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Author: MULAN -Plastic Molding Manufacturer
Determination of Surface Roughness of Blow Molded Products Mold Cavity The surface roughness of the blow molded product mold cavity is generally determined according to the surface requirements of the blow molded product itself and the material of the product. For some blow molded products with low surface requirements, the surface can be made rough. For example, for some relatively large blow molding products such as floating bodies on the water surface and pallets used in logistics, the surface is made rougher, which is conducive to the overall exhaust. However, for some containers with high transparency or high gloss on the surface, the surface needs to be highly polished. ( PC pure bucket, ABS car spoiler and PET, PVC, PP and other blow-molded containers). PE products are the most widely used in blow molding products. With PE blow molding molds, the surface of the cavity needs to be rougher to improve the exhaust efficiency. Otherwise, air bubbles will be trapped between the plastic parison and the mold, causing the Surface defects of "orange peel" appear on blow molded products. Because the temperature of the PE blow mold is low and the blowing pressure of the parison is small, the inflated parison will not be wedged into the trough of the rough surface, but will be located and cross the valley peak, so when using the PE blow mold, the surface Roughness will not affect the surface quality of blow molded products, but is conducive to exhaust and improve molding quality. The surface of the PE blow mold cavity can be sandblasted to obtain a relatively uniform surface roughness. Generally, emery, quartz sand or hard gravel can be used for sandblasting. The particle size of sand blasting should be selected appropriately, and the appropriate particle size should be selected according to the volume of blow molded products and the type of raw materials. Usually, for smaller PE bottle molds can use 60～120 grain size; for larger blow molding products molds, you can use 30～40 particle size; for the blow mold of LDPE material, the finer particle size can be used; for the conventional blow molding product mold of HDPE material, the coarser particle size can be used. Etching the cavity (also known as skin texture treatment) can also roughen the surface. It uses chemical methods or other methods on the surface of the mold cavity to form a pattern of a certain depth on the surface of the blow molded product. The etching depth is related to the material of the blow molded product and the material of the mold. The etched mold cavity has greater adhesion to the product, and a release agent can be used. When blow molding products with high surface quality requirements, the surface of the mold cavity needs to be polished. According to the requirements of blow molded products, after polishing, some can be matte treated or used 360 fine sand to wipe the mold cavity. For the blow molding cavity of engineering plastics, the cavity generally cannot be sandblasted, and its surface can be highly polished, and the mold exhaust is etched. Proficient in mould|blow molding products| Started in 1998, trustworthy.