Causes and Analysis of Whitening of Injection Molds

During the injection molding process, any product may have defective products. It is normal to produce bad products occasionally due to improper operation, but if a certain defective product appears frequently, it may indicate that there is a problem with the injection molding process. Among the many defective phenomena, mold whitening is a more common one. Today, we will go to the injection molding factory to have a deep understanding of the mold whitening phenomenon and its causes.

The mold whitening phenomenon can be divided into three different situations:

1. Bright spots appear on individual active components, the number is small, but large areas of bright spots may also appear;

2. The defective area of ​​the mold is white, and the overall contour is similar to the shape of the active component;

3. The main channel and each gate of the mold are whitened at the same time.

The injection molding factory has studied and analyzed the whitening phenomenon of the mold. The whitening phenomenon is caused by excessive internal stress during the injection molding process. When the internal stress of the mold exceeds the yield strength of the material, the material will form dense cracks on the surface under the influence of high pressure and high temperature. These cracks will refract different light under different light, thus forming various light spots. However, many people do not know why molds produce excessive internal stress and can only make some guesses.

Among the guesses about excessive internal stress, the following view is more popular: During the injection molding process, the movable parts are compressed and deformed due to the melt pressure. The more difficult the injection molding, the more obvious the compression deformation of the movable parts, and the greater the reaction force. Plastic Injection Molding Mold Manufacturers believe that when this force exceeds the yield strength of the material, the internal stress will cause the mold surface to turn white.