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Structural classification of plastic injection moulds

2023-10-31

According to the different structure of plastic products and different product requirements, the structure of injection molds is also different, some common injection mold structures, including single parting surface injection molds, multi-parting surface injection molds, inclined guide column side core injection molds, inclined pin inner core injection molds, and hot runner injection molds.

1. Single parting surface injection mold;
Single parting surface injection mold, also known as two-plate injection mold, is commonly found in large water injection molding molds. This kind of mold has a simple structure and strong practicability for molding plastic parts, so it is widely used. The disadvantage of this mold is that the gate is large, and a process to remove the gate is often added, and the gate marks will be left on the surface of the product. Therefore, it is suitable for injection molding products with low surface requirements.

2. Multi-parting surface injection mold;
Multi-parting surface injection mould has two or more parting surfaces, of which double parting surface is the most common. The double parting surface injection mold is often called the three-plate mold, because this mold is often used for the product of gating, so it is also called the fine water mold. The double parting surface injection mold is widely used, mainly for single cavity or multi-cavity mold with point gate, mold with lateral parting mechanism located on one side of the fixed mold, and mold with special structural requirements of plastic parts parting in order. The purpose of the first parting is to pull out the runner condensate, and the second parting is to break the feed port to separate the runner condensate from the plastic parts, so that the ejecting plastic parts do not need to remove the runner condensate treatment.

3. Oblique guide column side core-pulling injection mold;
When the side wall of the plastic part has the characteristics of through holes, pits, convex, etc., the molded part must be made of lateral movement, and the entire mechanism with the lateral movement of the core is called the lateral core-pulling mechanism or the lateral core-pulling mechanism. There are many kinds of lateral core-pulling mechanisms, including oblique guide column lateral core-pulling, hydraulic core-pulling and pneumatic core-pulling, among which the most common one is the oblique guide column lateral core-pulling mechanism, as shown in Figure 3.25. When opening the mold, the inclined guide pole first drives the slider to move outward, and when the side core is completely removed from the product, the ejecting mechanism begins to act and ejecting the product.

4. Inclined pin internal core-pulling injection mold;

When the inside of the product has backsnaps, it is necessary to use the inclined pin to form these backsnaps, and this kind of mold with the inclined pin is collectively referred to as the inclined pin internal core withdrawal injection mold. The structure of this kind of mold is relatively complex, and it is necessary to add a diagonal pin mechanism on the mold. When the mold is opened, the front and back molds are opened first, and then the ejector mechanism of the injection molding machine pushes the top plate of the mold to move in the direction of release. At this time, the inclined pin slowly releases the inverted position of the product, and after it is completely released, the product is ejector through the ejector mechanism on the mold.

5. Hot runner injection mold;
With the development of rapid automatic injection molding process, hot runner injection molds are being gradually promoted and used. The difference between it and the general injection mold is that the plastic in the pouring system in the injection molding process will not solidify, nor will it be demoulded with the plastic parts, so this mold is also called the no flow mold. The main advantages of this mold are as follows:
① Basically realize no waste processing, which saves raw materials and eliminates the process of cutting cold materials.
② Reduce the pressure loss of the feeding system and make full use of the injection pressure, which is conducive to ensuring the quality of plastic parts.

Hot runner injection mold is very easy to distinguish, generally with the above picture, cable, mold junction box, belong to the hot runner mold.
Therefore, the hot runner injection mold has complex structure, high cost and strict requirements for mold temperature control, which is suitable for mass production.

BHC precision focuses on the development and production of precision injection molds,ABS TPU Overmodling, Medical Industrial Parts, ABS Plastic Products, Electronic Plastic Products, Transparent plastic parts

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