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Unformatted text preview: ME 419- Fundamentals of Injection Molding
Assignment #4 (due Monday, March 22, 2004 1n class)
(On-campus students: the class on Monday, March 22 Will begin at 1: 00 p. m.) Name: 1. Three materials have been identiﬁed which satisfy the requirements of a part to be designed. .
These materials have the following properties. The part will be under a ﬂexural load during ‘
application. (Read the handout on “Material Cost Considerations”) ($/lb) Modulus (psi) Strength (psi) grns/cmA3)
n———_ “Given the following calculations for a rectangular, cantilever beam under a ﬂexural load. FLc _ FL3 _ whs
y— = I— = I BE] 12 O: You are selecting a material for a part which will be under a ﬂexural load during application. The
height (h) of the part can be changed (i.e., h is a variable) and the width, w, is ﬁxed. Determine
which of these resins (A, B, or C) is the most cost effective material based on part rigidity. (a) Determine the Cost per Volume of the materials (in $/in’\3) (b) Determine the ratio of moduli of the 3 materials (Use material “A” as the reference
material, i.e., E/EA for all three materials). (c) Derive the formula for the equivalent geometry (i.e., relationship between the height, h, and
the material modulus, E, given identical loading, deﬂection, y, and part width, w). ((1) Find the equivalent geometry (height) with respect to material “A” (e) Find‘ the equivalent cost for all three materials (ﬁjahk’ ) ...
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- Spring '04