■ Overview
For molds with multiple cavities, the design of the runner and gating system is crucial. A crucial parameter is the filling balance which ensures that material can fill the cavities simultaneously, preventing injection molding issues such as burrs and mold sticking. Therefore, filling balance is closely linked to product quality.
For the 128-cavity mold developed by our company GreeDaikinMold, filling balance is achieved through innovative runner system structure.
■ Key design point
1.Hot runner manifold layered design
2.The manifold’s runner adopts a graded and descending balanced design
For multi-cavity mold design, the balance of runner is a critical factor determining product quality. During the design process, various solutions are analyzed and simulated, and through comparison, a layered hot runner system is adopted. The hot runner internally employs a stepwise decreasing runner design concept.
The main gating scheme is as follows:
1. The mold manifold is divided into two layers—the first layer splits from the main injection nozzle into four groups of main runner systems;
2. The second layer consists of four manifold systems, each independently fed by a branch runner from the main nozzle. The runners within the manifold are divided into three layers, finally entering the hot tip from the sub-runners before filling the product. Here, each runner is balanced to ensure simultaneous filling for all 128 cavities, completing injection at the same time. This guarantees product quality, significantly improves yield, and greatly enhances product qualification rates.
