Research On NC Milling System Based On STEP-NC

With the rapid development of CNC technology, CNC machines play anincreasingly important role in the NC machining. The arising of STEP-NC in thefield of CNC machining provides a broad space of development for CNC opennessand intelligence, eliminating the data incompatibility issues which have troubledpeople for a long term. Therefore the research on STEP-NC NC milling system hasimportant theoretical and practical significance.Based on the analysis of the function structure model of STEP-NC CNC millingsystem in this thesis, the realization of key modules are designed, the developedSTEP-NC milling CNC system consists of four main key modules, STEP-NC NCprogram interpreter, microscopic processes planning, tool path planning and motioncontrol module. The interpretation method of STEP-NC NC program based onmemory is proposed, using regular expression to perform syntax checking forSTEP-NC file, and the STEP-NC NC program information extraction method basedon model and entities is proposed; and it is capable to generate the step sequence treefor extracted information; visually display processing object, and processing step, etc.The access and modification of process parameters, and machine functioninformation can be achieved through HMI; seven traditional milling strategies arestudied and a novel milling strategy is proposed: programming by repeating modelalong guide curve tool path, the generation algorithms of tool path of planes, holesand cavities in STEP-NC2.5D manufacturing features are studied; the generation ofPMAC motion code is analyzed. With VC++6.0as development platform, STEP-NCCNC milling systems is developed. Combined specific instances, the accuracy andreliability of STEP-NC CNC milling system is verifiedThrough the development of STEP-NC CNC milling system, the issue ofregarding information sharing and integration between CNC system and CAD/CAPP/CAM system is solved, which as a goal to improve the productivity andproduct quality of NC manufacturing.