Research and development of product structure and

  • Detail

Research on the development of product structure and configuration management in PDM system


with the drastic changes in the world market situation, the market has put forward higher requirements for the development cycle and time to market of products, product quality, product cost and value-added services (i.e. T, Q, C, s indicators). How to adapt to the market requirements, establish an information circulation mode conducive to their own development, and how to meet and adapt to new modes and philosophies such as virtual manufacturing technology, lean production, agile manufacturing, intelligent manufacturing technology, virtual enterprise, modern integrated manufacturing technology, are the practical issues that enterprises must solve. However, it is unrealistic to introduce or apply all new automatic management means and software systems, because enterprises have introduced some corresponding automatic application units based on the development of computer related technology in the long-term production process, and these application units play an important role. Then how to make full use of current resources to build a new operation mode on the existing basis, and gradually extruded polystyrene board manufacturing enterprises should be practical and realistic has become the focus of attention. PDM, as a software framework system, has received considerable attention and research. By implementing PDM system, we can build a reasonable and orderly information flow system, which provides support for the establishment and implementation of parallel environment. This paper mainly analyzes and studies the implementation method of product structure and configuration management, which is an important module in PDM system, and puts forward the viewpoint of module in software application and implementation

1. product structure and configuration functions, data analysis

product structure is an important basis and standard for factories or enterprises to design products and organize production. In a general sense, product structure refers to a tree structure composed of parts lists on a series of drawings of products. This tree structure is three-dimensional, which reflects the main line of the enterprise's activities. Through the intuitive form of product structure, each department of the enterprise (such as planning, design, production, materials, procurement, quality and sales, etc.) can view products from different perspectives and spaces on the basis of the same data

the important role of product structure and configuration management is mainly reflected in: product structure and configuration is one of the basic modules of product data management system. It is first of all the basis of process and task management in PDM system. Because workflow mainly controls engineering design activities, and the prerequisite for realizing control is to have sufficient product structure and configuration information, on this basis, the resources required for activity execution can be defined; Secondly, product structure and configuration management is one of the bridges to realize the integration function of PDM. After correctly maintaining the product structure and configuration information, we can provide the correct bill of materials and necessary resource requirements, and transfer the necessary human, financial, material and production object information of product design to the manufacturing resource planning system and information management system, so as to provide a basis for the planning and arrangement of the whole enterprise; In addition, the product structure is a necessary preparation for the realization of new models such as virtual enterprises. Only by maintaining the necessary product information, can we use the latest development technology of the network to operate distributed and remote virtual enterprises, so as to realize the remote distribution and driving of tasks, and realize customer-oriented e-commerce and e-collaboration activities

the main data description of structure and configuration management is shown in Figure 1, which only illustrates the relevant data in the main fields). It can be seen from the figure that product data mainly includes market demand information, product conceptual design data, product detailed design data, product manufacturing data, product after-sales customer data, etc. Its export proportion to emerging countries will also be greatly increased. First, there are many kinds of data, including explicit data related to product design (such as CAD data) and relevant implicit data (such as product demand description, design description, etc.), and not all of these data can be expressed by rules. Secondly, data changes dynamically. In actual design, product data will have different data generation processes with the progress of conceptual design, overall design and detailed design of products and different operation modes (top-down design mode or bottom-up design mode). Data is a process of gradual transformation from abstract to concrete with the development of product related activities. From the above two characteristics, we can see that the package capacity of product structure data is large and the expression range is wide, so the description of product data is more complex

Figure 1 Schematic diagram of basic product data

2. Classification management of product structure and configuration management data

according to the above data characteristics, how to organize the above data is one of the key problems of system implementation. The data that product structure needs to manage includes project plans, design data, product models, engineering drawings, technical specifications, process documents, spreadsheets Video and audio information and various data about parts, etc. These data include formal and informal data. Non formal data mainly refers to hypertext data, such as sound, graphics, image data, etc., which can be stored and transmitted in large binary blocks. Formal product data mainly refers to modelable data, which is divided into two categories: data directly related to products and data associated with products (such as the organization and resources used to develop products) [1]. In the two types of data, even the formal data can not achieve feature level fine-grained control, and can only manage the overall design results as packets or data blocks [2]. Therefore, the system adopts the same organization method for two different types of data - the integrated management of coarse texture. At the same time, in order to adapt to the characteristics of multi fields and multi data types in the product life cycle, classification methods can be used to control, form a centralized embodiment of explicit and implicit data, and meet the requirements of different views of the enterprise. In addition, it should be able to adapt to different rule drivers, so as to ensure the correctness, real-time and effectiveness of the data extracted from the substructure driven by relevant drivers. The basic classification method is: the parts of formal data that can be expressed by rules are organized by corresponding tool software. The organization results, like non formal data, are uniformly managed by the structure management module. According to the different processes of the product life cycle, dynamic and customizable classification means are provided according to the differences between fields and departments. Through the customization of interactive classification templates, systematic classification rules are established, Provide the basis for structure management

3. product structure and configuration management structure organization model

structure management is a comprehensive expression of product data. Like the product itself, product structure also has evolution attributes, and it is easy to use a linear method when controlling structure evolution attributes. In addition, it can be seen from the previous discussion that structure management and workflow are interdependent. The initiation of workflow depends on structure management and configuration information, and the complete expression and implementation of structure relationship depends on it. However, in the afternoon, the merchants' response to the transaction has slowed down, and the support of workflow and task flow form a dependency relationship between them. Therefore, the description method of structure should not only meet the basic information requirements driven by workflow, but also be able to expand dynamically driven by related processes. Therefore, the structure organization adopts the hierarchical expression method of structure tree, that is, the structure tree is divided into structure main stem and structure branches and leaves. The structure main stem builds the overall framework of the product structure, which only reflects the overall composition and correlation of the structure, and can be used as an information entry for task allocation and workflow management; Based on the main stem of the structure, the branch leaf relationship of the structure carries out specific design and change work according to the task allocation and process drive, forming different versions of the leaf nodes of the structure. In order to maintain the above hierarchical structure relationship and analyze the characteristics of product structure, the following relationships exist

Figure 2 basic relationship of product structure

the product is composed of components and parts, and the structural mainstay of the product is P in the data model_ Product Description: the structural main stem of the component is expressed by p-assembly. The part is a basic atomic component, and its structural main stem is described by its own main data attributes. The structural branches and leaves of corresponding products, components and parts are respectively marked with V_ product、V_ Assembly and V_ Part expression. Structural branches and leaves complete the evolution history of structural data and the corresponding evolution document management. Finally, the mapping relationship between the main diameter of the structure and the branches and leaves of the structure is used to realize the correspondence between the product structure space and the product version space. In order to realize the convenience of the above relationship description and the intuitive embodiment of the tree view, a hierarchical structure management model is established (as shown in Figure 3)

Figure 3 product hierarchical structure management model

in which the description objects of each classification folder of the main stem of the structure are:

1) Maintain the main characteristic information of the product in the attribute data, such as part number, material, specification, start effective date, end effective date, related production batch, etc

2). Relevant documents mainly maintain documents related to a node, such as market demand analysis, customer order requirements, reference technical materials, relevant design parameter descriptions and change notices

3). The main stem structure information maintains the structure information and related information of the product, describes the geometric subordination between the components that make up the product and the constraint relationship between the nodes and other objects in the PDM system

4). Structure branches and leaves mainly describe the attributes, design, manufacturing and structure related information of a specific version under the node, reflecting the overall information of the node version

4. Product structure and configuration management structure model design

according to the data characteristics and functional requirements of product structure and configuration management, the data model design of the module is carried out with reference to the model description of product structure and product configuration in step standard part214. In the database design of data model, the database is standardized and constrained according to the first, second and third paradigms of database design, but the main problems that need to be taken into account at the same time are: a) basic management unit of data: in order to reflect the data association relationship in the system, the product is taken as the basic management unit, and the corresponding data in the whole database is taken as the extraction and identification of the product, so the necessary attribute redundancy should be retained, To facilitate data management. B) Efficiency of data management: the data of the whole product should be reflected through the structure tree. The amount of data is relatively large. In the process of data search, the efficiency of data extraction must be considered. When establishing the data index, the combined index should be used as much as possible to improve the speed of data extraction

the main function of this module is the effective management and extraction of data. As one of the functional modules of PDM system, product structure and configuration management module should be as open and reusable as PDM system itself. Therefore, on the basis of distributed network, c/s structure, database management and graphical user interface, the module should be developed by using object-oriented technology and component-based method. The structure model of the module is shown in Figure 4:

Figure 4 product structure and configuration management structure model

the structure model reflects that the system is divided into four basic levels: data storage layer, data maintenance layer, system service layer and user interface management layer. The product structure and information extraction management module is the intermediate interface between the system service layer and the product data object maintenance layer; The product data classification management module acts as the intermediate interface between the product data object maintenance layer and the data storage layer; Directory management is the intermediate interface between system customization service and system storage layer

Copyright © 2011 JIN SHI