Layer-based machining: recent development and support structure design

There is growing interest in additive and subtractive shaping theories that are synthesized to integrate the layered manufacturing process and material removal process. Recently, layer-based machining has emerged as a promising method for integrated additive and subtractive shaping theory. In this paper, major layer-based machining systems are reviewed and compared according to characteristics of stock layers, numerical control machining configurations, stacking operations, input format and raw materials. Support structure, a major issue in machining-based systems which has seldom been addressed in previous research, will be investigated in this paper with considerations of four situations: floating overhang, cantilever, vaulted overhang and ceiling. Except for the floating overhang where a support structure should not be overlooked, the necessity for support structures for the other three situations is determined by stress and deflection analysis. This will be demonstrated by the machining of a large castle model.