Double-color mold without art line sealing glue

Abstract

The utility model provides a double-color mould without art line sealing glue, which comprises a first injection module and a second injection module, the second injection module comprises a second injection front mould core and a second injection rear mould core which are arranged in a mutually opening and closing manner, and the second injection front mould core and the second injection rear mould core are encircled to form a second injection accommodating cavity; a first injection product formed by injection molding of the first injection module and an injection product composed of a second injection product closely attached to and surrounding the first injection product are arranged in the second injection containing cavity, and a second injection insert extending into the second injection containing cavity is arranged on the second injection front mold core; the bottom of the second-injection insert is provided with an inward concave cavity and a pressing edge arranged around the cavity, and the pressing edge is in smooth transition connection with the inner wall of the second-injection front mold core; by means of pre-pressing sealing of the insert, burrs and indentations are eliminated, appearance flaws caused by an art designing groove are avoided, the surface of a product is smoother, lines are smoother, plastic melt is effectively prevented from overflowing by accurately controlling the pre-pressing height and the glue sealing width, the reject ratio of the burrs, glue leakage and the like is remarkably reduced, and the reliability and the production efficiency of the mold are improved.

Description

Technical Field

[0001] This utility model belongs to the field of two-color injection molds, specifically relating to a two-color mold that does not require sealing with decorative lines. Background Technology

[0002] Traditional techniques typically achieve sealing by adding a decorative groove at the junction of the first and second injection molding processes to conceal defects such as burrs and runoff caused by mold gaps. However, this method has significant drawbacks: First, the introduction of the decorative groove disrupts the overall appearance of the product, especially in consumer products with high aesthetic requirements (such as electronic products and appliance casings), where the visibility of the decorative groove directly affects the product's aesthetics. Second, when the parting line is a complex shape (such as a non-horizontal surface, curved surface, or closed loop), it leads to a decrease in mold yield, affecting product dimensional stability and surface quality. In existing technologies, even by optimizing process parameters or adjusting the mold structure, it is still difficult to completely solve the problems of burrs and runoff without a decorative groove, resulting in insufficient mold mass production and limiting its application in high-end manufacturing. Therefore, there is an urgent need for a two-color mold solution that can eliminate the decorative groove while ensuring stable sealing effects. Utility Model Content

[0003] (1) Technical problems to be solved

[0004] This invention provides a two-color mold that eliminates the need for decorative line sealing, aiming to solve the aforementioned problems.

[0005] (2) Technical solution

[0006] This utility model provides a two-color mold that does not require decorative line sealing, including a first-shot mold and a second-shot mold. The second-shot mold includes a front mold core and a rear mold core that are open and closed to each other. The front mold core and the rear mold core together form a second-shot receiving cavity. The second-shot receiving cavity contains an injection molded product composed of a first-shot product molded by the first-shot mold and a second-shot product that closely surrounds the first-shot product. The front mold core of the second-shot mold has a second-shot insert that extends into the second-shot receiving cavity.

[0007] The bottom of the two-shot insert is provided with an inwardly recessed cavity and a pressure edge arranged around the cavity. The pressure edge is smoothly connected to the inner wall of the two-shot front mold core.

[0008] Furthermore, the first injection module includes a first injection pre-mold core, and the first injection pre-mold core and the second injection pre-mold core are used in conjunction with the second injection post-mold core.

[0009] Furthermore, the injection module includes a front injection mold core and a rear injection mold core, which are used in conjunction with each other.

[0010] Furthermore, the pre-compression depth of the cavity recess is 0-0.05 mm.

[0011] Furthermore, the pre-compression depth is 0.03 mm.

[0012] Furthermore, the sealing width of the pressed edge is 0-0.5mm.

[0013] Furthermore, the width of the sealant is 0.3 mm.

[0014] Furthermore, the pressing edge is shaped like a racetrack.

[0015] Furthermore, the pre-mold core of the second injection is provided with a through hole that is adapted to the second injection insert, and the second injection insert passes through the through hole into the pre-mold core of the second injection.

[0016] Furthermore, the cross-sectional area of ​​the end of the two-shot insert near the two-shot receiving cavity is smaller than the cross-sectional area of ​​the end away from the two-shot receiving cavity.

[0017] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0018] The innovation of this invention lies in completely abandoning the traditional mold groove design. By using inserts to pre-seal the injection area, burrs and indentations at the parting line are eliminated, avoiding appearance defects caused by the presence of mold grooves, resulting in a smoother product surface and smoother lines. For complex parting lines such as non-horizontal surfaces, curved surfaces, or closed loops, the pre-pressure sealing of the inserts can evenly distribute pressure, ensuring a tight seal during mold closing and solving the problem of poor sealing effect on curved surfaces. By precisely controlling the pre-pressure height and sealing width, it effectively prevents plastic melt overflow, significantly reducing defects such as burrs and run-out, and improving mold reliability and production efficiency. The inserts adopt a modular design and can be quickly replaced through through holes without replacing the entire front mold core, reducing mold maintenance costs and time. This solution fundamentally breaks through the technical limitations of traditional mold grooves, providing an innovative solution for high-quality and high-efficiency production of two-color molds. Attached Figure Description

[0019] Figure 1 For the explosion of this utility model Figure 1 .

[0020] Figure 2 Components of this utility model Figure 1 .

[0021] Figure 3 This is a front sectional view of the present invention.

[0022] Figure 4 For the present utility model Figure 3 Enlarged image.

[0023] Figure 5 This is a side sectional view of the present invention.

[0024] Figure 6 For the explosion of this utility model Figure 2 .

[0025] Figure 7 For the explosion of this utility model Figure 3 .

[0026] Figure 8 Components of this utility model Figure 2 .

[0027] Figure 9 This is a schematic diagram of the structure of this utility model.

[0028] Figure 10 This is a cross-sectional view of the present invention.

[0029] Reference numerals: 1-First injection module, 11-First injection front mold core, 12-First injection rear mold core, 2-Second injection module, 21-Second injection front mold core, 22-Second injection rear mold core, 23-Second injection receiving cavity, 24-Through hole, 3-Second injection insert, 31-Cavity, 32-Pressure edge, 33-Pre-compression depth, 34-Sealing width, 4-Injection product, 41-First injection product, 42-Second injection product, 43-Parting line. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0031] like Figure 1-5 As shown, this utility model provides a two-color mold that does not require sealing with decorative lines, including a first-shot module 1 and a second-shot module 2. The second-shot module 2 includes a front mold core 21 and a rear mold core 222 that are mutually openable. The front mold core 21 and the rear mold core 222 together form a second-shot receiving cavity 23. The second-shot receiving cavity 23 contains an injection-molded product 4, which is a first-shot product 41 injection-molded by the first-shot module 1 and a second-shot product 42 tightly surrounding the first-shot product 41. The injection-molded product 4 is a hair product with a pure color. One product in the water-heated hair straightener is the water tank body, which is a double-injection molded plastic product with a long strip shape. The double-injection front mold core 21 is provided with a double-injection insert 3 extending into the double-injection receiving cavity 23. The bottom of the double-injection insert 3 is provided with an inwardly recessed cavity 31 and a pressing edge 32 surrounding the cavity 31. The pressing edge 32 is generally racetrack-shaped and smoothly transitions to the inner wall of the double-injection front mold core 21. The inward recess of the cavity 31 is set as a pre-compression depth 33, and the width of the pressing edge 32 is set as a sealing width 34.

[0032] In commercially available two-color molds, defects such as burrs and run-out are prone to occur at the junction of the first and second shots. To solve this problem, a decorative groove is usually set at the junction of the first and second shots to seal the glue and cover the indentation caused by the sealing. If the decorative groove is not set, the defect rate of burrs and indentations in the second shot is high, and the mold lacks stability and mass production capability. To solve the above problems, this application provides a novel method that eliminates the decorative groove sealing. After the first shot product 41 is formed, the second shot insert 3 is added directly to the second shot front mold core 21 to pre-press and seal the glue, preventing gaps caused by product shrinkage. This compensates for defects such as burrs and run-out caused by the lack of a decorative groove sealing, and provides excellent protection for the appearance.

[0033] Specifically, such as Figure 4-5 As shown, in one embodiment of this utility model, the theoretical value of the pre-compression depth 33 is typically 0-0.05mm. A reasonable setting of the pre-compression depth 33 ensures a tight seal between the second-shot insert 3 and the first-shot product 41, effectively preventing the second-shot product 42 from overflowing from the gap between the second-shot insert 3 and the first-shot product 41, thus avoiding defects such as burrs and glue run-out. The reason for setting a theoretical range for the pre-compression depth 33 is that if the pre-compression depth 33 is too large, it will create obvious indentations on the surface of the injection-molded product 4, affecting the appearance quality. It may also cause the dimensions of the injection-molded product 4 to be out of tolerance, as excessive compression will cause the product to have a large elastic recovery after demolding, thus affecting the final dimensional accuracy of the product. Furthermore, the pre-compression depth 33 must be adjusted according to the actual situation; it cannot be too small, otherwise the pre-compression sealing effect will be insufficient, and defects such as burrs and glue run-out will still occur.

[0034] Preferably, the pre-compression depth 33 is 0.03 mm. This height setting is adjusted according to the actual situation of the first-shot product 41 and the second-shot product 42, so that the joint between the first-shot product 41 and the second-shot product 42 can be better integrated, preventing problems such as delamination and loose bonding.

[0035] Specifically, such as Figure 4-5As shown in one embodiment of this utility model, the theoretical value of the sealing width 34 is typically 0-0.05mm. A reasonable setting of the sealing width 34 ensures full contact between the sealing surface and the object being sealed, forming a continuous and effective sealing area. Simultaneously, it allows for the even distribution of pre-pressure on the sealing surface, preventing excessive or insufficient local pressure and reducing excessive wear, deformation, or even damage to the sealing material caused by pressure concentration. The reason for setting a theoretical range for the sealing width 34 is that if the sealing width 34 is too small, the molten plastic may be squeezed out from the gaps in the sealing surface, resulting in defects such as burrs and flash, affecting product quality. Furthermore, when the sealing width 34 is insufficient, the bonding area between the two plastic materials is small, resulting in insufficient bonding strength, making the product prone to delamination and cracking during use. In addition, the sealing width 34 must be adjusted according to actual conditions and cannot be too large, as this will cause obvious extrusion marks on the product surface, affecting its appearance quality.

[0036] Preferably, the sealant width 34 is gradually set to 0.3mm, and this width value is adjusted according to the actual situation of the first-shot product 41 and the second-shot product 42.

[0037] Specifically, such as Figure 6 As shown, in one embodiment of this utility model, the injection module 1 includes a first injection pre-mold core 11. The first injection pre-mold core 11 and the second injection pre-mold core 21 are respectively used in conjunction with the second injection post-mold core 22. In the production process, the second injection post-mold core 22 is first used in conjunction with the first injection pre-mold core 11 to injection mold the first injection product 41. Then, the first injection pre-mold core 11 is replaced with the second injection pre-mold core 21, and the second injection product 42 is injection molded a second time to finally form the injection molded product 4. This structural design eliminates the need to design and produce the first injection post-mold core 12, reducing production costs while improving production efficiency. In other embodiments, such as... Figure 7 As shown, the first injection module 1 includes a front injection mold core 11 and a rear injection mold core 12. That is, both the first injection module 1 and the second injection module 2 have their corresponding front and rear mold cores. During production, the first injection product 41 is injection molded through the front injection mold core 11 and the rear injection mold core 12. The first injection product 41 is then transferred from the first injection module 1 to the second injection module 2 for injection molding of the second injection product 42, which achieves the same effect.

[0038] Specifically, such as Figure 8As shown, in one embodiment of this utility model, a parting line 43 is provided between the first-shot product 41 and the second-shot product 42. The parting line 43 is a closed loop composed of two straight lines and two approximately semi-circular curves. In two-color molds, an art groove is usually provided on the parting line 43. This hides defects such as burrs, glue leakage, and uneven tightness that occur when the first-shot product 41 and the second-shot product 42 are molded together, making the appearance more aesthetically pleasing and less likely to show flaws on the parting line 33. Furthermore, the pre-pressing and sealing by the second-shot insert 3 of this application ensures that the first-shot product 41 and the second-shot product 42 fit together perfectly when molded together, making the gaps between the lines of the parting line 33 more uniform and aesthetically pleasing. In other embodiments, the shape of the parting line 43 can be arbitrarily adjusted according to the actual situation of the product, and it can be rectangular, circular, or not closed.

[0039] Furthermore, such as Figure 8 As shown, the closed loop formed by the parting line 43 is not parallel to the horizontal plane. In a two-color mold, if the plane formed by the parting line is parallel to the horizontal plane, a decorative groove is not required, and the parting line can be perfectly closed through normal mold closing. However, if the plane formed by the parting line is not parallel to the horizontal plane and is a product with curvature, such as a mouse and the closed loop in a two-color mold that does not require decorative line sealing, the parting line 43 at one end of the injection molded product 4 curves upward to form an arc surface. In this case, uneven distribution of injection force during injection molding can lead to problems such as one side being loose and the other tight, flash, and glue leakage during mold closing. A decorative groove is required, but the decorative groove will affect the appearance. However, by pre-pressing and sealing with the two-shot insert 3, even when the parting line 43 is an arc surface, the one-shot product 41 and the two-shot product 42 can still be perfectly closed during mold closing, making the gap between the parting line 33 more uniform and aesthetically pleasing.

[0040] Specifically, such as Figure 9-10 As shown, in one embodiment of this utility model, the pre-mold core 21 of the second injection is provided with a through hole 24 that matches the second injection insert 3. The second injection insert 3 passes through the pre-mold core 21 of the second injection through the through hole 24. This structural design allows the insert 14 to be replaced directly through the through hole 24 without replacing the pre-mold core 21 when the second injection insert 3 is worn after long-term use. This is very simple, convenient, and reduces costs. At the same time, the pre-compression depth 33 of the insert 14 can also be adjusted through the through hole 24. In some other embodiments, the through hole 24 is not provided in the pre-mold core 21 of the second injection, but a groove facing the second injection receiving cavity 23 is provided to place the second injection insert 3, which can achieve the same effect.

[0041] Furthermore, such as Figure 10As shown, the cross-sectional area of ​​the end of the two-shot insert 3 near the two-shot receiving cavity 23 is smaller than the cross-sectional area of ​​the end away from the two-shot receiving cavity 23. This structural design allows the two-shot insert 3 to be securely attached to the two-shot front mold core 21, and the two-shot insert 3 will not move into the two-shot receiving cavity 23 due to the setting of the through hole 24.

[0042] The following is a detailed explanation of the working principle of this utility model:

[0043] The working principle of this utility model is based on the pre-pressure sealing mechanism of the two-shot insert 3. During the mold closing stage, the two-shot front mold core 21 and the two-shot rear mold core 22 close to form the two-shot receiving cavity 23. The molding area of ​​the first-shot product 41 is covered by the two-shot insert 3. The two-shot insert 3 protrudes from the two-shot front mold core 21, and its recess depth (the pre-pressure depth 33) is set to 0.03 mm. This height difference applies pre-pressure to the first-shot product 41, preventing melt from overflowing from the gap during injection molding of the second-shot product 42. Simultaneously, the outline width of the two-shot insert 3 is 0.3 mm larger than that of the first-shot product 41 (the sealing depth 33). The glue width is 34, forming a continuous sealing area, further blocking the glue overflow path; during the injection molding process, after the first injection product 41 is formed, the pre-pressure of the second injection insert 3 compensates for the gap caused by material shrinkage, ensuring that there is no gap at the parting line 43. When the second injection product 42 is injected, the melt fills the sealing area evenly, avoiding burrs caused by uneven local pressure. During the ejection stage, for non-horizontal closed loops (such as curved parting lines), the pre-pressure of the insert can adaptively adjust the pressure distribution to maintain the sealing effect. This design achieves high-precision sealing without a grooving groove through structural optimization and precise parameter control, combining functionality and economy.

[0044] The innovation of this utility model lies in its complete abandonment of the traditional decorative groove design. By setting a specially structured insert in the front mold core, combined with the synergistic effect of pre-compression height and sealing width, it achieves sealing without decorative lines; improves appearance quality: the pre-compression sealing of the injection area by the insert eliminates burrs and indentations at the parting line, avoiding appearance defects caused by the presence of decorative grooves, making the product surface smoother and the lines more fluid; enhances adaptability: for complex parting lines such as non-horizontal surfaces, curved surfaces, or closed loops, the pre-compression sealing of the insert can evenly distribute pressure, ensuring a tight seal during mold closing, and solving... It solves the problem of poor sealing effect under curved surface shape; improves mass production stability: by precisely controlling the pre-compression height (0-0.05mm) and sealing width (≥0.2mm), it effectively prevents plastic melt overflow, significantly reduces the defect rate of flash, glue running, etc., and improves the reliability and production efficiency of mold; reduces cost and maintenance difficulty: the insert adopts a modular design: it can be quickly replaced through the through hole without replacing the entire front mold core, reducing mold maintenance costs and time; this solution fundamentally breaks through the technical limitations of traditional artisan slots and provides an innovative solution for high-quality and high-efficiency production of two-color molds.

[0045] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

[0046] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A two-color mold that does not require decorative line sealing, characterized in that, It includes a first injection module (1) and a second injection module (2). The second injection module (2) includes a front injection core (21) and a rear injection core (22) that are open and closed to each other. The front injection core (21) and the rear injection core (22) together form a second injection receiving cavity (23). The second injection receiving cavity (23) contains a first injection product (41) that is injection molded by the first injection module (1). The front injection core (21) has a second injection insert (3) that extends into the second injection receiving cavity (23). The bottom of the second-shot insert (3) is provided with an inwardly recessed cavity (31) corresponding to the first-shot product and a pressing edge (32) arranged around the cavity (31). The pressing edge (32) is smoothly connected to the inner wall of the second-shot front mold core (21).

2. The two-color mold without the need for decorative line sealing as described in claim 1, characterized in that, The first injection module (1) includes a first injection pre-mold core (11), and the first injection pre-mold core (11) and the second injection pre-mold core (21) are used in conjunction with the second injection post-mold core (22).

3. The two-color mold without the need for decorative line sealing as described in claim 1, characterized in that, The first injection module (1) includes a front injection mold core (11) and a rear injection mold core (12), which are used in conjunction with each other.

4. The two-color mold without the need for decorative line sealing as described in claim 1, characterized in that, The pre-compression depth (33) of the cavity (31) is 0-0.05 mm.

5. A two-color mold without the need for decorative line sealing as described in claim 4, characterized in that, The pre-compression depth (33) is 0.03 mm.

6. A two-color mold without the need for decorative line sealing as described in claim 1, characterized in that, The sealing width (34) of the pressing edge (32) is 0-0.5mm.

7. A two-color mold without the need for decorative line sealing as described in claim 6, characterized in that, The width of the sealant (34) is 0.3 mm.

8. A two-color mold without the need for decorative line sealing as described in claim 7, characterized in that, The pressing edge (32) is generally in the shape of a racetrack.

9. A two-color mold without the need for decorative line sealing as described in claim 1, characterized in that, The pre-mold core (21) of the second injection is provided with a through hole (24) that is adapted to the second injection insert (3), and the second injection insert (3) passes through the through hole (24) into the pre-mold core (21).

10. A two-color mold without the need for decorative line sealing as described in claim 9, characterized in that, The cross-sectional area of ​​the end of the two-shot insert (3) near the two-shot receiving cavity (23) is smaller than the cross-sectional area of ​​the end away from the two-shot receiving cavity (23).

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