A multi-cavity mould can be understood, obviously referring to mold with multiple cavities. The multi-cavity mold comprises a multi-cavity of the same plastic part and a multi-cavity of different plastic parts. The use of multi-cavity molds for injection molding of plastic products can increase production efficiency and reduce costs, so the multi-cavity molds are becoming more popular.
Since the multi cavity mould must have multiple runners to supply the melt to each cavity, the rationality of the injection molding system design directly affects the quality of the injection molded parts, material consumption, production efficiency and economic benefits.
In order to ensure the uniformity and performance of the quality and performance of each cavity, the flow balance of the gating system during the injection process is very critical, so that the plastic melt can be filled the cavity with the same pressure and temperature at the same time. Therefore, filling balance is the most important factor to consider when designing a multi cavity mould.
The arrangement of the cavity and the runner is divided into two categories: balanced and unbalanced.
The feature of balance type is the length, shape and section dimension of the runner from the sprue to each cavity are correspondingly the same, it can realize even feeding of all cavities and fill the cavity at the same time. However, the unbalanced feature is that the lengths of the runners from the sprue to the cavity gates are not equal, which is not conducive to balanced feeding, but the unbalanced arrangement can significantly shorten the overall flow of the melt in the gating system. The compact mechanism reduces heat loss and injection pressure loss during flow and shortens the mold filling time.