# H2sol - Massachusetts Institute of Technology 2.008 Design...

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Massachusetts Institute of Technology 2.008: Design and Manufacturing II Problem Set 2 Solutions Problem Set 2 Solutions Problem 1-1. Injection Molding The gate and runner system that you use to move plastic into an injection molding cavity are critical design parameters. Suppose the polymer material that you are using has a viscosity µ of 950 N s/m 2 under your processing conditions. Suppose your initial gate and round runner system is 3 . 5 mm in diameter and approximately 25 mm long. Your part has a volume of approximately 20000 mm 3 and a projected area of approximately 1800 mm 2 . Your Engel machine claims that it can melt and deliver material at a rate of 165 cm 3 / sec. Assume that there is no pressure loss bewteen the mold cavity and the runner system, and none of the clamping force is lost in deforming the molds when they come together. (a) What is shortest injection time for the part? The injection time is bounded by the delivery rate of the Engels machine. The shortest time is therefore 20000 = 0 . 121 seconds. 160

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## This note was uploaded on 02/24/2012 for the course MECHANICAL 2.008 taught by Professor Jung-hoonchun during the Spring '04 term at MIT.

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H2sol - Massachusetts Institute of Technology 2.008 Design...

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