Determination of fabricating orientation and packing in SLS process

Rapid prototyping (RP) technology has been implemented in all industries needed to reduce the time for the development of new products. An orientation and packing in RP process, especially selective laser sintering (SLS), are considered as the most important factors to maximize the utilization of space in the build vat and reduce build time. However, the decision of these parameters is mainly dependent on the skill level and experience of the SLS machine operator. This paper addresses the methodology to find the optimal build layout, by considering an orientation and packing of multiple parts in SLS processing. For the optimal orientation, the fabricating height and the feeding powder quantity to reduce build time and the surface quality improvement of prototypes is considered as major objectives. In packing process, each prototype to be fabricated is modeled as a voxel structure to deal with the inefficiency of a bounding box approach. The developed orientation and packing system employs the adapted bottom-left (BL) approach with a genetic algorithm (GA) and is demonstrated in real prototypes for processing with SLS and illustrates a good enabling optimization building system to the real industries. (C) 2001 Elsevier Science B.V. All rights reserved.