The main channel is connected to the injection machine nozzle and the bypass channel of a channel, usually and the injection nozzle on the same axis, the section is round, and a certain degree of taper. Mainstream design points are as follows:
(1) the main channel designed to conical, the cone angle often take 2 ° ~ 4 ° liquidity check the plastic desirable 3 ° ~ 6 °, the flow channel surface roughness R0.63um, and the processing should be along the runner Axial polishing. Polypropylene (PP) flow is good, so the taper to take 3 °
(2) the main channel diameter spherical radius R2 than the injection molding machine nozzle ball radius R1 1 ~ 2 mm; spherical pit depth of 3 ~ 5 mm; main channel diameter of the beginning of the inlet d diameter than the injection nozzle nozzle diameter 0.5 ~ 1 ; General d = 2.5 ~ 5 mm
(3) the end of the main channel was rounded transition, fillet radius r = 1 ~ 3 mm.
(4) the main channel length L is less than 60 mm is better, the longest should not exceed 95 mm.
(5) the main channel is often set in the detachable main channel bushing; different main channel bushing structure and assembly as shown, the material commonly used T8A, heat treatment quenching hardness of 53 ~ 57HRC. This design should use the main channel shown in Figured.