Introduction of cooling method in mold of blow molding products


Author: MULAN -Plastic Molding Manufacturer

Introduction of cooling method in mold of blow molding products Too short cooling time will lead to warping and obvious shrinkage of blow molding products. In order to achieve high-speed blow molding, it is a good measure to improve the cooling efficiency of blow molding products, which can shorten the molding cycle and reduce energy consumption. However, the role of the cooling system is not only to increase productivity, a good cooling water system can improve Improve the surface quality of blown products and make them full. All in all, the quality of the cooling system is one of the important indicators to measure the blow mold. During the cooling of blow molded products, the outer wall is cooled faster due to contact with the low-temperature mold cavity, and the inner wall is in contact with the inflation air, and the heat transfer is very small, so the cooling is slower. The difference in the cooling rate of the inner and outer walls may cause warping of the product. One solution is to hold the pressure in the mold for a longer time, so that Blow molding products are taken out after they are fully shaped, which will prolong the entire cycle and affect production efficiency. To this end, the industry has researched and developed various internal cooling methods, that is, injecting water mist, liquid nitrogen or carbon dioxide, refrigeration air, circulating air or mixed media into the inside of the inflated parison to quickly cool the inner wall of the blow molded product. In internal cooling, liquid nitrogen and carbon dioxide are commonly used, because they are clean, non-chemical, and suitable for a variety of Blow molding products. The internal cooling method is used to form blow molded products, and the production efficiency is high; however, it is necessary to control the temperature of the internal cooling medium. If the temperature is too low, defects such as strain and spots on the inner surface of the plastic will occur, which will affect certain dimensions (such as containers) Neck size) versus container volume shrinkage. The method of using liquid nitrogen for blow molding internal cooling is very effective in the extrusion blow molding process. It can be used as both a coolant and an inflation gas, which can shorten the production cycle by up to 50%. The length of time to shorten the cycle mainly depends on the performance of the blow molded product, mainly related to the material, weight, wall thickness and shape of the product. The liquid nitrogen blow molding process has better economic benefits when the pressure-holding time of blow-molded products is greater than 20 s; manufacturers of blow-molded products in places with large batches of blow-molded products and where the supply of liquid nitrogen is convenient may wish to try. When the internal cooling method is used, some special products need to be combined with compressed air blow molding, which can ensure good molding of products and improve production efficiency. Proficient in mold| Blow Molded Products | Started in 1998, trustworthy.

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