PET bottles are widely used in the fields of household goods and daily chemical packaging due to their strong applicability, and PET bottles
are firstly formed by injection molding process and then by blow molding process to form PET plastic bottles, and the quality of PET bottles depends on the quality of the supplied embryos, so the PET embryo injection molding process is particularly important.
Because of the short stabilization time of PET material after melting point and the high melting point, it is necessary to use the injection system with more temperature control sections and less frictional heat generation during plasticization, and the actual weight of the product (including water mouth material) should not be less than 2/3 of the injection volume of the machine.
The design of the screw of PET preform injection molding machine is important for the preform injection molding process. The general screw used for PET injection is of poor quality and prone to problems, so the PET injection machine must have its own special screw. Because PET is a heat-sensitive material, it is easy to break the molecular chain at high temperature, which will lower the molecular weight and produce acetaldehyde, and reduce the quality of the preform; and in the material tube, it mainly relies on the rotational compression of the screw to make the ester particles produce shear heat and melt. The goal. Too high a compression ratio or too short a compression length will result in large shear; while a screw with too low a compression ratio will not generate enough shear heat to completely melt the ester pellets, making the bottles crystalline and white atomized, and will not be able to completely remove the air from the material tube, causing the bottles to bubble.
In the machine parts, we adopt the high efficiency mixing PET special screw, which has the super long length-diameter ratio and high plasticization rate, significantly improve the melt speed and injection volume, reduce the plasticization temperature and AA value, effectively improve the shrinkage problem of the products and improve the transparency. The inner distance of the injection molding machine tie rod is designed according to the tailor-made PET mold, 16-144 cavity molds can be matched, and it is more convenient for the robot to take out; the integrated design of piston and piston rod can provide better strength in use; the double cylinder design can provide greater injection force and perfectly inject various PET products.
In the whole bottle preform process equipment, besides PET injection, it also includes: hot runner bottle preform molds, ester pellet dehumidification dryer, mold cooling ice water machine, bottle preform removal robot arm, bottle preform conveyor belt and injection environment control air conditioning dehumidifier, etc. And each machine is to match the action of injection machine, so the fit of the whole PET injection equipment determines the quality and efficiency of PET injection.
We have developed a complete PET bottle preform production line system, providing a complete and mature PET injection molding process from bottle preform injection molding machine, robot, needle valve hot runner bottle preform mold and other series of products, which can provide better energy saving, system reliability, bottle preform quality and production efficiency. It can be widely used in beverage, edible oil, condiment, thin wall, daily chemical, pharmaceutical and other packaging fields at home and abroad.