Dissertations, 2000 and previous years; Entered 12/20/00 / DB reference years
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Author Paradis, Robert James
Source Dissert; Degree: M.S. Year: 1998 Institution: University of Lowell; Advisor: Supervisor: Robert Malloy
Abstract This research effort was undertaken to measure the relative advantages or limitations of the Direct Aim(R) rapid tooling process in comparison to conventional aluminum prototype injection mold tooling. In this study, single cavity prototype molds were constructed from both aluminum and Direct Aim(R). Prototype mold trials were then run using ABS and polycarbonate. The cost/benefit ratio of each method is used as a measure of overall performance.
The results of the study showed that the most significant benefit of Direct Aim(R) is the reduction in time required to fabricate a core and cavity set. A 31% reduction in total time was observed which translated into a 49% savings in total cost.
The trade-off is that the overall part quality and production capacity is slightly reduced. With Direct Aim(R) tooling, the dimensional variation with ABS during a production run was equal to that of aluminum tooling. In the case of polycarbonate, the dimensional variation during a production run was approximately 2-3 times greater. With the Direct Aim(R) process, warpage and sink marks in the ABS parts were 3 times worse than the ABS parts produced in an aluminum mold. Warpage and sink marks in the polycarbonate parts were 6 times worse than the polycarbonate parts produced in an aluminum mold.
The aluminum tool was capable of producing significantly more than 100 parts in both ABS and polycarbonate. The Direct Aim(R) tool's production capability was limited to 88 parts in ABS and 38 parts in polycarbonate. The cycle time with Direct Aim(R) was approximately 4 times longer than the aluminum tool. In addition, parts produced by the Direct Aim(R) process exhibited a significant degree of flashing while the aluminium core and cavity set exhibited no flash.XX