A Feature-based Approach for Integrated Product Design and Process Planning

Computer-Aided Process Planning (CAPP) is considered to be the bridge that links Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM). One of the imperative characteristics of CAPP is Automatic Feature Recognition (AFR). CAD files contain detailed geometric information of a part, which are not suitable for using in the downstream applications such as process planning. Different CAD or geometric modeling packages store the information related to the design in their own databases. Structures of these databases are different from each other. As a result no common or standard structure has been developed so far, that can be used by all CAD packages. For that reason this paper will propose an intelligent feature recognition methodology (IFRM) to develop a feature recognition system which has the ability to communicate with the different CAD/CAM systems. The proposed methodology is developed for 3D prismatic parts that are created by using solid modeling package by using CSG technique as a drawing tool. The system takes a neutral file in Initial Graphics Exchange Specification (IGES) format as input and translates the information in the file to manufacturing information. The boundary (B-rep) geometrical information of the part design is analyzed by a feature recognition program that is created specifically to extract the features from the geometrical information based on the geometric reasoning approach. A feature recognition algorithm is used to recognize different features of the part such as step, holes, etc. The system is written in C++ language on a PC-based system. Finally, a sample application description for a workpiece is presented for demonstration purposes.