THESIS
2017
Abstract
All layered manufacturing processes operate by trading off between part accuracy and
fabrication time. In particular, this is manifested in the strategy for generating the geometry
of each slice of the 3D model: if the slice thickness is large, the fewer slices can build the
part, taking up less time, but the surface roughness (and thus part accuracy) is poor. Since
the 1990’s, several slicing approaches have been proposed to reduce the printing time while
improving the accuracy. However, there is no optimal strategy known to date. On the one
hand, the high computational complexity of some algorithms renders them impractical. On
the other hand, adaptive slicing approaches have not been successfully implemented on any
commercial machine due to problems in material and process con...[
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All layered manufacturing processes operate by trading off between part accuracy and
fabrication time. In particular, this is manifested in the strategy for generating the geometry
of each slice of the 3D model: if the slice thickness is large, the fewer slices can build the
part, taking up less time, but the surface roughness (and thus part accuracy) is poor. Since
the 1990’s, several slicing approaches have been proposed to reduce the printing time while
improving the accuracy. However, there is no optimal strategy known to date. On the one
hand, the high computational complexity of some algorithms renders them impractical. On
the other hand, adaptive slicing approaches have not been successfully implemented on any
commercial machine due to problems in material and process control. In this paper, a novel
adaptive slicing algorithm based on slice contour reconstruction is present. This approach
can be adapted for standard additive manufacturing machines because it does not rely upon
adaptive layer thickness. At the same time, a simple geometric engine can allow our
approach to be transparently adapted to any existing machine by re-creating an updated 3D
product model using the modified layers. The contour reconstruction algorithm based on
Medial axis computation leads to 30%-50% reduction on volumetric deviation and
maximum horizontal distance deviation between the original triangulated part surface and
the deposited part surface. Alternatively, for a given user-specified surface finish, our
approach allows for larger layer thickness and consequently produces time saving of
20-30% over the traditional slicing strategy.
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