Home / News / Industry News / What is the working principle of the blow molding machine

What is the working principle of the blow molding machine

The bottle blowing process is a process of bidirectional stretching (longitudinal and transverse), in this process, the PET chains are bidirectionally extended, oriented and aligned, thereby increasing the mechanical properties of the bottle wall and improving the stretching, tensile and impact resistance. strength and good air tightness. Although stretching helps to improve the strength, it should not be stretched too much. It is necessary to control the stretch inflation ratio: the radial direction should not exceed 3.5-4.2, and the axial direction should not exceed 2.8-3.1. The wall thickness of the preform should not exceed 4.5mm .

Blowing is carried out between the glass transition temperature and the crystallization temperature, generally controlled between 90 and 120 degrees. In this range, PET exhibits a high elastic state, and it becomes a transparent bottle after rapid blow molding, cooling and setting. In the one-step method, this temperature is determined by the cooling time during the injection molding process (such as the Aoki blow molding machine), so the relationship between the injection and blowing stations should be well connected.

In the blow molding process, there are: stretching—, one blow—two blows. The time of the three actions is very short, but they must be well coordinated, especially the first two steps determine the overall distribution of the material and the quality of the blowing. Therefore, it is necessary to adjust: the starting timing of stretching, stretching speed, pre-blowing start and end timing, pre-blowing pressure, pre-blowing flow, etc. If possible, it is best to control the overall temperature distribution of the preform, the bottle The temperature gradient of the inner and outer walls of the billet.

LONES Plastic Machinery Co., Ltd. is located in Huangyan Zone, Taizhou City, focusing on fully automatic PET bottle blow moulding machine, semi-automatic and full-automatic bottle blowing machines,  bottle mold manufacturing, pet preform, bottle cap molds etc as well as a series of product solutions; products are widely used In: mineral water, beverages, food, medicine, chemistry, reagents and other fields.