Method for injection molding based on a main trim ring

Abstract

The present invention relates to a method for injection molding of a main decorative ring, belonging to the technical field of injection molds, and the following operating steps: First step: Design and assemble two sets of mold core cavities composed of a water cooling module and a demolding and ejection module on a fixed mold base. Second step: After the mold is closed and injection molding is completed, circulating water flows through the cooling water channels, and the water cooling inserts cool the main decorative ring product. Third step: After cooling is completed, the moving side mold is separated from the fixed side mold. At this time, the driving push block drives the ejection assembly to eject the main decorative ring product from the fixed mold base during the demolding process. Fourth step: When the ejection assembly ejects in the horizontal direction, at the same time, the limit column between the ejector plate and the ejector retainer plate slides upward under the guiding displacement of the driving push block to synchronously realize the upward demolding process of the main decorative ring product. It has the characteristics of compact structure, complete functions, good operation stability, and long service life. It solves the problem of low qualification rate of products during the injection molding process.

Description

Technical Field

[0001] The present invention relates to the technical field of injection molds, and particularly relates to a method for injection molding based on a main decorative ring. Background Art

[0002] The main decorative ring of the headlight, that is, the decorative frame, is an important component of the headlight. Usually, there are requirements for the clearance fit with the lens / inner fitting / mirror / light guide / thick wall, forming a visible surface covering the lamp body. Therefore, the main decorative ring is usually as large as the lamp body and the light distribution mirror, with a high-brightness appearance surface, and has requirements such as electroplating, leather texture, and optical reflection. The product qualification rate is usually not high, and the development difficulty is relatively large.

[0003] The main decorative ring of the headlight uses the product as an alternative name. The product size is 305*536*617mm (note: 617 is the height in the mold demolding direction), and the product material is PC2407 (a thermoplastic material).

[0004] Problems existing in the injection molding of the product:

[0005] 1. The product has a large drop. The front is a high-brightness leather texture appearance surface. According to the ejection direction, the leather texture angle of the product appearance is too small, and the appearance surface will be scratched. It is not realistic to make a core-pulling structure for the entire front mold because the mold drop is too large and the mold structure cannot achieve it. Therefore, it is necessary to solve the problem of demolding the A surface (the A surface is the back of the product) of the product and also solve the problem of ejecting the product on the back.

[0006] 2. The product is basically surrounded by sliders on all sides, and the space for the product's gate position is limited. It is not possible to reduce the filling injection pressure of the product by increasing the number of hot runner points. The flow path of the product is relatively long, and some positions are narrow, making it difficult to feed. How to reduce the filling injection pressure.

[0007] 3. The product has deep concave features and is relatively narrow. A high-temperature area will be formed on the mold. Using beryllium copper as the insert waterway cannot reach the deep position of the product. Only the cooling can be optimized through the heat conduction rate of beryllium copper.

[0008] 4. The mold structure of the product has four-sided sliders. Most of the plastic positions are ejected by the sliders, and the plastic position on the slider surface is relatively high. The mold needs to consider the problem of the product sticking to the slider to avoid scratching the product. The slider is driven by an oil cylinder, and an additional ejection structure is required inside the slider to avoid the product sticking to the slider, breaking or cracking the BOSS post.

[0009] 5. When the slider fails to eject and does not reset, and the mold is closed, there is a possibility that the ejector pin will scratch the leather texture surface of the fixed mold, resulting in damage to the A surface of the fixed mold, causing serious losses and affecting the product delivery. It is necessary to consider avoiding the scratching of the ejector pin and the appearance surface in the case of the failure of the internal ejection structure of the slider to reset. Summary of the Invention

[0010] The present invention mainly solves the deficiencies existing in the prior art, and provides a method for injection molding of a main decorative ring, which has the characteristics of compact structure, complete functions, good operation stability and long service life. It solves the problem of low qualified rate of products during the injection molding process.

[0011] The above technical problems of the present invention are mainly solved by the following technical solutions:

[0012] A method for injection molding of a main decorative ring, including the following operation steps:

[0013] The first step: Design and assemble two sets of mold core cavities composed of a water-cooling module and a demolding and ejecting module on a fixed mold base seat. These two sets of mold core cavities are mirror-image distributed. After the moving-side mold and the fixed-side mold are pressed together, injection molding of the main decorative ring product is carried out in the mold core cavities.

[0014] The second step: After the mold is closed and injection molding is completed, circulating water flows through the cooling water circuit, so that the water-cooling insert fixed by fixing screws cools the main decorative ring product, reducing the molding cycle.

[0015] The third step: After cooling is completed, the moving-side mold and the fixed-side mold are separated. At this time, the driving push block drives the ejecting assembly to eject the main decorative ring product from the fixed mold base seat.

[0016] The ejecting assembly drives the ejector pins on the ejector pin fixing plate through the ejector pin push plate at the front end of the ejector pin plate baffle to act on the back of the main decorative ring product, and performs the demolding process of the main decorative ring product in the horizontal direction.

[0017] The fourth step: When the ejecting assembly ejects in the horizontal direction, at the same time, the limit posts between the ejector pin push plate and the ejector pin fixing plate slide upward under the guiding displacement of the driving push block to synchronously lift the large slider to realize the upward demolding process of the main decorative ring product.

[0018] Preferably, the rear end of the driving push block uses a driving oil cylinder to provide power for the reciprocating operation of the driving push block. The driving oil cylinder and the fixed mold base seat are fixedly connected by a transition connecting plate. At the same time, the transition connecting plate is inserted into the lower part of the driving push block to realize the reciprocating guiding function during the demolding process.

[0019] Preferably, a ejector rod is added to the lower part of the ejector pin push plate to increase the stability of the demolding and ejecting in the horizontal direction. At the same time, a thimble tube is assembled on the side of the ejector rod, and a wear-resistant plate is assembled at the rear end of the ejector pin plate baffle. A thimble needle sleeved with the thimble tube is arranged in the wear-resistant plate to position the demolding structure of the main decorative ring product by using the thimble tube and the thimble needle.

[0020] Preferably, a push plate spring nested in the ejector pin push plate is used for resetting and buffering between the ejector pin push plate and the ejector pin plate baffle. A limit block is used for buffering between the front end of the ejector pin fixing plate and the fixed mold base seat.

[0021] Preferably, the water-cooling insert in the water-cooling module is processed and formed by combining machining and 3D printing technologies:

[0022] Step 1: Take a square stock base, drill a water channel in the square stock base with a gun drill, and then process a threaded hole with a reserved margin at the lower end of the square stock base through a punching machine.

[0023] Step 2: At the upper end of the processed square stock base, use 3D printing technology to fuse insert block I and insert block II. The cooling water channels in insert block I and insert block II are connected to the water channel in the insert in the square stock base.

[0024] Step 3: After 3D printing is completed, perform heat treatment to enhance the surface strength, and then perform NC surface machining. The water-cooling insert is processed by machining the depth dimension between insert block I and insert block II and the dimensions on both sides and the lower end of the square stock base, completing the processing process of the water-cooling insert.

[0025] Preferably, the metal raw material powder for 3D printing and the material of the square stock base are die steel, and the die steel material is selected from 2343 ESR, H13 or CR12.

[0026] Preferably, the heat treatment hardness of the water-cooling insert is HRC30 - 34.

[0027] Preferably, the fusion of insert block I and insert block II with the square stock base is achieved by the 3D principle of powder layer-by-layer welding.

[0028] The present invention can achieve the following effects:

[0029] 1. To protect the demolding angle requirement of the surface texture of the large decorative ring, the mold opening direction is demolded in the direction of the texture safety angle, and the ejection direction of the product on the rear mold is preferably in the direction with less undercut. The ejection uses an oil cylinder system to drive the ejector pins. At the same time, considering the influence of the inclination center of gravity of the ejector pins, the load-bearing structure is strengthened to make the ejection system more stable and reliable. The mold opening system and the ejection system are independent of each other, realizing the development of this type of large decorative ring mold.

[0030] 2. The application of 3D printing inserts in the mold. 3D printing technology can print special-shaped water channels, increasing the cross-sectional area of the cooling water channels in a limited space, strengthening the cooling of the product, and thus reducing the product cycle. Practical verification shows that through 3D printing inserts, the water channels on the mold are independently controlled, and the actual temperature of the insert is controlled at about 100 °C, achieving the same temperature as the mold core.

[0031] III. Characteristics of the oil cylinder slider: A simple spring-driven + limit block positioning method, and a recommended slider or ejection structure, which is practical and simple. After the mold is opened, the oil cylinder drives the slider to retreat. Under the action of the spring, the ejector pin structure drives towards the product. With the limit block positioning, the ejection structure always remains stationary relative to the product, allowing the slider to retreat safely from the product. When the movement stroke of the slider > the ejection stroke, the ejection mechanism no longer functions and moves away from the product together with the slider. When closing the mold, the oil cylinder drives the slider to close. When the limit block touches the moving mold core, the ejection structure starts to compress the spring and reset until the slider is closed and the ejection mechanism reset is completed. The structure operation is very simple, and it is also very convenient to modify and repair.

[0032] IV. The front headlight trim ring has relatively high requirements for the appearance surface, a high-gloss appearance surface, usually with leather texture, electroplating or leather texture + electroplating. When a ejector pin structure is made inside the slider, it often fails to reset the ejector pin or the reset limit structure breaks during movement. When the mold is closed, the ejector pin protrudes from the surface of the slider, and the A surface of the fixed mold collides with the ejector pin, damaging the leather texture surface, electroplated surface, etc. The damaged surface of the fixed mold can only be repaired by welding and tempering, increasing the risk of welding marks on the product surface. Sometimes, due to unclean surface welding treatment, the welding mold cracks, resulting in the entire mold core being scrapped and remade. On the premise of ensuring the effective ejection length, it is recommended to increase 2.5 - 3 mm concentric columns at the ejection position, with a wall thickness of 1 - 1.5 mm (determined according to the wall thickness of the product - the PC material is designed according to 0.5 times the basic wall thickness), controlling the distance between ejector pins at 3.5 - 4 mm, and the safety stroke of the product is 2.5 + 2.5 = 5 mm. Even if it does not reset within 4 mm stroke, it will not affect the mold closing process (ejection stroke < safety stroke), and it will not touch the A surface during mold closing, effectively preventing and protecting the A surface of the mold.

[0033] V. The principle of plastic flow is that the material flows towards the direction where the runner is easier, just like why a car can drive fast on the highway because the road is wide. When one side of the product's gate position is wide and the other side is narrow, during filling, the rubber material will only flow towards the wide and easier flowing direction. Very little rubber is diverted to the relatively close and narrow area. Even if the wall thickness is increased, it is not obvious, resulting in difficult filling and high filling pressure. We can fill the difficult area of the product by increasing the gate through drainage, making the filling relatively balanced, reducing the injection pressure, and solving the problem of difficult product filling.

[0034] The present invention provides a method for injection molding of a main trim ring, which, compared with the prior art, has the characteristics of compact structure, complete functions, good operation stability, and long service life. It solves the problem of low qualification rate of products during the injection molding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic structural diagram of the present invention.

[0036] Figure 2 is a partial structural cross-sectional view of the present invention.

[0037] Figure 3 It is a schematic structural view of the ejection assembly of the present invention.

[0038] Figure 4 It is a structural sectional view of the ejection assembly of the present invention.

[0039] Figure 5 It is a schematic structural view of the water-cooling module of the present invention.

[0040] Figure 6 It is a schematic structural view of the square stock base of the present invention.

[0041] Figure 7 It is a schematic structural view of the blank of the water-cooling insert of the present invention.

[0042] Figure 8 It is a schematic structural view of the water-cooling insert of the present invention.

[0043] Figure 9 It is a schematic structural view of the main decorative ring product after demolding of the present invention.

[0044] In the figure: fixed mold base seat 1, water-cooling module 2, demolding and ejection module 3, driving oil cylinder 4, transition connecting plate 5, driving push block 6, large slider 7, ejection assembly 8, main decorative ring product 9, ejector pin push plate 10, ejector plate baffle 11, ejector pin fixing plate 12, ejector pin 13, limit block 14, limit post 15, ejector rod 16, sleeve tube 17, wear-resistant plate 18, push plate spring 19, sleeve pin 20, water-cooling insert 21, fixing screw 22, cooling water channel 23, square stock base 24, inner water channel passage of the insert 25, threaded hole 26, insert block I 27, insert block II 28. Detailed implementation manners

[0045] The following is a further specific description of the technical solution of the invention through examples and in combination with the drawings.

[0046] Example: As Figures 1-9 shown, a method for injection molding of a main decorative ring includes the following operating steps:

[0047] First step: Design and assemble two sets of mold cavities composed of a water-cooling module 2 and a demolding and ejection module 3 on the fixed mold base seat 1. These two sets of mold cavities are mirror-image distributed. After the moving-side mold and the fixed-side mold are pressed together, the main decorative ring product 9 is injection molded in the mold cavities.

[0048] Second step: After the mold is closed and injection molded, circulating water flows through the cooling water channel 23, so that the water-cooling insert 21 fixed by the fixing screw 22 cools the main decorative ring product 9, reducing the molding cycle.

[0049] The water-cooling insert 21 in the water-cooling module 2 is processed and formed by combining machining and 3D printing technologies:

[0050] Step 1: Take the square stock base 24. The metal raw material powder for 3D printing and the material of the square stock base 24 are die steel, and the die steel material is selected as 2343 ESR, H13 or CR12. Drill the insert internal water channel 25 in the square stock base 24 with a gun drill, and then process the threaded hole 26 with a reserved margin at the lower end of the square stock base 24 by a punching machine.

[0051] Step 2: Use 3D printing technology to fuse the insert block I 27 and the insert block II 28 at the upper end of the processed square stock base 24. The cooling water channels in the insert block I 27 and the insert block II 28 are connected to the insert internal water channel 25 in the square stock base 24. The fusion of the insert block I 27 and the insert block II 28 with the square stock base 24 is realized by the 3D principle of powder layer-by-layer welding.

[0052] Step 3: After 3D printing, perform heat treatment to enhance the surface strength. The heat treatment hardness of the water-cooling insert 21 is HRC32. Then perform NC surface machining to complete the processing process of the water-cooling insert 21.

[0053] Third step: After cooling is completed, the moving-side mold is separated from the fixed-side mold. At this time, the driving push block 6 drives the ejector assembly 8 to eject the main decorative ring product 9 from the fixed mold base 1.

[0054] The rear end of the driving push block 6 is powered by a driving oil cylinder 4 to provide power for the reciprocating movement of the driving push block 6. The driving oil cylinder 4 and the fixed mold base 1 are fixedly connected by a transition connecting plate 5. At the same time, the transition connecting plate 5 is inserted into the lower part of the driving push block 6 to realize the reciprocating guiding function during the demolding process.

[0055] The ejector assembly 8 drives the ejector pins 13 on the ejector pin fixing plate 12 through the ejector pin push plate 10 at the front end of the ejector pin plate baffle 11 to act on the back of the main decorative ring product 9, and performs the demolding process of the main decorative ring product 9 in the horizontal direction. A push plate spring 19 nested in the ejector pin push plate 10 is used for reset buffering between the ejector pin push plate 10 and the ejector pin plate baffle 11. A limit block 14 is used for buffering between the front end of the ejector pin fixing plate 12 and the fixed mold base 1.

[0056] A ejector rod 16 is added to the lower part of the ejector pin push plate 10 to increase the stability of the horizontal demolding and ejection. At the same time, a guide bushing 17 is assembled on the side of the ejector rod 16, and a wear-resistant plate 18 is assembled at the rear end of the ejector pin plate baffle 11. A guide bushing pin 20 sleeved with the guide bushing 17 is arranged in the wear-resistant plate 18, and the guide bushing 17 and the guide bushing pin 20 are used to position the demolding structure of the main decorative ring product 9.

[0057] Step 4: When the ejection component 8 ejects in the horizontal direction, at the same time, the limit post 15 between the ejector plate 10 and the ejector retainer plate 12 slides upward under the guiding displacement of the driving block 6 to synchronously lift the large slider 7 to realize the upward demolding process of the main trim ring product 9.

[0058] In summary, the method based on the injection molding of the main trim ring has the characteristics of compact structure, complete functions, good operation stability and long service life. It solves the problem of low qualification rate of products during the injection molding process.

[0059] The above are only specific embodiments of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A method for injection molding of a main decorative ring, characterized in that The operation steps are as follows: The first step: Design and assemble two sets of mold core cavities composed of a water-cooling module (2) and a demolding and ejecting module (3) on the fixed mold base (1). These two sets of mold core cavities are mirror-image distributed. After the moving-side mold and the fixed-side mold are pressed together, the main decorative ring product (9) is injection-molded in the mold core cavities; The second step: After the mold is closed and injection-molded, circulating water flows through the cooling water channel (23), so that the water-cooling insert (21) fixed by the fixing screw (22) cools the main decorative ring product (9), reducing the molding cycle; The third step: After cooling is completed, the moving-side mold and the fixed-side mold are separated. At this time, the driving push block (6) drives the ejecting assembly (8) to eject the main decorative ring product (9) from the fixed mold base (1) during the demolding process; The ejecting assembly (8) drives the ejector pins (13) on the ejector pin fixing plate (12) through the ejector pin push plate (10) at the front end of the ejector pin plate baffle (11) to act on the back of the main decorative ring product (9), and performs the demolding process of the main decorative ring product (9) in the horizontal direction; A push plate spring (19) nested in the ejector pin push plate (10) is used for reset buffering between the ejector pin push plate (10) and the ejector pin plate baffle (11); a limit block (14) is used for buffering between the front end of the ejector pin fixing plate (12) and the fixed mold base (1); The fourth step: When the ejecting assembly (8) ejects in the horizontal direction, at the same time, the limit post (15) between the ejector pin push plate (10) and the ejector pin fixing plate (12) slides upward under the guiding displacement of the driving push block (6) to lift the large slider (7) synchronously, realizing the upward demolding process of the main decorative ring product (9).

2. The method for injection molding based on a main trim ring according to claim 1, wherein: The rear end of the driving push block (6) uses a driving oil cylinder (4) to provide power for the reciprocating movement of the driving push block (6). The driving oil cylinder (4) and the fixed mold base (1) are fixedly connected by a transition connecting plate (5). At the same time, the transition connecting plate (5) is inserted into the lower part of the driving push block (6) to realize the reciprocating guiding function during the demolding process.

3. The method for injection molding based on a main trim ring according to claim 1, wherein: A push rod (16) is added to the lower part of the ejector pin push plate (10) to increase the stability of the demolding and ejecting in the horizontal direction. At the same time, a thimble tube (17) is assembled on the side of the push rod (16), and a wear-resistant plate (18) is assembled at the rear end of the ejector pin plate baffle (11). A thimble pin (20) sleeved with the thimble tube (17) is arranged in the wear-resistant plate (18), and the thimble tube (17) and the thimble pin (20) are used for positioning the demolding structure of the main decorative ring product (9).

4. The method for injection molding based on the main decorative ring according to claim 1, wherein: The water-cooling insert (21) in the water-cooling module (2) is processed and formed by combining machining and 3D printing technologies: Step 1: Take a square material base (24), drill a water channel passage (25) for the insert inside the square material base (24) by gun drilling, and then process a threaded hole (26) with a reserved margin at the lower end of the square material base (24) by a punching machine; Step 2: At the upper end of the processed square material base (24), the insert block I (27) and the insert block II (28) are fused by 3D printing technology. The cooling water channels in the insert block I (27) and the insert block II (28) are communicated with the water channel passage (25) for the insert inside the square material base (24); Step 3: After 3D printing, perform heat treatment to enhance the surface strength, and then perform NC surface machining to complete the machining process of the water-cooling insert (21).

5. The method for injection molding based on the main trim ring according to claim 4, wherein: The metal raw material powder for 3D printing and the material of the square base (24) are made of die steel, and the die steel material is selected as 2343 ESR, H13 or CR12.

6. The method for injection molding based on a main trim ring according to claim 4 or 5, characterized in that: The heat treatment hardness of the water-cooling insert (21) is HRC 30 - 34.

7. The method for injection molding based on a main trim ring according to claim 4, wherein: The fusion of the insert block I (27) and the insert block II (28) with the square base (24) is achieved by the 3D principle of powder stacking and layer-by-layer welding.

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