Research And Implementation On NC Programming For Pocket In Aircraft Structural Part

Toolpath generation based on feature is one of the tendencies of NC programming, and it is also the key point in integrating CAD/CAPP/CAM. Considering the characteristics of aircraft structural parts, rapid NC programming based on feature is researched, and furthermore, the toolpath generation of pocket is realized. The research achievements include:1) By summarize the characteristics of pocket, the pocket is divided into three sub features, namely bottom sub feature, flank sub feature and corner sub feature. The geometry and CAPP information's format of these sub features are defined. The toolpath of pocket is generated automatically by integrating the feature information from the feature recognition and the CAPP information.2) A revised algorithm of toolpath generation for bottom sub feature is proposed by minimizing the toolpath length. With the fact that the first cut in every level is always slotting milling, the milling areas are divided into two regions and the chatter free parameters are applied to generate the toolpath.3) Plunge milling can remove excessive material in the corners of pocket effectively. A toolpath generation algorithm for plunge milling is proposed by calculating the milling tool's axis and milling area.4) A toolpath generation module for pocket is developed on the CATIA and integrated into the automatic NC programming system based on feature, which has been used in the NC programming for aircraft structural parts.