Stretch film has the same performance as rubber at room temperature, has a certain degree of durability, and at the same time has certain elasticity, high elongation, self-adhesiveness and Flexibility, deeply loved by the packaging industry. Especially when transporting loose parts, only scattered objects can be packaged, with long-lasting beam tightness. This is also due to the stretch coefficient of the stretch film to a certain extent, which is the key to determining its performance and quality. So next, let us get to know each other.

The stretch coefficient of a stretched film is one of the main process parameters in the calculation of the stretching process, and is usually used to determine the sequence and number of stretching. There are many factors that affect the stretch coefficient of the stretched film, including material properties, relative thickness of the material, stretching method (referring to whether there is a blank holder), the number of drawing times, the drawing speed, the fillet radius of the punch and the die, Lubrication etc. The calculation and selection principles of the stretching coefficient of the stretched film are the focus of various stamping process manuals (referring to whether there is a blank holder). The relative thickness of the material, the stretching method (with or without blank holder), and the number of draws are not easy to adjust during mold repair, so be careful!

During the deep drawing process of the heat treatment of the workpiece, due to the cold plastic deformation, the workpiece undergoes cold work hardening, thereby reducing its plasticity and improving its deformation resistance and hardness. In addition, if the mold design is unreasonable, intermediate annealing must be carried out to soften the metal. Restore plasticity. Note: Annealing is unnecessary in the general process. After all, it is necessary to increase the cost, increase the process and increase the choice of annealing, use it with caution! Annealing usually uses low temperature annealing, that is, recrystallization annealing. Two points should be paid attention to during annealing: decarburization and oxidation. Here we discuss oxidation. After the workpiece is oxidized, there will be oxide scale, which has two hazards: thinning the effective thickness of the workpiece and increasing the wear of the mold.

The performance advantages of stretched film can be said to be multifaceted, and these advantages come from its material selection and processing technology. If the process technology is not good enough, then it will not be able to achieve the effect of high-quality products. Therefore, it not only depends on the use of the product, its processing technology is also very important, but many people do not understand it very well. We can simply Start with a simple definition.