September 28, 2022
The history of the blow molding machine
Enoch Ferngren and William Kopitke were the first to demonstrate the blow molding process. The principle of this process originates from the blowing of glass supplies. In 1938, Ferngren and Kopitke built a blow molding machine and sold it to the Hartford Imperial Company. This is 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 in product types and productivity, more and more plastic products are soon produced by blow molding. In the US 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 was widely used. The volume of hollow containers 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 obtained hollow containers are widely used as industrial packaging containers.
According to the method of making the parison, blow molding can be divided into extrusion blow molding and injection blow molding. The newly developed ones include multi-layer blow molding and stretch blow molding.
The extrusion process is to extrude the plasticized plastic into the extrusion blowing die head through the screw, and then cooperate with the lower mold and compressed gas to realize the molding of the product.
The extrusion blow molding process consists of 5 steps: 1. The plasticized raw material is made into a plastic parison; 2. Part of the parison is cut off by closing the mold; 3. The mold cavity is filled with gas to make the mold The embryo is formed and cooled; 4. Open the mold and take out the formed container; 5. Trim the flash to obtain the finished product.
The preform (preform) is irradiated by an infrared high temperature lamp, and the body part of the preform (preform) is heated and softened. In order to maintain the shape of the bottle mouth, the mouth of the preform (preform) does not need to be heated, so it needs to be certain. cooling device to cool it.
2. Blow molding
In this stage, the preheated preforms (preforms) are placed in the blow molds that have already been prepared, and high-pressure inflation is carried out in them to blow and draw the preforms (preforms) into the desired bottles.
Blow molding machines on the market are generally divided into two types: automatic and semi-automatic.
The automatic bottle blowing machine completes the two operations of blowing the bottle together through the operation of the manipulator, eliminating the process of manually placing the preheated preform (preform) into the blow mold in the middle. Greatly accelerated the rate of production, of course, the price is higher than the semi-automatic.
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