Plastic mold common failure form – Wear and corrosion
- Plastic injection mold wear due to thermo setting plastics generally contain a certain amount of solid filler, softened after heating, melting plastic into a “hard spot”, punch mold cavity, and the mold cavity surface friction, resulting in type Cavity surface roughing, surface roughness becomes large and lose their luster, which will affect the appearance of plastic parts quality. Therefore, once found on the surface of the mold cavity nap phenomenon, should be promptly removed polishing. And after several polished cavity expansion, strict requirements on the size of plastic injection mold will be out of tolerance and failure. For example, the hardened tool steel bakelite die after a continuous pressure of 1.5 to 25,000, the mold surface wear thickness of 0.01 mm. There are data that mold 80,000 times as a filler of glass fiber plastic mold cavity wear is the amount of ordinary bake lite wear 6.5 times, indicating that the wear of glass fiber on the quenched steel is particularly evident. Therefore, when the plastic in the mica powder, quartz powder, glass fiber and other inorganic substances as a filler, pay special attention to the mold cavity wear problems.
- Plastic injection mold corrosion because many plastics contain chlorine, fluorine and other elements, heated to the molten state will decompose of hydrogen chloride (HC1) or hydrogen fluoride (HF) and other corrosive gases, corrosion mold cavity surface, which increased its Surface roughness values, but also exacerbated the mold cavity wear, resulting in failure.