hot runner system of plastic mold
Hot-runner molds offer significant processing advantages. Of primary importance is the material savings that results from elimination of the runner system. A hot-runner system represents in essence an extension of the machine nozzle through which the plastics melt flows directly into the cavities. For parts having identical weights, the amount of material to be plasticized is less than that required in a cold runner mold by the amount needed to fill the runner system. The required recovery time, and thus the overall cycle time, is shortened by a corresponding amount，leading to increased machine productivity. The use of hot-runner systems is suited especially for multiple cavity molds, molds for small parts and molds for quality parts subjected to high loads where no regrind may be processed. The processing and economic advantages of hot-runner molds are often achieved by converting cold runner molds even if the entire runner system cannot be eliminated because of the mold design. As a...