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Author: MULAN -Plastic Molding Manufacturer
Blow molding manufacturers use the one-step method of extrusion and blowing mainly for PVC, and the two-step method for PP and PVC. One-step extrusion blowing is to place the extruded parison in the pre-blowing mold for pre-inflation and capping (bottom of the bottle), then adjust the temperature of the preform to a temperature suitable for stretching orientation, and then It is placed in a forming mold for longitudinal stretching, inflation and cooling for setting. The pultrusion blowing process of PVC bottles is not complicated. Stretch blow molding equipment is composed of extruder, parison die, pre-blow mold, forming die, tempering box and clamping device. Due to the biaxial orientation of stretch blow molding, the obtained bottle has high strength, good gloss and low cost, but the investment is relatively high. The two-step extrusion blowing method is to cool and crystallize the extruded parison, and then heat the parison at a temperature lower than the melting point to maintain its crystalline structure, and then stretch and blow molding. The bottle manufactured by the two-step method has improved low-temperature brittleness, increased strength, transparency and barrier properties, etc., and can be used for food packaging. Generally speaking, stretch blow molding is to make a parison by extrusion, injection, etc., and then heat the parison to the stretching degree, and then pass through internal (such as mandrel) or external (such as clamp) Longitudinal stretching is carried out by mechanical force, and transverse stretching is carried out by compressed air inflation at the same time or later. Proficient in mold | Blow mold manufacturer |Since 1998, trustworthy.