Decision criteria for build orientation in layer-based machining

Abstract

Some inherent limitations exist in current Layered Manufacturing (LM) technologies (e.g. little choice of material, small part size and poor surface quality) and traditional NC machining (e.g. the confinement of tool accessibility to internal features). In order to overcome these limitations, a rapid manufacturing method called Robot based Layered Manufacturing (RoLM in brief) is developed. A robot with a milling cutter mounted on the end-effector is used to build a part layer by layer. Given a part model, the determination of build orientation is the first step in the manufacturing cycle and has large effects on the surface quality and build time. In this paper, a set of criteria is proposed to rank the build orientations for RoLM by considering mainly part accuracy and build time. Algorithms are developed to calculate tool accessibility, part stability, and the number of required support for overhangs.