【正文】 Thereafter, the structure of the die for each process can be performed from operations and the assigned features, while the process route is determined. Then the equipment such as a set of machinery or the product line can be selected to insure the stamping die meets design specifications. For example, Fig. 9 shows generation routes of process planning for the automobile panel shown in Fig. 3 . During process planning, different process routes can be found by different planners。 the angle of the vectors of the two hole15 if CBR is not suited, the RBR and ANN are select to plete the task cooperatively. During sequencing of forming operations, the structure of the die for each operation can be performed from the operations and assigned stamping features. The system can plan the equipment and operators for each operation to meet design specifications, and to achieve minimum machining time and maximum efficiency based on the above activity and knowledge. Finally, the optimal process plans obtained can be added into the case base of plans for the planning of other similar products. Customarily and practically, the relationships between operations consist of operations order constraint (doafter), which relates to the necessary order of operations to be used, and operations bination constraint, which relates to relevant operations that can be formed at one process and die together (mentioned in Sect. ). For example, flanging is after trimming, while piercing and trimming are always formed in one process. For the aims of economic efficiency and topquality, it is always remended to bine the potential operations together, while making the sequence operations practical. Therefore the initial main operation sequence is Blank ing→ Drawing → Trimming → Flanging for a flange feature prised part, and Blanking → Drawing → Trimming for no flange feature part. With operations sequencing and bination rules, auxiliary operations are added to the initial main operation sequences to form final process routing. The following is the bination rules for hole1 and hole3 shown in Fig. 3 : (Logical) bination (for hole1 and hole3): IF distance between hole1 and hole3 DIS amp。it not only represents feature parameters, tolerance, material, etc. as attributes of class or instance, but also represents geometrical objects by importing UG/UDO and UG/UDF referenced solid geometry as an instance attribute or child. And this realizes the connectivity and integration between the symbol of a feature and its geometrical object. It can also get an attribute value from a function, rule, expression and database. Operation feature Accordingly, stamping operation features are categorized into initial and subsequent, such as drawing, bending, flanging, trimming, hemming, restriking, and piercing and so on. The relevant appropriate operations are assigned to form stamping features of products based on feature operation criterion, parameters of the stamping feature and their correlativity. This assignment is a decisionmaking activity using a set of rules with decisionmaking tree and modelbased reasoning methods. For example, drawing→ trimming is reasoning from the main draw feature, flanging is reasoning from the flange feature, and piercing is reasoning from the hole. Fig. 5 show the typical illustration of flanging operation features reasoning from its stamping feature, and the sequence rules of these operation features are attached to the operation features. Customarily, relationships between features, especially the hierarchy, should be an important factor, while the operation feature is the reasoning. In , the features flange3, flange1 and bead1 should be in the form of a set together to deduce relevant appropriate operations. In this way of reasoning, the operation features can get fundamental knowledge for subsequent planning. In this paper, the operations features reasoned from stamping features are represented as objectoriented entities and UG/UDO, and the relationships are expressed as work based on the stamping feature model of the product (shown in Fig. 6). The operation features not only refer themselves to stamping features, but also relate to other operations, such as relevant forming dies and machinery with the relationships among them. The relationships between operations consist of operations order constraint and operations bination constraint. Another type of relation between processes and machines/dies is preference (preferredto). For example, flanging is always preferred to flanging die and relevant press machine, while trimming is always preferred to trimming die and press machine. ALL these constraints and relationships among them are reprsented as attributes, rules and methods in the operations. It is through the citation of stamping features that the description of the geometrical objects are realized in the operation features。KBEbased stamping process paths generated for automobile panels Jinqiao Zheng . Yilin Wang . Zhigang Li Abstract: As automobile body panels are one kind of sheet metal part with groups of free form surfaces, the process planning is more plicated than mon sheet metal stamping to implode effectively and practically. Based on KBE, new frameworks have been presented as intelligent master model at the system level and as procedure model at the activity level. In accordance with these frameworks, an intelligent CAPP system has been specifically developed. Based on feature technology, features have been extracted and represented by the objectoriented method. Stamping features and their parameters have been defined and extracted based on feature technology and stamping process rules. The whole product knowledge has been represented by frames which directly map to objects (or features) in the objectoriented sense. Relevant appr