Determining build orientation for layer-based machining

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 restriction of tool accessibility to internal features and small working area). In order to overcome these limitations, a rapid manufacturing method called robot-based layered manufacturing (RoLM) 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 a large effect on the surface quality and build time. In this paper, a method is proposed to determine the build orientation for RoLM by considering part accuracy and build time. Algorithms are developed to calculate tool accessibility, part stability, and the number of required support for overhangs.