Shulou(Shulou.com)06/02 Report--

1 the development and present situation of product data management system (PDM)

The basic concept and background of 1.1PDM Technology

Product data management (PDM) is a technology which is based on software technology and takes product as the core to realize the integrated management of product-related data, process and resources. PDM is clearly oriented to manufacturing enterprises, with products as the core of management, and data, processes and resources as the three elements of management information. It inherits and develops the core ideas of CIM (Computer integration Manufacture) and other technologies. Under the guidance of system engineering, it uses the idea of overall optimization to describe the product design process, standardize product life cycle management, and maintain the consistency and traceability of product data. The two main lines of information management are static product structure and dynamic product design process, and the core idea is the order of design data, the optimization of design process and the sharing of resources.

In the 1960s and 1970s, enterprises began to use CAD, CAM and other technologies in their design and production process. The citation of new technologies not only promotes the development of productive forces, but also brings new challenges. For manufacturing enterprises, although the computer-aided technology of each unit has become increasingly mature, each automation unit has its own system and lacks effective information communication and coordination with each other, which is the so-called "information isolated island" problem.

At the end of the 20th century, the rapid development of high and new technology characterized by information technology has promoted technological progress and economic globalization, accelerated technological innovation and management innovation, and fundamental changes have taken place in the business environment and market environment faced by enterprises. It is embodied in the following aspects:

(1) with technological progress and the application of high and new technology, the amount of information has increased rapidly.

(2) Global market and global competition.

(3) the user's demand for the product is diversified and personalized.

(4) the product upgrading is accelerated, the life cycle is shortened, and people's expectation for the delivery time is getting higher and higher.

(5) diversification of mode of production.

However, many enterprises still have some problems in the coordinated development of technology, management, technology and management and adapting to the new production mode and management mode, which affect the competitiveness of enterprises and the development of modern enterprises. These problems are as follows:

The main results are as follows: (1) the design means and processing technology are backward.

(2) the backwardness of management, especially the contradiction between advanced technology and backward management has become increasingly prominent. The comprehensive promotion of CAD technology greatly improves the design quality, reduces errors, reduces the rework rate, and greatly improves the product development ability and market competitiveness of enterprises. But on the other hand, it brings more difficulties to data management, and the backwardness of data management is more obvious. it is mainly manifested in: low information sharing program, slow information transmission speed, backward document management, outdated design methods and low efficiency of application integration.

(3) the new production mode, such as CIMS, concurrent engineering, lean production, agile manufacturing, etc., put forward higher requirements for information management technology, which not only requires supporting technology to support multi-disciplinary experts to work together, but also requires the organic integration of product information and development process, so that the right information can be sent to the right people in the right form at the right time.

Due to the demand for information management in many aspects mentioned above, many enterprises have realized that the orderly management of information will become the key factor for them to maintain a leading position in the future competition. Product data management (TI PDM) is a new information management idea and technology under this background.

Application status of 1.2PDM in small and medium-sized Enterprises

For most small and medium-sized enterprises, generally speaking, the introduction of domestic and foreign large-scale PDM software, the implementation of a medium-scale PDM project, need a lot of funds for software costs and implementation costs, and generally take a long time to deliver. In addition, in the process of implementation, enterprises are required to provide management and technical personnel to cooperate with the progress of the project, and sometimes for the needs of the project, it is necessary to increase additional investment to purchase all kinds of hardware equipment, all these factors, for the general domestic small and medium-sized enterprises, no matter in terms of time or funds, it is difficult to bear. This is an important reason why it is difficult for large-scale PDM software at home and abroad to find users in the customer base of small and medium-sized enterprises. For most small and medium-sized enterprises, they hope to make full use of the existing resources to develop the PDM system.

2 brief introduction of product data management system (PDM)

Architecture of 2.1PDM system

The architecture of PDM system can be divided into four layers: user interface layer, functional module and development tools layer, framework core layer and system support layer, as shown in figure 2-1.

1. User interface layer: provides users with an interactive graphical interface, including graphical browsers, various menus, dialog boxes, etc., which are used to support the operation of commands and the input and output of information. Through the graphical user interface provided by PDM, users can manage all kinds of objects in the whole system intuitively and conveniently. It is the means and medium to realize various functions of PDM, and it is at the top.

Figure 2-1PDM system architecture

2. Function module and development tool layer: in addition to system management, the main function modules provided by PDM for users are electronic warehouse and document management, workflow management, product structure and configuration management, integration tools and so on.

3. Framework core layer: provides the core structure and architecture to realize various functions of PDM. Because the object management framework of PDM system has the characteristics of shielding heterogeneous operating systems, networks and databases, users realize transparent operation of data, transparent call of application research and transparent management of process when applying various functions of PDM system.

4. System support layer: take the popular relational database system as the supporting platform of PDM, and support the management of PDM system objects in the underlying database through the data operation function provided by the relational database.

The architecture of PDM should have the following characteristics:

(1) adaptability to the basic computer environment.

Generally speaking, Qingsoft Yingtai PDM system is supported by distributed network technology, client / server structure, graphical user interface and database management technology. The connection with the underlying environment is realized through different interfaces, which ensures that a PDM system can support a variety of hardware platforms, operating systems, databases, graphical interfaces and network protocols.

(2) the openness of PDM kernel.

The openness of PDM kernel is reflected in that more and more PDM products adopt object-oriented modeling methods and technologies to establish system management model and information model, and provide object management mechanism to realize product information management. On this basis, a series of development tools and application interfaces are provided to help users easily customize or expand the original data model, access related information, and add new application functions to meet the different application requirements of PDM system.

(3) the variability of PDM function module.

Because the PDM system adopts client / server structure and has distributed function, enterprises can start from a single server and gradually expand to several, dozens, or even hundreds. When users choose functional modules, in addition to the necessary modules, other modules can be tailored according to the needs.

(4) plug-in function of PDM.

In order to manage all kinds of data generated by application system more effectively and provide it to users and application systems conveniently, it is necessary to establish a closer relationship between PDM system and application system, that is, application integration based on PDM system. This requires the PDM system to provide a neutral application interface, encapsulate or integrate the external application system into the PDM system, as a new sub-module of PDM, and can run conveniently in the PDM environment.

2.2 main functions of Qingsoft Yingtai PDM system

There are two ways to divide the functions of PDM system. One is to divide it into electronic warehouse, user-oriented functions (including document control, change control, configuration management, design retrieval and part library and project management, etc.) and practical support functions (including notification and communication, data transmission and conversion, image services, system management, etc.). The other is divided by software function modules, which can be divided into electronic warehouse and document management, workflow and process management, product structure and configuration management, parts classification management, engineering change management, project management, electronic cooperation, integration tools, browsing and browsing, etc., the first five functions are the basic functions of PDM system applications. This paper introduces the main functions of general PDM system according to the latter.

1. Electronic warehouse and document management

The so-called electronic warehouse is a metadata (data management data) library and its management system that implements a specific data storage mechanism in PDM. It holds metadata for all physical data and files related to the product, as well as pointers to physical data and files. The pointer specifies the database records where the physical data is stored and the file system and directory where the physical files are stored. There is a variety of product-related information throughout the product life cycle. This information exists in the form of a file or drawing file, collectively referred to as a document. Through document management, enterprises can organize, manage and control the establishment, modification, release and archiving of documents. Enterprise personnel can also find and reference all kinds of data and information needed more conveniently, quickly and effectively.

The electronic warehouse and document management of Qingsoft Yingtai PDM provide the functions of storage, retrieval and management of distributed heterogeneous data. In PDM, data access is completely transparent to users, users do not need to care about the specific location of electronic data storage, and whether they get the latest version, all these tasks are done by the PDM system. The security mechanism of electronic warehouse enables administrators to define different roles and give them different rights and scope of data access, and by assigning corresponding roles to users, the data can only be obtained or modified by authorized users. At the same time, the release and change of electronic data in PDM must go through a pre-defined approval process before it can take effect, so that users always get the correct information that has been approved.

2. User management

It is to manage all users who use PDM system, including user registration, user rights control, user role determination, user secret level determination and so on. User management is generally realized by establishing an organization-role-authority model.

3. Workflow and process management

Workflow and process Management WPM (Workflow and Process Management) is an active process management about how product data is established and modified. It controls the formation of any workflow or the task after the start of the process. It is used to define and control the way people create and modify data. It provides routing, action of driving events, lookup, inspection, access control, recovery and object editing. This function provides necessary support for the automatic management of the product development process.

Users can establish serial or parallel workflows, and technicians can coordinate their work in parallel. When users open their own task box, they can see the latest task list, and the project leader can view the implementation of the entire project at any time. The processing of WPM focuses on tasks related to product data. Usually WPM has the following three main functions: initial work management, when designers are ready to carry out a design work, in addition to the necessary design requirements and initial design ideas, some documents, tables and other data related to the design work, such as: purchased parts manual, standard parts manual, various component manuals, etc., are provided to designers, and the design data of other designers can also be queried in time. To meet the design needs of designers to the maximum extent.

These data can be generated and transmitted in WPM; workflow management is the management of the process of transfer and flow of product data and its references. A serial or parallel workflow can be established here, and the examination, approval, signing process and product change approval process in the product development process can be carried out in an orderly manner through the electronic program. When users open their task box, they can see the latest task list, and the personnel of review, approval, signature and other personnel can sign according to the pre-established process and attach signature opinions in the remarks column. The project leader can check the implementation of the entire project at any time. It makes thousands of PDM system users' individual processing results and flow of product data more organized, knowing what to do next; work history management, work history management provides a kind of review record data to help users understand the history of product project development process. On the basis of the existing product development workflow, the work history can be used as an important basis to formulate the workflow and process of the new product project.

4. Product structure and configuration management

The definition of product structure is that a group of interrelated parts are assembled according to a specific assembly relationship to form a component, and a series of parts and components are organically assembled together to form a product. The product is decomposed according to the assembly, and the assembly is further decomposed into subassemblies and parts, until the parts, and the resulting hierarchical tree structure is called product structure tree. Product structure and configuration management is a form of product data organization and management. It uses electronic warehouse as the underlying support and material list as its organizational core. It connects all engineering data and documents that define the final product, realizes the organization, management and control of product data, and provides different views and descriptions of product structure to users or application systems under certain objectives and rules. Such as design view, assembly view, manufacturing view, plan view and so on.

5. Project management

A highly functional project management can provide managers with "per minute" status information of projects and activities, and access to resources, planning and important path reporting capabilities through the interface with popular project management software, including PDM. However, at present, there are few considerations about project management in PDM systems, and many PDM systems can only provide information about workflow activities.

6. Application tool integration

Qingsoft Yingtai PDM manages all the data related to the product, while the managed data is generated by different systems, different types of data and different data models. How to ensure the consistency and integrity of these data is a very important problem. The system must be integrated into PDM, and the data must be uniformly controlled and managed by the PDM management framework.

7. Other management functions

In addition to the above six basic functions, the PDM system also provides scanning and imaging, browsing and scrolling functions to varying degrees. These functions can further improve the role of PDM.

2.3 benefits of adopting PDM in small and medium-sized enterprises

According to foreign statistics, the application of PDM can shorten the product design cycle by 25%, reduce engineering design modification by 14%, speed up the product launch schedule by 50% to 80%, and reduce the total cost by more than 25%. For domestic enterprises, the implementation of PDM is no longer a question of whether it is necessary, but a question of when. Because PDM brings the following benefits to enterprises:

1. Improve the design efficiency and shorten the time to market.

Get the data immediately when it is needed, speed up the completion of tasks, support concurrent engineering, allow authorized team members to access all relevant data at any time, and ensure that the data is always up-to-date. Generally speaking, designers spend about 30% to 70% of their time on processing information, such as finding information, retrieving information, waiting for copies of drawings, archiving new data, and so on. PDM almost completely avoids this kind of no-load time, PDM provides engineers with correct and appropriate tools, so that designers no longer need to know where to find published design or other data, as long as they can get these designs or data upon request, which greatly shortens the design process and improves design efficiency and production efficiency.

2. Improve the accuracy of design and manufacturing and reduce engineering changes.

According to a survey in the United States, if the cost of a change in the product conceptual design stage is $1, it will rise to $10 in the design, simulation and analysis stage, $1000 in the prototype testing phase and $10000 in the manufacturing phase. Obviously, it is very important to choose the right technology and improve the accuracy in the initial design stage to reduce the cost. After using the PDM system, everyone who participates in the same project can work with the same data and keep up-to-date data all the time, even when people are working in parallel, resulting in fewer engineering changes.

3. Make better use of creative team spirit

After adopting the PDM system, we can establish a cross-regional, cross-departmental and cross-disciplinary "virtual team", break the restrictions of space and departments, enable enterprises to make better use of human resources, allow people to exchange ideas with each other, and use effective and smooth information transmission tools to convey these ideas, which can promote the solution of problems through cooperation.

4. Better manage engineering changes

The PDM system allows multiple revisions and modifications of any design to be generated and saved in the database, and each version and revision should be "signed" and "dated", eliminating any differences over the existing design and providing complete change review clues.

5. An important step towards total quality management

Qingsoft Yingtai PDM system can be established to adapt to the IS09000 series verification and total quality management (TQM) environment. Many of the basic principles of TQM, such as identifying and solving problems through "personal authorization", are formal control, inspection, change management processes and responsibilities inherent in the PDM structure, and will also help to ensure that the PDM system chosen by users is consistent with international quality standards. PDM technology is an indispensable and important infrastructure technology for the reconstruction and development of enterprises. The implementation of all advanced management plans of enterprises is inseparable from PDM. PDM is a major enabling technology to promote the restructuring or reform of enterprises, and it is a necessary means for enterprises to improve their competitiveness. At present, many enterprises regard PDM as the skeleton that runs through the whole enterprise, which is the strategic decision for enterprises to maintain competitiveness.

3 theoretical research of PDM system based on Web technology

3.1Why Web PDM

Based on Web technology, Internet represents a trend of IT, which provides a mechanism for global electronic information sharing. It can be considered that PDM on Internet is a natural extension of this distributed equipment. Web browser has essentially become a new client type, which is a unity across all programs. Internet and Web technology are transforming the PDM software business. A few years ago, Internet performance only created a dent in the way engineering companies managed information. Today, HTML/Java-based Web users and Web-based server access are increasingly becoming synonymous with PDM systems.

Web technology has the following characteristics:

1) TCP/IP communication protocol has been widely used in wide area network and local area network, and has become an industrial standard. It provides smooth technical support for heterogeneous network interconnection.

2) as the general client software of all kinds of systems, the browser provides users with a unified graphical interface and reduces the difficulties encountered by users in learning new software.

3) any browser supports the HTTP protocol and HTML language used by WWW.

4) the Servlet on the Web browser can be connected to the back-end database to realize dynamic online message publishing.

5) Web is a client / server mode based on HTTP protocol, which has the characteristics of high speed, good maintainability, low cost and flexible function.

Through the use of Web technology, we can uniformly organize and manage the information of different formats among different departments within the enterprise, and then solve the problem of information sharing among enterprises and among departments in the enterprise. Through Web in the PDM system for global information query, browsing, to support the globalization, virtual enterprise information management.

3.2 connection structure of PDM system based on Web

Like other database management systems, PDM follows the connection structure. Before 1980, one-layer connection structure was widely used. The typical feature of one-layer connection structure is its self-contained monolithic program, which is composed of GUI, process logic and saved data. Then, in 1990, the two-tier structure method appeared. This structure divides the program into two different layers, named the client layer and the server layer.

The user interface and logical processes reside in the client layer, while the corresponding database resides in the server tier. The main advantage of a two-tier system on top of an one-tier system is that it makes the client "thinner". Therefore, the two-tier structure allows for faster processes than single-tier systems. The disadvantage, however, is that the client may still be "too fat" when the program becomes complex. This will result in slow responses and processes from the server.

In 1996, a revolutionary change took place in the computer network-the three-tier or multi-tier structure. This is an open, distributed structure that divides the "fat" client into two parts-the user interface and the logical process. The result is a three-tier structure of processes that allow faster response and user requirements. The system block diagram of this three-tier system is shown in figure 2-2. The World wide Web (WWW) is a typical example of applying a three-tier structure: the Web browser is the client tier, the database server is the third tier, and the TCP/IP service is the second tier.

Figure 2-2 three-tier structure system

3.3 advantages of PDM system based on Web technology

When the PDM system turns to the three-tier structure, we can see that there are many similarities between the Web technology and the PDM method in the structure and conceptual module. Figure 2-3 and Table 2-1 show the comparison of Web technology and PDM approach in structural and conceptual modules.

Figure 2-comparison between 3PDM method and Web three-tier structure

Table 2-Module comparison between 1Web technology and PDM technology

Web was originally developed to provide people with a new way of work and life, so that people can better communicate and communicate with each other, so that the processing of work and affairs can be better and more convenient. The basic starting point of PDM is to break the time and space boundary between departments, strengthen the cooperation among various departments, and manage the enterprise better and more effectively. The goal of Web technology is exactly consistent with the basic starting point of PDM. Therefore, Web technology is an enabling tool that can be used to overcome the previously mentioned obstacles and improve the ability and efficiency of PDM.

In PDM system, Web-based technology has many advantages, some of which are summarized as follows:

1. User-friendly: Web-based front-end software development makes them user-friendly and easier to interact with. In this way, the Web-based PDM system requires the least training compared with other systems, so the cost of implementing all systems is reduced. Simple and cheap Web browsers continuously expand the users of PDM in the enterprise, they can not find other equally convenient online access to such a vast information base software. By making users fast and active, browsers provide a "jump start" to achieve success in using PDM in organizations that would otherwise lose enthusiasm in this area. The browsers used by PDM are the same as those used in www (such as Microsoft Explorer, Netscape Navigator, etc.). They are designed to access data on Internet or Intranet.

2. Strong access and application capabilities: the rapid growth in the number of companies has made people realize that using web browsers as a PDM interface is incredibly valuable, easy to understand and able to support almost all users. These browsers run on all types of computers, from Unix machines to PC and Macintoshes, providing the same interface and feel across platforms. Further, the use of these Web browsers eliminates the need to install and maintain special "client" software on each computer.

3. Effectively connect the supply chain: Web-based PDM systems have many advantages over non-Web-based systems, so their connection with the supply chain is more effective, and accordingly lead to the improvement of supply chain coordination. This makes it easier for organizations to share important information with their suppliers and partners. The information available in Web-based PDM will help companies-- enable them to interact by effectively communicating any new product data and product change data to suppliers.

4. Effectively connect geometrically separated organizations: an Web-based PDM system allows geometrically separated teams to change data entered by people in different regions or even different countries on the same project. This type of collaboration will allow an organization to pool the expertise of its employees; no matter where they are in the world, with minimal cost and disruption of those interventions. The capabilities of project teams in different locations around the world also allow an organization to take advantage of time and geographical differences to take advantage of 24 hours of the day.

5. Make virtual organizations possible: a virtual organization is defined as an alliance of temporary companies that have expertise in a particular area and focus on a particular project. At the end of the project, the alliance disintegrates and the company returns to their day-to-day tasks until a new project is created. Compared with traditional types of companies with strict hierarchical structure, virtual organization has many advantages. It mainly provides greater flexibility and shares the expertise of the project team. The most important requirement for a successful virtual organization is effective communication between separate project teams. Through the use of Web-based PDM system, the efficiency of global communication can be greatly improved. Therefore, based on Web technology, partners and workers located in a wide area can be connected seamlessly.

3.4 conditional limitations of Web-based PDM system

First, the PDM system based on Web is limited by the current Web technology and the rate of information transmission. Although geometrically separated sites transmit information faster than traditional postal services or couriers, they are not as fast as local area network (LAN) or wide area network (WAN).

Second, through the PDM system based on Web, errors are not completely eliminated in the process of transmitting data or information. If the system is not used correctly, errors corresponding to the need for correct information may still occur. As mentioned earlier, a PDM system can lead to a reduction in time to market, and the possibility of human error increases as the pace of product development and product change accelerates.

Third, because of the increase in the flow of information between the enterprise and its supply chain, more consideration will be given to information security. For a project, identifying the level of information transmission without endangering the security of the enterprise and exposing trade secrets is a key step to implement Web technology in PDM system. This will depend on the closeness of the supply relationship and the level of effective communication required.

It is clear that Web technology is similar to the PDM method in many ways. If you run on a Web structure, PDM will become more adaptable and flexible. Both PDM and Web, if properly integrated, will enhance their capabilities and performance. Some disadvantages of Web-based PDM systems include: the current Internet does not have enough bandwidth for CAD file transfer, the possibility of errors in data transfer, and the ever-increasing security of information flow between a company and its supply chain. These shortcomings will inevitably pose a severe challenge to the Web-based PDM system in the future.

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