Injection molding die and method for manufacturing parts

Abstract

This invention relates to an injection molding die that maximizes material input, shortens the molding cycle, and homogenizes molding quality as much as possible, as well as a method for manufacturing parts. [Solution] The mold comprises a cavity (7) into which material is injected through an injection section (2), a separator (3) that opens or closes the communication between the cavity (7) and the injection section (2), and separates the part (1) from the injection section (2) when the communication is closed, and a storage section (4) that closes when the separator (3) opens the communication between the cavity (7) and the injection section (2), and opens when the separator (3) closes the communication between the cavity (7) and the injection section (2), and the movement of the separator (3) and the opening and closing of the storage section (4) are synchronized with each other. The manufacturing method includes the steps of closing the communication between the cavity (7) and the injection section (2), separating the part (1) from the injection section (2), and opening the storage section (4) for the material at the same time that the communication between the cavity (7) and the injection section (2) is closed.

Description

Technical Field

[0001] The present invention relates to an injection mold for injection molding and a method for manufacturing parts.

Background Art

[0002] All thermoplastic injection-molded products are manufactured in a process using an injection mold having a cavity plate and a punch plate. Cavities are formed in the mold so that these are appropriately machined and injection can be performed between the machined spaces for the parts to be injected.

[0003] These plates are guided by columns housed in the cavity plate and bushings in the punch plate so that both plates are perfectly aligned each time the mold is opened and closed, in order to reproduce a new molded product in the same dimensions and the same shape for each injection cycle.

[0004] The mold also includes a so-called discharge bridge that is correctly aligned with the above plates. This bridge is firmly attached to the mold and functions as a mechanism for discharging the molded product.

[0005] All thermoplastic injection-molded products require a process of melting the prepared material, and the material is supplied in a standardized form as a small cylinder.

[0006] The manufacturing process includes installing the mold in an injection molding machine. The molding machine has a fixed platen on the injection side and a movable platen on the discharge side. The cavity portion of the mold is arranged on the fixed platen of the molding machine, and the punch portion is arranged on the movable platen of the molding machine.

[0007] When the molding machine is closed, the punch platen merges with the mold cavity platen, and the mold guide ensures that the alignment of both platens is perfectly aligned, and that the work performed in the cavity and punch is perfectly evenly matched, forming the housing necessary for the molding material to completely fill the cavity.

[0008] Each molding machine has an appropriate injection system for its model. The material is stored in pellet form in a hopper attached as the injection material supply source, melted by a properly heated rotary conveyor, and then, under appropriate melting point and pressure control, becomes ready for injection into the mold cavity.

[0009] Cooling circulation paths circulate through holes formed in the cavity plate and punch plate, thereby accelerating the hardening of the material and ensuring that it reaches a hardness that does not hinder opening the mold and ejecting the molded product.

[0010] All injection molding dies have an opening called a material inlet. This is part of the die manufacturing process, through which the material injected from the molding machine is injected under pressure. This material inlet always requires machining and precision finishing to conceal imperfections that are inherent in molded parts and often should not be visible due to the complexity of the part itself or its destination.

[0011] Therefore, machining and precision processing steps are required to reduce or eliminate imperfections that arise from the material injected into the mold, which increase the cost of the molded product. [Overview of the Initiative]

[0012] Therefore, one object of the present invention is to provide an injection molding die and a method for manufacturing parts that can improve the finish of manufactured parts at a lower cost than conventional cutting and processing processes.

[0013] According to the injection molding die and manufacturing method of the present invention, the above-mentioned problems are solved, and additional effects described below are obtained.

[0014] The injection molding die and manufacturing method according to the present invention are described in their respective independent clauses, while other optional features are described in the dependent clauses.

[0015] The injection molding die according to the present invention comprises a cavity through which a material is injected, and the material hardens to form a part.

[0016] Furthermore, the injection molding die includes a movable separator that opens or closes the communication between the cavity and the injection section, the separator separating the part from the injection section in the closed position, and a storage section that closes when the separator opens the communication between the cavity and the injection section, and opens when the separator closes the cavity and the injection section, with the movement of the separator and the opening and closing of the storage section being synchronized with each other.

[0017] In other words, the cutting or separation of the part from the injection molding section is performed during the manufacturing process itself, and at this point the material has not yet hardened, thus eliminating the need for further cutting or cold working after the part has been cast.

[0018] The blocking or separation by the separator can be performed throughout the molding cycle, either in accordance with the filling cycle of the product to be molded, or simply to block the material passage as if plugging it, at the same time that the component is filled into the cavity.

[0019] The separation process must be carried out as quickly as possible to prevent the components from hardening due to the drop in temperature.

[0020] The separator remains in the position where the component was separated from the injection unit until the required cooling time for the component has elapsed. As a result, the component is discharged completely separated from the injection unit.

[0021] When the molding machine is closed again in preparation for the next molding cycle, the separator returns to its original injection position.

[0022] Therefore, when the separator performs separation or cutting during the molding cycle, it is operated by an actuator to perform the separation or cutting with a gentle motion, thereby ensuring high finish quality, which is essential for parts that require a visually pleasing final finish. In this way, the need for costly secondary processing of the finished product is completely eliminated.

[0023] It should be noted that liquid materials behave like hydraulic fluids, i.e., they are incompressible. Therefore, an additional volume or space is required to store the material introduced between the injection unit and the molded part by the movement of the separator.

[0024] Without this additional volume, the separator cannot move when the mold is closed. To enable movement, the above-mentioned storage section is provided, offering additional volume for accommodating the material moved by the separator.

[0025] The movement to open the storage section can be achieved using an actuator as appropriate, and this movement provides an additional volume that can accommodate the moved material, preferably somewhat larger than the volume of the material to be stored, so that the free storage can be carried out as easily as possible. This can be achieved using the same operating principle as the actuator that operates the separator, but the direction of operation is reversed. [Brief explanation of the drawing]

[0026] For a better understanding of the above explanation, drawings are attached. These drawings illustrate specific embodiments as schematic and non-limiting examples. [Figure 1] This is a schematic diagram showing the injection process in an injection molding die according to the present invention. [Figure 2]It is a schematic diagram showing the process of separating parts in the injection mold according to the present invention.

Embodiments for Carrying Out the Invention

[0027] An object of the present invention is to enable the production of a part (1) only by an injection molding process and to enable the separation of the part (1).

[0028] The principle of operation focuses on the physical deformation of the material itself rather than a mechanical method for achieving the above.

[0029] For a thermoplastic material to be injected, it undergoes a drastic structural change from solid to liquid in a short time, and the material is injected from the injection part (2) at its melting point.

[0030] Currently, in order to simplify the second operation of the injection part (2), even if the molding cycle becomes long, it is common to minimize the input. However, this method has disadvantages such as increasing the molding pressure and further increasing the molding temperature.

[0031] In this regard, the present invention takes the opposite approach, maximizing the input of the material, shortening the molding cycle, and making the molding quality as homogeneous as possible.

[0032] By the above-described injection molding, since the characteristics of the material itself help to fill and seal the cavity of the mold during the injection process, it is possible to separate the injection part (2) from the part (1) without performing rough cutting as in the prior art.

[0033] Therefore, preferably, a separator (3) arranged on the punch plate (9) is inserted between the injection part (2) and the part (1), so that when the cavity (7) formed in the cavity plate (8) of the mold is filled, the injection part (2) can be separated from the part (1) as if plugging it.

[0034] To make this possible, it is essential to perform the process while the material is still liquid, for example, at the very moment injection is complete. Therefore, the coordination of the movements between the related components is extremely important.

[0035] Such movements can be achieved with various types of actuators (5, 6), such as mechanical, hydraulic, or combinations of motors and gears.

[0036] It should be noted that while this specification is intended for hydraulic systems, it is clear that it can be used with any type of actuator.

[0037] In this embodiment, two hydraulic cylinders (5, 6) are used, which are connected by a duct (10) in the shaft portion or low-pressure portion like a conduit. The first hydraulic cylinder (5) is used to advance the separator, and the second hydraulic cylinder (6) is used to open the reservoir (4) for storing excess material equal to the volume of the separator (3). That is, when one rises, the other descends.

[0038] A liquid substance subjected to pressure behaves like a hydraulic fluid, meaning it is incompressible. Therefore, it is necessary to create space within the pressurized cavity (7) for a separator (3) of a certain volume to move, thereby blocking communication between the cavity (7) and the injection unit (2), i.e., separating the injection unit (2) from the component (1).

[0039] If such a space is not formed, the separator cannot be inserted into the mold cavity (7). Therefore, by forming a reservoir (4) in the pressure-saturated cavity (7) as described above, a variable volume equivalent to at least the volume of the separator (3) that separates the injection unit (2) from the part (1) is secured.

[0040] The operation is as follows: When the mold is closed, the separator (3) is stationary and the reservoir (4) is closed, and the injection process is carried out. For this purpose, two hydraulic cylinders (5, 6) operate in accordance with the injection process. The second hydraulic cylinder (6) is activated to close the reservoir (4), while the first hydraulic cylinder (5), receiving the same pressure as the second hydraulic cylinder (6), pushes back the separator (3) located at the end of the injection section (2).

[0041] In this way, the passage for the molding material is opened, and the material injected from the injection unit (2) can be filled into the cavity (7). As soon as the cavity (7) is filled, the first hydraulic cylinder (5) is activated. This first hydraulic cylinder (5) moves the separator (3), completely separating and isolating the part (1) from the injection unit (2). This is because the second hydraulic cylinder (6) has opened the storage unit (4) using the pressure of the first hydraulic cylinder (5) in order to accommodate the material moved by the separator (3).

[0042] When the molding cycle is complete, the mold ejects the two objects separately: the molded part (1) and the material present in the injection section (2).

[0043] This invention offers further advantages: improved finish quality and faster manufacturing cycles.

[0044] Regarding the quality of the finish, in addition to avoiding rough cutting, the entire cooling cycle, which is crucial in determining the final texture, is performed with the mold completely closed to ensure that no further damage is done to the visible surface of the product.

[0045] This invention makes it possible to reduce the number of filling cycles and improve cavity filling without applying excessive pressure by using a large material inlet.

[0046] The finish of a product makes it easier to visually determine where a part was molded, which in turn improves the visual appeal of individual parts.

[0047] Although specific embodiments of the present invention have been described, it will be obvious to those skilled in the art that the injection molding die and manufacturing method described above can be modified in various ways without departing from the scope defined in the appended claims, and that all detailed structures are technically interchangeable with equivalents.

Claims

1. An injection molding die for manufacturing parts, The device comprises a cavity plate (8) having a cavity (7) into which the material forming the part (1) is injected through an injection unit (2), and further, A movable separator (3) that opens or closes the communication between the cavity (7) and the injection unit (2), wherein in the closed position the separator (3) separates the component (1) from the injection unit (2), The separator (3) includes a storage section (4) that closes when the separation between the cavity (7) and the injection section (2) is open, and opens when the separator (3) blocks the connection between the cavity (7) and the injection section (2). An injection molding die in which the movement of the separator (3) and the opening and closing of the storage section (4) are synchronized with each other.

2. The injection molding die according to claim 1, wherein the separator (3) is movable by a first actuator (5).

3. The opening and closing operation of the storage section (4) is achieved by a second actuator (6), as described in any of the claims, for injection molding.

4. The injection molding die according to claim 2 or 3, wherein the first and second actuators (5, 6) are synchronized with each other.

5. The injection molding die according to claim 4, wherein the first and second actuators (5, 6) are hydraulic cylinders.

6. The injection molding die according to claim 5, wherein the first and second actuators (5, 6) are connected to each other via a duct (10) positioned between two containers housing the shafts of both cylinders (5, 6), and when one of the hydraulic cylinders (5) is displaced in one direction, the hydraulic pressure generated by that displacement causes the second cylinder (6) to be displaced in the opposite direction.

7. A method for manufacturing parts, The process involves injecting the material that forms the part (1) into the cavity (7) of the injection mold through the injection unit (2) in a fluid state, The process involves blocking communication between the cavity (7) and the injection unit (2), and separating the part (1) from the injection unit (2) when injection is complete. In order to accommodate the material that has moved in the blocking step, the process involves opening the storage section (4) for the material while blocking communication between the cavity (7) and the injection section (2), A manufacturing method comprising the step of discharging the manufactured part (1) when the material has hardened.

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