The Material of Plastic
PET (Polyethylene Terephthalate) is a non-porous thermosetting material that may be used to make anything that has to be watertight. Because it is lightweight, safe, and totally recyclable, PET is a popular choice for beverage bottles.
Establishing the technique
The PET bottle blow molding method involves warming a pre-moulded PET preform before it is automatically positioned into a mold. The preform is then pumped with high-pressure food-grade compressed air, which expands to produce the mold’s shape. The bottle is removed once the plastic has cooled, and the process is repeated. This method may be used to make a wide selection of bottles with a volume of up to 1 litre.
PET fully active blow molding machines are now imported mostly from SIDEL of France, KRONES of Germany, and Fujian Quanguan of China. Although the manufacturers differ, the basic principles of their equipment are the same, and they typically consist of five key components: billet supply, heating, bottle blowing, control, and auxiliary gear.
The blow molding method
The method of blow molding PET bottles.
Preform, heating, pre-blowing, mold, and the manufacturing environment are all important components in the PET bottle blow molding process.
PET chips are the initial injection that are molded into the preforms before being used to make blow-molded bottles. The percentage of secondary items recovered must be less than five percent, the number of times recovered must not cross twice, and the weight or viscosity of the molecule must not be exceedingly low. The NFSL (National Food Safety Law) prohibits the use of secondary recovery items in food and medicinal packaging. Preforms that have been injection molded can be utilized for up to 24 hours. To be reheated, preforms that are not utilized after heating should be kept for at least 48 hours.
The PET material quality has a significant impact on the preform quality. Materials are quite easy to change their shape and must be used, and a preform molding method that is acceptable should be devised. Experiments have demonstrated that foreign PET preforms with the similar viscosity are simpler to gust mold than the domestic preforms; while the similar batch of the preforms may have various manufacturing time, the molding process of the blow may also change considerably. The complexity of the molding process of the mold is determined by the quality of the preform.
The oven, whose temperature is regulated manually and changed actively, completes the heating of the preform. The light tube (far-infrared) in the oven indicates that radiantly (far-infrared) warms the preform. The bottom of the fan and the oven cross the heat to maintain an equal temperature within the oven. The preforms rotate together in the heating oven as it moves ahead, ensuring that the preforms’ walls are evenly heated.
The height, cooling plate, and other aspects of the heating oven must all be fixed in order for it to operate properly. It is possible to change the shape of the mouth of the bottle. The mouth of the bottle grows larger and hardens the head and neck when the blow is molding if the adjustment is not perfect. As well as other flaws
In the second-stage bottle blowing process, pre-blowing is a critical step. The pre blowing process begins as the bar of the draw drops during the molding process of the blow, allowing the preform to acquire shape. The pre-blowing orientation, pressure, and flow of the blowing are three essential process components in this process.
The complexity of the molding process of the blow and the quality of the function of the bottle are determined by the form of the bottle’s pre-blow. The usual shape of a pre-blow bottle is the shape of the spindle, but aberrant shapes include the sub-bell and handle. Local heating if improper, pre-blowing pressure that is insufficient or flow of the blowing, and other factors contribute to the aberrant form. The bottle size is determined by the pressure and direction. All bottles in the entire equipment must have the same size and form during manufacturing. If there is a discrepancy, the cause should be investigated thoroughly.
Mold and auxiliary machine
Auxiliary machine refers to the piece of equipment that maintains a consistent mold temperature. The mold’s consistent temperature is crucial in preserving the product’s stability. The temperature of the bottle body is often high, whereas the temperature of the bottom bottle is typically low. Because the degree of molecular orientation is determined by the cooling action at the cold bottle’s bottom, it is best to keep the temperature between 5 to 8 degree centigrade; however, the bottom’s temperature of the bottle is considerably greater.
The bottle must meet the criteria of both the stress and pressure tests. The purpose of the test of stress is to protect the chain of molecules from splitting and leaking during the connection between the bottle’s bottom and the lubricant (alkaline) during PET bottle filling. The purpose of the test is to prevent the bottle from overfilling. After exploding into a high-pressure gas, quality checking is performed. To meet these two requirements, the thickness of the central point should be kept within a particular range.
The above article articulates the general conditions of PET bottle process laid down in detail. Incase you are looking for pet bottle blow moulding machine manufacturers do check out Maiwei Machines as they produce high quality product at affordable rates