Drive geometry construction method of machining features for aircraft structural part numerical control machining

Abstract

Feature-based manufacturing methodologies offer opportunity for numerical control machining effectively and efficiently. However, the loss of drive geometries caused by the complex shape and machining process of aircraft structural parts undercuts the advantage of feature-based manufacturing tools. To better address the gap between the process planning and tool path generation for aircraft structural part, a drive geometry construction approach based on the topological relationships and machining process of machining features for process planning are proposed. The created drive geometries correspond with the optimized machining process. The drive geometries that define the machining areas of machining features are categorized into guide lines and guide faces in accord with the machining mode, such as 2.5- to 3-axis machining and multi-axis machining. In contrast to the traditional performing of intersection operations with a series of slice planes and the part model manually, the drive geometries are constructed by extracting the existing topological entities and creating some auxiliary topological entities automatically. The drive geometry preparing time and the consumption of computer memory are reduced significantly. The proposed approach has been tested and used in a pilot feature-based programming system that is developed for some aircraft manufacturers in China.