1. Definitions:
The main runner refers to the segment from the point of contact between the injector nozzle and the mold.
2. Design considerations:
(1). The face shape of the main runner is usually round.
(2). For the convenience of demodulation, the mainstream road is generally made with slant, but if the main runner passes through multiple boards at the same time, it is important to pay attention to the Angle of the hole in each piece and the size of the hole.
(3). The design of the main runner size shall be determined according to the flow characteristics of the plastic material.
(4). The main runner is mostly conical in design.
A. small end diameter D2=D1+ (0.5~1mm)
B. Small end ball radius R2=R1+ (1~2mm)
(D1 and R1 are the diameter of the injection machine and the radius of the injection head.)
3. The gate set
Because the main runner is to contact with high temperature plastic and nozzle contact and collision, the main part of the mold is usually designed to be disassembled and replaced, for short, for short pouring or sprue.
(1) the function of this is mainly as follows.
A. It is convenient to enter the positioning hole when the mold is installed, and it is well positioned on the injection molding machine to match the nozzle hole of the injection molding machine, and can withstand the anti-pressure of the plastic without being pushed out of the mold.
B. as a way to the mainstream of the gating system, the plastic transition to die within the cylinder, ensure smooth material flow effectively to reach the cavity, there should be no plastic overflow during injection, at the same time ensure that mainstream way setting out is convenient.