Automatic Feature Extraction and CNC Code Generation in a CAPP System for Micromachining

Abstract

Feature extraction from a part model and Computer Numerical Control (CNC) code generation for machine tool control are the two extreme activities of a typical CAPP system. The present work discusses about a new methodology for automatic part feature extraction and CNC code generation for the invention of micro features in tool based micromachining processes. It has two main components; the first one deals with Extensible Mark-up Language (XML) based feature extraction from feature based model and interactive feature recognition. The second one deals with autonomous CNC code generation based on manufacturing features using various mathematical logic. Feature extraction through XML files avoids complex feature extraction process and automation of CNC code generation avoids human expertise and compatibility issues. The developed system integrated with micromachine tool through RS 232 communication interface. Hence for the given micro features, CNC code generation take place automatically and transferred to the micromachine tool in online with minimal user interface. The application of the proposed system verified with a case study. The developed system is limited to the parts having micro external step and drill features. Incorporation of more micro features, consideration of various other process planning activities and its part program generation ensures a complete CAPP system for micromachining.