Bottle blowing machine refers to equipment for blowing bottles. The simple explanation is that this machine can blow plastic particles (softened into liquid) or good preforms into bottles through technical means.
At present, most bottle blowing machines are still two-step, that is to say, plastic raw materials must be made into preforms before blowing. At present, pet environmentally friendly plastics are widely used.
The bottle blowing step of the bottle blowing machine is divided into two parts.
Irradiate preforms (embryos) with infrared high-temperature lamps to heat and soften the embryos. In order to maintain the shape of the bottle mouth, the embryo mouth does not need to be heated, so a certain cooling device is needed to cool it.
At this stage, the preformed preforms are put into the completed blow mold and inflated with high pressure. Blow air and pull the preform (embryo) into the desired bottle.
The automatic bottle blowing machine combines the two operations of bottle blowing through the operation of a manipulator to avoid the process of manually putting the preheated preform into the bottle blowing mold. It greatly speeds up production.
Process of blow molding machine
The bottle blowing process of the bottle blowing machine is a two-way stretching process. In this process, the pet chains are bidirectionally extended and oriented, which improves the mechanical properties of the bottle wall, improves the tensile, tensile and impact strength, and has good air tightness. Although stretching helps increase strength, it should not be overstretched. Control the proportion of stretch air blowing times: not more than 3.5-4.2 times in the radial direction and not more than 2.8-3.1 times in the axial direction. The thickness of the embryo wall shall not exceed 4.3mm.
Bottle blowing is carried out between the glass transition temperature and the crystallization temperature, generally controlled between 90 and 110 degrees. Within this range, pets behave in a highly elastic state. After rapid blow molding and cooling, the pet turns into a transparent bottle.
In the blow molding process, there are three actions: stretching, primary blow molding and secondary blow molding. The time of the three actions is very short, but it must be coordinated, especially the first two steps determine the overall fabric and quality of the bottle blowing. Therefore, it is necessary to set the parameters such as the start time, stretching speed, start and end time, pre-blowing pressure, pre-blowing air flow and other parameters of the pre-blowing, if possible, it is best to control the overall temperature distribution of the embryo and the embryo. The temperature gradient of the outer wall.
During rapid blow molding and cooling, there is induced stress on the bottle wall. For aerated beverage bottles, it can resist internal pressure, which is beneficial, but for hot-fill bottles, it must be ensured that it is completely released beyond the glass transition temperature.