At present, the application scope of preform molds is relatively extensive. It has the characteristics of high quality, energy saving, high efficiency, long service life, etc., and is favored by more and more manufacturers. So what are the factors that affect preform molding? Let's take a closer look.
First, the polymer in the extruder transport, melting, mixing, pumping into the forming stage of the embryo; In this stage, the factors affecting the wall thickness distribution are: 1, the molecular weight distribution of the material and the average molecular weight; 2. Temperature control system and screw rotation speed of blow molding machine, including temperature control system including hopper temperature, temperature of barrel 1, area 2, area 3, and area 4, temperature of flange, and 1 and 2 areas of storage die head , 3 zones, 4 zones temperature.
Second, the stage of extrusion of the embryo from the gap between the die lip and the core is referred to as the blanking stage. At this time, the common phenomenon is the mold from the expansion of the mold and the embryo elongation. Factors affecting these two phenomena are: 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 core. of.
Third, the stage of pre-blowing embryos In order to avoid contact and adhesion of the inner surface of the embryos, and to improve the uniformity of the wall thickness of the products, pre-blowing of the embryos is required. In the pre-blowing stage of the parison, the air is injected from the bottom of the parison toward the parison to protect the parison and reduce its draw. At this stage, factors affecting wall thickness distribution include: pre-blowing pressure and pre-blowing time.
Fourth, in the high-pressure stage of the embryo, high-pressure inflation of the embryo, so that close to the mold cavity, plastic molding products. At this stage, the common phenomenon is that the parison is deformed under high pressure and deformed, and the parison is in contact with the mold cavity. Factors influencing such situations include: material shrinkage; blowing pressure and time; mold material and structure; mold exhaust system and mold cooling system, such as cooling water distribution, cooling water inlet temperature.
Although there are many factors affecting the quality of blow molding products, when the production conditions and product requirements are determined, adjusting the blowing process factors can effectively improve the quality of products. After all, optimized process factors can increase production efficiency, reduce raw material consumption, and optimize the overall performance of the product.