The shape calculator can provide the shape parameters of structural parts upon fixing the type and size of the structural parts. This calculator will compute all design values for each shape parameter based on the design specification of the structural part.
The model generator can perform the 3D solid modeling process for the structural parts. It can be used to construct the solid model of the structural part by integrating all geometric operations of each structural part during the modeling process according to the type, quantity, location, direction, and shape parameters of candidate structural parts. Since the parameters of the solid model are computed auto-matically by the system rather than resulting from interac-tions with the user, the modeling process for this solid model is performed automatically by the 3D CAD system.
The knowledge base contains both design processes and design guidelines. The design processes outline the design and modeling process for each of the structural parts. The design guidelines are utilized to decide the type, size, quan-tity, direction, and position of each of the structural parts.
In the design knowledge base, dies are systematically classified into main parts and standard parts to construct progressive dies using standardized 3D approaches. The grasp of the connection among various main and standard parts is essential to obtain an appropriate design process for each of the main and standard parts. Itemized modeling processes for each part, as well as the geometric operations used in such processes, are obtainable in the knowledge base. In addition, the design guidelines of the main parts, hole identification rules of the standard parts, 3D diagrams with design parameters, itemized text, and formulas are collected in e-book forms for reference, training, and debugging missions.
3.4 The design database
The design database offers design specifications for the main and standard parts. The design specifications specify the category of each of the main and standard parts.
The design specifications for each of the main and stan-dard parts are depicted in 2D diagrams. Besides, each dia-gram is followed by a table that itemizes the related shape parameters and standard sizes. All information in the design database is collected in e-book forms for easy access.
This system has been implemented on top of the CATIA CAD system with its “add-on” Part Design, Assembly Design, and Knowledge Advisor modules. The Part Design module is chargeable for commanding and execut-ing the process of constructing 3D models. Hence, the inference coordinator is built in this module. The part selec-tor utilizes the Formula Editor and the Rule Editor modules, while the shape calculator employs the Generative Shape Design module. The model generator uses Visual Basic
Fig. 6 Design specifications for socket head cap screws
(VB) to develop programs for generating solid models. The Assembly Design module is used to assemble the standard parts into the main parts. The VB is also used to construct the alphanumeric and graphic user interfaces.
4 Construction procedure for the automated structural design system
The proposed system is constructed based on CATIA 3D CAD software in the Windows XP operating system. This
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system is designed to be used in a PC and is developed using the CATIA software’s built-in modules, including Part Design, Assembly Design, and Knowledge Advisor. Upon
Fig. 8 Organization diagram of functional features for progressive dies
users’ inputs of the design information, our system is able to automatically generate the designed solid model for the main and standard parts of a progressive die using the