Transparent components have their own special features and functions.
Polycarbonate injection molding will inevitably be used in auto parts.In the process of injection molding, we often encounter some thick wall transparent injection parts.For performance reasons, these plastic parts are made from PC machinery.
When the average wall thickness exceeds 6mm and the maximum wall thickness exceeds 12mm, two problems often occur in the injection molding process of plastic parts:
One is the surface shrinkage and the other is the bubble inside the product.
For thicker walls, deformation is not the main problem.
The injection molding of PC transparent plastic parts has the most problems:
shrinkage
The main reason is that the wall thickness is too thick, resulting in product shrinkage.In this process, more melt must be injected to prevent shrinkage, and higher mold temperatures are required to shrink the entire product (opaque products require lower mold temperatures without worrying about vacuum bubbles).
The countermeasures are as follows:
Increase the number of gate on the mould, increase the size of cold slug well.
2. Reduce the injection speed, increase the back pressure and barrel temperature, increase the holding pressure and time, extend the cooling time, and increase the mold temperature.
bubble
There are two reasons for bubbles: one is the gas in the melt, and the other is the vacuum bubbles produced by shrinkage.
The gas inside the melt is mainly due to air and small amounts of plastic being broken down.The solution is to dry the material thoroughly;Although the problem of vacuum bubble is difficult to solve, the mold and molding process need to be improved.