Plastic Products Factory considers the flow efficiency and heat of the cross-section shape of each shunting channel, and usually adopts the cross-section shape of three shunting channels
(1) Circular section
① the advantages of circular cross section are the smallest specific surface area and the largest volume, while the contact area with the mold is the smallest and the resistance is small, it helps melt flow and reduces its temperature to be transmitted to the mold, and is widely used in side gate molds (Except for side gate molds with push plates).
② the disadvantage of circular cross section needs to be opened on concave and convex dies at the same time and should be consistent with each other, so it is difficult to manufacture and time consuming.
③, design parameters, shape of circular connection Lane and its design parameters hole design 15 inclined plane is to prevent the flow channel opening from stabbing backwards and affecting flow channel condensate demoulding.
④ the ratio of perimeter to cross-sectional area is surface area (The channel surface area with volume of ratio), Use it to measure the flow efficiency of the flow channel. That is, the smaller the specific surface area, the higher the flow efficiency.
(2) Trapezoidal section
① the advantage of trapezoidal section is that it is processed on one side of the mold and saves time. The application is as follows:
A. The mold of the three-plate type point gate of the plastic mold, the diversion channel between the pushing plate and the plate.
B. The side gate Haff mold, the shunting Road is on the mold surface of the Haff block, and when the plastic parts are fed from the side, the section of the shunting road cannot be rounded.
C. There is a push plate mold in the side gate mold, and the shunting channel can only be made on the concave mold and cannot be opened on the push plate.
In the above cases, trapezoidal runners are used more often than semi-circular runners are avoided.
② the disadvantage of trapezoidal runner is that compared with circular runner with the same cross-sectional area, trapezoidal runner has a longer circumference, thereby increasing the friction and temperature loss between the melt and the shunt.
(3) The flow efficiency of U-shaped section is lower than that of circular and regular hexagonal sections, but it is easy to process and demoulding than circular and square connecting and selling runners. Therefore, u-shaped cross-section shunt has excellent comprehensive performance. The friction and temperature loss of the shunt melt and shunt of the U-shaped cross-section are smaller than the shunt of the trapezoidal cross-section, which is an improvement of the trapezoidal cross-section. U-shaped cross-section shunt can be used in situations where trapezoidal cross-sections can be used.
The H size of the U-shaped cross-section shunt channel can be equal to D of the circular cross-section.