【正文】 THEN TRUE ELSE FALSE。 while the relevant dies and machinery can be represented in operation by options and the constraints expressed as relevant rules, functions or methods. Process information model (PIM) for path Planning Now the PIM of process planning can be defined as the foundation to process planning. And the PCS of IMM is created to control and monitor the stamping feature and its operation features by the control variable or state variable. The process planning of large plicated stampings is a dynamic process. The PIM must involve all data, such as process planning data, analysis data, die design data, and circumstance, etc. The basic knowledge expression of the model should have adaptability to the changes of geometry, attribute, features, constraints and the way of thinking. Using the knowledge multiexpression format of KBE technology, the integrated information model of process planning for large plicated stampings is built based on the feature model. The process information model is shown in Fig. 7. The objectoriented method and feature technology are adopted mainly to form the model. There are three basic classes of features: stamping design features, operation features, and sequence features, in which process knowledge, . database, parameter, rules, and experience, acts as rules and attributes of the objects. Using feature technology and the geometry extraction method, the stamping design features, such as the main forming feature (. drawing, bend), flange, hole, emboss, notch, and so on, that are defined first as UG/UDO, can be extracted from a 3D solid model. Relevant appropriate operations can then be assigned from stamping design features of a product using a set of rules with a decisionmaking tree and modelbased reasoning methods of featureoperation criteria. Hierarchy and framework of the product model and semantic of featureoperationtools are used to establish the relationship information for PIM. With PIM, where the knowledge is encapsulated in objects or decisionmaking knowledge procedures, the process planning can be pleted through corresponding sets of knowledgereasoning. This model is a dynamic expanded information model, in which the information can be added and updated along with the process of planning. Information management and control is a part of PCS in IMM of process planning, which can monitor the change or modification of process plan ning, and timely update the information to insure the process information model and process planning synchro nization. In process planning, the information management and control begins its control and judgment from the time that the stamping design features have been created until the planning ends. Process path planning and tools option Generally, the forming of an automobile panel includes several operations, such as drawing, trimming, flanging, piercing, restriking, hemming, etc. Among the operations, drawing, trimming and flanging are the main operations to form the main shape of the product, and other operations are auxiliary operations, which work together with the main operations to form plex shapes of the product. To get precedence relations among operations based on the PIM, the main operations must first be determined, and then the decisions are made about how to arrange the initial main operations, how to bine the auxiliary operations with the main operation, and how to insert auxiliary operations to the operation sequence. For the integration of planning, it should consider the stamping dies’ capability, cost and capacity of machinery or workshop as critical issues at the sequencing level. Theoretically, casebased reasoning (CBR), rulebased reasoning (RBR), and modelbased reasoning (MBR) are all applied for process planning. In this paper, CBR, RBR and artificial neural work are joined up as the decision making methods after modelbased reasoning during process planning, which is shown in Fig. 8. Firstly, the modelbased reasoning is used to form a code of the product and operation for CBR based on feature entities and their interrelationships, and relevant rules or knowledge for others reasoning. Then the CBR is selected to get similar plans for the case base。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 appropriate operations features have been assigned to stamping features of a product based on featureoperation criteria, parameters of the stamping feature and their correlativity. This assignment is a decisionmaking activity using a set of rules with a decisionmaking tree and modelbased reasoning methods. With knowledge between operations, such as operations order constraint (doafter) and operations bination constraint, process paths have been improved based on relevant intelligent reasoning methods. Based on the relationships (preferredto) between processes and machines/dies, the structure of die and machine for each process can be identified, sinc