数控技术应用专业英语教学课件作者刘小芹5.注射模设计课件幻灯片.pptVIP

 English on Mechanical Engineering Lesson 5 Injection Mold Design Text The function of a mold is twofold: imparting the desired shape to the plasticied polymer and cooling the injection molded part. It is basically made up of two sets of components: the cavities and cores and the base in which the cavities and cores are mounted. Fig.1 shows typical layouts and description of parts in the mold, including the cavities and cores. The mold, which contains one or more cavities, consists of two basic parts: (1) a stationary molds half on the side where the plastic is injected, (2) A moving half on the closing or ejector side of the machine. The separation between the two mold halves is called the parting line. In some cases the cavity is partly in the stationary and partly in the moving sections. The size and weight of the molded parts limit the number of cavities in the mold and also determine the machinery capacity required. Text The mold components and their functions are as following: (1) Mold Base—Hold cavity (cavities) in fixed, correct position relative to machine nozzle. (2) Guide Pins—Maintain proper alignment of two halves of mold. (3) Sprue Bushing (sprue)—Provide means of entry into mold interior. (4) Runners—Convey molten plastic from sprue to cavities. (5) Gates—Control flow into cavities. (6) Cavity (female) and Force (male)—Control the size, shape and surface texture of mold article. (7) Water Channels—Control the temperature of mold surfaces to chill plastic to rigid state. (8) Side (actuated by cams, gears or hydraulic cylinders)—Form side holes, slots, undercuts and threaded sections. (9) Vent—Allow the escape of trapped air and gas. (10) Ejector Mechanism (pins, blades, stripper plate)—Eject rigid molded article from cavity or force. (11) Ejector Return Pins—Return ejector pins to retracted position as mold closes for next cycle. The distance between the ou