Development Of STEP Application To Crane Metal Structure Products

STEP(STandard for the Exchange of Product model data)is an international standard for product data expression and exchange. Its purpose is to provide a neutral mechanism without depending on the specific system, which can represent the data of the entire product's life cycle, and keep the consistency and integrity of the data during the data exchange between the systems of CAD/CAM/CAPP in order to help the information integration and concurrent engineering in the enterprise, as well as date sharing and coordinate work among different corporations.STEP is constituted of various integrated resources and application protocols. An application protocol is a sub set of the standard which is applied in some sort of product or a specific implementation, and instructs how to interpret a specific product data model by STEP integrated resources and requires compulsively application systems to conform its rules in data exchanging, transferring and storing. The crane's metal structure product is different from general machine parts for its unique features. Up to now, there is no report about the application of STEP in crane's metal structure products. The work presented in this paper aims at expanding STEP's application into crane's metal structure products to advance CAD/CAPP/CAM application level of related enterprises.In chapter 1, the concepts and functions of STEP, its development and applications are introduced, the research work and its meaning presented in the paper are stated.In chapter 2, the content and the description language EXPRESS of STEP are introduced. The structure and format of STEP neutral files are analyzed and studied as.Because VC++ is used to develop the STEP application system in the paper, in chapter3, the schema conversion between EXPRESS language and C++ is stated and discussed, which provide measures and regulations for the following system design.The design of application protocol must be according to the characteristics of its applying area. Therefore, in chapter 4 are introduced the crane structure product's characteristics and its manufacture craft.In chapter 5, the process of setting the application protocol of crane's metal structure product, QJ-AP, is introduced. The AAM, ARM and AIM of QJ-AP are built up.In chapter 6, the pre- and post- processor of neutral files are developed based on QJ-AP, the addition of processing information and material information within CAD geometry mode, and CAD/CAPP integration based on neutral files are realized. An application example is given, in which an neutral file of crane metal structure product model that includes geometry, material, manufacturing craft and tolerance information are created, and the crane's metal structure product's manufacturing craft card and component specification are created from the neutral files automatically.At the final part, chapter 7, the main results of the research work are summarized and the future research directions are prospected.