1. Definitions:
The main runner refers to the section from the contact part of the injector nozzle and the mold to the branch runner.
2. Design Guide:
(1) The end face of the sprue is usually circular.
(2). In order to facilitate demoulding, the main runner is generally made with a slope. However, if the main runner passes through multiple plates at the same time, pay attention to the slope and size of the holes on each block.
(3) The size of the main runner shall be designed according to the flow characteristics of plastic materials
(4) The main runner is mostly conical in design (as shown in the figure). Pay attention to:
A. Small end diameter D2=D1+(0.5~1mm)
B. Radius of small end ball R2=R1+(1~2mm)
(D1 and R1 are respectively the diameter of the injection outlet of the injection machine and the spherical radius of the injection head)