Research On Feature Extraction And Database Technology Of STEP-NC Turining

At present, the method of numerical contronl programming is still based on the ISO 6983 which was built more than 50 years ago. The ISO 6983 only includes some simple movement instructions and accessorial instructions without other information such as the geometry of parts, cutter path, cutter selecting and so on. This limitation brings on some problems. For example, NC programming is too difficult, information between design and manufacture can't be completely shared. Seriously restrict the development of numerical control system. STEP(Standard for the Exchange of Product model date, ISO 10303) is the standard that was built in the last century. STEP-NC is the extended part of STEP standard in computer numerical control filed. STEP-NC makes much room for the opening and intelligence of computer numerical control. It also can solve the incompatibility data in computer numerical control system that puzzled the people for many years. After deeply analyzing the STEP-NC standard and integrate with the project from Wuhan technology bureau-"Research and Development of New Genaration Numerical Control system-STEP-NC". This thesis does some research about feature extraction and database technology of STEP-NC turining manufacture. the details are given as follows: The realization of the feature map is discussed. The turning feature in STEP-NC is analysed. And then by means of the feature map, the information in the STEP-NC turning feature is extracted out. This step makes the parts information conversion from the design field to the manufacture field. The method that transforms the STEP-NC turning feature in EXPRESS format to SQL(Structured Query Language)data structure is researched. And then the geometry information table and machining information table of the turning feature are established. This step makes the real consistency, precision, share of the turning feature data, and makes it possible to get reliable maintenance, update in time of the turning feature data. The turning feature in EXPRESS format is introduced. And the method that expresses the EXPRESS in XML-Schema format is discussed. And then the formula that mapping from EXPRESS to the XML-Schema is established, by use of the formula, we can easily transform the turning feature information into EXPRESS format to XML-Schema. And makes the turning feature information shared by other users. This step builds up the theoretic foundation of future Networked Manufacturing and Collaborative Manufacturing. Based on the forenamed research production, the software part of STEP-NC turning system is designed based on the Linux operating system with the partition of the modules is also given. This step builds up the foundation of the development of STEP-NC turning system based on the Linux operating system.