Research on product data of PLM II
III. establishment of process information model for PLM
process information model is the basis of PLM oriented system and the key to realize the integration and management of product life cycle information. The establishment of process information model is mainly from two aspects:
first, analyze the process business object entity
the second is to define the data model involved in the business object entity
3.1 process data analysis
analyze the content, results and supporting data of the tasks decomposed in the model one by one. Through the analysis, we can get the setting of preloading load and preloading speed; The data of each character stage can be divided into supporting data and result data. Supporting data is the data needed to complete the task; The result data is the result after the task is completed. The final analysis results of each stage task are shown in Table 1. The process summary task in the table is to determine the coefficient of material rigidity, which is the most important part of PLM oriented process preparation. Broadly speaking, process summary is the summary of knowledge related to process preparation. Specifically, the process summary includes two aspects: one is to track the actual production process of a process, compare it with the old process, check the advantages and disadvantages, and finally evaluate the effectiveness of the process, which generally occurs in the late stage of the process preparation cycle; The second is to extract valuable process knowledge in the process of process preparation
3.2 process data object definition
object oriented method is a software development method that uses the concepts of object, class, instance and inheritance to construct software systems. Its basic principle is to implement the natural division of the problem field, and identify and define the relevant entities in the objective world according to the human way of thinking to understand the objective world. Therefore, it is a more intuitive, more natural and easier to understand conceptual modeling method circle. In recent years, object-oriented technology has been widely used in complex enterprise system modeling. Combined with the above analysis results of process preparation process data, the data object of process preparation process is defined by using object-oriented technology
the definition of data object in process preparation is shown in Figure 3. Data objects are divided into two categories: support data and result data. Some data objects in the supporting data are the common basis for various tasks of process preparation, such as product characteristics, production conditions, policy standards, etc; There are also some data objects that are the basis for the implementation of a specific task, such as material characteristics for process route design, typical examples for process specification design, etc. Process knowledge is a special set of data objects, which belongs to both supporting data and result data in the process of process preparation. According to the object-oriented method, the process knowledge objects can be divided into four types according to their functions to complete the experiments that are usually required: manufacturing objects, process objects, resource objects and decision objects. The process knowledge objects involved in the process preparation process can be summarized under one of these types. Each specific object can be divided into two levels: object level and method level. The object layer includes four elements: object class set, but two-thirds of the product exports belong to medium and low-end products, object attribute set, object attribute constraint set and object instance set; The method layer describes the name, related objects and relationships of the operation method to solve the problem
3.3 establishment of process information model
combined with the analysis of process preparation process data and the definition of data object, according to the role of data in process preparation, the process preparation process data model is divided into three sub models: process basic data model, process result data model and process knowledge model
process basic data model is an abstract description of the process related basic theoretical data and enterprise related standard data based on the implementation of various tasks in the process of process preparation
process result data model is the result data generated by the execution of process preparation tasks. The result data here is the result in a broad sense, including the data guiding production and some information managing the process preparation process
process knowledge model is the basis to ensure the rapid, efficient and comprehensive acquisition of process knowledge in the process of process preparation, and apply the knowledge to the actual process preparation process
the basic process data model has the same form as the process result data model. The process result data is usually obtained from the basic process data or its processing results. The basic process data should be universal, not limited to a specific product, so the establishment of its model should be based on the product object as the basic unit; The process result data is directly used to guide the production of products, and the organizational unit of its model should be the component of product processing and production, that is, the part object. The three models are represented by object-oriented E-R diagram
with the continuous development of PLM technology and enterprise management mode, if we can make full use of these technologies to meet the needs of enterprise informatization, it will inevitably bring greater improvement to the application effect of process informatization. However, the process standards are not very standardized and complete, and need further research. In addition, the implementation of PLM solution is a complex system engineering, which requires scientific implementation strategies as guidelines, and develops a set of scientific, practical and effective implementation methods according to the respective positions of enterprises, suppliers and software in the implementation process
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