Feature-based automatic NC programming for aero-engine casings

Traditional numerical control (NC) programming methods based on commercial computer-aided manufacturing systems usually require a large number of manual interactions with high-skilled experience, which not only results in low efficiency but also unstable machining quality. Especially since the structural complexity and machining requirements keep increasing, the NC programming is becoming a bottleneck problem in machining complex parts like aero-engine casings. This article proposes a feature-based automatic NC programming approach for aero-engine casings. A machining feature classification towards the geometric and machining characteristics of aero-engine casings is given. Then, a feature-based method to extract machining regions by considering the alternatives in selecting turning or milling operations is discussed. After the construction of machining operations, an undercut region detection method is also presented to evaluate the interim machining effects reasoned by each individual machining operation for excessive cutting avoidance. By implementing the proposed approach, a feature-based NC programming system is developed on a commercial computer-aided manufacturing platform and a real aero-engine casing is chosen to demonstrate the feasibility of the proposed approach.