Automatic feature extraction in PRIZCAPP

Present work deals with a CAPP system developed for prismatic parts. This paper specifically discusses the methodology developed for the automatic extraction of features from the wire-frame model of a part created in AutoCAD. Size, location and shape elements of a feature are used to define SIZE-LOCATION-SHAPE-ALGORITHM (SLSA) in the present work. It can recognize features like slots, steps, holes and pockets of different profile geometries by matching with a basic hole feature. Based on its location a feature (basically a hole feature) is classified into hole, step or slot feature. At present 20 predefined hole feature geometries are present. The output from feature extractor can be used for the generation of manufacturing instructions viz., setup planning, process selection, sequence generation, machining parameters selection etc. The unique feature of this system is that, it works on a wire-frame model of the part and needs no help from the user in extracting features. The working of the system and algorithms used for feature extraction have been explained.