Information extracting and modeling of SDAI based STEP-NC numerical control program

Based on standard for the exchange of product model data-numerical controllers (STEP-NC) and standard data access interface (SDAI), a two-level part-entity data structure was constructed to transform STEP-NC data to C++ data. And data dictionary model, entity instance data structure model and part instance data structure model were also described. In the course of information extracting, data were constructed in a step-by-step manner. The cell entity instance was constructed by backtrack recursive procedure, then the entity attribute content was matched, finally the part-level data structure was constructed. This process avoids the conflict between entity constructing and entity instance constructing in SDAI later binding. In such way, a STEP-NC information extracting prototype system was developed. By inputting IS014649 example data, the information were extracted and the part was also displayed.