Several Influencing Factors Affecting Preform Mold Forming

The application range of the preform mold is relatively wide. It has the characteristics of high quality, energy saving, high efficiency and long service life, which is favored by more and more manufacturers. Then, what are the factors that affect the molding of the preform mold? Let's find out together.

1. The polymer is transported, melted, kneaded, and pumped out of the extruder to form a parison; at this stage, the factors that affect the wall thickness distribution are: 1. The molecular weight distribution and average molecular weight of the material; 2. The temperature control system and screw speed of the blow molding machine. The temperature control system includes the temperature of the hopper, the temperature of the 1st, 2nd, 3rd and 4th areas of the barrel, the flange temperature and the 1st and 2nd areas of the storage die. , Zone 3, Zone 4 temperature.

2. The stage where the parison is extruded from the gap between the die lip and the die core is called the blanking stage. At this time, the common phenomena are parison release expansion and parison vertical extension. The factors affecting these two phenomena are: the die diameter and wall thickness control system of the blow molding machine. The control system includes an axial wall thickness control system and a circumferential wall thickness control system, which is used to adjust the gap between the die lip and the die core. of.

3. In the parison pre-blowing stage, in order to avoid the contact and adhesion of the inner surface of the parison, and to improve the uniformity of the wall thickness of the product, the parison should be pre-bloated. In the pre-blowing stage of the parison, the air is injected into the parison from below the parison to protect the parison and reduce its vertical extension. At this stage, the factors affecting the wall thickness distribution are: pre-blowing pressure and pre-blowing time.

4. In the high-pressure blowing stage of the parison, the parison is inflated with high pressure to make it close to the mold cavity to realize the plastic molding of the product. At this stage, the common phenomenon is that the parison is blown and deformed by high pressure, and the parison is deformed by contact with the mold cavity. The factors that affect this kind of situation are: the shrinkage rate of the material; the pressure and time of air blowing; the material and structure of the mold;