Injection_Molding_Solutions - Injection Molding 1. Compute...

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Injection Molding 1. Compute the percentage volumetric contraction of a polyethylene molded part, based on the value of shrinkage given in Table 13.1. Solution : S = 0.025 for polyethylene from Table 13.1. Volumetric contraction = 1.0 - (1 - .025) 3 = 1.0 - 0.92686 = 0.07314 = 7.314% Note that we are not using the parameter S from Table 13.1 in the way it was intended to be used. Its intended use is to compute the oversized dimension of a mold cavity in injection molding. Instead, we are using the shrinkage term to calculate the amount of (volumetric) reduction in size of the part after the polymer is injected into the cavity. In fact, a slightly different shrinkage parameter value may apply in this case. 2. The specified dimension = 225.00 mm for a certain injection molded part made of ABS. Compute the corresponding dimension to which the mold cavity should be machined, using the value of shrinkage given in Table 13.1. Solution
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This note was uploaded on 01/24/2011 for the course IE 215 taught by Professor Groover during the Fall '08 term at Lehigh University .

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