In layered manufacturing, a three-dimensional polyhedral object is built by slicing its (virtual) CAD model, and manufacturing the slices successively. During this process, support structures are used to prop up overhangs. An important issue is choosing the build direction, as it affects, among other things, the location of support structures on the part, which in turn impacts process speed and part finish. Algorithms are given here that (i) compute a description of all build directions for which a prescribed facet is not in contact with supports, and (ii) compute a description of all build directions for which the total area of all facets that are not in contact with supports is maximum. A simplified version of the first algorithm has been implemented, and test results on models obtained from industry are given.
Bibliographical noteFunding Information:
I This work was funded in part by a joint research grant by DAAD and by NSF. ∗Corresponding author. E-mail addresses: firstname.lastname@example.org (J. Schwerdt), email@example.com (M. firstname.lastname@example.org (R. Janardan), email@example.com (E. Johnson), firstname.lastname@example.org (J. Majhi). 1Part of this work was done while visiting the University of Minnesota in Minneapolis. 2Research also supported in part by NSF grant CCR-9712226.