Research Of The Open NC System Based On STEP-NC

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.Then based on the further research of STEP-NC, establish the open NC system software and the hardware platform which are based on STEP-NC. About the establishment of the hardware platform, adopt the NC platform that is based on the PMAC movement controller, and describe the connection of the whole hardware platform in details and achieve the primary communication. As to the design of the software platform, it includes system management software and the real time controlling software, we use COM technique in the system management software toimprove the reusing and transplanting ability.Finally, describe the design of the simulating module of the tool path and servo matching and data collecting method of the movement controller.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.