The car door panel mould is located on the inner side of the car door and is installed in four positions on the front, rear, left and right of the car door. It is an important part of the car interior parts. The door panel of the car is an appearance part, and no welding line is allowed. When injection moulding, it is necessary to adjust the welding line to the non-appearance area or eliminate the welding line. Kelong's door panel mould adopts a 3-point sequential needle valve hot runner system, which is controlled by an oil cylinder or a cylinder. The opening and closing of 3 hot nozzle heads to achieve the injection moulding effect without welding lines. The selection of the glue inlet position is mainly determined by the mould flow analysis, and the type of glue mouth is mainly used for large nozzles and diving. But one thing needs to be noted: the glue feeding position is in the non-appearance position or the position that is not easy to see after the door panel is assembled, such as the glue opening at the bottom of the door panel mould.