Structural Classification Differences of Plastic Injection Molds
Structural Classification Differences of Plastic Injection Molds
According to the structure of plastic products and different product requirements, the structure of injection mold is also different. Some common injection mold structures include single parting surface injection mold, multi parting surface injection mold, inclined guide post side core pulling injection mold, inclined Pin core pulling injection mold, and hot runner injection mold.
1. Single parting surface injection mold;
Single parting surface injection molds are also called two-plate injection molds, which are commonly found in Dashuikou injection molding molds. This type of mold has a simple structure and strong practicability for molding plastic parts, so it is widely used. The disadvantage of this kind of mold is that the gate is large, and a process of removing the gate is often added, and gate marks will be left on the surface of the product. Therefore, it is suitable for injection molding products that do not have high requirements on the surface of the product.
2. Multi-parting surface injection mold;
Multi-parting surface injection molds have two or more parting surfaces, of which double parting surfaces are the most common. Double parting surface injection molds are often called three-plate molds. Since this kind of mold is often used for products with point gate injection, it is also called fine nozzle mold. Double parting surface injection molds are widely used, mainly used for single-cavity or multi-cavity molds with point gates, molds with side parting mechanism on the side of the fixed mold, and plastic part structures that require sequential parting mold.
Multi-parting surface injection mold
The purpose of the first parting is to pull out the coagulation of the runner, and the second parting breaks the feed port to separate the coagulation of the runner from the plastic parts, so that the ejected plastic parts do not need to be removed from the runner Congeal handling.
3. Injection mold for lateral core pulling of inclined guide pillar;
When the side wall of the plastic part has features such as through holes, recesses, and bosses, the molding parts must be made to move laterally, and the entire mechanism that drives the core to move laterally is called a lateral core-pulling mechanism or a lateral core-pulling mechanism. Core pulling mechanism. There are many types of lateral core-pulling mechanisms, including inclined guide post lateral core-pulling, hydraulic core-pulling, and pneumatic core-pulling, among which the most common one is the inclined guide-pillar lateral core-pulling mechanism, as shown in Figure 3.25. When opening the mold, the inclined guide column first drives the slider to move outward, and when the side core is completely out of the product, the ejector mechanism starts to move to eject the product.
Injection mold for lateral core pulling of inclined guide column
4. Injection mold with oblique pin inner core pulling;
When there are undercuts inside the product, it is necessary to use oblique pins to form these undercuts. Such molds with oblique pins are collectively referred to as oblique pin inner core-pulling injection molds. This type of mold structure is relatively complex, and it is necessary to add a tilt pin mechanism to the mold. When opening the mold, first open the front and rear molds, and then the ejector mechanism of the injection molding machine pushes the top plate of the mold to move toward the demoulding direction. The stripping mechanism ejects the product.
Injection mold for oblique pin inner core pulling
5. Hot runner injection mold;
With the rapid development of 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 gating system will not solidify during the injection molding process, nor will it be demolded with the plastic part, so this mold is also called a runnerless mold. The main advantages of this mold are as follows:
①Basically, waste-free processing is realized, which not only saves raw materials, but also saves the process of cutting off cold materials.
②Reduce 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
Hot runner injection molds are easy to distinguish. Generally, those with the above pictures, cables, and mold junction boxes are all hot runner molds.
Therefore, the structure of the hot runner injection mold is complex, the cost is high, and the control of the mold temperature is strict, which is suitable for mass production.
