| STEP-NC(ISO14649), the data model standard of the computerized numerical control was constituted by ISO/TC184/SCI. STEP-NC is an extension of STEP that organizes manufacturing operations into a series of "workingsteps."Each step defines an operation that can be performed on a CNC machine tool. The workingsteps defined by STEP-NC are equivalent to the machining orders represented by traditional M and G codes. However, unlike M and G codes, the working steps embody the there-dimensional geometry information,t oolrequirements information and feature definition information so that the machinetool can dynamically plan an operation and intelligently re-plan an operation using the available resources.In this dissertation,we introduced the source,the background,the meaning of the subject and the current research situation of STEP-NC standard both athome and abroad, After the data modal of the STEP-NC program is analyzed in detailed;a prototype of CNC system with the STEP-NC is established. And Intelligent functions of the system, such as: Automatic generation of Tool path, Optimization of nonlinear Working-steps Sequence, and etc, are researched in detailed.Based on open architecture and modular idea, we set up the STEP-NC translator composed of Code interpreter, Scheduler,Tool path generator, and Data Base module, after analyzing the logical relationship of the main entities in the STEP-NC NC program arithmetic of extracting and updating milles technology and mill machinees function were proposed.In this dissertation,we start with the study of STEP-NC standard and set up the systematic structure model of numerical control based on STEP-NC principle and method. From the view of technology, we confirm the rational and feasible research approach of numerical control and develop the overall scheme. In this way, we can develop our own numerical control system based on STEP-NC,which fill the gap that our country is in this domain and narrow the gap with developed countries. |
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