Mold Concerns
Standard horizontal clamp presses deliver molten resin to the mold through a hole in the center of the stationary press platen. A material-delivery system—usually consisting of a sprue, runners, and gates—then leads the resin through the mold and into the cavity. Unlike sprues, which deliver material depthwise through the center of the mold plates, runners typically transport material through channels machined into the parting line. Runner design influences part quality and molding efficiency. Overly thick runners can lengthen cycle time needlessly and increase costs associated with regrind. Conversely, thin runners can cause excessive filling pressures and related processing problems. The optimum runner design requires a balance between ease of filling, mold design feasibility, and runner volume. Refer to our Mold Design Guide for more information. |