The cause of the shrinkage of plastic molds

Any product will be degraded during production, because the external environmental factors are too much, the instability of air quality and the sudden pause of machinery and equipment will affect the quality and production of the product, so the shrinkage of plastic mold It is very inevitable, don't worry, the solution to this shrinking phenomenon depends on the technical control behind.

Poor shrinkage occurs in the shape of a pit on the surface of the molded part, and generally occurs in a thick portion of the volume where the volume shrinkage is large. During the cooling of the molded article, volume shrinkage occurs, whereby a pulling force that contracts toward the center portion occurs. At this time, due to the balance between the rigidity of the surface cold layer and the contraction force of the resin, when the cold layer is weak, a pulling force is generated toward the center of the molded part, and appears to be concave on the surface of the product. When the cold material layer is strong, vacuum bubbles are generated at the center of the molded part. In thicker areas, the balance between the rigidity of the cold surface and the shrinkage of the resin is closely related to the cooling rate of the surface of the molded part, and a vacuum bubble is formed when the cooling rate is faster. Conversely, shrinkage occurs when it is slower. In addition, the cooling rate becomes slower, the volumetric contraction difference becomes smaller, and the shrinkage condition also becomes smaller. The influence factor of the external environment is the influence of air quality. The control of air quality is to choose to work in the clean room. The clean room is a relatively advanced working environment. It is absolutely safe to work in this environment. . The solution to the sudden pause of the machine is to check the quality of the equipment frequently, so that you can control the external environment.