Process planning for combined additive and subtractive manufacturing technologies in a remanufacturing context

In recent years, additive manufacturing (AM) techniques provide the capability to build parts directly from CAD models by adding materials layer by layer. This technique allows producing complex parts that are not able to be manufactured by machining. However, AM techniques also present some limitations, such as poor surface quality, reduced dimensional accuracy, limited materials available and long production time when compared to CNC machining. To overcome these limitations, the combination of additive and subtractive (i.e. CNC machining) technologies is today considered as a promising solution for current manufacturing issues. This paper demonstrates the feasibility of combining these technologies for the manufacture of given parts from end-of-life (EoL) parts (or existing parts). The proposed approach aims to reuse existing parts directly to produce new parts (or final parts), avoiding the material recycling stage. The final parts are then intended for another product, namely the existing parts have a new life in their life cycle. This paper particularly focuses on the design of process planning for combined additive and subtractive processes, using the concept of AM and machining features. The design of process planning is performed based on the knowledge of additive and subtractive processes, the technological requirements, and the available resources. To respect constraints and considerations in manufacturing processes, different rules are defined and applied in the design of process planning. Finally, the efficacy of the proposed approach is demonstrated through the case study.