Feature Recognition From Step Ap 242 File For Computer Aided Fixture Design Of Prismatic Parts

Abstract

present global market demands high level of automation and flexibility for newlinemeeting the market challenges and competition. The ever changing product based newlineindustrial scenario demands frequent design changes and considerable reduction of newlineproduct development cycle. To automate the design and manufacturing, extracting the newlinemanufacturing information is necessary and Product Manufacturing Information (PMI) newlineplays a vital role in this automation. PMI information helps in Product Lifecycle newlineManagement (PLM) and interoperability between different CAD systems thereby, the newlinemarket challenges can be met by considerably reducing the lead time for product newlinerealization. Fixture planning is one among the major manufacturing activities, which newlineplays a significant role in deciding the production cycle and lead time for manufacturing. newlineThe work piece deformation during machining depends to a great extent on the clamping newlineforces and the locator configuration associated with fixture design. Thus, fixture design newlineplays a vital role in the product quality in terms of precision, accuracy, and surface finish. newlineComputer Aided Fixture Design (CAFD) aims to automate the fixture design process by newlineutilizing the data from the geometry information and orientation of the work piece. The newlinework piece geometry information can be extracted using Automatic Feature Recognition newline(AFR) technique, which recognizes the features from CAD models and the relevant data newlinecan be used for fixture planning. In this research, an attempt is made to extract the newlinegeometry information from CAD models for suggesting locator positions in fixture newlinedesign. Initial research was done on extracting information from IGES based neutral file newlineformat and due to the limitations of the IGES file format, subsequently data extraction newlinewas performed from STEP files. The developed CAD model is exported as a neutral file newlinein STEP AP 242 format. FiXplan, automatic feature extraction software was developed newlinein-house for the extraction of features and dimensions using the geometric reasoning newlinetechnique.