The Working Principle of PET Bottle Preform Injection Molding Machine
The working principle of the PET bottle preform injection molding machine mainly includes the following steps. First, add PET granule raw materials to the hopper of the injection molding machine. The raw materials are heated to a molten state in the barrel through a heating device. This process requires precise temperature control to ensure that the PET material can be fully melted without decomposition or deterioration.
When the PET material reaches the appropriate molten state, the screw of the injection molding machine starts to rotate and push forward, injecting the molten PET material into the mold cavity. The mold is designed according to the shape and size of the required preform and usually consists of two parts, namely the fixed mold and the movable mold. During the injection process, the injection pressure and speed need to be precisely controlled to ensure that the PET material can evenly fill the mold cavity and avoid defects such as lack of material and bubbles.
After the injection is completed, the mold will maintain a certain pressure for the holding stage. The purpose of this stage is to compensate for the volume reduction caused by cooling shrinkage and ensure the dimensional accuracy of the preform. After holding for a period of time, the cooling stage begins. By circulating a cooling medium such as cooling water in the mold, the preform is quickly cooled to a solid state.
Finally, the mold opens, and the ejection device ejects the formed preform from the mold. The entire production process cycles continuously to produce high-quality PET bottle preforms.
