Pre-processing methodology for optimizing stereolithography apparatus build performance

The performance of a rapid prototyping technology depends, to a great extent, on the way parts are oriented and packed on the machine's build platform. The present work focuses on stereolithography systems. It describes a pre-processing methodology that 'automates' the procedure of finding 'good' fabrication orientations and packing arrangements. The method proposed consists of two separate, but interrelated, stages: the orientation and the packing stage. At first, each part is appropriately oriented to achieve better surface quality and either minimal support structure or lower build time or minimal projection area. The second stage considers the projections of the parts on the fabrication platform. The associated 2D bin-packing problem is addressed by a genetic algorithm in conjunction with a new improved placement rule. The performance of the present approach is demonstrated via two sets of case studies, which concern simple nearly orthogonal-shaped parts and representative 'real-world' objects/parts. (C) 2006 Elsevier B.V. All rights reserved.