I. Causes of indentation
1. Different thickness of plastic products
2, the internal pressure of the mold is not enough
3, mold cooling is not sufficient
4, due to the lack of cooling time caused by deformation
In the process of producing products, notch is the most frequent occurrence of bad phenomenon, injection mold plastic in the cooling of the volume contraction, early cooling part of the surface hardening, the inside will produce bubbles, so-called Dent, is the cooling of the slow part in the direction of the bubble contraction produced a prominent concave.
Shrinkage of large material is also easy to produce dents, when you want to change the molding conditions to eliminate the dent, you should set the conditions to shrink the direction of the small set. That is, the mold temperature, the barrel temperature is reduced, the ejection pressure increases, but should pay attention to this may cause the residual internal stress.
Because the dent to inconspicuous as well, so if it does not affect the appearance of the time, there is deliberately in the mold processing into a corrosive appearance, such as stria, granular and so on. And if the molding material is hips, the use of lower mold temperature to reduce the finish is also effective. But once these methods have dents, it is difficult to repair the polished products.
1, increase the ejection pressure, extend the holding time, reduce the barrel temperature and mold temperature, and force the cooling in the place where the dent is produced.
2, Short: In the place where the indentation is produced, the edge is thickened when the material in the place where the dent is produced has a narrow place.
3. Long-term: the thickness of the design product should be completely avoided, the reinforcement of the concave scar is easy to produce, and the narrow shape should be as short as possible.