The Runner Design
Aug 25, 2023
The Runner Design Concept The runner refers to the melt flow passageway between the end of the main runner and the gate, which is used to change melt flow direction and allocate it to each cavity in a stable and balanced way. The basic design principle of the branch runner is little pressure/heat loss, with the minimum quantity of plastic retained in the runner. Sectional Shapes of the Branch Runner: –Circular, with the minimum specific surface area (runner surface area/runner volume), but during production, both sides of the mold plate need to be aligned. –The commonly applied forms, trapezoid and U-shape are easy to process. –Semicircle. –Rectangle, larger specific surface area and high resistance to flow, thus seldom applied. The Principle of the Runner Design The runner is usually designed on either half of the plastic injection mold. When considering the layout of the cavity and the branch runner, it is better to ensure that when projected on ...