An octree-based algorithm for the optimization of extraneous material removal in laminated object manufacturing (LOM)

Abstract

Layered Manufacturing (LM) has emerged as the technology of choice for creating prototypes from CAD models. Laminated Object Manufacturing (LOM) is a form of layered manufacturing technology developed by Helisys Inc. Here the solid is built from stacked-up layers of paper (or other laminates) backed with a heat-activated adhesive. A laser is used to cut the profile of the solid and crosshatch the extraneous material on each layer for easy removal. Layered manufacturing has greatly reduced the time required to make models and prototypes. There is, however, great scope for making the processes faster and more accurate by using better algorithms. Experiments have shown that the cross-hatching of the extraneous material contributes between 30 to 50% of the build time in the case of the LOM process. This paper targets the cross-hatching of extraneous material as a means to reduce the build time of the LOM part. In this paper, an octree-based, variable-size cross-hatching algorithm for generating the laser path is presented. Results on test parts have produced up to a 50% reduction in the cross-hatching time of the object as compared to the traditional fixed-size cross-hatching approach. An AutoLISP/AutoCAD environment was used for validation of the laser path generated by the algorithm.