tion  generated  by  the  computer.  Of  course,  the  user can  al-      Fig. 7. 2-D strip layout solution for the sample stamped metal  part

ways override the computer-generated strip layout by modifying the default solution with interactive tools residing in the CAD system.

The prototype system currently holds 120 perse KS rules. The time to design an optimal strip layout for the above sample part was less than 30 minutes running on a personal computer with 2.4 GHz Pentium CPU and 512 MB of memory. This is sig- nificantly less than industrial practice, which is around 4–5 days to design strip layouts for parts of equivalent complexity.

5 Conclusion

The paper presented a knowledge-based blackboard framework for stamping process planning. The knowledge architecture con- sists of specialist KSs controlled by a strategy KS. A prototype system has been implemented in CLIPS interfaced with Solid Edge CAD system through C++. The system contains 120 KS rules. The system has been partially validated. The power of the current system is limited by its KS rule set. Future work is aimed at increasing the rule set for the specialist KSs and including new strategy KS to provide more powerful reasoning strategies. In addition, new graph theoretic strategy rules are being developed to solve specific sub-problems, e.g., a coloring algorithm for clustering various stamping operations.

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