ادغام طراحی محصول، برنامه ریزی فرایند، برنامه ریزی و کنترل FMS با استفاده از نمایش اطلاعاتXML

An efficient model for communications between CAD, CAPP, and CAM applications in distributed manufacturing planning environment has been seen as key ingredient for CIM. Integration of design model with process and scheduling information in real-time is necessary in order to increase product quality, reduce the cost, and shorten the product manufacturing cycle. This paper describes an approach to integrate key product realization activities using neutral data representation. The representation is based on established standards for product data exchange and serves as a prototype implementation of these standards. The product and process models are based on object-oriented representation of geometry, features, and resulting manufacturing processes. Relationships between objects are explicitly represented in the model (for example, feature precedence relations, process sequences, etc.). The product model is developed using XML-based representation for product data required for process planning and the process model also uses XML representation of data required for scheduling and FMS control. The procedures for writing and parsing XML representations have been developed in object-oriented approach, in such a way that each object from object-oriented model is responsible for storing its own data into XML format. Similar approach is adopted for reading and parsing of the XML model. Parsing is performed by a stack of XML handlers, each corresponding to a particular object in XML hierarchical model. This approach allows for very flexible representation, in such a way that only a portion of the model (for example, only feature data, or only the part of process plan for a single machine) may be stored and successfully parsed into another application. This is very useful approach for direct distributed applications, in which data are passed in the form of XML streams to allow real-time on-line communication. The feasibility of the proposed model is verified in a couple of scenarios for distributed manufacturing planning that involves feature mapping from CAD file, process selection for several part designs integrated with scheduling and simulation of the FMS model using alternative routings.

Computer Integrated Manufacturing (CIM) is still moving target in industrial and manufacturing engineering research and applications. There are numerous reports outlining individual islands of automation within the CIM model, with a significant effort in research papers being focused on a particular task, and much less effort devoted to integration of these manufacturing engineering and planning tasks. Integration involves the transfer of data between applications, but also should focus on data and model integrity, distributed processing of the data, incorporation of knowledge into the planning tasks, and so on. Computer aided process planning (CAPP) is rightly seen as an integration fabric for CIM with its relations to design (CAD), manufacturing (CAM), scheduling, and control tasks. By virtue of being an integrator between CAD, CAM, and scheduling/control, process planning involves decision making process on various levels of details with the final goal of generating feasible and/or optimal process plan. The need for integration requires that such model is transparent between these tasks and that it is easily saved or transferred. This paper proposes such neutral data model in the form of XML model and describes its details and application in manufacturing process planning. The paper is organized as follows. Section 2 describes previous work in process plan representation and modeling. Section 3 describes process planning representation object model (PPRM), which includes major entities and relations between them. Section 4 explains process planning XML representation that is built for the PPRM object model and describes methods for writing data in XML format and parsing XML streams into object model. Section 5 explains a few scenarios of integration between feature mapping, process selection, scheduling, and FMS control using data in XML format and describes a case studies that were carried out to verify the approach. The paper ends with conclusions and the list of references.

This paper has demonstrated the flexible use of an XML data representation in process planning modeling and integration. The XML schema has been developed for validation of XML process plan files. Flexible approach for writing the XML data from an FMS model and parsing data back has been explained. Benefits of this approach were demonstrated in few small examples. The use of proposed XML-based model in integration of feature mapping, process planning, scheduling, and FMS control using a simulation model is demonstrated on couple of scenarios. Practical implication of the developed approach is a significantly shorter development cycle in integration of various manufacturing software modules. Providing flexible XML mapping between applications allows rapid application integration, run-time adjustments, and maintains independent implementation of individual application algorithms. XML data exchange also allows for integration of applications written in different languages.