Expert system for castability evaluation: Using a fixed-features based design approach

Symbolic representation of three-dimensional objects to aid local and global shape analysis for defect prediction of casting design

“…A knowledge-based expert system, called EX-CAST, was developed to provide the casting designer with a tool for on-line castability evaluation of a part design [6]. The EXCAST system was implemented with an interactive CAD environment on a Sun Workstation 3/60 UNIX using Sun Common LISP and the AutoCad graphics package.…”

“…There are about 250 rules for local shape analysis. It takes about 10 minutes to design a connecting rod and less than 1 minute to extract the skeleton for simple shape such as character L. The EXCAST system has been used for flywheel design at the Cummins Engine Company [6]. The advice given by the system was exactly same given by the human experts who did not know the system.…”

“…Therefore, a search tree for finding such a sequence is generated. In design for manufacturability evaluation, however, the system is mainly concerned with the problem of finding possible manufacturing errors so that the system can provide error messages and some recommendations to the designer [6]. Therefore, the system in design (especially casting design) uses a control strategy (not search strategy) to find the sequence of rules which can be fired for manufacturability evaluation.…”

“…There are many definitions of a feature. These definitions are derived from views of various application areas [1][2][3][4][5][6]. These different views of a feature can be categorized based on the application area intended.…”

“…The other approach, designing-with-features [6,[18][19][20], uses predefined manufacturing features as designing features, such as block, hole, pocket, etc., to create a desired part. The advantage of feature-based design is its ability to capture the complete manufacturing feature information of a design, since it uses predefined manufacturing features as designing features.…”