Machining feature sequencing for aircraft structural parts

To improve quality and efficiency of NC machining sequencing, an approach to order the machining features of aircraft structural parts is introduced in accordance with the principle of hierarchical planning, knowledge and geometry-based reasoning method. The main contents consist of: (1) Machining cell and its geometric descriptions are established, and the method for decomposing generalized pocket (GP) into machining cells is proposed. (2) Based on the GP relationship tree, data model and algorithm for generating machining chain are presented. (3) Machining process segmenting, feature grouping and sequencing rules are formulated by communicating with related experts. (4) Priority graph and relationship matrix of features are applied to describe the machining precedence. The developed approach has been applied in Intelligent NC Programming System of Aircraft Structural Parts and is validated through a case study.