Medicinal PET Bottle Molding Method

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PET bottle molding methods are extrusion blow molding and injection blow molding process in two ways, there are one-step and two-step stretch blow molding method of the points, in one-step molding, parison molding, cooling, heating, Remove and stretch blow molding and the bottle were successively performed on a machine, two-step rule by extrusion or injection molding parison, and the parison is cooled to room temperature, becoming semi-finished products, and then the parison into reheated and stretch blow-molding machine to become the bottle. That parison molding, stretch blow molding is done on the two machines, respectively. One-step injection blow molding PET bottles, injection blow molding equipment requires two mold that is injection mold and blow mold preforms. The injection molded preform is mainly composed of the parison mold cavity and the mandrel, its parameters are chosen size of each part is correct or not is the key to whether the shape of the bottle, so it is necessary to mold the parison size parameter binding molding a reasonable selection .

The ratio of the height of its thread diameter neck portion (1) PET bottle preform and the mandrel may determine the aspect ratio (L / D). Mandrel aspect ratio value principle is generally not more than 10 than l, this is because the parison mold mandrel is cantilever, and by the effect of high injection pressure during filling. Selected aspect ratio is larger mandrel bent when it is large, is likely to cause the parison wall thickness distribution is uneven, but through the program to control the melt filling speed or filling process, the sliding thimble temporarily fixed core the head end to the mandrel on the mandrel aspect ratio advisable at this time a large value. Preform bottle height is the height reference coefficient obtained by multiplying the height, the height of the bottle is generally 92% -95%. In order to ensure good transparency of the parison, after filling the melt into a parison mold, the temperature was quickly lowered to less 145 ℃, but than the glass transition temperature of the polyester material (82 ℃) higher and closer to the glass temperature, the higher the transparency of blown bottles. Parison mold cooling water temperature up to 10 ℃ -35 ℃, in order to quickly cool the parison, but also take a liquid or gas continuous cooling mandrel, wherein the mandrel cool air can be more uniform temperature distribution, the air pressure is usually about 1MPa.