Fig. 3 3D model picture of the GB/T 2855.9-19903.2. Establish parametric models library Using the Family Table function of Pro/E, it’s easy to produce a series of features similar to the parametric 3D models which have built. This method is suitable for establishing a standardized library. The parametric 3D models are constrained fully by fundamental equations, and then the Family Table function could drive 3D models to generate new 3D models. The major steps to establish models’ family table library are listed below. z Modify the parameter names of the models: Selecting the desired parameters, all dimensions parameters of the models are modified based on the Chinese National Standards. Once the parameter is selected, it would be highlighted. z Constraint the size relations of the models: Defining the relationships between the features, models and components by fundamental equations. Expressing the driving dimensions with the size symbols, and building the functional relationships between driving dimensions and driven dimensions, completing the relationships’ constrains between the features, models and components.  z Establish models’ family table: Using the Family Table function of Pro/E to build family tables of the models. In each family table, a new vertical line is added then a new driving dimension is added, a new horizontal line is added then a new sub-component is added. Table 1 is family table of the upper die seat of middle guide, which the Chinese National Standard is GB/T 2855.9-1990. 3.3. Tree structure XML file of die sets
The die sets standard parts library includes sliding guide cast iron die sets, anti-friction bearing cast iron die sets, sliding guide steel platedie sets, anti-friction bearing steel platedie sets, new standard of sliding guide die sets and new standard of anti-friction  bearing die sets six categories, each category could be distributed into four or six subclasses of die sets, and each die sets contains several standard parts . Tree structure file of the die sets is written in XML based on Unicode according the above classifications to show the structure of the die sets standard parts library, and the tree structure XML file is shown in fig. 4. 3.4. Man-Machine interactive interface program design The Man-Machine interactive interface is an important part of the die sets standard parts library. The library includes tree structure of the die sets, 2D structure picture of the standard parts, 3D render model picture of the standard parts, and Access table of the standard parts，provides four buttons for user to operate and select . On the one hand, the Man-Machine interactive  interface faces the users providing user-friendly search and user interface; on the other hand, it should be geared to the needs of application program to call and run the files, complete of the specified command. The Man-Machine interactive interface is designed based on Python. its primary functions include analyzing the tree structure XML file to create structure tree of the die sets library and showing the classification of the die sets, calling the parts’ 2D pictures from 2D structure picture library, calling the 3D models pictures from 3D model picture library, calling geometric parameters of the part  from database, and displaying these information on the interface.Fig. 5 is the Man-Machine interactive interface designed, which shows the tree structure on the left and the GB/T 2855.9-1990 part which is selected, shows the corresponding 2D structure picture on the right, and shows the part’s geometric parameters on the below. 3.5. Design application program using VC ++6.0 and Pro/Toolkit Application program is designed by VC ++6.0 and Pro/E Software Development Kit (Pro/TOOLKIT), which can access control Pro/E safely and be integrated with Pro/E by automatic registration method. As shown in Fig.
6, it shows that the application program has been integrated with Pro/E. The Man-Machine interactive interface could be called by clicking the secondary menu. Selecting any one set of geometric parameters of  the part on the interface, the corresponding new 3D solid of the standard part is built automatically by the application program, which fetches the corresponding part from models’ family table library according to gauge of the National Standard.  Fig.7 is the fifth 3D model of GB/T 2855.9-1990 which is selected in Fig. 5 4. Conclusion Die carrier standard parts library allows designers to query different types and different specifications standard parts easily through the tree structure, to retrieve 2D structure picture and 3D model picture and parameter data information, to get three-dimensional model directly. The Man-Machine interactive interface designed is simple, elegant, and easy to operate. The Die carrier standard parts library could save time greatly and improve throughout design efficiency.  Acknowledgements   The research work is supported by Shaanxi Major Subject Construction Project, President Fund of Xi’an Technological University (XGYXJJ0414), and Shaanxi Provincial Programs for Technology Research and Development under Grant No.2010K01-076, namely “The Research and Application of Digital Manufacturing Execution System” . References  [1]Xiao Xiangzhi, Wang Xiaopei. China Die & Mould Engineering Canon. Beijing:  Electronic Industry Press,2007.  [2]WU Yi-zhong,XU Hua,WANG Qi-fu.Study and Implementation of a 3D Standard-Part Library System Based on Component Object Model.Mechanical Science and Technology, 2004, 1. [3] Parametric Technology Corporation. Pro/TOOLKIT User Guide Manual. USA: Published by PTC,1998.  [4]Mark Lutz, David Ascber. Learning Python. China Electric Power Press,2001 [5]Fabio Arciniegas. XML Developer’s Guide. Tsinghua University press,2003 Pro/E的模具标准件库英文文献和中文翻译(2):http://www.751com.cn/fanyi/lunwen_55800.html