Dissertations, 2001 and previous years; Entered 12/31/01 / DB reference years
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Author Qiu, Dan Degree: Ph.D. Year: 2001 Institution: Rutgers The State University of New Jersey - New Brunswick; Advisor: Director Noshir A. Langrana
Abstract Rapid Prototyping and Layered Manufacturing (RP and LM) technologies have been developed rapidly in the last decades. It was for prototype part fabrication originally, but now it's being investigated for fabrication of functional parts. At Rutgers, the RP and LM research group has focused on Fused Deposition (FD) methods. The sequence of fabrication steps in FD includes: filament fabrication, FD, post processing. The FD toolpath parameters alter with change of material significantly. Therefore, for a functional part to be constructed successfully, a high quality multi-material toolpath generation is critical to fabricate a perfect green part. This is the major focus of this research. A multi-material CAD system has been developed which includes single-material toolpath generation, multi-material toolpath generation, virtual simulation and void analysis sub-systems. The present development has several new important advances in FD for the first time. Multiple .stl files can be collected to create on e multi-material toolpath. The intelligent toolpath features embedded include: minimum number of continuous paths, closest next starting point and extended path style. The analytical method computes void location and size. Based on the void location and size computation, adaptive roadwidth which is the largest roadwidth is obtained to satisfy the void size tolerance. Adaptive roadwidth toolpath then recalculated which makes void-free part. In multi-material system, a new feature called material offset parameter was introduced to match the intersecting material boundaries. The virtual simulation allows graphical visualization of the material deposition process. Roadshape and size can be utilized in the virtual simulation. Part quality can be predicted and analyzed from the simulation results. If needed, the toolpath parameters and/or feature selections can be altered iteratively until the virtual part quality is satisfying. The current RP and LM technologies focuses on fabricating single material part. The cu rrent development enhances the research and development toward multi-material LM CAD. XX