Research On Format Conversion From STEP-NC To XML And Data Management

NC technology is the foundation of manufacturing automation, flexible, integrated production foundation. The modern CAD / CAM, FMS and CIMS are built on the NC Technology. If there is not the NC technology, advanced manufacturing technology will become a forest without trees. ISO6983 standards are now widely used in NC code, however, it can not bring CNC machine tools and other computer-aided system for bidirectional exchange of information along with other shortcomings make it difficult to meet the growing demands of production efficiency of modern manufacturing. Thus, STEP-NC is put forward as a new generation of NC code standards to replace the ISO6983 standards.STEP-NC is the extension of STEP (Standard for the Exchange of Product Model Data) standard to the field of NC, and is a new data standards redefined for CNC systems. It is based on STEP standard, contacts the design information and manufacturing information of product, solves the bottleneck problem of information bidirectional exchange between CNC machine tool and computer-aided system (CAX). The emergence of STEP-NC is a revolution in the field of NC technology, and will give a far-reaching impact on the development of NC technology even the entire manufacturing industry. According to the Stepstools Company's research, the application of STEP-NC can reduced 75% production data preparation time in CAD stage, 35% processing time in CAM planning stage and 50% processing time.However, the most of STEP-NC based NC programs adopt the ISO 10303 Part 21 physical file format. Although it a neat format, it is difficult to understand and explain for person who without related fields knowledge. And, since this format is not suitable for the Internet transmission, it's a tremendous impact on the company's production and development. Extensible Markup Language (eXtensible Markup Language, XML), as an excellent network language, has been widely used, but its product information modeling capacity is insufficient. Therefore, by combining the advantages of STEP-NC and XML, the technical staff will be able to inquire about and update the STEP-NC data in the database, realize network manufacturing, and improve the collaboration capabilities and competitiveness. In this thesis, through the research on STEP-NC and XML file formats, a procedures to realize the conversion between STEP-NC and XML Format are developed, which is used to solve the problem STEP-NC document network transmission bottlenecks, and has a very important significance for the application of STEP-NC in the network manufacturing.The first chapter of this thesis mainly introduces some problems appeared in the application of the traditional standard ISO6983 NC code, the development of STEP and STEP-NC and the research status quo of the format conversion between STEP-NC and XML data at home and abroad. The second chapter introduces the basic principles of EXPRESS language, EXPRESS entitiy descriptions as well as EXPRESS realize method of STEP-NC, analyses the characteristics structure of the STEP-NC simply, and emphasizes on the generation method of STEP-NC document. The third chapter initially researches on the text structures of the STEP-NC document, and spliting the STEP-NC statements into some separate paragraphs with certain sense by using the symbols appear in the statement. Then establishes the XML Schema according to the mapping between EXPRESS language and XML. Finally realizes the conversion form STEP-NC documents to the XML file and releases the XML file on the network by using the server. The research content of the fourth chapter is saving the XML file into Access, managing and maintaining the entity description information in the Access. The thesis also advances that we can establish an entitiy description information database in Access, so users can choose appropriate entitiy description information according to the needs of different situation. The entitiy description information stored in Access is in the data sheet. Through the Access documents export capabilities, it can be re-created into correct XML documents.