The shrinkage problem of hard rubber parts (surface concave shrinkage and internal shrinkage) is caused by the defect that the space left by the concentrated shrinkage can not be adequately supplemented by the melt from the direction of the inlet when the melt is cooled and contracted. Therefore, factors that are not conducive to the subsidy will affect us to solve the problem of shrinkage.
Most people know that die temperature is too high to cause shrinkage problems, usually like to reduce the temperature of the die to solve the problem. But sometimes if the die temperature is too low, it is not conducive to solve the shrinkage problem, which is not noticed by many people.
Mold temperature is too low, melt glue cooling is too fast, slightly thicker glue level is far from the water inlet. Because the middle part is cooled too fast, the shrinkage channel is blocked and the melt glue can not be adequately supplemented in the distance, which makes the shrinkage problem more difficult to solve. The shrinkage problem of thick injection parts is particularly prominent.
Moreover, too low die temperature is not conducive to increase the overall shrinkage of injection parts, so that the concentrated shrinkage increases, shrinkage problem is more serious.
Therefore, when solving the difficult shrinkage problem, it is good to remember to check the die temperature. Experienced technicians usually touch the surface of the die cavity with their hands. Each material has its appropriate die temperature. For example, the shrinkage of PC material will be improved if the hole is properly pressed, but if the die temperature is too high, the shrinkage of injection parts will occur.