| Summary: | 碩士 === 國立中正大學 === 機械工程學系 === 85 === The use of CAD system and the development of reverse
engineering techniques have
drastically changed the traditional procedure of mold design
and manufacture. As proven in industry applications, it reduces
the cost and the labors of manufacture, and it increases
efficiency and the competitive edge. Therefore, in order to
enhance the level of design automation, the industry has
shown much interests in this technology.A CAD system
is ideal for conceptual design.But for complex
objects with contour geometry, it is difficult to construct the
models precisely without appropriate geometric
information.On the other hand, reverse engineering
utilizes the scanning of objects and can capture the
geometry of complex objects. However, the creation of CAD
models from the scanned data is not a simple
process. Therefore, how to integrate reverse
engineering techniques with CAD system capabilities has
become the major research issue.
The goal of this research is to develop an integrated
environment that combines reverse engineering and
CAD design capabilities. By taking advantage of the
strong points of both technologies, it can significantly
reduce the product development time. In the developed
system, the digitized data obtained by CMM or laser
scanning is preprocessing to filter out the measurement
noise. Edges or surface boundaries are then detected by edge
finding techniques.NURBS surfaces are then fitted to
the segmented regions. At this stage, the surface modeling
relies heavily on curve and surface modeling techniques that
are usually seen in traditional CAD system. As a result, the
speed and efficiency of surface creation is highly improved.The
resulting surface patches are then connected to form a
closed volume, or a solid model.In the end, the created CAD
model can be transferred to other CAD/CAM system by
standard IGES translation.
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