Strip thin part injection mold and injection molding system
By using an inverted mold structure and a relay injection method, the problems of poor consistency and excessive waste in the injection molding process of long and thin parts are solved, achieving efficient material distribution and shrinkage control, and improving the surface quality and yield of injection molded parts.
Patent Information
- Application Number
- CN202422944152.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2034-11-29
AI Technical Summary
Existing injection molding methods are difficult to effectively solve the problems of poor consistency and excessive waste in the injection molding process of long and thin sheet injection molded parts, especially for long and thin parts with a length of 1500mm-2500mm, a width of more than 300mm, and a main wall thickness of less than 3.0mm. Traditional cold gate injection leads to many injection molding defects.
The inverted mold structure is adopted, and a main injection port and multiple sequential injection ports are set on the lower mold plate. The main injection port is set in the center along the length direction, and the sequential injection ports are set on both sides along the length direction of the cavity, forming a relay injection method. An open groove transition structure is set at the main injection port, which, together with the main hot nozzle and the sequential hot nozzle, achieves uniform injection of the plastic material.
It effectively reduces the formation of gate marks and weld lines, improves the yield of injection molded products, reduces shrinkage defects, ensures balanced injection pressure in the mold cavity, and improves the surface quality and consistency of injection molded parts.
Smart Images
Figure CN223493764U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of injection molding technology, specifically relating to an injection mold and injection system for injection molding long, thin parts. Background Technology
[0002] With the increasing variety of home appliances and the improvement of consumers' aesthetic tastes, the exquisite appearance of home appliances has become an important demand. How to make the appearance of appliance casings more upscale and textured is the focus of related processing technologies. After the traditional casing of home appliances is formed, the surface still needs to undergo a spraying process. However, the spraying process has obvious disadvantages: it is expensive, cannot be recycled, and has a high scrap rate. Moreover, ordinary spraying materials contain VOCs (volatile organic compounds), benzene compounds, heavy metals, and other substances. During the operation, workers are in a toxic environment, which will also cause serious environmental pollution.
[0003] Faced with the global energy crisis, ecological degradation, and the impact of green trade barriers, green home appliances have become a new hotspot in international and domestic market competition, making "green trade" an inevitable trend. Based on this, paint-free technology has emerged. The injection molding technology upon which paint-free technology is based has advantages such as high design freedom, low cost, environmental friendliness, and recyclability. It mainly involves adding metallic powders or pearlescent powders to the injection molding material, giving the surface of the molded part a unique light and shadow effect and metallic luster, allowing the part to achieve or rival the appearance of a painted part without secondary treatment; it is superior to traditional painting processes in terms of economy, environmental protection, and even aesthetics.
[0004] However, glitter-based paint-free materials are prone to inconsistencies during injection molding, especially for long, thin sheet-like injection molded parts, such as those with a length of 1500mm-2500mm, a width greater than 300mm, and a main wall thickness of less than 3.0mm. For these products, the existing injection molding method involves a cold gate with edge-entry, but this results in a large process flow, numerous injection defects, and significant waste. Utility Model Content
[0005] The purpose of this utility model is to provide an injection mold and injection system for long, thin parts, aiming to improve the injection molding yield of long, thin parts; this utility model is achieved through the following solution.
[0006] A first aspect of this utility model provides a long, thin injection mold, comprising an upper mold plate and a lower mold plate that are joined together to form a long, thin cavity; characterized in that: a main injection port and a plurality of sequential injection ports are provided on the lower mold plate; the main injection port is centrally located on the lower mold plate along the length direction, and the plurality of sequential injection ports are arranged on both sides of the main injection port along the length direction of the cavity; the main injection port includes a sealing hole relative to the outer side of the cavity and an open groove relative to the inner side of the cavity, the narrow end of the open groove is connected to the sealing hole, and the open end faces the cavity.
[0007] The advantages of the injection mold for long, thin parts provided by the above technical solution are as follows: It adopts an inverted mold structure, meaning the injection port acts directly from the lower mold plate side onto the back side of the long, thin part (relative to the outer surface of the long, thin part). Multiple sequential injection ports are arranged along the length of the cavity on both sides of the main injection port. When the material injected from the main injection port diffuses to the corresponding sequential injection port, it continues to be injected through each sequential injection port, forming a relay injection method. Because the material injected from the main injection port has already formed a solidified layer by the time it flows to the relay sequential injection port, it can effectively reduce the formation of gate marks and weld lines. Furthermore, an open groove-shaped transition structure is provided at the main injection port to facilitate the rapid diffusion of the material injected from the main injection port.
[0008] As a preferred technical solution, the narrow end of the open groove is circular, and the open end of the open groove is elliptical; the major axis of the ellipse coincides with the length direction of the cavity, and the minor axis is perpendicular to the length direction of the cavity.
[0009] The advantages of the above-mentioned preferred solution are: it facilitates the rapid diffusion of the injected material along the length direction, which is more conducive to rapid filling than the traditional injection method and ensures the injection pressure balance of the cavity.
[0010] As a preferred technical solution, the diameter of the narrow end of the open groove is 0.9-1.15 times the thickness of the main material of the long thin strip, the minor axis of the ellipse at the open end of the open groove is 1.25-1.5 times the thickness of the main material of the long thin strip, and the major axis of the ellipse at the open end of the open groove is 1.4-1.5 times the minor axis.
[0011] The beneficial effects of the above preferred solution are as follows: Since plastic will shrink to a certain extent during the molding process, the shrinkage of adjacent areas will be different, which will lead to shrinkage. Material thickness is the fundamental reason for the different shrinkage. By configuring the above ratio, the shrinkage at the location of the open groove can be effectively reduced.
[0012] As a preferred technical solution, the main injection port and the plurality of sequential injection ports are arranged at equal intervals.
[0013] The advantages of the above-mentioned preferred solution are: it facilitates the timing control of the glue injection operation at each injection port, and the glue injection is more uniform.
[0014] As a preferred technical solution, the lower template is provided with a gradient area groove around the open groove, and the depth of the gradient area groove gradually becomes shallower from the near end to the far end of the open groove.
[0015] As a preferred technical solution, the maximum depth of the gradient area groove is 0.15-0.25 times the thickness of the main material of the product.
[0016] As a preferred technical solution, the top view projection of the gradient area groove is a rectangular area or an elliptical area, the length dimension of the rectangular area or elliptical area is 100-120mm, and the width dimension is 0.3 times the length dimension.
[0017] The advantages of the above-mentioned preferred solution are as follows: by setting a gradient area groove, the thickness of the product material in the area around the open groove during injection molding is increased, reducing the occurrence of shrinkage marks in the area around the open groove; at the same time, it can further reduce the diffusion resistance in the main injection port area.
[0018] A second aspect of this utility model provides a long, thin-part injection molding system, characterized in that it includes: a main hot nozzle, a plurality of sequential hot nozzles, and the long, thin-part injection mold described above; the lower mold plate is provided with a main hot nozzle mounting groove and a sequential hot nozzle mounting groove corresponding to the main injection port and the sequential injection port, and the main hot nozzle and the sequential hot nozzle are correspondingly assembled in the hot nozzle mounting groove.
[0019] As a preferred technical solution, both the main hot nozzle and the sequential hot nozzle are equipped with their own valve needle assemblies. The valve needle assembly includes a valve needle control mechanism and a valve needle. The valve needle control mechanism drives the valve needle to block or open the sealing hole of the main injection port and the sealing hole of each of the sequential injection ports.
[0020] As a preferred technical solution, it also includes a controller that controls the valve needle control mechanism of each valve needle assembly to drive the valve needle to block or open the sealing hole of the main injection port and the sealing hole of each of the timing injection ports.
[0021] The long, thin-part injection molding system provided by the above technical solution is based on the main injection port and multiple sequential injection ports of the long, thin-part injection mold described above. It is equipped with a main hot nozzle and multiple sequential hot nozzles. When the glue injected from the main injection port diffuses to the corresponding sequential injection ports, it is then injected sequentially through each sequential injection port, forming a relay injection method. The injection of glue into each injection port can be manually controlled according to the sequence, or it can be injected into each injection port according to the sequence through an automated valve needle assembly. Attached Figure Description
[0022] Figure 1 This is an example diagram of the long, thin product described in a specific embodiment of this utility model.
[0023] Figure 2 A longitudinal cross-sectional view of the long, thin-part injection mold and injection system provided for a specific embodiment of this utility model.
[0024] Figure 3 for Figure 2 Enlarged view of section A.
[0025] Figure 4 A schematic diagram of an open groove in a long, thin injection mold provided for a specific embodiment of this utility model.
[0026] Figure 5 An enlarged view of the open groove portion in the injection mold for a long, thin part, provided as a preferred embodiment of this utility model.
[0027] Figure 6 An oblique top view showing the distribution relationship between the hot nozzle and the long, thin part in a long, thin part injection molding system provided as a preferred embodiment of this utility model.
[0028] Figure 7 An inclined bottom view of the distribution relationship between the hot nozzle and the long thin part in a long thin part injection mold system provided for a preferred embodiment of this utility model.
[0029] Figure 8 A detailed diagram showing the distribution relationship between the main hot nozzle, the open groove, and the long, thin part in the injection molding system for a preferred embodiment of this utility model.
[0030] Figure 9 A detailed view of the back side of a long, thin part injection molded by the long, thin part injection molding system provided in the preferred embodiment of this utility model.
[0031] Explanation of icon numbers:
[0032] 200 - Long, thin strip; 201 - Exterior surface; 202 - Back side;
[0033] 10-Lower template, 11-Main injection port, 12-Sequential injection port, 111-Sealing hole, 112-Open groove, 1121-Narrow end, 1122-Open end, 113-Area groove, 31-Main hot nozzle, 32-Sequential hot nozzle, 151-Main hot nozzle mounting groove, 152-Sequential hot nozzle mounting groove, 51-Valve needle, 1125-Glue material. Detailed Implementation
[0034] The technical solutions of the present utility model embodiments will be explained and described below with reference to the accompanying drawings. However, the following embodiments are only preferred embodiments of the present utility model and not all of them. In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "front", "back", etc., indicating the orientation or positional relationship, are all based on the orientation or relative positional relationship shown in the accompanying drawings. They are intended to facilitate a clear description of the structure of the product or device and are not used to limit the actual orientation of the product or device during production, use, sales, etc.
[0035] Furthermore, the terms "first" and "second" are used only for distinguishing purposes in the description and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more, unless otherwise expressly defined.
[0036] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Under the premise that they do not conflict with each other, the technical features in each specific embodiment can be used interchangeably.
[0037] This embodiment provides an injection mold and injection system for long, thin-walled parts, used to perform injection molding of such products. The long, thin-walled part 200 refers to a product with a length of 1500mm-2500mm, a width greater than 300mm, and a main wall thickness of less than 3.0mm. See [link to documentation]. Figure 1 As shown.
[0038] like Figure 2 As shown, the long thin part injection mold provided in this embodiment includes an upper mold plate (not shown in the figure) and a lower mold plate 10. The upper mold plate and the lower mold plate 10 are joined together to form a long thin cavity. A main injection port 11 and multiple sequential injection ports 12 are opened on the lower mold plate 10. Moreover, the main injection port 11 is centrally located on the lower mold plate 10 along the length direction, and the multiple sequential injection ports 12 are arranged on both sides of the main injection port 11 along the length direction of the cavity.
[0039] This embodiment employs an inverted mold structure, meaning the injection port acts directly from the lower mold plate 10 onto the back side 202 of the long, thin product (relative to the outer surface 201 of the long, thin product, see [link]). Figure 1Multiple sequential injection ports 12 are arranged along the length of the cavity on both sides of the main injection port 11, so that when the glue injected from the main injection port 11 diffuses to the corresponding sequential injection port, it is injected through each sequential injection port 12 in succession, forming a relay injection method; because the glue injected from the main injection port 11 has formed a solidified layer when it flows to the position of the relay sequential injection port 12, it can effectively reduce the formation of gate marks and weld lines.
[0040] like Figure 3 As shown, the main injection port 11 includes a portion located relatively to the outer edge of the cavity (i.e., Figure 3 The sealing hole 111 (lower center) and the corresponding cavity (inner center) Figure 3 The open groove 112 (located near the top) has a narrow end that aligns with the sealing hole 111, with the open end facing the cavity of the mold. In this embodiment, by providing a transition structure in the form of an open groove in the main injection port 11, the adhesive injected into the main injection port 11 can be rapidly diffused.
[0041] Combination Figure 3 and Figure 4 As shown, the narrow end 1121 of the open groove 112 is circular, with a diameter similar to that of the sealing hole 111 of the main injection port; the open end 1122 of the open groove 112 is elliptical, with its major axis coinciding with the longitudinal direction of the mold cavity and its minor axis perpendicular to the longitudinal direction of the mold cavity. This facilitates the rapid diffusion of the injected material along the longitudinal direction of the main injection port 11, which is more conducive to rapid filling than traditional injection methods, while ensuring the balance of injection pressure in the cavity.
[0042] Furthermore, considering that plastics shrink during molding, differences in shrinkage between adjacent areas can lead to shrinkage, with material thickness being the fundamental cause of these differences. Therefore, this embodiment specifies the parameters of the opening groove as follows: the diameter of the narrow end of the opening groove is 0.9-1.15 times the thickness of the main material of the long, thin strip; the minor axis of the ellipse at the open end of the opening groove is 1.25-1.5 times the thickness of the main material of the long, thin strip; and the major axis of the ellipse at the open end of the opening groove is 1.4-1.5 times the minor axis. By configuring these proportions, shrinkage defects at the location of the opening groove 112 during product injection molding can be effectively reduced.
[0043] In this embodiment, there may be at least two or more sequential dispensing ports 12, which are equally spaced on both sides of the main dispensing port 11. This facilitates the timing control of the dispensing operation of each sequential dispensing port 12, and also results in more uniform dispensing.
[0044] Combination Figure 5As shown, in a preferred embodiment, a gradient area groove 113 is provided on the lower mold plate 10 around the open groove 112. The depth of the gradient area groove 113 gradually decreases from the near end to the far end of the open groove 112. The maximum depth of the gradient area groove 13 is 0.15-0.25 times the thickness of the main product material. Furthermore, the top view projection of the gradient area groove 113 is a rectangular or elliptical area, with a length dimension of 100-120 mm and a width dimension of 0.3 times the length dimension. In this preferred embodiment, by providing the gradient area groove 113, the product material thickness in the area surrounding the open groove 112 during injection molding is increased, reducing the likelihood of shrinkage marks in the area around the open groove 112. Simultaneously, the gradient area groove 113 can further reduce the diffusion resistance in the main injection port 11 area.
[0045] See also Figure 2 The embodiment shown also provides a long strip thin part injection molding system, including: a main hot nozzle 31 and a plurality of sequential hot nozzles 32, and the long strip thin part injection mold described above; the lower mold plate 10 is provided with a main hot nozzle mounting groove 151 and a sequential hot nozzle mounting groove 152 corresponding to the main injection port 11 and the sequential injection port 12, and the main hot nozzle 31 and the sequential hot nozzle 32 are respectively assembled in the main hot nozzle mounting groove 151 and the sequential hot nozzle mounting groove 152.
[0046] Furthermore, both the main hot nozzle 31 and the sequential hot nozzles 32 are equipped with their own valve needle assemblies. Each valve needle assembly includes a valve needle control mechanism and a valve needle 51. The valve needle control mechanism drives the valve needle to block or open the sealing hole of the main injection port 11 and the sealing holes of each sequential injection port 12. Additionally, the long strip thin-part injection molding system also includes a controller that controls the valve needle control mechanism of each valve needle assembly to drive the corresponding valve needle 51 to block or open the sealing hole 111 of the main injection port 11 and the sealing holes of each sequential injection port 12. The valve needle assemblies and controller are existing technologies and will not be described in detail here.
[0047] The long, thin-part injection molding system provided in this embodiment is based on the main injection port and multiple sequential injection ports of the long, thin-part injection mold described above. Correspondingly, a main hot nozzle and multiple sequential hot nozzles are configured. When the glue injected from the main injection port diffuses to the corresponding sequential injection ports, it is then injected sequentially through each sequential injection port, forming a relay injection method. The injection of glue into each injection port can be manually controlled according to the sequence, or the injection of glue into each injection port can be carried out sequentially by an automated valve needle assembly.
[0048] Combination Figure 6 and Figure 7 As shown, the main hot nozzle 31 and multiple sequential hot nozzles 32 inject glue into the mold cavity in a sequential manner in an inverted manner to form a long strip of thin part 200 with the back side facing down and the outer surface facing up.
[0049] Combination Figure 8 As shown, when the main hot nozzle 31 injects adhesive into the mold cavity, the adhesive material diffuses through the sealing hole 111 and then through the open groove 112. The open groove 112, while serving as a transition structure, also acts as a cold runner; it is connected to the product and cools down below the glass transition temperature of the adhesive material. The adhesive material 1125 at the open groove 112 can then be ejected along with the product for subsequent shearing, such as... Figure 9 As shown.
[0050] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of the first application. Therefore, any equivalent variations made in accordance with the claims of this application are still within the scope of this application.
Claims
1. A long, thin injection mold, comprising an upper mold plate and a lower mold plate that are joined together to form a long, thin cavity; characterized in that: The lower template has a main injection port and multiple sequential injection ports. The main injection port is centrally located on the lower template along its length, and the multiple sequential injection ports are located on both sides of the main injection port along the length of the cavity. The main injection port includes a sealing hole relative to the outer side of the cavity and an open groove relative to the inner side of the cavity. The narrow end of the open groove is connected to the sealing hole, and the open end faces the cavity.
2. The injection mold for long, thin parts according to claim 1, characterized in that, The narrow end of the open groove is circular, and the open end is elliptical; the major axis of the ellipse coincides with the length direction of the cavity, and the minor axis is perpendicular to the length direction of the cavity.
3. The injection mold for long, thin parts according to claim 2, characterized in that, The diameter of the narrow end of the open groove is 0.9-1.15 times the thickness of the main material of the long, thin piece; the minor axis of the ellipse at the open end of the open groove is 1.25-1.5 times the thickness of the main material of the long, thin piece; and the major axis of the ellipse at the open end of the open groove is 1.4-1.5 times the minor axis.
4. The injection mold for long, thin parts according to claim 1, characterized in that, The main injection port and the multiple sequential injection ports are arranged at equal intervals.
5. The injection mold for long, thin parts according to any one of claims 1-4, characterized in that, The lower template has a gradient area groove around the open groove, and the depth of the gradient area groove gradually decreases from the near end to the far end of the open groove.
6. The injection mold for long, thin parts according to claim 5, characterized in that, The maximum depth of the gradient area groove is 0.15-0.25 times the thickness of the main material of the product.
7. The injection mold for long, thin parts according to claim 6, characterized in that, The top view projection of the gradient area groove is a rectangular area or an elliptical area, the length dimension of the rectangular area or elliptical area is 100-120mm, and the width dimension is 0.3 times the length dimension.
8. A long strip thin part injection molding system, characterized in that, include: The mold includes a main hot nozzle, multiple sequential hot nozzles, and a long, thin-part injection mold as described in any one of claims 1-7; the lower mold plate is provided with a main hot nozzle mounting groove and a sequential hot nozzle mounting groove corresponding to the main injection port and the sequential injection port, and the main hot nozzle and the sequential hot nozzle are respectively assembled in the hot nozzle mounting groove.
9. The injection molding system for long, thin parts according to claim 8, characterized in that, Both the main hot nozzle and the sequential hot nozzle are equipped with their own valve needle assemblies. The valve needle assembly includes a valve needle control mechanism and a valve needle. The valve needle control mechanism drives the valve needle to block or open the sealing hole of the main injection port and the sealing hole of each of the sequential injection ports.
10. The injection molding system for long, thin parts according to claim 9, characterized in that, It also includes a controller that controls the valve needle control mechanism of each valve needle assembly to drive the valve needle to block or open the sealing hole of the main injection port and the sealing hole of each of the timing injection ports.