Research Of NC Program Generating Method Based On STEP-NC Milling Model

STEP-NC (ISO14649) is the extending of the Standard for the Exchange of Product Data Representation (STEP) in the manufacturing field. As the criterion of new CNC system data interface, it's object-oriented and feature-oriented. CNC program based on STEP-NC not only transfers 3-D geometry information to the CNC controller, but also the technical and manufacturing information, which overcomes lots of disadvantages of CNC program based on traditional ISO6983 standard such as information losing, program difficult to revise and so on.The paper mainly focuses on CNC program generation method which is based on STEP-NC milling model, the major work is as following:This paper gives a deep research on the STEP / STEP-NC standard. The CNC program generation procedure is studied, including geometry information extraction, feature identification, technical planning and file generation. Firstly, under the environment of ST-Developer10, geometry and topology information is extracted from the STEP file utilizing ROSE function. Secondly, manufacturing information is recognized from the extracted geometry and topology information using hint-based geometry induced method combing the STEP feature. Then, roughcast automatic generation and macroscopically technical planning are done based on the identified results. Last, geometry information, feature information, roughcast information and technical planning information all make the AP-238 file.With the STEP-NC standard is used comprehensively, the machine control system can identify this file format. So it achieves the data sharing among different CAM systems. The geometric data can be read by CAD system and it achieves two-way data flow between CAD and CAM systems, and it promotes the CAD / CAM integration.