Pet Bottle Preform are typically formed from hot runner molds. It is preferred to have a heat shield between the mold and the injection molding machine template. The thickness of the plate is approximately 12 mm and the heated plate must withstand high pressures. Exhaust gas must be sufficient to avoid local overheating or chipping, but the depth of the vent should not exceed 0.03 mm, otherwise flashing will easily occur.
It can be measured by air to air. When producing PET preforms between 270 and 295 °C, the enhanced PET can be set at 290 – 315 °C.
Usually, the injection speed needs to be fast, which prevents premature coagulation during the injection process. But too fast, high shear rates can make the material brittle. Injections are usually completed in 4 seconds for the production of PET preforms.
The lower the better, to avoid wear. Generally no more than 100 bar. The production of PET preforms usually does not require back pressure.
Do not use excessive residence time to prevent molecular weight degradation. Try to avoid temperatures above 300 °C. If the shutdown time is less than 15 minutes. Only air injection is required; if it is more than 15 minutes, clean it with a viscosity PE and lower the temperature of the barrel to the PE temperature until it is turned back on.
(1) There should not be too much recycled material, otherwise it will easily cause a “bridge” during the blanking, which will affect plasticization.
(2) If the mold temperature is not well controlled or the material temperature is not properly controlled, it is easy to produce “white fog” and it is opaque. The mold temperature is low and uniform, the cooling rate is fast, the crystallization is small, and the product is transparent.
Jilian Plastic Mould is a professional manufacturer of 5-Gallon Pet Preform. If you choose us, you can effectively avoid some problems in the production process and ensure that you can get satisfactory products.