Pattern forced demolding mold structure utilizing product shrinkage

Abstract

The utility model discloses a grain forced demoulding mould structure utilizing product shrinkage, which comprises a front mould assembly and a rear mould assembly, the rear mould assembly comprises a rear mould core, an ejector pin, a material pulling pin and a base, and the front mould assembly and the rear mould assembly are assembled to form a product cavity during injection molding. The product cavity comprises a product cavity for forming a product after injection molding and a runner cavity for forming a material handle; the rear mold core is located on the side face of the product cavity, the ejector pin penetrates through the rear mold core to be located at the bottom of the product cavity, the runner cavity is located between the bottom of the product cavity and the top of the ejector pin, the tail end of the material pulling pin is fixed to the base, and the head end of the material pulling pin penetrates through the ejector pin to be arranged in the runner cavity. The ejector pin is provided with a driving device and moves up and down in the rear mold core, and the material pulling pin moves up and down in the ejector pin. According to the utility model, the die development cost can be reduced, and the production efficiency is improved; the product has no joint line on the side surface and is delicate in appearance; the product end face joint line can be better controlled, and the burr risk is reduced.

Description

Technical Field

[0001] This utility model relates to the field of injection molding machine mold structure technology, specifically a mold release structure that utilizes the texture of product shrinkage. Background Technology

[0002] There are many types of products produced by injection molding. Some products have strong demolding structures. These products often have mating snaps and protruding structural textures on the outer demolding surface, such as bottle caps with anti-slip textures on the outside. To prevent product damage during injection molding and demolding, which would affect the product's appearance, the mold is usually designed as a slider structure. However, this not only increases the cost of mold making, but also reduces production efficiency. Utility Model Content

[0003] This invention addresses the problem of product tearing during demolding of injection molded products with mating fasteners and protruding structural textures on the outer demolding surface. It utilizes the shrinkage that occurs when plastic products are injected into the mold and cooled to design a demolding structure that uses the shrinkage of the plastic to prevent tearing and can reduce costs and increase efficiency by utilizing the texture of the product shrinkage.

[0004] Therefore, the present invention provides the following technical solution:

[0005] A mold structure utilizing product shrinkage texture for forced demolding includes a front mold assembly and a rear mold assembly. The rear mold assembly includes a rear mold core, an ejector pin, a pull pin, and a base. During injection molding, the front mold assembly and the rear mold assembly close to form a product cavity. The product cavity includes a product cavity that forms the product after injection molding and a runner cavity that forms the sprue. The rear mold core is located on the side of the product cavity. The ejector pin passes through the rear mold core and is located at the bottom of the product cavity. The runner cavity is located between the bottom of the product cavity and the top of the ejector pin. The tail end of the pull pin is fixed to the base, and the head end passes through the ejector pin and is located in the runner cavity. The ejector pin is equipped with a driving device and moves up and down within the rear mold core. The pull pin moves up and down within the ejector pin.

[0006] This solution addresses the shrinkage that occurs during the cooling process of plastic products after injection molding. It designs a mold structure that utilizes shrinkage to prevent tearing and reduces costs while increasing efficiency. The mold structure is based on an existing mold structure, with the addition of a pull pin component. The pull pin can move up and down within the ejector pin. During injection, its tip is positioned at the product sprue and surrounded by the sprue formed after injection. The sprue is the excess part of the product during injection. The tail end of the pull pin is fixed relative to the rear mold core. During demolding, the rear or front mold moves, and the pull pin moves together with the rear mold, pulling the sprue and the product along with it, separating the product from the front mold. Then, the injection molding machine drives the ejector pin to rise, pushing the product and the sprue upwards while the pull pin remains stationary. This allows the tip of the pull pin to detach from the sprue. The movement of the ejector pin is driven by the ejector plate. The ejector plate is located at the bottom of the ejector pins and can be driven by electric or pneumatic means. After the injection molding machine installs the mold, it injects material into the mold. After the hot material cools, the injection molding machine drives the rear mold components to move in the demolding direction. At this time, the pull pin is embedded in the sprue, which drives the product that has not separated from the sprue to move with the rear mold components. The front mold components are ejected, and the product is separated from the front mold. The product that has not been completely cooled is further cooled and shrunk under the action of the rear mold cooling water pipe. After the product material has cooled, shrunk, and deformed, the external texture structure of the product separates from the rear mold cavity, creating a gap. After the product has cooled, the injection molding machine drives the ejector plate and ejector rod, and the product moves in the demolding direction. The sprue separates from the pull pin, and the product is ejected from the rear mold cavity. It then moves with the ejector plate in the demolding direction under the action of the ejector pins, and the product demolding is completed.

[0007] As a preferred embodiment of this utility model, the product is a bottle cap. Bottle caps are a common injection-molded product. The outer side of the bottle cap usually has anti-slip textures or other raised patterns. During injection molding, a slider is usually set in the mold to avoid scratching the surface of the bottle cap. By adopting this solution, the slider can be eliminated, reducing the complexity of the mold and speeding up the production time.

[0008] In a preferred embodiment of this invention, during the molding and demolding of the front and rear mold components, the front mold component remains stationary while the rear mold component is driven to move up and down by the injection molding machine. The rear mold component of this design is equipped with a main drive mechanism that drives its upward and downward movement. The rear mold component also includes an ejector drive mechanism that can drive the ejector plate to rise and fall independently. The rising and falling of the ejector plate can also drive the ejector pins to rise and fall, similar to existing molds. This design, by having the front mold component fixed and the rear mold component driven to move up and down by the injection molding machine, concentrates the drive mechanism in the rear component, resulting in a compact mold structure and simplified control process.

[0009] In a preferred embodiment of this invention, the front mold assembly includes a front mold core, a water-running inner core, and a front mold core. The front mold core and the rear mold core are fitted together. The water-running inner core passes through the front mold core, and the front mold core passes through the water-running inner core. The bottom of the front mold core, the water-running inner core, and the front mold core, together with the rear mold core, ejector pin, and the top of the pull pin of the rear mold assembly, close the mold during injection molding to form a product cavity. This solution is a feasible structure for forming a product cavity, and the pull pin is also part of the cavity.

[0010] In a preferred embodiment of this invention, the front mold core, the water-running core, and the bottom of the front mold core are located inside the product cavity to form an inner core, while the rear mold core, ejector pin, and the top of the pull pin are located outside the product cavity to form an outer core. This embodiment is designed for products shaped like bottle caps, where the inner core is protruding and is located inside the grooved outer core during injection molding.

[0011] In a preferred embodiment of this utility model, the front mold assembly and rear mold assembly form multiple product cavities during injection molding, and injection runners are provided between these multiple product cavities. These injection runners are connected to the runner cavities of the multiple product cavities. When producing the bottle cap products targeted by this solution, for the same size, a mold using a slider structure produces four bottle caps at a time, while a mold using the pull-pin structure of this solution can produce eight bottle caps at a time. Each bottle cap cavity is equipped with a corresponding set of ejector pins and pull-pins, and all ejector pins can be driven by the same ejector plate, thereby greatly improving production efficiency.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The original structure required a slider mold, which was costly. The current method can reduce mold development costs. Slider molds have low production efficiency, while the current method improves efficiency. Sliderless production results in products with no parting lines on the sides, leading to a refined appearance. Sliderless production also allows for better control of the parting lines on the product's end faces, reducing the risk of burrs. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the present invention during mold closing.

[0015] Figure 2 This is a schematic diagram of the structure during mold making for this utility model.

[0016] Figure 3 This is a schematic diagram of a structure for the material pulling pin to detach according to this utility model.

[0017] In the diagram: 1. Front mold assembly; 2. Rear mold assembly; 3. Product cavity; 4. Product.

[0018] 5. Material holder; 11. Front mold core; 12. Water channel core; 13. Front mold core

[0019] 21. Rear mold core; 22. Ejector pin; 23. Pull pin. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Please see Figures 1-3 ,

[0022] A mold release structure utilizing the shrinkage texture of a product includes a front mold assembly 1 and a rear mold assembly 2. The rear mold assembly 2 includes a rear mold core 21, an ejector pin 22, a pull pin 23, and a base. During injection molding, the front mold assembly 1 and the rear mold assembly 2 are closed to form a product cavity 3. The product cavity 3 includes a product cavity that forms the product 4 after injection molding and a runner cavity that forms the sprue 5. The rear mold core 21 is located on the side of the product cavity. The ejector pin 22 passes through the rear mold core 21 and is located at the bottom of the product cavity. The runner cavity is located between the bottom of the product cavity and the top of the ejector pin 22. The tail end of the pull pin 23 is fixed to the base, and the head end passes through the ejector pin 22 and is located in the runner cavity. The ejector pin 22 is equipped with a driving device and moves up and down within the rear mold core 21. The pull pin 23 moves up and down within the ejector pin 22.

[0023] Product 4 is a bottle cap.

[0024] When the front mold assembly 1 and the rear mold assembly 2 are closed for injection molding and demolded after injection molding, the front mold assembly 1 remains stationary while the rear mold assembly 2 is driven up and down by the injection molding machine.

[0025] The front mold assembly 1 includes a front mold core 11, a water channel core 12, and a front mold core 13. The front mold core 11 is configured to cooperate with the rear mold core 21. The water channel core 12 passes through the front mold core 11, and the front mold core 13 passes through the water channel core 12. The bottom of the front mold core 11, the water channel core 12, and the front mold core 13, together with the top of the rear mold core 21, the ejector pin 22, and the pull pin 23 of the rear mold assembly 2, close the mold during injection molding to form the product cavity 3.

[0026] The bottom of the front mold core 11, the water-running core 12, and the front mold core 13 are located inside the product cavity 3 to form an inner core. The top of the rear mold core 21, the ejector pin 22, and the pull pin 23 are located outside the product cavity 3 to form an outer core.

[0027] The front mold assembly 1 and the rear mold assembly 2 have multiple product cavities 3 formed by mold closing during injection molding. Injection runners are provided between the multiple product cavities 3, and the injection runners are respectively connected to the runner cavities of the multiple product cavities 3.

[0028] The working principle and usage process of this utility model: During injection molding, the head of the pull pin 23 is located at the position of the material handle 5 of the product 4 and is surrounded by the material handle 5 formed after injection molding; after the injection molding machine installs the mold, the injection molding machine injects material into the mold. After the hot material cools down, the injection molding machine drives the rear mold assembly 2 to move in the demolding direction. The ejector pin 22, the pull pin 23 and the rear mold core 21 move together, and the pull pin 23 pulls the material handle 5 and the product 4 integrated with the material handle 5 and moves at the same time, so that the product 4 separates from the front mold core 11, the water channel core 12 and the front mold core 13 of the front mold assembly 1. The product 4 that has not been completely cooled is further cooled and shrunk under the action of the rear mold cooling water pipe; after the material of the product 4 has cooled, shrunk and deformed, the external texture structure of the product 4 separates from the rear mold core 21 and a gap is generated.

[0029] After product 4 has cooled down, the rear mold core 21 and the pull pin 23 remain stationary, while the injection molding machine drives the ejector plate to move the ejector pin 22 and product 4 in the demolding direction. Since product 4 and sprue 5 are fixed together and rise while the pull pin 23 remains stationary, the head of the pull pin 23 can detach from sprue 5. As sprue 5 separates from pull pin 23, product 4 is ejected from the mold cavity of the rear mold core 21 and moves in the demolding direction under the action of the ejector pin 22 until product 4 is completely demolded.

[0030] The movement of ejector pin 22 is driven by ejector plate (not shown in the figure). Ejector plate is located at the bottom of ejector pin 22 and is driven by electric, pneumatic, spring or other means. One ejector plate can drive multiple ejector pins 22 at the same time.

[0031] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A strong draw mold structure utilizing product shrinkage lines, characterized by: The front mold assembly and the rear mold assembly are combined to form a product cavity during injection molding, the product cavity comprises a product cavity for forming a product after injection molding and a flow channel cavity for forming a handle; The rear mold core is located at the side of the product cavity, the ejector pin passes through the rear mold core and is located at the bottom of the product cavity, the flow channel cavity is located between the bottom of the product cavity and the top of the ejector pin, the tail end of the pulling pin is fixed to the base and the head end is arranged in the flow channel cavity through the ejector pin; The ejector pin moves up and down in the ejector pin.

2. A strong demolding structure using product shrinkage according to claim 1, characterized in that: The product is a bottle cap.

3. A strong draw mold structure utilizing product shrinkage according to claim 1, wherein: The front mold assembly is fixed during injection molding and demolding after injection molding, and the rear mold assembly is driven by the injection molding machine to move up and down.

4. A strong draw mold structure utilizing product shrinkage according to claim 1, wherein: The front mold assembly comprises a front mold core, a water channel inner core and a front mold core, the front mold core is arranged in cooperation with the rear mold core, the water channel inner core passes through the front mold core, and the front mold core passes through the water channel inner core, the bottom of the front mold core, the water channel inner core and the front mold core is combined with the top of the rear mold core, the ejector pin and the pulling pin of the rear mold assembly to form a product cavity during injection molding.

5. A strong draw mold structure utilizing product shrinkage according to claim 4, wherein: The bottom of the front mold core, the water channel inner core and the front mold core is located inside the product cavity to form an inner core, and the top of the rear mold core, the ejector pin and the pulling pin is located outside the product cavity to form an outer core.

6. A strong draw mold structure utilizing product shrinkage according to claim 1, wherein: The product cavity formed by the combination of the front mold assembly and the rear mold assembly during injection molding is provided with a plurality of product cavities, and an injection flow channel is arranged between the plurality of product cavities, and the injection flow channel is in communication with the flow channel cavities of the plurality of product cavities respectively.

Images