Hybrid knowledge model of process planning and its green extension

The green process planning model was a necessary research field of the green manufacturing, which has drawn increasing attention from many scholars. This study proposes a multi-method [Backus–Naur Form (BNF) frame, binary tree,production rules, and objective-oriented methodology] hybrid frame model of process planning and reasoning mechanism. In this model, the hierarchical BNF frame was applied to modeling the structure of parts, the stages of process decisions and the existing green process indicators set. Then, two “procedure” programs were designed for the information exchange among the above models. This green-process planning model was proposed based on the traditional intelligent process planning model and was intended to introduce an overall (compared with the traditional partial green-process planning model) green-process decision mode. In the last section of this paper, a case study of the green-process planning for a stepped shaft is provided along with a number of essential knowledge models to illustrate the feasibility of this hybrid knowledge model.