Author: MULAN -Plastic Molding Manufacturer
Injection molds are an integral part of injection molding. Xingye Injection Molding Factory has introduced the number of cavities, gate locations, hot runners, design principles of assembly drawings and material selection of injection molds. Let's continue to introduce the design of the exhaust system of the injection mold of the plastic mold.
In addition to the original air in the cavity, the gas in the cavity also contains low molecular volatile gases produced by heating or curing the injection molding material. It is necessary to consider the sequential discharge of these gases. Generally speaking, for molds with complex structures, it is difficult to estimate the exact position of the airlock in advance.
Therefore, it is usually necessary to determine its position through mold testing, and then open the exhaust slot. Vent slots are usually opened where the cavity fills. The exhaust method is to use the gap between the mold parts to open the exhaust groove.
Exhaust is required for molded injection molded parts, and exhaust for demolded injection molded parts. For injection molded parts with deep cavity shells, after injection molding, the gas in the cavity is blown away. During the demoulding process, the exterior core of the plastic part forms a vacuum, making it difficult to demould.
If the mold is forced to be demoulded, the plastic mold is easily deformed or damaged. Therefore, it is necessary to introduce air, that is, to introduce air between the injection molded part and the core, so that the plastic injection molded part can be demoulded smoothly. At the same time, several shallow grooves are processed on the parting surface to facilitate exhaust.
1. The template of the cavity and the core needs to use a tapered positioning block or a precision positioning block, which is installed on the four sides or around the mold. 2. The contact surface between formwork board A and reset rod should be flat pad or round pad to avoid damage to board A. 3. The perforated part of the guide rail should be inclined more than 2 degrees to avoid burrs and burrs, and the perforated part should not be a thin leaf structure.
4. In order to prevent dents in injection molded products, the width of the ribs should be less than 50% of the appearance wall thickness (the ideal value is 40%). 5. The wall thickness of the product should be average, and at least a sudden change should be considered to avoid dents. 6. If the injection molded part is electroplated, the movable mold also needs to be polished.
The polishing requirements are second only to the mirror polishing requirements to reduce the generation of cold materials during the forming process. 7. Ribs and grooves in poorly ventilated cavities and cores must be embedded to avoid dissatisfaction and burning. 8. Inserts, inserts, etc. should be positioned and fixed firmly, and anti-rotation measures should be taken for the wafer.
Copper and iron sheets are not allowed to be placed under the plug-in. If the pad is higher, the soldered portion should form a larger surface contact and be ground flat. For more information about plastic molds, please visit Xingye's official website: http://www.dgxingyesj.com/.