Design of a rapidly reconfigurable pin-type molding device for near-net shape solid object generation
Abstract
Molding processes are common methods for generating three-dimensional solid geometry. Unfortunately, the long lead times and high tooling costs make this method impractical for small scale part production or custom geometry generation. Rapid prototyping provides an alternative, in that new parts are generated quickly and easily with no new tooling required. There are, unfortunately, material limitations for the final geometry when this method is employed. This research investigates a method for forming solid geometry in a user selected material with relatively low tooling surface generation time and cost using a reconfigurable mold. This thesis will detail the development of a prototype reconfigurable pin-type molding device for the rapid generation of custom three dimensional solid geometries. The motivation behind this research is to produce a relatively low cost, reusable mold for various applications including: rapid prototyping with user specified materials, simple duplication of existing geometries, and customized medical applications such as bone replacement using a porous polymer bone scaffold. In this research, a scheme has been developed for the generation and implementation of multiple reconfigurable surfaces for use in solid geometry generation. Discussed will be the process behind the development of the reconfigurable pin-type molding device and its implementation in generating 3D solid geometries. An analysis of this mold’s effectiveness at creating desired geometries was conducted. This analysis explored the interaction between adjacent reconfigurable surfaces and the effects of varying the orientation of the geometry within the mold on the part accuracy. The results of the analysis were verified through physical experimentation using a prototype reconfigurable molding device. These results showed that the objects surface finish is of the highest quality, or most accurate, when pins used to form that surface are oriented normal to the surface. Results also showed that the highest error between the produced part and desired part occurs at the interaction between adjacent surfaces. However, these errors can be minimized through the use of an interpolative surface barrier placed over the discrete pin surfaces. Finally, the applications of using the reconfigurable mold for generating composite structures and bone replacement geometries were tested to determine their feasibility. The results showed these areas to be promising applications for the reconfigurable molding device and worthy of further exploration.
Degree
M.S.M.E.
Advisors
Cipra, Purdue University.
Subject Area
Mechanical engineering
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