PET preform molds are mainly used to produce PET plastic packaging products to meet the needs of plastic bottle manufacturers.
PET preform mould forming method
1. Extrusion blow molding: It is the extrusion blow molding of the parison, which is then heated and drawn into a finished product.
2. Injection blow molding: is the injection blow molding of the parison, and then the finished product is produced through the mold.
But whether it is extrusion blow molding or injection blow molding, the parameter selection of each part is the key to plastic molding. Therefore, we need to study and analyze the size of the PET preform mold to obtain the correct data.
Factors of forming PET preform mold
Factor 1: The length of the core rod in the PET preform mold is usually 10:1. Since the parison receives the largest injection pressure during the filling process, if the length and diameter are relatively large, the mandrel will bend more, which often leads to uneven wall thickness distribution of the parison. The height of the mandrel is also referred to according to the specific height of the parison. When these parisons of the correct size are produced, the temperature stabilizes at approximately 145 degrees Celsius, resulting in highly transparent plastic parts.
Factor 2: The melting temperature of the preform is also the main factor in its formation. For PET molds, the temperature in the equipment has a great influence, so the temperature of the barrel will be increased to ensure the temperature of the PET melt. When the temperature of the barrel is 280 degrees Celsius, the temperature of the melt is 290 degrees Celsius to ensure high transparency of the produced plastic parts.
Factor 3: The value and expansion rate of the preform is also one of the factors that affect the molding of plastic parts. During the molding of the plastic part, the parison is subjected to axial stretching. The smaller the axial stretch, the greater the expansion rate, and the uneven distribution of the bottle wall thickness of the resulting plastic part and the uneven transition between the bottle body and the bottle body. phenomenon.
Factor 4: The size of the preform and the threaded hole should be uniform. When the size of the parison is determined, it is necessary to ensure that the size of the preform opening and the threaded opening in the PET mold are uniform. If it is not uniform, the sealing performance of the produced plastic part will be poor.