Preform moulds

Multi-cavity preform moulds do not use the cold runner design. An often-used design for the runners is hot plate design. In hot plate design, every two cavities share a heating zone the temperature of which is measured by a thermocouple. There will be a sprue at the bottom of the preform of no more than 5 mm. After stopping the injection molding process for a while, there is a chance the runners are blocked and must be cleared by a time consuming process. Hot plate design is economical and is popular in China.