1 Introduction
PDM (Product Data Management, PDM for short) is a technology that manages all product-related information (including electronic documents, digital files, database records, etc.) and all product-related processes (including approval/issuance processes, engineering change processes, etc.). It is a comprehensive engineering data management technology that integrates data management capabilities, network communication capabilities and process control capabilities of the database.
With the increasingly strong trend of international industrial restructuring and transfer, industrial developed countries are shifting a large number of traditional industries to developing countries. The focus of their transfer is manufacturing, and the development of China's manufacturing industry is facing a rare opportunity. To this end, the Ministry of Science and Technology has integrated the scientific and technological resources related to the 863 Program and the tackling plan on the basis of the original information-based engineering project, and organized the implementation of key technologies research and application demonstration projects for manufacturing informatization, with a view to substantially improving China's manufacturing industry. The technological innovation capability and international competitiveness, the optimization and upgrading of the industrial structure of the manufacturing industry, the industrialization with information technology, the transformation of traditional industries with high technology, and the leap-forward development of China's manufacturing industry.
Over the past 20 years of reform and opening up, China has become a big country using all kinds of molds. Through unremitting efforts, Shenzhen's mold manufacturing industry has developed from a low-level manufacturing industry with a focus on workshops to become a pillar industry in Shenzhen, and has become a leader in the national mold manufacturing industry. The state has vigorously promoted the manufacturing information technology, which has brought new opportunities to further enhance the technical level of Shenzhen mold enterprises and maintain the leading position of Shenzhen molds in the country. In this paper, the author discusses the characteristics of the mold manufacturing production mode and the demand for information technology in the research process of Shenzhen Mould Enterprise (only for plastic mold enterprises, the same below), and discusses the application of PDM technology for mold manufacturing.
2 main application functions of the PDM system
The main application functions of the PDM system include: document control, product structure and configuration management, workflow and process management, project management, information classification and retrieval, application system integration, change control, etc., which provide product design, manufacturing and technical support services. A large amount of data tracking and storage functions are required to control the processing and use of product information, and to manage the product development process, as shown in Figure 1.
PDM can not only effectively define, organize and manage conceptual design, engineering analysis, detailed design, process design, manufacturing, sales, maintenance, and product-related data throughout the life cycle of product retirement, so that product data is throughout life. Consistent, up-to-date, shared and secure during the cycle. It also provides a unified integrated operation platform for CAx/DFx applications. It is a bridge between CAD/CAPP/CAM system, MIS system, MRPII/ERP, workshop management and control system. link. Through the effective implementation and management of the PDM system, the correct product data can be provided to the designer in time, avoiding cumbersome data search and improving design efficiency; ensuring that the detailed data of the product design can be accessed in an orderly manner and improving the reuse rate of the design data. Reduce duplication of effort; effectively control engineering changes, decision makers can easily conduct design reviews; control product design processes, provide a collaborative design environment for parallel design; system integration for the entire product development process (including suppliers, MRPII, sales) , support and maintenance services, etc.).
3 Characteristics and trends of the mold manufacturing production model
3.1 Characteristics of the production mode of the mold manufacturing industry
Molds are special tooling for the production of specific product parts. For example, plastic molds are used to process plastic materials into large, uniform shapes. In modern industrial production, 60%-90% of industrial products require the use of mold processing technology, and the mold industry has become the basis of industrial development. Today, as new products emerge in an endless stream, many products are developed and produced in dependence on mold production. According to the prediction of the International Production Technology Association, 75% of the rough processing of machinery manufacturing industry parts in the 21st century and 50% of the finishing process need to be completed by molds, among which the automobile, electrical appliance, communication, petrochemical, construction and other industries are the most prominent. How to submit the mold to the user at the lowest cost and the shortest cycle under the premise of ensuring the quality of the mold is the main goal pursued by the current mold industry. The characteristics and trends of the mold manufacturing production model are summarized as follows:
(1) Production of individual orders for a single item. Mold orders are arrived at random, and the order quantity changes seasonally.
(2) Almost every order has its own particularity. From the order decision of the product to the whole process of manufacturing, each set of molds has certain independence. The enterprise needs to prepare corresponding production schedule for each order. Moreover, in the different stages of mold development, the production schedule should be formulated and revised from coarse to fine.
(3) Each mold must be creatively designed. Due to the particularity of the appearance, structure and molding process of different products, it is necessary to individually design each pair of molds. Therefore, the mold design is often divided into four stages: part process analysis and design, mold overall plan design, overall structure design, and construction drawing design. In the development of the mold, the design takes a long time, about 1/3 of the entire development cycle.
(4) Mold quality management is a multi-level quality management system involving users. When the mold quotation and the contract order are signed, the enterprise needs to negotiate with the user to determine the product map and related technical requirements; in the stage of mold structure design, detailed design, process design, etc., the enterprise needs to coordinate with the user; In the process of acceptance of the final product, the company also needs the cooperation of users.
(5) Despite the use of advanced high-efficiency, high-precision machine tools and automated production techniques in modern mold production, the standard and general-purpose parts and components are fully adopted, but the mold cavity and core surface finishing processing (eg polishing, Grinding, etc.), mold fitter and assembly still rely on the manual labor of the skilled workers, the workload will account for 25%-45% of the total workload of the mold (in terms of working hours). Therefore, the standardization of manufacturing processes has become the technical basis for controlling the rational production of molds.
3.2 Development trend of manufacturing production mode in Moxian County
As a high value-added technology-intensive product, mold technology has become an important indicator for measuring the manufacturing level of a country. With the development of modern advanced manufacturing technology, the mold manufacturing model has also shown the following development trends:
(1) As the CAD/CAM technology of the mold has developed into a relatively common common technology, the hardware and software prices of the CAD/CAM technology of the mold have been reduced to the extent generally accepted by SMEs, especially the popularization and application of microcomputers. More mold companies have created good conditions for the popularization of mold CAD/CAM technology. Therefore, it is inevitable that mold companies use CAD/CAM technology to design and manufacture molds.
(2) The selection of high-quality steel and corresponding surface treatment technology to improve the life of the mold has been increasingly valued by enterprises.
(3) Manufacturers demand to reduce costs and speed up product launch by reducing physical prototypes and improving product quality. This demand is particularly prominent in the mold manufacturing industry. Therefore, integrating digital analysis technology in mold CAD/CAM technology and obtaining a complete CAD/CAB/CAM solution is an important development direction at present.
(4) The popularization and level of CAD/CAM technology, as well as the development of database technology and computer network technology, have created conditions for the mold enterprises to achieve parallel design and manufacturing, and become an advantage for enterprises to effectively shorten the mold development cycle and reduce the risk of mold development. arms.
4 The overall goal of applying PDM technology in mold manufacturing
The overall goal of applying PDM technology in the mold manufacturing industry should include
(1) The integrity and standardized management of product information.
The product information managed by the PDM system will involve various parts such as mold design, process, manufacturing, operation and service. The implementation of the PDM system should fully consider the requirements of the above departments and provide the necessary information sharing environment. At the same time, through the implementation of product configuration management, the consistency, uniqueness, integrity and scientificity of the internal product information of the enterprise are realized.
(2) Scientific and flexible management of work processes.
Due to the particularity of the order received by the mold company and the individualized requirements of mold design and manufacturing, the workflow of the mold product in the whole life cycle presents multi-loop characteristics. Therefore, the implementation of the PDM system should be both efficient and easy to change, in order to achieve process optimization and reengineering.
(3) Effective project management.
The production management of the mold enterprise is a typical project management according to a single implementation. Each pair of molds reflects its independence from order taking, design to production and testing. It requires special project leaders to manage personnel and needs to be formulated. Specialized design, design-specific processes, organization-specific production processes. Therefore, in the implementation of PDM system, whether to achieve effective project management is the key to determining the success of PDM system.
(4) Full integration of CAD/CAM/CAE.
As mold companies apply CAD/CAM/CAE technology for mold design and manufacturing, it is inevitable that the PDM system should be a platform for fully integrating CAD/CAM/CAE technology to ensure that anyone in the company's related projects is at any location. At any time, you can get the correct and unique product information you need, and avoid the confusion of product information caused by the error of the intermediate information processing.
(5) Requirements for concurrent engineering.
The multi-loop workflow characteristics in the mold manufacturing process make the application of parallel engineering a powerful tool to effectively improve product development efficiency and enhance the competitiveness of enterprises. The implementation of concurrent engineering requires PDM systems to support heterogeneous computer environments, provide a single source of product data, implement process management and monitoring, and support virtual product development.
(6) Adaptation of the collaborative environment.
When implementing PDM management, mold companies should also fully consider the application system to adapt to the external collaborative environment. Especially when large enterprises adopt distributed databases, they should ensure data communication in heterogeneous environments and real-time requirements for data transmission. At the same time, the computer network of the PDM system should be scalable and open.
5 Data Model for PDM System in Mold Manufacturing Industry
5.1 Personnel data model
The personnel data model includes three parts: personnel organization, role setting, and role permission setting.
According to the different modes of mold development of mold enterprises, their personnel organization is different, and they are summarized in the following three types:
(1) Traditional enterprise type: that is, personnel are allocated according to the profession. The work of each department is single in nature, the staff is relatively fixed, and the work flow is mainly serial, as shown in Figure 2.
(2) Dynamic type: that is, product development organizes personnel according to the project, and each group includes all the design, process, production, management, and after-sales service personnel required to complete a specific mold development. As the project transitions, the people change relatively. The workflow is mainly serial in the group, and the business is parallel, and the non-production departments such as sales, administration, and finance are relatively fixed. In the production arrangement, it can be divided into the manufacture of the whole product according to a single product; and the centralized processing, which is assembled by product grouping, as shown in Figure 3.
(3) Outsourcing assembly type: After the design of the mold is completed, the oEM supplier organizes the production of parts, and the mold company purchases standard parts and mold parts and assembles them for sale. This type of mold enterprise personnel cost and equipment investment is relatively small, production organization is flexible, but the production cost is relatively high, the main personnel of mold development are designers and assembly technicians, as shown in Figure 4.
Although the organization of different companies is different, their role settings and permission settings are roughly the same. Therefore, when the organizational structure of the enterprise is determined, the personnel data model can be determined. The personnel data model can be described in the table, and the personnel data table established according to Figure 2 is shown in Table 1.
5.2 Product Structure Model
PDM systems typically use a product structure tree to describe the product structure. The product structure tree is generated from the product assembly drawing and the product parts list. The product structure tree describes the product part information, assembly hierarchy relationships, and assembly relationships. The general injection mold product structure tree is shown in Figure 5.
In Figure 5, the first layer is the root node, which represents the product; the second layer is the leaf node, which represents the various components that make up the mold; the third layer is also the leaf node (the following layers are all leaf nodes), representing the components that constitute each component. Part or component.
The above tree can be further subdivided according to the needs of management, up to the blank or raw material of each part.
5.3 Workflow Management Model
Workflow management usually needs to define the following aspects:
(1) The name and scope of the workflow.
(2) The number, sequence and logic of the workflow phases.
(3) Corresponding to the personnel role and voting mode of each stage.
(4) Special tasks that need to be completed at the beginning and end of each phase.
(5) Product data version change rules throughout the workflow.
The workflow management model describes the above in tabular form based on the actual workflow.
6 Key technologies for applying PDM systems in mold manufacturing
6.1 Product Configuration Management
Due to the characteristics of the single-piece production of the mold enterprise, it is particularly important to implement the configuration management of the product.
Product configuration refers to the grouping of products according to the quantity, nature and relationship of all parts inside a product. The objectives of its management are:
(1) Establish an overall model of the product and visually describe all the data of the product and their relationship.
(2) Establish product configuration rules to provide uniform, accurate product information to the design, production, and management departments.
(3) Establish a consistent list of product materials to avoid rework and waste.
(4) Establish a history of product changes - version management to ensure that the correct product version is available to anyone at any time.
According to the product structure tree and configuration rules of the mold, the product configuration sub-model under different configuration conditions can be obtained. The product configuration submodel obtained according to Fig. 5 is shown in Fig. 6.
6.2PDM system integration with CAD/CAM/CAE
6.2.1 Several modes of integration with CAD/CAM
(1) Encapsulation mode: The encapsulation mode integrates all CAD/CAM applications to enable sharing of information between different applications, while the PDM system can separate feature data and data files in different databases for different applications. Conduct effective management. When the PDM system encapsulates the CAD/CAM/CAE application, the corresponding CAD/CAM/CAE system can be directly activated in the graphics file of the PDM system, and the corresponding graphic file is displayed as a graphic in the system. Conversely, in the CAD/CAM/CAE system, the PDM system can also be directly accessed to perform corresponding data management operations, but the PDM system is not allowed to manage data within the file, such as features, parameters, and assembly data. Generally, the encapsulation mode is used for the integration of the PDM system with the 2D CAD software, and the degree of automation is low, but the implementation workload is small and easy to implement.
(2) Interface mode: The interface mode deciphers the internal relationship of the product by programming the interface program, so that the product structure tree in the PDM can be automatically generated according to the assembly tree in the CAD assembly file, and the latest product can be extracted from the PDM product structure tree. Product structure relationship, to modify the assembly files in CAD, so that the two remain asynchronous and consistent. Therefore, the standard data interface is used to establish the relationship between the product configuration of PDM and the assembly structure of various CAD softwares, so that multiple CAD softwares can share the same product structure, but the data must have a unified data structure. The interface mode is more automated, and the internal data of the file can be automatically exchanged between the PDM system and the CAD system. There are certain PDM functions in the CAD menu, and some CAD functions are also available in the PDM menu. In general, the interface mode is used for the integration of PDM systems with 3D CAD software. However, the development of the interface mode is heavy, the requirements for personnel are high, and the maintenance of the system requires manual processing.
(3) Integrated mode: In the integrated mode, the PDM system provides fully automatic two-way related exchange for all types of information, including product data, feature data and application-oriented data. The integrated model can be used to establish a structural relationship between unified product data. As long as one of the relationships changes, the other changes accordingly. All PDM functions can be used in the CAD environment, and the CAD product assembly relationship and PDM are always maintained. The product structure tree is synchronized. In general, the integrated model is used for tight integration of PDM and CAD, and only software vendors can provide this model. For the enterprise, it has the least amount of development work and is most convenient to use. However, it takes a long time for the implementation unit (software vendor) to invest a lot of effort in developing the user interface. The cost of development is also higher.
6.2.2 Integration of PDM System and CAE
Since the CAE software mainly produces analytical calculation results for specific parts, the integration can be implemented in a package mode. At the same time, the management of CAE data is implemented by defining management rules for CAE analysis calculation results in the PDM system. The result of the integration is that the CAE software can be activated at any time in the PDM system, and the CAE file type can be identified, and information can be exchanged with the PDM system in the CAE environment to complete operations such as depositing, deleting, deleting, changing, and checking.
6, 2.3 mold manufacturing integration mode selection
Combining the application environment and advantages and disadvantages of the above various integration modes, combined with the characteristics of the mold manufacturing production mode, the integration of PDM and CAD/CAM generally selects the interface mode. In fact, in the enterprises that have implemented PDM management, most of them adopt the interface mode. Some PDM software vendors have even prepared interfaces for PDM and more common 3D CAD software on the market in advance, such as the integration of SMARTEAM with UG and PRo/E.
6.3 Implementation of Concurrent Engineering
Parallel engineering refers to the work of the downstream environment while considering the work of the downstream environment. Through the unified management of product data, product design, process design, production preparation, test preparation, etc. are carried out in parallel to minimize the product. Development cycle to reduce development costs.
Parallel engineering must rely on PDM technology. PDM's data integration and management functions can provide a single product data source to ensure the correct and unique product data in parallel work; PDM management and monitoring of the process can ensure the effective implementation of concurrent engineering; PDM for virtual product development The support can timely realize the information exchange within and outside the enterprise, and effectively reduce the development risk. How to submit the mold to the user at the lowest cost and the shortest cycle under the premise of ensuring the quality of the mold is the main goal pursued by the current mold industry. Therefore, achieving parallel engineering in the mold manufacturing industry is undoubtedly a wise choice.
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