(3) Wear and corrosion of the cavity surface
The plastic melt flows in the cavity with a certain pressure, and the solidified plastic parts are released from the mold, causing friction on the molding surface of the mold and causing wear. The root cause of the failure of the plastic mold wear is the friction between the mold and the material. However, the specific form of wear and the wear process are related to many factors, such as the pressure, temperature, material deformation speed and lubrication status of the mold during operation.
When the material used in the plastic mold and the heat treatment are unreasonable, the cavity surface of the plastic mold has low hardness and poor wear resistance, and the performance is as follows: the dimensional difference of the cavity surface due to wear and deformation; the roughness value becomes higher due to the pulling of the hair The surface quality deteriorates.
Especially when solid materials are used to enter the mold cavity, it can exacerbate the wear of the cavity face. In addition, the plastics contain chlorine, fluorine and other components to decompose the corrosive gases HC1 and HF, causing corrosion and wear on the cavity surface of the plastic mold, resulting in failure. If the wear and tear are accompanied by wear and damage, the coating or other protective layer on the surface of the cavity is destroyed, which will promote the corrosion process. The intersection of the two types of damage accelerates the corrosion-wear failure.