Flow channel balance: The geometric paths of the plastic from the barrel to each cavity should be equal. An unbalanced flow channel design may lead to insufficient injection pressure, packing pressure, or plastic injection in some cavities, causing plastic part deformation. In the design of the manifold, efforts should be made to make the diameter, length, and turning angle of each flow channel consistent, so as to evenly share the pressure drop and shear stress at each injection point.

Regarding the characteristics of different plastic materials, the diameter of the flow channels inside the manifold also needs to be carefully considered. For example, for heat - sensitive plastics, a smaller flow channel diameter can be considered, while for plastics sensitive to shear stress, the flow channel diameter needs to be increased.