Research On Techniques Of Information Extraction And Toolpath Planning Based On STEP-NC

To realizing data integration between product design and manufacturing, Europe and American proposed a new NC programming interface called STEP-NC, which is used to reaplace ISO6983. STEP-NC provides a integrated and uniform data model for product design and manufacturing, and extends STEP standard (ISO10303) into NC manufacturing field. The function of STEP-NC is that it is a neutral mechanism for exhanging data between CAD/CAM and CNC, which is independent on certain CAM system or CNC system, so it enhance significantly the portability of the part program.The aim of this paper is that, first the design information and process information are extracted from AP238 NC program, then make use of these information to generate toolpath. To realize this aim, four parts are deeply researched: the method of extracting data from AP238 NC program,the method of managing and processing data,the method of determining the sequence of workingsteps and the method of toolpath generating based machining features.Data extraction is the foundation to realize the aim of this research. AP238 NC program contains integrated product information with a complex stucture, so ROSE C++ class library and STIX library are used to increase the efficiency of data extraction, which are provided by STEP Tools inc. And the information about machining feature is processed, because it dosen't conform to machine runner's custom. Then all information is stored in Oracle database.It is needed to determine the executing sequence of the workingsteps, which isn't defined in AP238 NC program. A algorithm is designed to determine the optimal sequence based on minimum time.Toolpath generation is main work in this paper,. Two toolpath generation algorithms are designed for pocket and planar. The algorithms are based on machining features, which are more excellent on modularization and reuse.