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Author: MULAN -Plastic Molding Manufacturer
In the process of blow molding production and processing of blow molding toys, the factors that will affect the product mainly include inflation pressure, blowing speed, inflation ratio and blow mold temperature. The following is proficient in blow molding to explain to you from five aspects: 1. Inflation pressure In the blow molding process, compressed air has two functions: one is to use the pressure of compressed air to inflate the semi-molten tube blank and cling to the cavity wall to form the desired shape; It is used for cooling blow molding products. The air pressure depends on the type of plastic and the temperature of the parison, and is generally controlled at 0.2-1.0MPa. For plastics with low melt viscosity and easy deformation (such as PA, HDPE), take a lower value; for plastics with high melt viscosity (such as PC), take a higher value, and the parison wall thickness also takes a higher value . The blowing pressure is also related to the volume of the product. Higher inflation pressure should be used for large-volume products, and lower inflation pressure should be used for small-volume products. 2. Blowing speed In order to shorten the blowing time so that it is beneficial to obtain a more uniform thickness and a better appearance of the product, it is required to inject a large flow of air at a low air flow rate to ensure that the parison can be uniform and smooth in the mold cavity. Rapid expansion shortens the cooling time in the mold cavity and improves product performance. The low air velocity can also avoid the occurrence of a Venturi effect in the parison to form a partial vacuum and cause the parison to collapse. This can be ensured by using a larger blow tube. 3. Inflation ratio When the size and quality of the parison are constant, the larger the size of the product, the greater the inflation ratio of the parison, but the thinner the thickness of the product. The inflation ratio is usually determined according to the type and nature of the plastic, the shape and size of the product, and the size of the parison. As the inflation ratio increases, the thickness of the product becomes thinner, and the strength and stiffness decrease; at the same time, molding becomes difficult. Generally, the inflation ratio is controlled at about l: (2-4). 4. The temperature of the blow molding mold has a great influence on the quality of the product (especially the appearance quality). Usually, the temperature distribution of the mold should be uniform, and the product should be cooled as uniformly as possible. The temperature of the mold is related to the type of plastic, the thickness and size of the product. For different types of plastics, the mold temperature of a small number of plastics (PC blow molding bottles) should be controlled in sections. 5. Molding cycle Blow molding production cycle includes processes such as extrusion of parison, mold clamping, cutting of parison, blowing, deflation, mold opening, and product removal. The principle of this cycle selection is to shorten as much as possible on the premise of ensuring that the product can be shaped without deformation, so as to improve production efficiency. Proficient in blow molding 23 years experience in blow molding customization. The supporting equipment is complete, with multiple blow molding machines, injection molding machines, mold opening equipment, printing equipment, and packaging machines, which can meet the customization of different complex and special-shaped blow molding parts. The self-owned warehouse is 2000㎡, and raw materials are stored all year round, which can be quickly put into production. Long-term cooperation with brand raw material manufacturers, strict control of loss in the production process, and high cost performance.