Extrusion blow molding is used to treat a variety of different polymers including polyethylene, polyvinyl chloride, polypropylene and much more. This process begins with under conventional extrusion tube. When the tube reaches the desired length of the mold is closed to catch and hold the open end of the neck and pinched the bottom closed. Then puffs pin inserted into the neck end of the heat tube to form a threaded opening and expanding the tube in the mold cavity. When the mold is completely cooled opened to remove the excess plastic bottles and trimmed from the neck and bottom areas.
Stretching gust Moulding
The main stretch blow molding applications including bottles, packaging and the like, produce visual quality goods and excellent dimensional compared to extrusion blow molding. The first process requires plastic to be injection molded into a 'preform' with a threaded neck finish of the bottle at one end.
Puffs to enlarge
The preform is then heated and blown, using high-pressure air, into the bottle using a mold. At the same time the preform is drawn with a core rod to fill the mold. Strain hardening occurs as part of the process of stretching several polymers, Polyethylene Terepthalate which allows the bottle to resist deformation under pressure resulting from carbonated beverages, usually around 60 psi.
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