CN101254642A - Two-color one-time molding injection mold and injection molding method - Google Patents

Abstract

The invention discloses an injection mold for two-color one-shot molding and an injection molding method using the mold. The two-color one-time molding injection mold consists of a mold cavity (1) and a core (2), and a movable partition (4) is used to separate the mold cavity into two parts. The injection molding process of the injection mold using two-color one-time molding is: close the mold, and the partition separates the mold cavity; inject the first material; then inject the second material; close the injection port 1; then retreat the partition; close the injection Port 2 and complete the cooling and holding pressure after opening the mold and ejecting the plastic part. Or, after the first material is injected and cooled and kept under pressure, the partition is withdrawn, and then the second material is injected. The injection mold and molding method of the present invention are used for the injection molding of two-color plastic parts, the production process is simple, the quality of the produced product is stable, the mold used is simple in structure, easy to manufacture and low in cost.

Description

Two-color one-time molding injection mold and injection molding method

Technical field

The invention relates to a plastic injection mold and an injection molding method using the mold, in particular to an injection mold for two-color one-shot molding and an injection molding method.

Background technique

At present, many products use plastics of two different colors or different materials, such as the combination of transparent materials and opaque materials, red and white two-color products. For such multi-material or multi-color plastic parts, the following two methods are usually used in molding.

1. Use the secondary molding method: two plastic materials are molded twice; the product is first injection molded from one set of molds for one material, and after the mold is taken out, it is put into another set of molds for the second injection molding forming. This molding process needs to be completed by 2 sets of molds, but does not require a special two-color injection molding machine. The two-color parts formed in this way have poor bonding strength, low part precision and rough surface. At the same time, it takes a long time to form a product, and it is difficult to manage.

2. One-time molding using a rotary mold: multiple plastic materials are injected on a special injection molding machine and molded in several times, requiring a set of rotary molds. The rotary mold contains multiple sets of cavities and cores. The shapes of each cavity are different, and a product of one material is molded respectively, while the shape of the cores is exactly the same. After the first material is injected, the front and rear molds of the mold are rotated at the center, and then the second material is injected. Using this method can make the appearance of the product beautiful. However, the cost of the mold is expensive, the technical requirements are high, and the service life of the mold is limited.

Contents of the invention

The object of the present invention is to provide a two-color one-time molding injection mold and injection molding method, which can realize the injection molding of various plastics with one pair of molds, and the mold has a simple structure and is easy to manufacture and use.

The technical scheme adopted by the present invention to solve the technical problem is: the two-color one-shot molding injection mold consists of a mold cavity and a core to form a cavity, and a movable partition is used to separate the cavity into two parts, and the separated core part Use inserts. The partition separates the mold cavity when the mold is closed, and retreats for a certain distance after injecting one material before injecting the second material.

In a multi-cavity mold, a divider can be placed in one of the cavities, or a divider can be placed in multiple cavities.

Dividers can be placed on the movable side and controlled using hydraulic cylinders.

When using a two-color one-shot injection mold to process two-color plastic parts, a two-color injection molding machine is required. The injection molding machine has two barrels and two nozzles. The steps of two-color injection molding are as follows:

Step 1: Close the mold, and push the divider to the working position to separate the cavity.

Step 2: Inject the first plastic material into the separated mold cavity with the first nozzle.

Step 3: Inject the second plastic material into the mold cavity with the second nozzle.

Step 4: Close the first nozzle.

Step 5: Set back the divider a wall thickness distance.

Step 6: Close the second nozzle.

Step 7: Carry out cooling under pressure.

Step 8: Open the mold and eject the plastic part.

The following steps can also be taken:

Step 1: Close the mold, and push the divider to the working position to separate the cavity.

Step 2: Inject the first plastic material into the separated mold cavity with the first nozzle, and carry out cooling and holding pressure.

Step 3: Set back the divider a wall thickness distance.

Step 4: Inject the second plastic material into the mold cavity with the second nozzle, and carry out cooling and holding pressure.

Step 5: Open the mold and eject the plastic part.

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

When the invention is used to produce double-material or double-color plastic parts, during injection molding, due to the limitation of the separator, the first injection will be in a limited area. The second injection is performed after the separator is withdrawn, and the material of the second injection will be directly bonded to the formed material of the first injection, so that the two materials are combined into a whole. Since the material from the first injection is not completely cooled during the second injection, a high bond strength can be obtained.

Using the invention to produce two-color plastic parts requires only one pair of moulds, and can be molded at one time, thereby improving processing efficiency and ensuring quality and good product appearance.

The mold of the invention has a simple structure, which is close to that of an ordinary injection mold, and does not need to be rotated during the molding process, so the manufacture and maintenance of the mold are relatively simple, and the cost is significantly reduced.

Description of drawings

Figure 1 is a schematic view of an embodiment of the present invention prior to injection of a first material.

Figure 2 is a schematic view of an embodiment of the present invention after injection of the first material.

Figure 3 is a schematic illustration of an embodiment of the invention prior to injection of a second material.

Figure 4 is a schematic illustration of an embodiment of the invention after injection of a second material.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

In the embodiment shown in Figures 1 to 4, the two-color one-time molding injection mold consists of a mold cavity (1) and a core (2), and a movable partition (4) is used to divide the cavity into two parts. part, the part of the core in the divider is made into an insert (3). The partition (4) is located on the moving mold side and is controlled by a hydraulic cylinder (5).

When using this mold for injection molding, follow the steps below:

Step 1: Close the mold, and push the partition (4) to the working position where it fits the cavity (1) to separate the cavity.

Step 2: Inject the first plastic material (61) into the separated mold cavity through the gate (11) with the first nozzle, and carry out cooling and holding pressure.

Step 3: Back off the partition (4) by a wall thickness distance.

Step 4: Inject the second plastic material (62) into the mold cavity through the gate (12) with the second nozzle, and carry out cooling and holding pressure.

Step 5: Open the mold and eject the plastic part.

Through the above steps, the material injected for the second time is fused with the material injected for the first time to complete the injection molding of the two-color plastic product.

Claims (5)

1. A two-color one-time molding injection mold is characterized in that: a mold cavity is formed by a mold cavity (1) and a core (2), and a movable partition (4) is used to separate the mold cavity into two parts, The separated core parts are made into inserts (3). The partition (4) partitions the mold cavity when the mold is closed, and withdraws for a certain distance after injecting one material before injecting the second material. 2. The two-color one-time molding injection mold according to claim 1, characterized in that: the mold cavity (1) and the core (2) can form a plurality of mold cavities, and one or more mold cavities Use separators in . 3. The multi-material one-time molding injection mold according to claim 1 or 2, characterized in that: the partition (4) is on the side of the movable mold. 4. A method of injection molding utilizing the two-color one-shot molding injection mold as claimed in claim 1, wherein the injection molding step is as follows: Step 1: Close the mold, and push the divider to the working position to separate the cavity. Step 2: Inject the first plastic material into the separated mold cavity with the first nozzle. Step 3: Inject the second plastic material into the mold cavity with the second nozzle. Step 4: Close the first nozzle. Step 5: Set back the divider a wall thickness distance. Step 6: Close the second nozzle. Step 7: Carry out cooling under pressure. Step 8: Open the mold and eject the plastic part. 5. A method of injection molding utilizing the two-color one-shot molding injection mold as claimed in claim 1, wherein the injection molding steps are as follows: Step 1: Close the mold, and push the divider to the working position to separate the cavity. Step 2: Inject the first plastic material into the separated mold cavity with the first nozzle, and carry out cooling and holding pressure. Step 3: Set back the divider a wall thickness distance. Step 4: Inject the second plastic material into the mold cavity with the second nozzle, and carry out cooling and holding pressure. Step 5: Open the mold and eject the plastic part.

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