Research On The NC Model Of STEP-NC Interpreter

STEP-NC(ISO 14649), The data model standard of the computerized numerical control was constituted by ISO/TC184/SC1. STEP-NC is an extension of STEP that organizes manufacturing operations into "work -ing steps. " Each step defines an operation that can be performed on a CNC machine tool. The working steps defined by STEP-NC are roughly equivalent to the machining commands represented by traditional M and G codes. However, unlike M and G codes, the working steps are linked to three-dimensional geometry, tool requirements and feature definitions so that the machine tool can dynamically plan an operation using the available resources and intelligently re-plan an operation when necessary.In the dissertation, we recommending source, background, meaning of the subject and the current studying situation both at home and abroad of STEP-NC standard, and then recommend application activity model, application reference model, application interpret model in detail. Through this we made you can mastered application protocol (AP238 ), using standard .function unit, and its file structure of STEP-NC standard.On the base of researching of the STEP-NC standard, we set up the interpreter model composed of EXPRESS interpreter Code interpret-ter, Scheduler, Tool path generator, Executor and Monitor and CNC system base on PMAC . We realize how to draw process information from STEP-NC file into mid-file and how to draw the data from the database, According to processing method, processing technology, cutter message described in the STEP-NC file, The interpreter create PMAC order to urge the numerical control machine tool processed work-piece.In this dissertation, we start with studying STEP-NC standard and set up the systematic structure model of numerical control based on STEP-NC according to STEP principle and method of standard. Analyzed from technology, we confirm the rational systematic research approach of numerical control with feasible reality and develop the overall scheme. In this way we can develop our own numerical control system based on STEP-NC according to national conditions, which fill the gap that our country is in this domain and narrow the gap with developed country.