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Author: MULAN -Plastic Molding Manufacturer
Design optimization of mold exhaust for blow molding products The exhaust system should be fully considered in the design and manufacture of blow molding molds, and the following common measures can be taken. 1. Product surface design When designing the surface of blow molding products, you can design necessary characters, patterns or grooves in the mold to facilitate the exhaust of the mold; but also avoid large areas of smooth surface, or engrave shallow The pattern, which is conducive to the exhaust of the mold. 2. Treatment of mold cavity Not all mold cavity surfaces of blow molding products are as smooth as possible. A slightly rough cavity surface is not only conducive to the exhaust of the mold, but also improves the surface effect of the product. Commonly used methods for cavity surface treatment include cavity surface sandblasting, surface etching pattern, cavity polishing and other methods. But for some surface requirements are very high Blow-molded products, such as high-end cosmetic containers made of polystyrene, are not suitable. 3. Exhaust hole or exhaust groove An effective way to solve the problem of blow molding mold exhaust is to set up exhaust grooves or vent holes in the mold cavity and on the parting surface. 1) Vent structure There are many ways, such as: inlaid exhaust structure, which can use the preset gap between inlays to achieve relatively smooth exhaust in a large area. It can either adopt a laminated sheet structure or concentric circles The structure of the circular ring inlay. 2) Set up exhaust grooves on the parting surface of the blow molding product mold Setting up exhaust grooves on the parting surface can discharge air as quickly as possible. Generally, the exhaust grooves are designed on the shoulder and bottom of the parting surface. If there are special needs, they can be opened at special positions. The width of the exhaust groove is generally 5~25 mm; the depth of the exhaust groove needs to be selected according to the production process of the blow molding product, the volume of the container and the wall thickness. Choose between 0.01~0.2 mm, the larger the volume, the deeper the groove will be. 3) Open vent holes in the mold cavity When it is necessary to open a vent hole in the mold cavity, the diameter of the vent hole close to the mold cavity is generally designed to be 0.1~0.3 mm. If the diameter is too large, it is easy to leave bumps on the surface of the blown product and affect the surface of the product. If it is too small, pits will appear, and when designing the position of the vent hole in the mold cavity, it is necessary to consider the layout that does not interfere with the water cooling system. for large volume For blow molding products, the diameter of the vent hole can be larger, and a specific vent plug can be installed for exhaust. In addition, exhaust grooves can also be provided at the inserts in the mold cavity. 4. Vacuum negative pressure exhaust During the manufacture of blow molding product molds, some small holes are drilled in the cavity of the mold to connect them to the vacuum negative pressure system, which can quickly remove the air remaining in the cavity of the mold and make the blow molding parison and the cavity tightly fit. In addition, this method is also beneficial to some special products that require deep drawing, cannot be inflated inside blow molding products, require high surface quality, and have hollow interlayers. Blow molding products. The control of the vacuum exhaust system needs to be jointly controlled with the electrical control system of the blow molding machine to effectively guarantee the accuracy and reliability of the control. Proficient in mould|blow molding products| Started in 1998, trustworthy.