today morning, I design a mold from USA, he requires his mold to use a Stack gate, I want to share it with everyone, stack gate has two or more regulated gates stacked on the same runner. It is a good design for plastic materials which has a narrow range of melting temperature and poor fluidity. The melt material is reheated due to friction as it passes the regulated gates and flow resistance pin. It re-plasticizes the melt material and improve it’s liquidity. It causes significant drop in injection pressure. An injection molding machine with sufficient injection pressure needs to be used with a stack gate design.