IPDB › China Industry › Manufacturing & Processing Machinery
China, Chinese Design Rules Textbook for Plastic Injection Mold Design1 Industrial Products Supplier Manufacturer Details, price list catalog:
China Industrial Products Supplier Manufacturer List Catalog
Other MouldsPlastic PartsPlastic Product
Shenzhen Meibang Precision Technology Co., Ltd.
Preview:
Product Description OverviewRunner design dictates part quality and productivity. The design rules that follow providegeneral guidelines for runner design.Runner sizeRunner cross sectionThe cross-sectional area of a runner should not be smaller than that of the sprue, to permit rapid,unaltered flow of the material to the gating area.Cold runner diameterThe selection of a cold runner diameter should be based on standard machine tool cutter sizes. Theminimum recommended runner diameter for most materials is 1.5 mm (0.06 inches). Typical runnerdiameters for various unfilled generic materials are shown in Typical runner diameters for unfilledgeneric materials.See Determining runner dimensions for more information on this topic.Trapezoidal runnersThe depth of a trapezoidal runner is approximately equal to its width, with a 5o to 15o draft (taper)on each side wall.ScrapUse a small runner size to minimize scrap volume.Raising melt temperatureSmaller runner size is preferred over larger runner size in order to generate viscous (frictional)heating. Viscous heating generated in the runner system is an effective way to raise the melttemperature instead of using a high barrel temperature, which is likely to cause materialdegradation.Branched runnersEach time a runner is branched, the diameter of the branch runners should be smaller than the mainrunner, because less material flows through the branches and it is economically desirable to useminimum material in the runners.Where N is the number of branches, the relationship between the main runner diameter (dmain) andthe branch runner diameter (dbranch) isRunner intersectionsAll runner intersections should have a cold solid slug well to help the flow of material through therunner system and into the cavity. the diagram below shows that the length of the well is usuallyequal to the runner diameter.FIGURE 1. The cold slug well is typically an extension of the runner at an intersection with another runner.Hot runnersWhen designing Hot runner systems, it is necessary to consult suppliers for availability of the propermanifold and drops.Easy ejectionRunner design must provide for easy ejection and easy removal from the molded part, with propercross-sectional and draft angle. For most materials, the runner surface must be polished to facilitateflow and part ejection. Extended runner systems should have multiple sprue pullers and ejectionlocations.
Purchasing Request
Note: Send your purchase request, and we will screen suppliers or manufacturers for you free of charge...