Today is Monday, just experienced 520 and 521 Dongguan Plastic mold factory do not know the majority of my colleagues, your pockets okay? I want to say that these two days I have been working overtime, pockets seems to have nothing to change ah. Today, we introduce the plastic mold thermosetting plastic shrinkage.
1. The cause of contraction
Heat shrinkage: is due to thermal expansion and contraction of plastic parts caused by cooling after the shrinkage. Heat shrinkage is proportional to the mold temperature and is the most important factor affecting shrinkage. Structural changes cause shrinkage: due to cross-linking reaction, the molecules from the linear structure into a network structure, the molecular chain spacing narrow, the structure becomes close, resulting in volume shrinkage.
Elastic recovery: plastic parts removed from the mold after the role of the pressure in the plastic parts disappear, due to elastic recovery, will result in plastic parts of the negative shrinkage (expansion).
Plastic deformation: plastic parts stripping, the molding pressure quickly reduced, but the mold wall pressed around the plastic parts, to produce plastic deformation.
2. Factors that affect the shrinkage are: mold structure, forming process and plastic varieties
Plastic varieties: different varieties, different shrinkage, the same kind of plastic, different grades, different shrinkage, the same kind of grades, different batches, shrinkage may also be different Plastic parts structure: wall thickness, shrinkage, Shrinkage is small, complex shape, small shrinkage.
Note: The above information is made by Jiezheng mold finishing in the Internet welcome reproduced, indicate the source!