Double-color forming process for solving poor appearance of product and injection mold

Abstract

The invention belongs to the technical field of double-color injection molding, particularly provides a double-color molding process and an injection mold for solving the problem of poor appearance of a product, and aims at solving the problems of appearance defects caused by wall thickness during injection molding of a flash charging plug shell, deformation during secondary injection of a product subjected to primary injection, adhesion to a front mold during mold opening, nonuniform cooling and the like. The invention provides a double-color forming process and an injection mold for solving the problem of poor appearance of a product. According to the technology, the cavity design is optimized through CAE mold flow analysis, a second-injection area prone to deviation is fused into a first-injection cavity, and deformation is avoided through double-color forming; the mold is provided with a delayed mold opening mechanism, it is ensured that a product is left in a movable mold during mold opening, and meanwhile, a cooling water jacket and a spiral cooling water jacket are arranged to achieve uniform cooling. According to the invention, the appearance and size problems of sink marks, warping and the like of products are effectively improved, and the yield and production efficiency of mass production are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of double-color injection molding, and particularly relates to a double-color molding process and injection mold for solving product appearance defects. BACKGROUND

[0002] The development of flash charging technology cannot be separated from an important mechanism, namely, a charging plug with flash charging function. The charging plug bears the core functions of electric energy conversion, transmission and system linkage. As the energy hub of new energy vehicles, the charger not only completes basic electric energy transmission, but also realizes battery health management, electric power resource optimization and other extended functions through intelligent control. With the development of vehicle-to-grid interaction technology, its role is evolving from a single charging device to a mobile energy storage node, becoming an important carrier of new power systems. However, the shell of the flash charging plug has the problem of appearance defects caused by the excessive wall thickness of some areas during injection molding. In order to solve this problem, the product with a thickness of 2.4mm is divided into two products with a wall thickness of 1.2mm, and a double-color molding process is used to solve the shrinkage and stress marks on the appearance of the product. However, there are still the following technical barriers: 1. After the injection molding of the first shot product is completed, it is rotated to the second shot area, resulting in no support area in the front mold area. When the plastic of the second shot is injected into the mold, the area without iron block support is extruded and deformed due to excessive injection pressure.

[0003] 2. The structure of the product and its appearance requirements make the product easy to stick to the front mold side when the mold is opened.

[0004] 3. Due to the screw position or product structure, the conventional straight waterway water jacket cannot be designed to closely follow the shape of the product, which will cause the area close to the waterway to cool quickly, and the area far away to cool slowly, resulting in warping, shrinkage and internal stress on the product.

[0005] Therefore, the above problems have become technical problems that need to be solved. SUMMARY

[0006] The present application provides a double-color molding process and injection mold for solving product appearance defects, which effectively improves the product surface appearance defects and solves the size instability problem caused by product warping, thereby greatly improving the qualification rate of mass-produced products.

[0007] Technical scheme: In order to achieve the above purpose, the present application provides a double-color molding process for solving product appearance defects, comprising the following steps: S1, injection cavity design, using CAE software to analyze the mold flow, to predict the two shot filling process is easy to one shot product offset area, the area corresponding to the two shot product part to one shot cavity, one shot product prone to offset position to enhance, two shot injection when plastic will be in the product deformation before the product back, at this time one shot product back has support, continue to injection one shot product front and rear area exist injection pressure, both sides are stressed so that the product is no longer deformed; S2, injection verification of the injection cavity designed in S1, no adverse injection product appearance can be mass injection; S3, first one shot cavity injection, at this time two shot cavity is not injection, when one shot complete filling-holding-cooling three stages, the injection machine starts to open the mold, after the mold is opened, the one shot product is rotated to the two shot injection position; S4, injection mold closing, two shot cavity injection, after filling-holding-cooling, the product is taken out.

[0008] Further, the one shot product is an internal part, and the two shot product is an appearance part wrapped outside the one shot product.

[0009] A two-color forming injection mold for solving product appearance defects, comprising: The fixed mold comprises a fixed mold plate, a hot runner distribution plate, the hot runner distribution plate is connected with the fixed mold plate through a limiting bolt, the bottom of the hot runner distribution plate is provided with a one shot fixed mold insert and a two shot fixed mold insert, and the fixed mold plate is embedded with a one shot fixed mold core and a two shot fixed mold core which are respectively embedded with the one shot fixed mold insert and the two shot fixed mold insert. The movable mold comprises a movable mold plate, the movable mold plate is embedded with a one shot movable mold core and a two shot movable mold core, and the one shot movable mold core and the two shot movable mold core are combined with the one shot fixed mold core and the two shot fixed mold core to form a one shot cavity and a two shot cavity. The delayed mold opening mechanism comprises a mold locking pull rod arranged on the side surface of the hot runner distribution plate, a mold locking intermediate arranged on the side surface of the fixed mold plate, a spring arranged between the mold locking intermediate and the fixed mold plate, and a mold locking buckle arranged on the side surface of the movable mold plate, the mold locking pull rod is provided with a avoiding groove capable of accommodating the mold locking intermediate and a bottom compression head capable of compressing the mold locking intermediate, the length of the avoiding groove is greater than the vertical width of the mold locking intermediate, and the mold locking buckle can be locked with the mold locking intermediate to lock the movable mold plate and the fixed mold plate.

[0010] Further, the mold locking buckle is vertically provided with a slot for inserting the mold locking pull rod, and the mold locking buckle is transversely provided with a smooth inclined surface between the avoiding groove and the compression head. The fixed mold plate is provided with a stepped hole, the limiting bolt is connected with the hot runner distribution plate through the stepped hole, and the bottom of the limiting bolt can move up and down in the lower part of the stepped hole.

[0011] Through the above-mentioned delayed mold opening mechanism, the fixed mold core and the movable mold core are not opened first when the mold is opened, the insert on the fixed mold is separated from the fixed mold core under the driving of the hot runner plate, at this time the maximum clamping force on the fixed mold side is first removed, then the fixed mold core and the movable mold core are opened, at this time the clamping force on the movable mold side is greater than that on the fixed mold side, and the product remains in the movable mold. This structure solves the risk of product sticking to the front mold.

[0012] Further, the fixed mold further comprises a fixed mold panel arranged on the upper part of the hot runner distribution plate, and a group of injection ports are arranged on the fixed mold panel; The hot runner distribution plate is embedded with a first flow channel and a second flow channel, and the injection ports are respectively communicated with a first mold cavity and a second mold cavity through the first flow channel and the second flow channel.

[0013] Further, the first fixed mold insert is internally provided with a cooling water jacket, and the second fixed mold insert is internally provided with a spiral cooling water jacket, and the spiral cooling water jacket is provided with a spiral cooling flow channel.

[0014] Further, the cooling water jacket is located on the outside of the first flow channel, and the spiral cooling flow channel uniformly covers the outside of the second flow channel.

[0015] The cooling water jacket and the spiral cooling water jacket take away heat, greatly reduce hot spots, and improve product quality. Since the two-shot product is an appearance part, the spiral cooling water jacket can more uniformly take away heat, greatly reduce hot spots and uneven cooling. Improve product quality, and more uniform cooling means smaller product warping, deformation and internal stress, which can eliminate or reduce the visibility of weld marks and improve surface quality. Greatly improve the cooling efficiency. Higher cooling efficiency can directly shorten the cooling time, thereby significantly improving the production efficiency Further, the movable mold further comprises a movable mold bottom plate arranged below the movable mold plate, and a square iron block is arranged between the movable mold bottom plate and the movable mold plate to form an air layer.

[0016] Further, the air layer is internally provided with an ejection assembly, the ejection assembly comprises a liftable bottom plate, a ejector rod penetrating through the movable mold bottom plate and connected with the bottom plate, a spring sleeved on the ejector rod, a ejector pin arranged on the bottom plate, and the ejector pin can penetrate through the movable mold plate and communicate with the first mold cavity and the second mold cavity. The ejection assembly is used for ejecting the product from the mold cavity after the injection is completed.

[0017] The above technical solution can be seen that the present application has the following beneficial effects: 1. The present application uses CAE software to analyze the mold flow, predict the area prone to filling deviation, and put the corresponding part of the two-shot product on the one-shot product without affecting the appearance of the product, and then verify it through actual injection molding. The operation of the one-shot product is strengthened, and the two-shot injection plastic will flow to the back of the one-shot product before the product deforms, at which time the back of the one-shot product has support. When the injection continues, the front and rear areas of the one-shot product exist injection pressure, and the product is no longer deformed under the force of both sides. This scheme perfectly solves the problem of one-shot product deformation, enabling the production of qualified products.

[0018] 2. The mold in the present application adopts hot runner direct glue technology. In order to reduce the excessive heat generated in the hot runner gate area, a spiral cooling jacket based on 3D printing technology is designed in the hot runner gate area, which perfectly solves the overheating phenomenon in the hot runner gate area, reduces the injection cycle and improves the injection efficiency.

[0019] 3. The delay mold opening mechanism in the present application makes the fixed mold and the movable mold not open at first, and the insert on the fixed mold is driven by the hot runner plate to separate from the fixed mold at first, at which time the maximum clamping force on the fixed mold side is removed, and then the fixed and movable molds are opened, at which time the clamping force on the movable mold side is greater than that on the fixed mold side, and the product remains in the movable mold, solving the risk of product sticking to the front mold. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The structure diagram of the double-color forming injection mold for solving the poor appearance of the product Figure 2 The half-open mold diagram of the double-color forming injection mold for solving the poor appearance of the product Figure 3 The full-open mold diagram of the double-color forming injection mold for solving the poor appearance of the product Figure 4 The Figure 3 The enlarged diagram of A in the middle.

[0021] In the figure: 1 - fixed mold, 11 - fixed mold plate, 12 - hot runner plate, 121 - one-shot runner, 122 - two-shot runner, 13 - limit bolt, 14 - one-shot fixed mold insert, 15 - two-shot fixed mold insert, 16 - one-shot fixed mold, 17 - two-shot fixed mold, 18 - fixed mold panel; 2 - movable mold, 21 - movable mold plate, 22 - one-shot movable mold, 23 - two-shot movable mold, 24 - movable mold bottom plate, 25 - square iron block; 3 - delay mold opening mechanism, 31 - locking pull rod, 311 - avoidance groove, 312 - pressure head, 32 - locking intermediate, 33 - locking buckle; 4 - ejector assembly, 41 - base plate, 42 - ejector pin, 43 - ejector. DETAILED DESCRIPTION

[0022] It should be understood that the specific embodiments described herein are merely exemplary and not intended to limit the application.

[0023] A double-color molding process for solving the problem of poor product appearance, comprising the following steps: S1, injection cavity design, using CAE software for mold flow analysis, predicting the area that is easy to be offset by the first shot product during the filling process, and designing the corresponding part of the second shot product in the first shot cavity. The position of the first shot product that is easy to be offset is enhanced, and the plastic will flow to the back of the product before the product deforms during the second injection. At this time, the back of the first shot product has support, and the front and back areas of the first shot product exist during the injection, and the product is no longer deformed under the force of the two sides. S2, injection verification of the injection cavity designed in S1, and batch injection after the appearance of the injection product is not bad; S3, first, the first shot cavity is injected, and the second shot cavity is not injected at this time. When the first shot completes the filling, pressure maintaining and cooling, the injection machine starts to open the mold, and after the mold is opened, the injection mold is rotated to make the first shot product reach the second shot injection position. S4, the injection mold is closed, the second shot cavity is injected, and the product is taken out after filling, pressure maintaining and cooling.

[0024] Using double-color injection molding, the first shot injection has no difference from single-color injection molding and there is no problem. However, when the first shot product is rotated to the second shot, the part of the first shot product has no support on the sidewall during the second shot injection, and the high injection pressure deforms the first shot product, resulting in that qualified products cannot be produced. Based on this situation, CAE is used for mold flow analysis to predict the area that is easy to be offset during the filling process. The wall thickness part that should be formed by the second shot is designed to be formed by the first shot. In this way, during the second shot injection, the injection plastic will flow to the back of the product before the product deforms under the action of the flow separation and flow blocking of the part. The back of the first shot product has support. During the continuous injection, the front and back areas of the first shot product exist under the injection pressure, and the product is no longer deformed under the force of the two sides.

[0025] Further, the first shot product is an internal part, and the second shot product is an appearance part covering the first shot product.

[0026] As shown in Figures 1-4 A double-color molding injection mold for solving the problem of poor product appearance, comprising: The fixed mold 1 comprises a fixed mold plate 11, a hot runner distribution plate 12 connected with the fixed mold plate 11 through a limiting bolt 13, a first fixed mold insert 14 and a second fixed mold insert 15 arranged at the bottom of the hot runner distribution plate 12, and a first fixed mold core 16 and a second fixed mold core 17 embedded in the fixed mold plate 11 and combined with the first fixed mold insert 14 and the second fixed mold insert 15 respectively; The movable mold 2 comprises a movable mold plate 21, a first movable mold core 22 and a second movable mold core 23 embedded in the movable mold plate 21 and combined with the first fixed mold core 16 and the second fixed mold core 17 to form a first cavity and a second cavity respectively; The time-delay mold opening mechanism 3 comprises a locking rod 31 arranged on the side of the hot runner distribution plate 12, a locking piece 32 embedded in the side of the fixed mold plate 11 and provided with a spring between the locking piece 32 and the fixed mold plate 11, and a locking buckle 33 arranged on the side of the movable mold plate 21, wherein the locking rod 31 is provided with a avoiding groove 311 capable of accommodating the locking piece 32 and a pressing head 312 capable of compressing the locking piece 32, the length of the avoiding groove 311 is greater than the vertical width of the locking piece 32, and the locking buckle 33 can be locked with the locking piece 32 to lock the movable mold plate 21 and the fixed mold plate 11.

[0027] The locking buckle 33 is vertically provided with a slot capable of accommodating the locking rod 31, and is transversely provided with a smooth inclined surface between the avoiding groove 311 and the pressing head 312; The fixed mold plate 11 is provided with a stepped hole, the limiting bolt 13 is connected with the hot runner distribution plate 12 through the stepped hole, and the bottom of the limiting bolt 13 can move up and down in the lower part of the stepped hole.

[0028] In the mold closing state, the locking rod 31 is inserted into the locking buckle 33, at this time the avoiding groove 311 faces the locking piece 32, the locking piece 32 is also popped out under the action of the spring, and the locking buckle 33 is locked with the locking piece 32. When the mold is opened, the fixed mold plate 11 moves together with the movable mold plate 21, and the hot runner distribution plate 22 is separated therefrom, until the limiting bolt 13 moves to the variable diameter part of the stepped hole, the fixed mold plate 11 cannot move together with the movable mold plate 21 any more, at the same time the pressing head 312 on the locking rod 31 completely presses the locking piece 32 into the mold, the locking buckle 33 is unlocked with the locking piece 32, and the mold is continuously opened to be completely opened, so that the insert is separated from the product first, the fixed mold core is separated from the product secondly, and finally the product is left on the movable mold 2, thereby solving the risk of product sticking to the front mold through the time-delay mold opening mechanism 3.

[0029] Specifically, the fixed mold 1 further comprises a fixed mold panel 18 arranged on the upper part of the hot runner distribution plate 12, and a group of injection ports are arranged on the fixed mold panel 18. The hot runner distribution plate 12 is embedded with a one-shot runner 121 and a two-shot runner 122, and the injection port is communicated with a one-shot cavity and a two-shot cavity through the one-shot runner 121 and the two-shot runner 122 respectively.

[0030] Specifically, the one-shot die insert 14 is internally provided with a cooling water jacket, the two-shot die insert 15 is internally provided with a spiral cooling water jacket, and the spiral cooling water jacket is provided with a spiral cooling runner.

[0031] Specifically, the cooling water jacket is located outside the one-shot runner 121, and the spiral cooling runner uniformly covers the outside of the two-shot runner 122.

[0032] For the two-shot product as an appearance part, the conventional straight waterway water jacket cannot closely adhere to the product shape due to the screw position or product structure and other reasons when designing, which will cause the cooling to be fast near the waterway and slow far away, and easy to produce warping, shrinkage and internal stress on the product. Therefore, the spiral cooling water jacket consistent with the product surface profile is manufactured based on the 3D printing technology. This makes the cooling liquid more uniformly take away heat, greatly reduces the hot spot and uneven cooling, and improves the product quality.

[0033] In a preferred embodiment, the movable die 2 further comprises a movable die bottom plate 24 arranged below the movable die plate 21, and a square iron block 25 is arranged between the movable die bottom plate 24 and the movable die plate 21 to form an overhead layer.

[0034] The overhead layer is provided with an ejection assembly 4, which comprises a liftable bottom plate 41, a ejector rod 42 connected through the movable die bottom plate 24 and the bottom plate 41, a spring sleeved on the ejector rod 42, a ejector pin 43 arranged on the bottom plate 41, and the ejector pin 42 can communicate with the one-shot cavity and the two-shot cavity through the movable die plate 21.

[0035] The external driving device lifts the bottom plate 41 through the ejector rod 42, the bottom plate drives the ejector pin 43 to move upwards, the ejector pin 43 deeply penetrates into the cavity to lift the product, thereby realizing automatic demolding.

[0036] The complete molding process of the present application is as follows: When the mold is in the closed state: the fixed die 1 is fixed on the fixed die side of the injection molding machine, and the movable die 2 is fixed on the movable die side of the injection molding machine by a clamp plate.

[0037] After the mold is closed, the one-shot nozzle is opened, and plastic is injected into the one-shot cavity of the mold, and the two-shot is not injected at this time. After the one-shot completes the three stages of filling, pressure maintaining and cooling, the injection molding machine starts to open the mold.

[0038] When the mold is closed, the locking intermediate 32 is locked with the locking buckle 33 under the action of the spring. When the mold is opened, the locking intermediate 32 and the locking buckle 33 are still locked together, so the fixed mold plate 11 and the movable mold plate 21 cannot be opened at this time. Under the drive of the injection molding machine, the movable mold plate 21 moves with the fixed mold plate 11 to the movable mold side. Since the first injection mold insert 14 and the second injection mold insert 15 are installed on the hot runner distributor plate 12 and cannot move with the fixed mold plate 11, the first injection mold insert 14 and the second injection mold insert 15 are separated from the plastic product.

[0039] When the injection molding machine is opened to a certain distance, the locking intermediate 32 is driven by the locking pull rod 31 to compress the spring and move to the inside of the mold until the locking buckle 33 and the locking intermediate 32 are separated. The injection molding machine continues to run, and since the fixed mold plate 11 is locked by the limiting bolt 13 and cannot continue to move with the movable mold plate 21, the movable mold plate 21 and the fixed mold plate 11 are opened at this time. The fixed mold plate 11 stops moving, and the movable mold plate 21 side continues to move until the mold is completely opened. At this time, the mold 2 continues to move until it reaches the set opening position.

[0040] Then the movable mold 2 is rotated 180 degrees under the drive of the injection molding machine. At this time, the first injection product is below the second injection fixed mold insert 15, the injection molding machine is closed, and the second injection nozzle starts to fill, hold pressure, and cool. Then the mold is opened, and finally the second injection product is ejected under the action of the ejection assembly 4 and leaves the injection molding machine device with the help of the robot.

[0041] The above is only the preferred embodiment of the present application. It should be noted that for ordinary skilled in the art, without departing from the principles of the present application, several improvements can be made, and these improvements should be considered as the protection scope of the present application.

Claims

1. A two-color molding process for solving appearance defects of a product, characterized by, It comprises the following steps: S1, injection cavity design, using CAE software for mold flow analysis, to predict the two shot filling process easy to be offset by the area of the first shot product, the area corresponding to the two shot product part in the first shot cavity, the first shot product easy to be offset position is enhanced, the two shot injection when the plastic will flow to the product back before the product deformation, at this time the first shot product back has support, continue to injection when the first shot product before and after the area exists injection pressure, both sides are stressed at the same time so that the product is no longer deformed; S2, injection verification of the injection cavity designed in S1, no adverse effects on the appearance of the injection product can be mass injection; S3, first, the first shot cavity injection, at this time the two shot cavity is not injected, when the first shot completes the filling-holding-cooling three stages, the injection machine starts to open the mold, after the mold is opened, the injection mold is rotated to make the first shot product to the two shot injection position; S4, injection mold closing, two shot cavity injection, after filling-holding-cooling, the product is taken out.

2. The bi-color molding process for solving product appearance defects according to claim 1, wherein The first shot product is an internal part, and the two shot product is an appearance part wrapped outside the first shot product.

3. A double-color molding injection mold for solving appearance defects of a product, for implementing the double-color molding process for solving appearance defects of a product according to any one of claims 1 to 2, characterized by, It comprises: The fixed mold (1) comprises a fixed mold plate (11), a hot runner distribution plate (12), the hot runner distribution plate (12) is connected with the fixed mold plate (11) through a limiting bolt (13), the hot runner distribution plate (12) is provided with a first shot fixed mold insert (14) and a two shot fixed mold insert (15) at the bottom, and the fixed mold plate (11) is embedded with a first shot fixed mold core (16) and a two shot fixed mold core (17) which are respectively embedded with the first shot fixed mold insert (14) and the two shot fixed mold insert (15); The movable mold (2) comprises a movable mold plate (21), the movable mold plate (21) is embedded with a first shot movable mold core (22) and a two shot movable mold core (23), and the first shot movable mold core (22) and the two shot movable mold core (23) are combined with the first shot fixed mold core (16) and the two shot fixed mold core (17) to form a first shot cavity and a two shot cavity; The delayed mold opening mechanism (3) comprises a clamping rod (31) arranged on the side of the hot runner distribution plate (12), a clamping intermediate (32) embedded on the side of the fixed mold plate (11), a spring arranged between the clamping intermediate (32) and the fixed mold plate (11), a clamping buckle (33) arranged on the side of the movable mold plate (21), the clamping rod (31) is provided with an avoidance groove (311) capable of accommodating the clamping intermediate (32), and the bottom is provided with a pressure head (312) capable of compressing the clamping intermediate (32), the length of the avoidance groove (311) is greater than the vertical width of the clamping intermediate (32), and the clamping buckle (33) can be locked with the clamping intermediate (32) to lock the movable mold plate (21) and the fixed mold plate (11).

4. The dual-color molding injection mold for solving a product appearance defect according to claim 3, wherein The clamping buckle (33) is vertically provided with a slot for inserting the clamping rod (31), and the clamping buckle (33) is horizontally provided with a smooth inclined surface between the avoidance groove (311) and the pressure head (312); The fixed mold plate (11) is provided with a stepped hole, the limiting bolt (13) passes through the stepped hole and is connected with the hot runner distribution plate (12) at the top end, and the bottom of the limiting bolt (13) can move up and down in the lower part of the stepped hole.

5. The dual-color molding injection mold for solving a product appearance defect according to claim 3, wherein The fixed mold (1) further comprises a fixed mold panel (18) arranged on the upper part of the hot runner distribution plate (12), and a group of injection ports are arranged on the fixed mold panel (18); The hot runner distribution plate (12) is embedded with a first jet channel (121) and a second jet channel (122), and the injection ports are respectively communicated with a first cavity and a second cavity through the first jet channel (121) and the second jet channel (122).

6. The dual-color molding injection mold for solving a product appearance defect according to claim 5, wherein The first fixed mold insert (14) is internally provided with a cooling water jacket, and the second fixed mold insert (15) is internally provided with a spiral cooling water jacket, and the spiral cooling water jacket is provided with a spiral cooling flow channel.

7. The dual-color molding injection mold for solving a product appearance defect according to claim 6, wherein The cooling water jacket is located on the outside of the first jet channel (121), and the spiral cooling flow channel uniformly covers the outside of the second jet channel (122).

8. The dual-color molding injection mold for solving product appearance defects according to claim 3, wherein The movable mold (2) further comprises a movable mold base plate (24) arranged below the movable mold plate (21), and a square iron block (25) is arranged between the movable mold base plate (24) and the movable mold plate (21) to form an overhead layer.

9. The dual-color molding injection mold for solving a product appearance defect according to claim 8, wherein The overhead layer is provided with an ejection assembly (4), the ejection assembly (4) comprises a liftable bottom plate (41), a ejector rod (42) connected with the bottom plate (41) through the movable mold base plate (24), a spring sleeved on the ejector rod (42), a ejector pin (43) arranged on the bottom plate (41), and the ejector pin (42) can pass through the movable mold plate (21) and be communicated with the first cavity and the second cavity.

Images