Process History Of Blow Molding Machine

Enoch Ferngren and William Kopitke were the first to demonstrate the blow molding process. The principle of this process is derived from glassware blowing. In 1938, Ferngren and Kopitke built a blow molding machine and sold it to the Hartford Imperial Company. This was the beginning of the commercial blow molding process. In the 1840s, the variety and quantity of plastic products were very limited, so the blow molding process did not develop rapidly until much later. With the increase of product types and the improvement of productivity, more and more plastic products will be produced by blow molding soon. In the U.S. soft drink industry, the number of plastic containers has grown from zero in 1977 to 10 billion in 1999.

The blow molding process began to be used to produce low-density polyethylene vials during World War II. In the late 1950s, with the birth of high-density polyethylene and the development of blow molding machines, blow molding technology has been widely used. The volume of the hollow container can reach thousands of liters, and some production has adopted computer control. Plastics suitable for blow molding include polyethylene, polyvinyl chloride, polypropylene, polyester, etc., and the resulting hollow containers are widely used as industrial packaging containers.

According to the parison production method, blow molding can be divided into extrusion blow molding and injection blow molding, and the newly developed ones are multi-layer blow molding and stretch blow molding.

The extrusion process is to extrude the plasticized plastic into the extrusion blowing die through the screw, and then cooperate with the following mold and compressed gas to realize the molding of the product.

The extrusion blow molding process consists of 5 steps:

1. Make the plasticized raw material into a plastic parison;

2. Cut off part of the parison and cut off the parison by closing the mold;

3. Fill the mold cavity with gas to form the parison and cool it down;

4. Open the mold and take out the formed container;

5. Trim the flash to get the finished product.