve insert 12 and the second hot runner shut-off valve insert 13 to prevent them from rotating and shifting during operation.

[0041] Working principle: At the start of injection molding production, the mold first performs the mold closing action. During the closing process of the upper mold base 2 and the lower mold base 6, the guide post 14 and the guide sleeve 15 first slide to achieve the initial centering and guidance of the upper and lower molds. At the end of the mold closing, the positioning pin 17 is further precisely inserted between the upper mold base 2 and the lower mold base 6 to complete the final precision positioning.

[0042] After the mold is closed, the molten PA6+20%GF material is injected into the main runner bushing 7 by the injection molding machine through the panel 1 fixed to the upper mold base 2. Then, it is diverted to the multiple needle valve hot runners inside the hot runner plate 4 through the runner branch interface 8. At this time, the hot runner control component 9 issues a command to precisely control the opening timing and stroke of the first hot runner shut-off valve insert 12 and the second hot runner shut-off valve insert 13, so that the molten material can be injected independently and quantitatively into each upper shell cavity and lower shell cavity until it completely fills the product space defined by the inner wall of the cavity and the small open shell core insert 20.

[0043] During the pressure holding and cooling stages, an independent cooling system begins to operate. Each independent cooling water circuit performs high-precision temperature control on a corresponding set of upper and lower shell cavity areas, ensuring that the eight products are cooled and solidified under almost identical temperature conditions, thereby maximizing dimensional consistency and effectively controlling product deformation.

[0044] After cooling, the mold performs the mold opening action, and the upper mold base 2 and the lower mold base 6 separate to the safe distance defined by the mold opening limit pin 19. Then, the ejection mechanism of the injection molding machine drives the ejector rod 22, and the ejector rod 22 drives the ejector rod 23 to move forward under the smooth guidance of the guide rod 24, ejecting the already formed small open shell upper shell and lower shell from their respective small open shell core inserts 20 for demolding.

[0045] After the product is removed, during the next mold closing process, the reset rod 25 is subjected to the mold closing force, which drives the entire ejection system to retract to the initial position. During this process, the spring column 26 provides springback assistance for the reset action of the reset rod 25, thus completing a complete work cycle.

[0046] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A multi-cavity small-opening shell mold, comprising: Upper mold base (2), upper mold fixing plate (3) fixedly connected to the upper mold base (2), and lower mold base (6) which can be opened and closed and fitted to the upper mold base (2), and lower mold fixing plate (5) fixedly connected to the lower mold base (6); The upper mold fixing plate (3) and the lower mold fixing plate (5) define a plurality of upper shell cavities for forming the upper shell of the small open space and a plurality of lower shell cavities for forming the lower shell of the small open space. Its features are, The mold also includes a hot runner system and an independent cooling system; The hot runner system includes: a main runner bushing (7) fixedly connected to the inlet end of the upper mold base (2), and a hot runner plate (4) fixed between the upper mold fixing plate (3) and the upper mold base (2); the hot runner plate (4) is provided with a plurality of needle valve hot runners that are connected to the main runner bushing (7) through a runner branch interface (8), and each needle valve hot runner is connected to an upper shell cavity and a lower shell cavity respectively through a first hot runner shut-off valve insert (12) and a second hot runner shut-off valve insert (13), and is electrically connected and controlled by a hot runner control component (9); The independent cooling system includes multiple independent cooling water circuits, each of which is arranged around one of the upper shell cavities and one of the lower shell cavities.

2. The multi-cavity small-opening shell mold according to claim 1, characterized in that, The lower mold fixing plate (5) is fixedly installed with a small open-end shell core insert (20) for forming the internal structure of the small open-end shell through a core insert fixing block (21).

3. The multi-cavity small-opening shell mold according to claim 1, characterized in that, It also includes a guide post (14), a guide sleeve (15) and a positioning pin (17). The guide post (14) is vertically fixed to the lower mold base (6). The guide sleeve (15) is opened on the upper mold base (2) and corresponds to the position of the guide post (14). The guide post (14) and the guide sleeve (15) are slidably engaged. The positioning pin (17) is inserted between the upper mold base (2) and the lower mold base (6).

4. The multi-cavity small-opening shell mold according to claim 1, characterized in that, It also includes a fixing screw (16), a lower mold support column (18), and a mold opening limit pin (19). The fixing screw (16) passes through the upper mold base (2) and the upper mold fixing plate (3) and fastens them together. The two ends of the lower mold support column (18) abut against the lower mold base (6) and the lower mold fixing plate (5) respectively. The mold opening limit pin (19) is installed on the upper mold base (2) or the lower mold base (6).

5. The multi-cavity small-opening shell mold according to claim 1, characterized in that, It also includes an ejection system, which includes an ejector rod (22), an ejector rod (23), a guide rod (24), a reset rod (25), and a spring column (26). One end of the ejector rod (22) is connected to the ejector rod (23) in a transmission manner. The ejector rod (23) slides under the guidance of the guide rod (24). The reset rod (25) drives the ejection system to reset under the action of the mold closing force. The spring column (26) provides elastic assistance for the reset action of the reset rod (25).

6. The multi-cavity small-opening shell mold according to claim 1, characterized in that, It also includes a panel (1) which is fixedly connected to the side of the upper mold base (2) away from the lower mold base (6).

7. The multi-cavity small-opening shell mold according to claim 1, characterized in that, The hot runner system also includes a hot runner component fixing plate (10) and a hot runner insert rotation positioning component (11). The hot runner component fixing plate (10) is used to stabilize the relevant components of the hot runner plate (4), and the hot runner insert rotation positioning component (11) is used to ensure the accurate positioning of the first hot runner shut-off valve insert (12) and the second hot runner shut-off valve insert (13).

8. The multi-cavity small-opening shell mold according to claim 1, characterized in that, The sealing surface and the mutual friction surface in contact with the molten material of the upper mold fixing plate (3) and the lower mold fixing plate (5) are made of steel, and a chromium nitride coating is provided on the sealing surface and the mutual friction surface.

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