Injection mold, injection molding method and injection molding part for island-type two-color injection molding parts

Abstract

The present invention provides an injection mold, an injection molding method and an injection molded part for an island-type two-color injection molded part, comprising a rear mold, a first front mold and a second front mold; the first front mold comprises an island region, a gap connecting the island region and an external space is formed on the peripheral side of the island region, and both sides of the gap are provided with a gradual protrusion. By providing a gap on the first front mold and providing a gradual protrusion on both sides of the gap, when the first color block is injected, a gap for connecting the island region and the external space can be formed on the first color block, and a deformation part corresponding to the gradual protrusion is formed on both sides of the gap, and then the deformation part is closed to the gap by the force applied in the process of closing the second front mold, and a channel is formed at the bottom of the gap, so that when the second color block is injected, the injection liquid can enter the island region through the channel, the structure is simple, the operation is convenient, the cost is low, and the convenience of injection molding of products with islands is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of injection molding, and in particular to an injection mold, an injection molding method and an injection molded part for an island-type two-color injection molded part. Background Art

[0002] A two-color mold is a mold that uses two plastic materials to be molded on the same injection molding machine, and is molded twice, but the product is only ejected once. The requirements for the product are generally that the same color products must be connected, or connected through other flow channels, and the requirements for the mold are to use two identical rear molds or two identical front molds that are inverted.

[0003] There are currently three methods for products with isolated islands: 1. Make water entry directly on the isolated island; 2. Make a lifting structure on the rear mold, and move the second color movable parts backward to make space to connect to the isolated island from the bottom; 3. Open a gap on the front to connect the isolated island with the outside world.

[0004] The existing Chinese patent application with publication number CN215619551U discloses an island-shadowless two-color closed-mouth character mold, including a bottom mold and a top mold, the bottom mold is provided with an injection bottom cavity and an island injection molding component, the top mold is provided with a single-color injection top cavity and a two-color injection top cavity, the single-color injection top cavity is provided with an island closed molding column that cooperates with the island injection molding component, the cross-sectional area of ​​the island closed molding column gradually decreases toward the direction approaching the island injection molding component, the island injection molding component includes a square top column and a runner ejector pin, the square top column is provided with a pouring channel that cooperates with the two-color injection molding top cavity, and the injection bottom cavity cooperates with the single-color injection top cavity and the two-color injection top cavity in turn.

[0005] In the prior art, water is directly added to the island, which increases the weight and cost of the flow channel. If the area of ​​the island is not large enough to add water, this method cannot be implemented. The rear mold is used as a lifting structure, and the second color movable part retreats to make room to connect the island from the bottom. The mold structure is complex, which increases the cost and the maintenance risk in production. A gap is opened on the front of the product to connect the island to the outside world, which greatly changes the appearance of the product.

[0006] At present, the market is in urgent need of an injection molding method that has a simple structure, low cost, and does not change or only slightly changes the appearance of the product and is used to solve the problem of isolated material position injection. Summary of the invention

[0007] In view of the defects in the prior art, the object of the present invention is to provide an injection mold, an injection molding method and an injection molded part for an island-type two-color injection molded part.

[0008] According to the present invention, an injection mold for an island-type two-color injection molded part comprises a rear mold, a first front mold and a second front mold, wherein the rear mold and the first front mold cooperate to form a first-color injection space, and the rear mold and the second front mold cooperate to form a second-color injection space; the first front mold comprises an island area, a notch connecting the island area and the external space is formed on the peripheral side of the island area, and both sides of the notch are provided with a gradual protrusion; any of the gradual protrusions gradually convex from the end away from the notch to the end close to the notch, and the side surface of any of the gradual protrusions close to the notch is coplanar with the corresponding side surface of the notch, and the side surface of any of the gradual protrusions close to the notch is smoothly connected to the top surface of the gradual protrusion through an R angle.

[0009] Preferably, the top surface of the gradually changing raised portion extends upward from an end away from the notch to an end close to the notch through a continuous arc surface.

[0010] Preferably, the R angle connecting the side surface of the gradual protrusion close to the notch and the top surface of the gradual protrusion is greater than 50 degrees and less than 90 degrees.

[0011] Preferably, the height of the side surface of the gradual protrusion close to the notch is less than or equal to half the size of the notch.

[0012] According to an injection molding method for an island-type two-color injection molded part provided by the present invention, the injection molding method comprises the following steps: S1, closing a first front mold and a rear mold and injecting a first color block; S2, taking out the first front mold, closing a second front mold and a rear mold, when the second front mold is closed, the cavity of the second front mold presses and bends the portion of the first color block corresponding to the gradual protrusion, and causes the portion of the first color block corresponding to the gradual protrusion to deform and close toward the notch, when the second front mold is closed in place, the portion of the first color block corresponding to the gradual protrusion forms a channel connecting the island area and the external space at the bottom of the notch; S3, injecting the second color block, and the injection liquid enters the island area through the channel; S4, after the second color block is completely formed, separating the second front mold and the rear mold to take out the injection molded part.

[0013] Preferably, for step S2, when the second front mold is closed, the temperature of the first color block is 50°C-80°C.

[0014] Preferably, the volume of the portion of the first color block corresponding to the gradual protrusion is greater than or equal to the volume of the first color block extending to the notch.

[0015] According to an injection molded part provided by the present invention, the first color block includes a shaping portion, the shaping portion includes at least one isolated island area, the second color block covers a large surface of the first color block having the shaping portion, and the shaping portion protrudes from the second color block; the shaping portion includes a notch connecting the isolated island area and the external space, the shaping portions on both sides of the notch are provided with deformation portions, and any of the deformation portions extends toward the middle of the notch.

[0016] Preferably, the upper surface of the deformation portion is coplanar with the upper surface of the shaping portion, and the connection between the lower surface of the deformation portion and the shaping portion forms an arc-shaped connection angle.

[0017] Preferably, the two deformation parts located on both sides of the notch are in contact or clearance fit.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention sets a notch for connecting the isolated island area and the external space on the first front mold, and sets gradient protrusions on both sides of the notch, so that when the first color block is injected, a notch for connecting the isolated island area and the external space can be formed on the first color block, and deformation parts corresponding to the gradient protrusions are formed on both sides of the notch, and then the deformation part is closed to the notch by the force applied during the closing process of the second front mold, and a channel is formed at the bottom of the notch, so that when the second color block is injected, the injection liquid can enter the isolated island area through the channel. The structure is simple, the operation is convenient, the cost is low, and the appearance of the product is not changed or is slightly changed, which helps to improve the convenience of injection molding of products with isolated islands.

[0020] 2. The present invention arranges the top surface of the gradual protrusion to extend upward from the end away from the notch to the end close to the notch through a continuous arc surface, and the side surface of the gradual protrusion close to the notch and the top surface of the gradual protrusion are smoothly connected through an R angle. This helps to apply the force of the second front mold surface to the deformation part of the first color block when the second front mold is closed, causing the deformation part to extend toward the notch.

[0021] 3. The present invention closes the second front mold when the temperature of the first color block is 50° C.-80° C., which helps to enable the deformation part of the first color block to deform under the action of force and helps to reduce the occurrence of collapse of the deformation part. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0023] Figure 1 It is a top view of the main structure of the first front mold of the present invention;

[0024] Figure 2 This is a schematic diagram of the present invention mainly showing the second front mold and the rear mold starting to close the mold;

[0025] Figure 3 The present invention mainly embodies the schematic diagram of the second front mold and the rear mold closing process;

[0026] Figure 4This is a force diagram of the deformation part on the first color block when the second front mold and the rear mold are molded together;

[0027] Figure 5 This is a front schematic diagram mainly showing the overall structure of the first color block of the present invention;

[0028] Figure 6 It is a front schematic diagram mainly showing the overall structure of the injection molded part of the present invention.

[0029] As shown in the figure:

[0030] Back mold 1 channel 6

[0031] First front mold 2 First color block 7

[0032] Second front mold 3 Second color block 8

[0033] Isolated island area 4 Modeling department 9

[0034] Gradual protrusion 5 Deformation portion 10 DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0036] like Figure 1 As shown, an injection mold for an island-type two-color injection molded part provided according to the present invention includes a rear mold 1, a first front mold 2 and a second front mold 3. The rear mold 1 and the first front mold 2 cooperate to form a first color injection space, and the rear mold 1 and the second front mold 3 cooperate to form a second color injection space.

[0037] The first front mold 2 includes an island region 4, a notch connecting the island region 4 and the external space is formed on the peripheral side of the island region 4, and both sides of the notch are provided with a gradual protrusion 5. Any gradual protrusion 5 is gradually convex from the end away from the notch to the end close to the notch, and the side surface of any gradual protrusion 5 close to the notch is coplanar with the corresponding side surface of the notch, and the side surface of any gradual protrusion 5 close to the notch is connected to the top surface of the gradual protrusion 5 through an R angle.

[0038] It should be noted that when performing the second color injection molding, the island area 4 is located in the second color injection molding space formed by the cooperation of the second front mold 3 and the rear mold 1, and the cavity shape and size of the second front mold 3 meet the requirements that when the second front mold 3 is closed, downward pressure will be applied to the part of the first color block 7 corresponding to the gradient raised portion 5.

[0039] It is more important to note that the R angle in this application refers to the arc of the angle between the side of the gradual protrusion 5 close to the notch and the top surface of the gradual protrusion 5. In order to ensure that the portion of the first color block 7 corresponding to the gradual protrusion 5 can be deformed to extend toward the notch when subjected to the downward pressure applied by the second front mold 3, the R angle connecting the side of the gradual protrusion 5 close to the notch and the top surface of the gradual protrusion 5 is set to be greater than 50 degrees and less than 90 degrees. The top surface of the gradual protrusion 5 is set to extend upward from the end away from the notch to the end close to the notch through a continuous arc surface.

[0040] Specifically, the shape and volume of the gradual protrusion 5 need to be adaptively set according to actual conditions, wherein the height of the gradual protrusion 5 near the side of the notch is less than or equal to half the size of the notch, and the volume of the gradual protrusion 5 is less than half the volume of the notch.

[0041] A feasible implementation is: the first front mold 2 includes two island regions 4 of similar shape, the two island regions 4 are arranged side by side and spaced apart, and the gaps connecting the two island regions 4 with the external space are located on the sides away from each other. The second front mold 3 includes a cavity corresponding to the island region 4, and the cavity of the second front mold 3 and the mold surface corresponding to the circumference of the island region 4 are a whole plane, so that a downward force can be applied to the first color block 7 and the gradient protrusion 5 when the second front mold 3 is closed.

[0042] The present application also includes an injection molding method for an island-type two-color injection molded part, the injection molding method comprising the following steps:

[0043] S1, closing the first front mold 2 and the rear mold 1 and injecting the first color block 7. Specifically, the first front mold 2 and the rear mold 1 are closed to form a first color injection space, and then the injection liquid for injecting the first color block 7 is injected into the first color injection space to form the first color block 7.

[0044] S2. Take out the first front mold 2, and close the second front mold 3 and the rear mold 1. When the second front mold 3 is closed, the cavity of the second front mold 3 bends the portion of the first color block 7 corresponding to the gradual protrusion 5, and causes the portion of the first color block 7 corresponding to the gradual protrusion 5 to deform and close toward the notch. When the second front mold 3 is closed in place, the portion of the first color block 7 corresponding to the gradual protrusion 5 forms a channel 6 at the bottom of the notch that connects the island area 4 and the external space.

[0045] It should be noted that in order to ensure that the first color block 7 and the corresponding part of the gradual protrusion 5 have appropriate structural strength, so as to be able to deform under the force of the second front mold 3 and the deformed part 10 will not collapse, the second front mold 3 is molded when the temperature of the first color block 7 is selected to be 50℃-80℃.

[0046] Since the portion of the first color block 7 extending to the gap is formed by deformation of the portion of the first color block 7 corresponding to the gradual protrusion 5, the volume of the portion of the first color block 7 corresponding to the gradual protrusion 5 is greater than or equal to the volume of the first color block 7 extending to the gap.

[0047] S3 , injecting the second color block 8 , and the injection liquid enters the isolated island area 4 through the channel 6 .

[0048] S4. After the second color block 8 is completely formed, the second front mold 3 and the rear mold 1 are separated to take out the injection molded part.

[0049] The present application also includes an injection molded part, including a first color block 7 and a second color block 8, the first color block 7 includes a shaping portion 9, the shaping portion 9 includes at least one island area 4, the second color block 8 covers the large surface of the first color block 7 having the shaping portion 9, and the shaping portion 9 protrudes from the second color block 8.

[0050] The shaping part 9 includes a gap connecting the isolated island area 4 and the external space. The shaping parts 9 on both sides of the gap are provided with a deformation part 10, and any deformation part 10 extends to the middle of the gap. The upper surface of the deformation part 10 is coplanar with the upper surface of the shaping part 9, and the lower surface of the deformation part 10 forms an arc connection angle with the connection of the shaping part 9. The two deformation parts 10 on both sides of the gap are in contact or clearance fit.

[0051] A feasible implementation is: the shape of the molding part 9 is similar to an "8" shape, and a notch is provided on the upper and lower sides of the "8"-shaped central axis of the molding part 9. The upper surfaces of the four deformation parts 10 are coplanar with the upper surface of the molding part 9, and ideally, the lower surface of the deformation part 10 forms an arc connection angle with the molding part 9, and the two deformation parts 10 located on both sides of any notch are in contact or clearance fit. Thus, the surface of the injection molded part is slightly changed or even unchanged.

[0052] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0053] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. An injection mold for island-type two-color injection molded parts, characterized in that: It comprises a rear mold (1), a first front mold (2) and a second front mold (3), wherein the rear mold (1) and the first front mold (2) cooperate to form a first color injection molding space, and the rear mold (1) and the second front mold (3) cooperate to form a second color injection molding space; The first front mold (2) comprises an isolated island region (4), a gap connecting the isolated island region (4) and the external space is formed on the peripheral side of the isolated island region (4), and both sides of the gap are provided with gradually changing protruding portions (5); Any of the gradually changing raised portions (5) are gradually raised from the end away from the notch to the end close to the notch, the side surface of any of the gradually changing raised portions (5) close to the notch is coplanar with the corresponding side surface of the notch, and the side surface of any of the gradually changing raised portions (5) close to the notch is smoothly connected to the top surface of the gradually changing raised portion (5) through an R angle.

2. The injection mold for island-type two-color injection molded parts according to claim 1, characterized in that: The top surface of the gradually changing raised portion (5) extends upward from an end away from the notch to an end close to the notch through a continuous arc surface.

3. The injection mold for island-type two-color injection molded parts according to claim 1, characterized in that: The R angle connecting the side surface of the gradually changing raised portion (5) close to the notch and the top surface of the gradually changing raised portion (5) is greater than 50 degrees and less than 90 degrees.

4. The injection mold for island-type two-color injection molded parts according to claim 1, characterized in that: The height of the side surface of the gradual protrusion (5) close to the notch is less than or equal to half the size of the notch.

5. An injection molding method for island-type two-color injection molding parts, characterized in that: Using the injection mold for island-type two-color injection molded parts according to any one of claims 1 to 4, the injection molding method comprises the following steps: S1, closing the first front mold (2) and the rear mold (1) and injecting the first color block (7); S2, taking out the first front mold (2), and closing the second front mold (3) with the rear mold (1); when the second front mold (3) is closed, the mold cavity of the second front mold (3) presses and bends the portion of the first color block (7) corresponding to the gradual protrusion (5), and causes the portion of the first color block (7) corresponding to the gradual protrusion (5) to deform and close toward the notch; when the second front mold (3) is closed in place, the portion of the first color block (7) corresponding to the gradual protrusion (5) forms a channel (6) at the bottom of the notch that connects the isolated island area (4) and the external space; S3, injecting the second color block (8), and the injection liquid enters the isolated island area (4) through the channel (6); S4. After the second color block (8) is completely formed, the second front mold (3) and the rear mold (1) are separated to remove the injection molded part.

6. The injection molding method for island-type two-color injection molded parts according to claim 5, characterized in that: With respect to step S2, when the second front mold (3) is closed, the temperature of the first color block (7) is between 50°C and 80°C.

7. The injection molding method for island-type two-color injection molded parts according to claim 5, characterized in that: The volume of the first color block (7) and the corresponding portion of the gradually changing raised portion (5) is greater than or equal to the volume of the first color block (7) extending to the notch.

8. An injection molded part, characterized in that: The injection mold for an island-type two-color injection molded part according to any one of claims 1 to 4 is used for injection molding, comprising a first color block (7) and a second color block (8), wherein the first color block (7) comprises a molding portion (9), wherein the molding portion (9) comprises at least one island region (4), and the second color block (8) covers a large surface of the first color block (7) having the molding portion (9), and the molding portion (9) protrudes from the second color block (8); The shaping portion (9) comprises a gap connecting the isolated island region (4) and the external space, and the shaping portions (9) on both sides of the gap are provided with deformation portions (10), and any of the deformation portions (10) extends towards the middle of the gap.

9. The injection molded part according to claim 8, characterized in that The upper surface of the deformation portion (10) is coplanar with the upper surface of the shaping portion (9), and the connection between the lower surface of the deformation portion (10) and the shaping portion (9) forms an arc-shaped connection angle.

10. The injection molded part according to claim 8, characterized in that: The two deformation parts (10) located on both sides of the notch are in contact or clearance fit.

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