The geometrical and topological information of 3D computer aided design （CAD） models should be represented as a neut- ral format file to exchange the data between different CAD systems. Exchange of 3D CAD model data...The geometrical and topological information of 3D computer aided design （CAD） models should be represented as a neut- ral format file to exchange the data between different CAD systems. Exchange of 3D CAD model data implies that the companies must exchange complete information about their products, all the way from design, manufacturing to inspection and shipping. This informa- tion should be available to each relevant partner over the entire life cycle of the product. This led to the development of an international standard organization （ISO） neutral format file named as standard for the exchange of product model data （STEP）. It has been ob- served from the literature, the feature recognition systems developed were identified as planar, cylindrical, conical and to some extent spherical and toroidal surfaces. The advanced surface features such as B-spline and its subtypes are not identified. Therefore, in this work, a STEP-based feature recognition system is developed to recognize t--spline surface features and its sub-types from the 3D CAD model represented in AP203 neutral file format. The developed feature recognition system is implemented in Java programming language and the product model data represented in STEP AP203 format is interpreted through Java standard data access interface （JSDAI）. The developed system could recognize B-spline surface features such as B-Spline surface with knots, quasi uniform surface, uniform surface, rational surface and Bezier surface. The application of extracted B-spline surface features information is discussed with reference to the toolpath generation for STEP-NC （STEP AP238）.展开更多
Manufacturing features represent area of interest on the machinable surface of a part, which can provide a unique set of removable volumes from part. Feature description in standard for exchange of product(STEP) AP224...Manufacturing features represent area of interest on the machinable surface of a part, which can provide a unique set of removable volumes from part. Feature description in standard for exchange of product(STEP) AP224 is an efficient neutral format for the development of feature based process planning. Process planning information of features can be converted to numerical control(NC)code to have complete manufacturing information of part. STEP-NC code provides an efficient manufacturing information model compared to G-M codes. In this work, an interface is developed for extraction of feature information available in AP224(AIM) format and the ruled-based approach is used to select different process planning parameters. A graphical user interface(GUI) is developed for the interface for displaying features information as represented in AP224 file. Furthermore, the interface generates STEP-NC code in AP238 format. The developed interface has three modules. 1) Module I: Reading interface for STEP AP224 file and development of GUI. 2)Module II: Selection of feature based process planning parameters. 3) Module III: Writing interface for STEP-NC(AP238). The developed interface has been implemented in Java through Java standard data access interface(JSDAITM). The generated STEP-NC AP238 code for the test part has been successfully simulated on STEP-NC Machine TM, an AP238 simulator. This article also provides an in-depth view of application interpreted model(AIM) representation format of STEP for AP224 and AP238.展开更多
文摘The geometrical and topological information of 3D computer aided design （CAD） models should be represented as a neut- ral format file to exchange the data between different CAD systems. Exchange of 3D CAD model data implies that the companies must exchange complete information about their products, all the way from design, manufacturing to inspection and shipping. This informa- tion should be available to each relevant partner over the entire life cycle of the product. This led to the development of an international standard organization （ISO） neutral format file named as standard for the exchange of product model data （STEP）. It has been ob- served from the literature, the feature recognition systems developed were identified as planar, cylindrical, conical and to some extent spherical and toroidal surfaces. The advanced surface features such as B-spline and its subtypes are not identified. Therefore, in this work, a STEP-based feature recognition system is developed to recognize t--spline surface features and its sub-types from the 3D CAD model represented in AP203 neutral file format. The developed feature recognition system is implemented in Java programming language and the product model data represented in STEP AP203 format is interpreted through Java standard data access interface （JSDAI）. The developed system could recognize B-spline surface features such as B-Spline surface with knots, quasi uniform surface, uniform surface, rational surface and Bezier surface. The application of extracted B-spline surface features information is discussed with reference to the toolpath generation for STEP-NC （STEP AP238）.
文摘Manufacturing features represent area of interest on the machinable surface of a part, which can provide a unique set of removable volumes from part. Feature description in standard for exchange of product(STEP) AP224 is an efficient neutral format for the development of feature based process planning. Process planning information of features can be converted to numerical control(NC)code to have complete manufacturing information of part. STEP-NC code provides an efficient manufacturing information model compared to G-M codes. In this work, an interface is developed for extraction of feature information available in AP224(AIM) format and the ruled-based approach is used to select different process planning parameters. A graphical user interface(GUI) is developed for the interface for displaying features information as represented in AP224 file. Furthermore, the interface generates STEP-NC code in AP238 format. The developed interface has three modules. 1) Module I: Reading interface for STEP AP224 file and development of GUI. 2)Module II: Selection of feature based process planning parameters. 3) Module III: Writing interface for STEP-NC(AP238). The developed interface has been implemented in Java through Java standard data access interface(JSDAITM). The generated STEP-NC AP238 code for the test part has been successfully simulated on STEP-NC Machine TM, an AP238 simulator. This article also provides an in-depth view of application interpreted model(AIM) representation format of STEP for AP224 and AP238.
