5 th International & 26 th All India Manufacturing Technology, Design and Research Conference (AIMTDR 2014) December 12 th –14 th , 2014, IIT Guwahati, Assam, India 214-1 A New Hybrid Approach to Recognize Machinable Features of PrismaticParts from STEP AP 203 File Bitla Venu 1 , VenkateswaraRao Komma 2* , Deepanshu Srivastava 3 1 Research Scholar, Department of Mechanical Engineering, M. N. National Institute of Technology, Allahabad, 211004, Email: b.venu1973@ gmail.com 2* Assistant Professor, Department of Mechanical Engineering, M. N. National Institute of Technology, Allahabad, 211004, Email: kvrao@mnnit.ac.in 3 Research Scholar, Department of Mechanical Engineering, M. N. National Institute of Technology, Allahabad, 211004, Email: deepanshu.sripb@gmail.com Abstract Feature Recognition (FR) plays major role in engineering significance of a part model and serves as an important support tool for integrated manufacturing. Feature-based systems typically act as inter link between the CAD and CAM activities. These systems can be broadly classified into human-assisted feature definition systems, automatic feature recognition systems and design by features systems. Researchers have come to realize that the best system architecture for a feature-based system would be a blend of the above mentioned systems. In this paper, a new hybrid approach is proposed to recognize machinable features of prismatic part with multiple features on different faces, which is represented in Standard for Exchange of Product Model Data (STEP) AP 203 file format. The hybrid approach uses syntactic pattern recognition, graph based feature recognition and other heuristics to recognize the machinable features of prismatic parts. The product model data represented in STEP AP 203 format is accessed through Java Standard Data Access Interface (JSDAI). Feature recognition is performed in two stages. In the first stage, syntactic pattern recognition method is used to recognize simple orthogonal features. In the second stage, graph based method is used to recognize the remaining features, which were difficult to recognize with the syntactic pattern recognition method. Other heuristics are also used in both the stages to recognize the features. Keywords: Feature, STEP, Prismatic, JSDAI. 1 Introduction Thelinkbetweendesignandmanufacturing is identified as an important fieldof research and the developments in this area is crucialtothesuccess of theCAD/CAMindustry. Variousresearchers havecome upwithdifferent waysandmeanstointegrateCADandCAM. Automatic feature recognition from CAD solid model for downstream applications like process planning greatly impacts the level of CAD and CAM integration. The CAD/CAM cycle in a feature-based design environment includes identifying machinable entities/features (viz. holes, slots, pockets etc.) is a foremost activity. A feature can be defined as characteristic of the part which carries significance or higher semantic meaning to a particular application. Therecognition of featuresinvolvesidentification ofhigherlevelfeaturessuch asslots,holes,tapers,andsoonfromasetoflowerlevel featuressuchasfaces, planes,edges,vertices etc. From this point of view, part features can be divided into the following three categories: i) design features, ii)manufacturing features and iii)geometric features. The extraction and recognition of features from the CAD model is done at the lower levelgeometric features. In the following section, a brief review of the literature is presented in which machinable features were recognized. 2 Literature review The literature review covers the research related to feature recognition techniques for the past two decades, with more emphasis onSTEP and IGES neutral file format articles. There are different file formats to exchange the product model data.The popular formats areDXF (Drawing Exchange Format), STL (Stereo Lithography), IGES (Initial Graphic Exchange Specifications) and STEP.DXF and STL files are obsolete after the evolution of IGES and STEP. IGES can represent design and topology information of a product model.This format lacks in life cycle support and difficult to understand file format.To overcome the difficulties in IGES file format and other neutral file format exchange, a new international standard for product model data exchange (ISO 10303) called STEP is designed to support product model throughout its entire life cycle. The data exchange does not mean just verbal communication, but the companies must exchange complete information about design, manufacturing and maintenance to disposal,hence more emphasis