Research On Open CNC System Construction And Key Technology Of STEO-NC-Based

As a new type of NC programming interface which can replace G/M code, STEP-NC not only contains the machinery parts and all the information needed in the entireprocess, but also can enforcement processing tasks "proactively". In a certain extent, ithas greatly improved the independent degree and process efficiency of numerical control,and will be helpful for manufacturing’s open-ended, efficiency and intelligent in thefuture.The paper aims to research and develop a module with which STEP-NC file can beautomatically generated in VC++6.0software environment, the module can read in AP203file and automatically output STEP-NC file. In order to realize the function of themodule, the paper briefly introduces the standard system and related concept of STEPand STEP-NC, discusses the key technologies involved in the development of thismodule, such as geometry information extraction and storage, entity object mapping,features identification, blank construction and process planning etc. and elaboratelyshows every linked information processing method and the intermediate state through thebearing base instance. The specific process and the method is as follows: Firstly,extracting geometry information contained in AP203files of processing part, classifyingand storing the information according to its type and topological relations, recognizingthe features by the method of body generation based on the graph. Secondly, makingprocess planning based on the characteristics needed to be processed of the blank. Finally,writing all information into STEP-NC program in accordance with the ISO14649format.The paper writes programs which can extract all the geometry information of the part andrealize simple feature recognition, such as holes, grooves and cavity for the informationprocessing links using C++language, combines all these information with prior presetrelated process parameters and eventually generates STEP-NC program meet ISO14649standard. This module has been proved preliminary feasible and effective by bearing seatinstance. STEP-NC can be directly served as process information for future NC system, thismodule provides an independent front information processing module for the STEP-CNC system and lays the foundation for the following research.