Section size of shunt surface
large cross-sectional area is conducive to reducing flow resistance of flow channels. However, when the cross-section size of the shunt channel is too large, one is to waste materials, the other is to increase the exhaust burden of the mold, and the third is to increase the cooling time, and the molding cycle also increases, reducing labor productivity, lead to increased costs.
The smaller section circumference is conducive to reducing the heat loss of molten plastic. However, when the section size is too small, the flow resistance of the melt will increase, which will prolong the filling time and easily cause defects such as insufficient filling, burning, silver grain and shrinkage marks of plastic products, therefore, the section size of the shunt channel should be determined according to the fluidity of the melt, the weight of the molded plastic part and the projected area.
The size of plastic products is different, the plastic varieties are different, and the cross section of the shunt channel will also be different. However, there is a design principle: it is necessary to ensure that the ratio of the surface area to the volume of the shunt is minimal, that is, when the length of the shunt is certain, it is required that the ratio of the surface area or lateral area of the shunt Road to its cross-sectional area is minimal.