During the blowing process during the second world war, started for the production of low density polyethylene bottle. The late 50 's, with the birth of high density polyethylene and development of blow molding machine, blow-moulding technology has been widely applied. Hollow container volume up to thousands of litres of production has been using computer control. Suitable for blow molding of plastic polyethylene, PVC, polypropylene, polyester, and empty containers are widely used for industrial packaging containers.
According to preform production methods, blow moulding extrusion blow molding and injection blow moulding can be divided into, newly developed multi-layer blow molding and stretch blow molding.
Extrusion is plastics after the original by plasticizing screw in the extrusion die head, coupled with the following mold and compressed gas to the attainment of molding.
The extrusion blow molding process consists of 5 steps:
1 plastic made from the plastic-type embryo,
2.die close to capture part of the germ and cut off the germ;
3.cavity filled with gas making embryos forming and cooling;
4 to open the mold, take out the container after forming,
5.finishing up Flash to get the finished product.