Shulou(Shulou.com)06/01 Report--

The content of this article mainly focuses on what is the basic principle of the integration of ERP and PDM. The content of the article is clear and clear. It is very suitable for beginners to learn and is worth reading. Interested friends can follow the editor to read together. I hope you can get something through this article!

1 Overview of Enterprise Resource Planning (ERP)

MRP is a new production management technology developed in the United States in the early 1960s. In this system, the bill of materials (BOM) is used to expand the final product requirements of the system into the manufacturing process requirements for parts and raw materials. Issue a manufacturing or purchasing plan on the premise of considering the existing storage and production lead time.

MRP does not cover all the production and operation activities of enterprises, so it has some limitations. In order to make the plan cover the production and operation activities of the whole enterprise, and at the same time make the plan more reasonable and practical, on the basis of MRP, it is expanded up to the enterprise's business plan (Business Planning), the main production plan: the job plan that extends down to the workshop level and the order control of the workshop, and balances the capacity of all levels of the plan to make the plan reasonable and feasible.

At the same time, if the actual execution of a certain level of plan deviates from the original plan, the plan and even the superior plan should be adjusted to form a closed-loop main production planning and control system, namely manufacturing resource planning (MRP Ⅱ) system.

In the fierce market competition, business activities must reasonably organize and effectively use their equipment, personnel, materials and other manufacturing resources, with the lowest cost, the shortest delivery time and the best quality to meet the needs of customers. Therefore, enterprises must adopt advanced and effective production management technology to organize.

Coordinate, plan and control the production and operation activities of the enterprise. MRP Ⅱ is a kind of scientific management thought and software system put forward under this background. Manufacturing Resource Planning (MRP) Ⅱ is an information system that effectively plans and controls all operations and production activities within a manufacturing enterprise. It is a closed-loop production planning and control system developed on the basis of material requirements planning MRP, and material requirements planning MRP is its core.

The concept of 1.1ERP

ERP is enterprise resource planning, which embodies an idea of integrated management of enterprises in the information age. It was first put forward by Gartner Group in the early 1990s to describe the next generation of Manufacturing Resources Planning,MRP Ⅱ software. ERP system defines the ERP system through a series of functional standards. ERP should have the following functions:

● functional Integration beyond the scope of MRP Ⅱ

Including logistics, capital, quality, process operations, formulations, product data, maintenance, laboratory and warehouse management within the enterprise.

● supports hybrid manufacturing environment

It includes the manufacturing environment which can support both discrete and process, the ability to combine business processes according to the object-oriented business model and the application in the international scope.

● supports proactive monitoring capabilities to improve business performance

Including the use of control and engineering methods throughout the enterprise, simulation of its functions, decision support and graphical capabilities for production and analysis.

● supports an open client / server computing environment

It includes client server architecture, GUI (graphical user interface), CADE (computer aided design engineering), object-oriented technology, SQL relational database query, internal integrated engineering system, commercial system, data acquisition and external integrated environment.

In essence, ERP still takes MRP Ⅱ as the core, but it far exceeds the traditional MRP Ⅱ system in function and technology. It is an enterprise resource planning based on customer-driven, time-based and oriented to the whole supply chain management. The core of ERP is to realize the effective management of the whole enterprise supply chain. It is an integration of functions involving many aspects with supply chain management as the core. Its characteristics are as follows:

● embodies the idea of managing the resources of the whole supply chain.

In the era of knowledge economy, it is impossible for enterprises to participate in market competition effectively by relying on their own resources, and all parties involved in the business process, such as suppliers, manufacturing plants, distribution networks and customers, must be brought into a close supply chain in order to effectively arrange the production, supply and marketing activities of enterprises and meet the needs of enterprises to make use of all market resources of the whole society to carry out production and operation quickly and efficiently. In order to further improve production efficiency and gain competitive advantage in the market.

In other words, the competition of modern enterprises does not only refer to the competition between a single enterprise and a single enterprise that produces the same product in the same industry, but also the competition between one enterprise supply chain and another enterprise supply chain. The ERP system realizes the management of the whole enterprise supply chain and meets the needs of market competition in the era of knowledge economy.

● embodies the ideas of lean production, concurrent engineering and agile manufacturing. ERP system supports the management of hybrid production mode, and its management ideas are shown in two aspects:

One is "lean production (Lean Produttion)", which is a kind of enterprise management strategy system first put forward by the Japanese. That is, when enterprises organize production according to the mode of mass production, customers, sales agents, suppliers and cooperative units are all brought into the production system, and the relationship between enterprises and their sales agents, customers and suppliers is no longer just a simple business relationship, but a partnership of shared interests, which constitutes the supply chain of an enterprise, which is the core idea of lean production.

The second is "Agile Manufacturing (Agile Manufacturing)". When the market changes and the enterprise encounters a specific market and product demand, the basic partners of the enterprise may not necessarily meet the requirements of the development and production of new products. At this time, the enterprise can organize a short-term or one-off supply chain composed of specific suppliers and sales channels to form a "virtual factory (Virtual Enterprise)".

Regarding the supply and cooperation unit as an integral part of the enterprise, using the method of "concurrent engineering (Concurrent Engineer)", organizing production, putting the new product into the market in the shortest time, and always maintaining the high quality, diversity and flexibility of the product is the core idea of "agile manufacturing".

● embodies the idea of planning in advance and controlling things in advance.

The planning system in ERP system mainly includes: master production plan, material requirement plan, capacity plan, purchasing plan, sales execution plan, profit plan, financial budget and human resource planning, etc., and these planning functions and value control functions have been fully integrated into the whole supply chain system.

On the other hand, ERP system defines accounting subjects and accounting methods related to Transaction processing, so as to automatically generate accounting entries when transaction processing occurs, and ensures the consistency of synchronous records and data of capital flow and logistics.

Thus, according to the current situation of financial funds, we can trace the context of the funds, and further trace the relevant business activities, change the situation that the capital information lags behind the material information, and facilitate the realization of mid-event control and timely decision-making.

● ERP system is closely related to enterprise business process reengineering (Business Process Reengineering,BPR). The development of information technology accelerates the transmission speed and real-time performance of information, expands the scope of business coverage and the exchange of information, and provides extremely favorable conditions for enterprises to make corresponding decisions in real-time information processing.

In order to enable the business process of the enterprise to foresee and respond to the changes of the environment, the business process of the enterprise must keep the information agile and smooth. Therefore, in order to improve the competitive advantage of supply chain management, it will inevitably bring about changes in business process, information process and organizational structure. This change is not limited to the interior of the enterprise, but includes the supply and demand partners on the supply chain, and systematically considers the business process of the whole supply chain.

The technologies and operations used by ERP system applications must be able to adapt to the changes in enterprise business processes. Only in this way can the "Reactive" of the original MRP Ⅱ system to environmental change be raised to the "Proactiv" of ERP to internal and external environmental changes through system and network information. The concept and application of ERP have expanded from the internal enterprise to the enterprise and demand market and supply market, as well as the reorganization of the business process and organization of the whole supply chain.

The structure and function of 1.2ERP system

The enterprise resource planning system (ERP) consists of sales, production, procurement, inventory, finance, human resources, quality and customer relationship management modules and after-sales service modules. Its structure and interrelationship are shown in figure 2.1.

Figure the architecture and functions of the 2.1ERP system

In terms of function, MRP as a production planning and control module is an indispensable core function of ERP, and MRP Ⅱ is an important part of ERP. In addition to the manufacturing, sales and cost accounting functions of MRP Ⅱ system, ERP realizes the information integration of supply chain management with the help of network communication technology, expands the coverage of business and the exchange of information, accelerates the circulation speed and real-time of information, promotes the reform of business process, information process and organizational structure, and improves the rapid response ability of enterprises to the market. It also enhances the adaptability of enterprises to the changes of internal and external environment, and creates conditions for real-time information processing and decision-making.

ERP realizes the integrated management of all the resources of the enterprise, that is, it is a management information system that manages the logistics, capital flow and information flow of the enterprise. Its main contents include the following aspects:

● master production plan

Master production planning is an important planning level of ERP. It is a description of "what will be produced". It acts as a connecting link between the preceding and the following, and plays a role in the transition from macro planning to micro planning. It mainly includes the following contents: ① compiles the production plan outline; ② market forecast; ③ compiles the main production plan: ④ approves and issues the master production plan; ⑤ implements the master production plan.

● material requirements Planning

Material requirement planning is used to solve the problem of "what must be manufactured and purchased". The main contents are as follows: ① generates BOM; ② to prepare material requirement plan; ③ executes material requirement plan.

● capacity requirements Plan

Capacity requirements planning is to convert material requirements into capacity requirements, and to convert the load hours required by production orders issued by material requirements and major production orders that have been issued but not yet completed into the capacity requirements of each work center and time zone according to the factory calendar. The main contents are: the preparation of ① crude capacity requirements plan; the preparation of ② capacity requirements plan; ③ capacity control.

● inventory management

The main function of inventory management is to establish buffers between processes. These include:

① integrated inventory management, mainly formulating overall inventory management policies, plans, business objectives, and is responsible for the implementation of forecasting bulk inventory, safety inventory and transportation inventory.

② project and inventory management, mainly for the management of assembly parts, sub-assembly parts, parts and purchasing materials. Project decisions include classification, self-made and purchasing decisions, as well as inventory replenishment order decisions and order batch calculation methods:

③ material and inventory management, used to manage the storage and handling, movement and recording of materials, through periodic stocktaking to maintain the accuracy of inventory records.

● financial management

The core of financial management is accounting, and its main functions include establishing subjects, dealing with accounting processes and accounting for financial affairs.

● cost management

Cost is the expense incurred by an enterprise in its production and operation activities, and its main functions are cost budget, cost planning, cost accounting and cost assessment, etc.

● project management

Project management is a systematic management method that makes full use of limited resources through effective planning, organization, leadership and control in order to achieve a specific goal in a specific time range. Its main functions include project control, project network planning, project budget, project history and so on.

● quality management

The main functions of quality management include the management of measurement, quality system and quality control.

2 Overview of Product Database Management (PDM)

PDM first appeared in the late 1980s to solve the problem of computer management of a large number of engineering drawings, technical documents and CAD files, and then gradually developed to three areas of product development: the management of design drawings and electronic documents, the management of bill of materials (BOM) and the integration of engineering documents, and the tracking and management of engineering change requests / instructions.

Now the PDM technology comes from the name of the United States, it is a summary and expansion of engineering data management (Engineering Data Management), document management (Document Management), product information management (Product Information Management), technical data management (Technical Data Management), technical information management (Technical Informati On Management), image management (Image Management) and other product information management technologies.

The concept of 2.1PDM

PDM is the abbreviation of Product Data Management (Product data Management), which refers to the general name of a certain kind of software. EdMiller, president of the international consulting firm CIMdata, defines: "PDM is a technology used to manage all product-related information (including part information, configuration, documents, CAD files, structure, permission information, etc.) and all product-related processes (including process definition and management)."

In 1995, D.Burdik of GartHer Group defined PDM as "PDM is a key enabling technology for enterprise design and production to build a concurrent product art environment. A mature PDM system enables all people involved in creating, communicating and maintaining design intentions to freely share and transfer all heterogeneous data related to products throughout the life cycle."

PDM is a technology that takes the product as the core to realize the integrated management of product-related data, process and resources. To be more detailed, we can understand PDM like this: from a product point of view, PDM system can help organize product design, improve product structure modification, track design concepts in progress, and find out archived data and related product information in a timely and convenient manner.

From a process point of view, the PDM system can coordinate and organize process events such as design review, approval, change, workflow optimization and product release throughout the product life cycle. Its purpose is to transmit the right information, in the right form, to the right person at the right time, and to complete the right task.

From what has been discussed above, it can be understood that from a technical point of view, PDM is a management technology, which manages all product-related information and processes. From the perspective of software system, PDM is a kind of management software, which provides basic functions such as data, file, document change management, version management, product structure management and workflow management to help engineers and others manage product information and development steps. From the perspective of tools, PDM is a software technology based on database and a software development platform between database and application software. it can integrate or encapsulate a variety of development environments and tools.

Therefore, PDM is an ideal platform for enterprise global information integration; it is an enabling technology to support enterprise process reengineering, concurrent engineering and CIMS engineering; at the same time, it is also an object-oriented electronic reference room, which can integrate all the information in the product life cycle. At present, PDM is a very popular and fast-growing technology. It has been highly valued by the business circles of the United States, Europe, Japan and other industrially developed countries. According to the estimate of American CIMdata company, the application of PDM will develop at an annual growth rate of 30% in the next five years. PDM has just started in our country, it has been widely concerned by the business community of our country, and reached a consensus.

The architecture of 2.2PDM

The architecture of PDM is shown in figure 2.2. Supported by the distributed data processing technology under the network environment, it adopts the Cpact S (client / server) architecture and object-oriented design method to realize the information management of the product life cycle, coordinate and control the work flow and project progress, and establish a parallel product development cooperation environment within the enterprise.

Figure the architecture of 2.2PDM

● interface layer

The user interface layer adopts a general graphical user interface to facilitate user operation.

● function layer

It is composed of four subsystems: product design, process management, manufacturing process management and product information integration management (configuration management, interface management, etc.). First of all, in the process of implementing PDM, the corresponding CAx system and ERP system must be encapsulated through application tools to achieve the integrated management of the system and form the basis of information integration. Secondly, the comprehensive and organic integration of product design to manufacturing must be realized on the basis of design, process and manufacturing process modeling. On the basis of process coordination, product information integration is realized.

● core layer

The core layer is the technical key to the implementation of PDM system, which provides models such as product project management, document management, structure management, workflow management, configuration management, version management, etc., and carries out intermediate transformation of product data, such as file conversion in STEP, data access based on SOL specification and inter-file, etc., to form a unified data acceptable to PDM system.

● system layer

This layer mainly provides functions such as database operation, utility operation of the operating system and data storage under the network.

The main functional composition of 2.3PDM

The PDM system integrates all the product-related information and processes for management. Its research object is the product, and its main functions are:

Management and control of ● documents (Document) and folders (Folder)

The functions of document management include: addition, deletion and modification of documents; version management and control of documents; management of the relationship between documents; query where documents are used; and workflow processing of documents. The management functions of folder are: establishment, deletion and change of folder, examination and approval of folder, distribution and so on. These functions are mainly used to collect, store and deliver various CAD drawing files, raster files, character files and corresponding working processes.

● product structure and configuration management

Mainly manage the structure and configuration of products, its functions include: generating product structure tree; generating specific product configuration: browsing product structure information and various related information; printing various BOM tables: BOM table changes and version control. Among them, each member of B0M (Bill Of Material, Bill of Materials) contains many kinds of attribute data, such as design attributes, processing procedures, related documents, release history, effectiveness control and so on.

Management of ● engineering changes

The process and management of engineering changes are quite complex, and a simple design change may involve the work of many other departments. Its main functions are: to establish a project change order: to find out which design and manufacturing departments are affected by a project change; to put forward the reasons for the project change: to determine the validity of the project change (time, batch number): to collect the data related to the project change, and to approve and issue: manage the version of the project change.

Design and Management of ● Workflow

Mainly define the design steps, as well as the rules that define the relevant steps in the process, and approve the provisions of each step. The assignment of technicians includes the development and management of preventive steps, administrative tracking and approval management, change processes and the release of messages.

Integration of ● and CAD

Every PDM system can be well integrated with its corresponding CAD system, such as PM and CATIA, Metaphase and I-DEAS, IMAN and UGII,PRO/PDM and PRO/Engineer and so on. In addition, each PDM system can be integrated with CAD system in IGES, VDSA, STEP and other standard formats.

The emergence of PDM brings a new platform and integration framework for the integration of various subsystems in the CIMS environment. The so-called integration framework refers to the software system that enables all kinds of applications in the enterprise to realize information integration, function integration and process integration in the heterogeneous and distributed computer environment.

PDM is such a system, which is based on software technology and with products as the core, and realizes the integrated management of product-related information, processes and resources. PDM integrates the information isolated island of computer in product design, analysis, manufacturing, process planning and quality management, uniformly manages the data in the whole life cycle of the product, and provides a platform and bridge for information transmission to realize the integration of enterprise global information.

PDM system covers all the information in the product life cycle, and provides a mechanism for enterprises to macroscopically manage and control all product-related information. Based on this technology, PDM system can realize product data sharing in distributed environment, provide an integrated application platform for heterogeneous computer environment, and thus better realize a new generation of computer integrated application system. Figure 2.3 shows the functional division of the PDM application system.

Figure 2.3PDM application system function division

Among them, the following functional modules are particularly important in the integrated application of ERP and PDM.

● Electronic reference Room and document Management (Data Vaultand Document Management)

Electronic reference room is the core of PDM, which is generally built on the basis of relational database, mainly ensures the security and integrity of data, and supports a variety of query and retrieval functions. It consists of data for managing data (metadata) and pointers to physical data and files that describe different aspects of the product. It can easily realize information sharing with product data as the core.

Object-oriented data organization can provide fast and effective access to information and achieve information transparency and process transparency. A fully distributed electronic reference room allows users to access enterprise product information quickly and seamlessly, regardless of the physical location of users and data.

● product configuration management (Product Configuration Management)

The product configuration management takes the electronic reference room as the bottom support and the bill of materials BOM (Bill Of Material) as its organizational core, connects all the engineering data and documents that define the final product, and maintains and manages the product objects and their relationships. Product configuration management can establish a perfect BOM table, realize its version control, retrieve and query the latest product data efficiently and flexibly, and realize the security and integrity control of product data.

Product configuration management enables all departments of an enterprise to share a unified product configuration throughout the product life cycle, and generate corresponding product structure views corresponding to product definitions in different stages. such as design view, assembly view, process view, purchasing view, production view and so on.

● Workflow and process Management (Workflow And Process Management)

Workflow and process management mainly realizes the tracking and control of product design and modification process. It includes the submission and modification of engineering data, control or monitoring approval, document distribution control, automatic notification control and so on. It mainly manages what happens when a user operates on data, the flow of data between people, and the activity of tracking all transactions and data during the life cycle of a project. This module provides a guarantee for the automatic management of the product development process, and supports the reorganization of the enterprise product development process in order to obtain the maximum economic benefits.

● Design Retrieval and part Library Management (Design Retrieval/Component Libraries) Design Retrieval and part Library is to classify and organize the existing part information according to the attributes of parts, so as to provide support for making maximum use of existing design achievements and creating new products.

Integration of 3ERP and PDM

In order to realize the integration of ERP and PDM, it is necessary to comprehensively analyze the differences between them in basic function, starting point, underlying technology, system structure and so on, so as to find the best solution.

The difference between 3.1ERP and PDM

ERP system and PDM system are two kinds of application software to help enterprises improve the efficiency of production and management. There are the following differences between them.

● function and Information

On the whole, ERP mainly manages the production, finance, sales and other fields of the enterprise, and its purpose is to fully deploy and balance the resources of all aspects of the enterprise (manpower, capital, information, materials, equipment, time, etc.), so as to provide powerful tools for enterprises to strengthen financial management, improve the level of capital operation, establish an efficient supply chain, reduce inventory, improve production efficiency, reduce costs and improve customer service. At the same time, it provides a scientific basis for senior managers to make business decisions, and finally establish the competitive advantage of the enterprise in an all-round way.

The function of PDM covers all the technical information and technical processes related to the product. The main task is to control the configuration of the product and use change control and product information to manage the development, modification and use of product definition data.

ERP focuses on the management of plans, materials and processes, while PDM focuses on product design and process data management.

● user side

ERP mainly serves enterprise financial personnel, supply and marketing organizations, production planners or management decision-makers. Its user interface will be optimized for all kinds of users mentioned above, combined with their special expertise and generate appropriate database information views to facilitate understanding and use of the system. In many cases, the main form of information in the ERP system is printed report files such as plan reports or purchase orders, and the main definition and management character data.

PDM mainly serves engineering designers and project managers for document operation, member authority control, quality assurance and professional services. It centrally manages various forms of digital product information, structure information, process information, CAD files, CAPP files, geometric models, images, unstructured documents and so on. Its basic information forms are online graphical documents, BOM and structural trees, etc.

The connection between 3.2ERP and PDM system

ERP is a technology for unified management of all resources and processes related to manufacturing in an enterprise. it focuses on the management of logistics in the manufacturing field. Its representative functions are: master production plan, material requirement plan, raw material purchase plan, workshop operation plan, tooling and equipment management, financial system management, inventory management and so on. Therefore, the ERP system is mainly used in planning, workshop, supply and marketing, financial inventory and so on. ERP system manages material data, and BOM table is the data basis of ERP system.

In the whole production process of the enterprise, PDM system focuses on the management of product composition information flow and the generation of product information data. At the same time, it supports the product formation process based on concurrent engineering according to the constraints of the managed product logic information and some process conditions. Its representative functions are: data storage and management, product information structure and product information configuration and management, project management, workflow management, product change information management, standard parts management and so on.

Therefore, PDM system is mainly oriented to product design, integrates CAD/CAPP/CAM system, and generates omni-directional product information flow according to graphics and documents. It manages the important elements of PDM system, such as product data, drawings, technical documents and product structure tree.

Although ERP system and PDM system have different functions, they manage the information controlled by production system, and overlap in many aspects, forming some cross functions, including bill of materials, part classification, component information, configuration management, business process, product structure and so on. They are different from each other, relate to each other, and focus on each other. As shown in figure 2.4, the organic combination of the two can effectively promote communication and communication among design, production, procurement and sales departments.

Both ERP and PDM systems manage product-related information, but the purpose and function of management are different. The data related to the product is generated in the process of product design and processing, that is, it is generated under the management of PDM, while in the ERP system, these information is only used as the basic data input system, according to which master production plan, material requirement plan, capacity plan, purchasing plan and so on.

In order to ensure the effective and rational operation of ERP and PDM systems in enterprises, it is necessary to ensure the consistency of data related to products in the two systems. The application of PDM in China is not as long as ERP, but in the construction of domestic enterprise informatization, more and more enterprises realize the importance of PDM and provide a broad development space for the market of PDM. A considerable number of these enterprises have implemented ERP system in advance. An unavoidable problem for this kind of enterprises in information construction is how to integrate PDM and ERP.

The information overlap between figure 2.4ERP and PDM

Information interaction between 3.3ERP and CAD/CAPP subsystem

A product can only be formed through three processes: engineering design, process manufacturing design and manufacturing. The integration of PDM system and ERP system also runs through these three processes. The information managed by the PDM system includes the product design information generated by the CAD system, such as part attributes, product structure relations, etc., as well as the process information generated from the CAPP system, including the working procedure, work number, man-hour, consumed materials and so on. These information are the basic data of the production management of the enterprise and the input data of the ERP system. The flow of this information between PDM and ERP systems is shown in figure 2.5.

Figure the flow of information between 2.5ERP and PDM

CAD is a tool to assist designers to build, modify and optimize product models with high speed and efficiency. Generally speaking, this information includes both graphic and document forms. In manufacturing enterprises, graphic information is mainly related to manufacturing departments, while document information is mainly related to planning, process management and process departments.

The ERP system accepts the document information output by the CAD system as the basis for its operation. The document information shown in figure 2.2 includes part family information, product structure, technical parameters, parts resources and so on. One of the most important is the product structure information.

CAPP is the use of computer-aided generation of reasonable, coordinated and optimal parts processing process. Process rules usually include processing routes, processing parameters, tooling and equipment, etc. In manufacturing enterprises, the main function of process planning is to guide the processing of parts, which belongs to the category of technical information.

From the point of view of integration, the function of process planning will be expanded, which is not only the basis for guiding parts processing, but also the basis for the capacity requirement planning of ERP system, which makes the process planning become information with both technical and management significance. The information connection between the ERP system and CAPP is that the ERP system directly obtains the part machining process plan and work information from the CAPP system. The specific process is as follows:

The relationship between ● process Planning and capacity requirement Planning

The process plan is the detailed processing instruction to transform the part from the blank state to the final product process. In a process plan, a processing step is called a process, and a process plan is a sequence of processes sorted according to a certain procedure. In the ERP system, the parts that need to be manufactured are outputted by the material requirements planning module, and the work orders of all parts are input to the capacity requirements planning module.

The capacity requirement planning module first formulates the detailed operation plan of the part processing according to the process rules of the parts, and then balances the capacity according to the processing capacity provided by each work center according to the load of each work center in the detailed operation plan. and according to the balance requires material requirements plan or master production plan to be adjusted.

When the capacity is balanced, the detailed job plan is output to the workshop job control module. The load balancing system calculates the standard processing time for the processes of all parts during the planning period and adds them according to the working time of the parts in the work center, so as to obtain the ability required for detailed job planning. The balance between this capacity and the capacity provided by each work center in the basic production information is the basis for adjusting the material requirements plan and the master production plan.

● work Center Information

The work center information is the basis for the capacity balance of the capacity requirements planning module. Usually, the collection of work center information is carried out by the process department, so it is necessary to know the details of the work center, such as machine tool power, maximum machining size, machining accuracy and so on. A perfect CAPP system has a work center database, and the required information can be obtained by using the interface ERP system.

The Bridge between 3.4ERP and PDM system

From the information interaction between ERP and CAD/CAPP subsystem above, we can see that PDM is actually the core module connecting CAD/CAPP and ERP. It manages the "ERP" and "CAD/CAPP" technologies related to the product, and plays an important intermediate process in the transformation from "CAD/CAPP" technology to "ERP" technology and from "ERP" to "CAD/CAPP" technology. In this way, two-way seamless data transmission is formed, which avoids the generation of a large number of coincident data. Through the above analysis, the author uses figure 2.6 to summarize the information exchange between ERP and PDM.

As can be seen from figure 2.6, although the ERP system and the PDM system have different functions and functions, they both manage the information controlled by the production system and overlap in many ways. The data of these coincident parts can be represented by a more subdivided figure 2.7. The data set managed by PDM is B and C (B set is enterprise management decision information, C is workshop bottom control data set), and the information intersection between ERP and PDM is An (BuC).

Picture the information exchange between 2.6ERP and PDM

Figure 2.7ERP and PDM data overlap

The core of the ERP system is the product structure. In the ERP system, the parts at the workshop level and the whole production assembly process must be defined. This information manages the production and assembly through the planning view, which defines the assembly process of the parts and parts in the workshop, so it is material-oriented and production process-oriented. In the PDM system, the product structure is also the core, but it is mainly oriented to product capability and configuration. The data information is mainly decided by the designer and reflects the design view of CAD/CAM system development.

The design view developed by the design engineer puts more emphasis on the function of the product and how to configure it. The product structure and the corresponding documents and design process work together to provide a complete product-oriented definition, which is the design state. Therefore, we can know that PDM and ERP are closely related in the following aspects:

The process action object in ● ERP system, that is, the component or product in physical form, is the material representation of the process action object (geometric or topological information describing the product state from the conceptual point of view) and the logical relationship between the process action object in PDM system. The product structure tree (BOM table) is the key to connect the two systems.

The production process sequence in the ● ERP system is the physical execution and verification of the information logic relationship generated by the PDM process sequence, the optimization basis of the production process in the ERP system, and the theoretical basis for determining the corresponding material support, which is the logical route for the development and perfection of the product information and information logic managed by the PDM system.

● ERP and PDM have a high degree of consistency in management objectives. Although there are differences in management objects and processes between ERP and PDM, their management objectives are to reduce errors and rework through scientific scheduling and control, so as to ensure the early completion of products in the shortest possible time, through the least cost of resources, and by the most economical means and methods.

In addition, ● can find the abstract geometric and topological information of the product, which is not only the product of PDM domain process, but also the activity guidance basis and result verification condition of ERP domain process. Therefore, in order to strengthen the relationship between ERP and PDM, we must use unified product geometry and topology information to communicate with the related processes, and use unified data representation, data structure and other underlying resources of the database as far as possible.

The product of ● enterprise is the result of the coupling of the logical relationship of the two process sequences. The process sequence in PDbM is carried out according to the design route of gradual refinement from the whole to the part, while the process sequence in EBP is carried out according to the manufacturing and assembly process from the part to the whole. The final product of the enterprise is the result of the coupling of these two process sequences from different routes and fields in time coordinates.

Therefore, the information intersection of ERP and PDM systems is the product bill of materials BOM and process summary table. With the continuous expansion of PDM and ERP systems, there is a large area of overlap in the product structure of the two systems. It is natural to use ERP and PDM views to integrate them together with the product structure as a bridge.

Analysis of Integrated Interface Mode between 4ERP and PDM

ERP and PDM systems are used in the field of engineering design and management respectively, but they are really combined to realize the overall information integration of enterprises, and few of them can effectively share enterprise resources and information. Domestic PDM software has not developed ERP interface, and similarly, ERP software can not achieve seamless integration with PDM.

OMG (object Management Organization) is currently developing specifications for PDM enabled components (PDM enabler). An enabling component is a physical entity that implements or supports a specific abstract process, which enhances the efficiency of product development by providing a flexible way to share product data.

After the completion of the PDM enabling component specification, the PDM system that follows the specification can transfer the data of one PDM system to another PDM system, and realize the connection mechanism of the application system, that is, the PDM application system can manage the data in the ERP system or another PDM system, which greatly facilitates the integration of the system. The specification is still under discussion and has not yet been finally formed.

The integration of PDM and ERP systems is an urgent problem for manufacturing enterprises. The effective integration of the two systems can improve the operation efficiency of enterprises and greatly reduce information redundancy and information conflicts. When implementing the integration of PDM and ERP in an enterprise, many difficulties will be encountered, such as the control of data, organizational obstacles, and how to determine the specific data transferred between systems according to the specific business process, which is closely related to the actual situation of the enterprise.

There is no best ready-made solution for the integration of PDM and ERP. Enterprises must determine the solution according to their actual application environment and target requirements. Usually, it is necessary to fully study the enterprise operation mode, development goals and business processes, and determine how to share and exchange information, so as to ensure that "the right information reaches the right people at the right time and in the right form."

Any way of integration must first consider what to give priority to and what to follow. This is a very critical issue in workflow management. Attempts to automate business processes and workflow systems usually lead to dual control of product data, and human intervention often leads to failure, at least in workflow automation.

These issues should be considered first when integrating. Only the integration that accords with the actual situation of the enterprise is the best integration, and the specific integration interface should be considered according to the actual situation of the enterprise. Based on the previous analysis, figure 2.8 illustrates that the interface between ERP and PDM should have the following characteristics:

● compiles the bill of materials in the PDM system according to the product structure in the ERP system

● builds the product structure in ERP system according to the bill of materials in PDM system.

● saves the basic records of parts in PDM system as basic records of materials in ERP system.

● saves the basic records of materials in ERP system as basic records of parts in PDM system.

● saves the basic records of drawings in PDM system as drawing reference pointers in ERP system.

● saves the basic records of documents in PDM system as document reference pointers in ERP system.

Interface form between 4.1ERP and PDM

After understanding the problem of connecting bridge between ERP and PPDM, the interface form of the two systems integration is discussed from the technical point of view. The interface between ERP and PDM system has four modes: active, passive, through integration and bridge integration, each of which has its own advantages and disadvantages and can be selected according to the specific conditions of the enterprise when needed.

Figure 2.8ERP and PDM interface to transmit information

● initiative

As shown in figure 2.9, the ERP PDM writes the information needed by ERP directly into the database of the ERP system, while ERP, as a static system, only accepts the product configuration information published by PDM. This integration method is more suitable for enterprises that are good at engineering design. It is generally used in customized or self-developed ERP systems.

Figure 2.9 active

In the form of active interface, the synchronization of information between PDM system and ERP system is generally good, but there are some problems in security, such as write data conflict, that is, when PDM system writes data to ERP system, ERP system is also writing data. Generally speaking, this approach is not recommended for large ERP systems such as BAAN, ORACLE and SAP.

● passive

As shown in figure 2.10, the ERP system reads the required data from the PDM system and writes it into its own database. There are two ways for passive: one is fully passive, that is, the PDM system completely exposes the database structure of its expression and storage information, and when reading the information, the ERP system judges which information is added, which is modified, and which has been deleted; the other is semi-passive, that is, the PDM system not only exposes its database structure, but also provides some handshake signals to be stored in the handshake signal table separately.

Figure 2.10 passive

Using the passive interface form, the synchronization between the PDM system and the ERP system is better, and the security is stronger than the active one. Generally, the interface work is completed by the ERP software provider, which is suitable for the self-developed ERP system. This method is based on ERP, PDM as slave, PDM only as the working platform of designers. ERP generates product configuration and creates and manages BOM, which is more suitable for enterprises with the goal of improving production efficiency and manufacturing flexibility.

● cut-through integration mode

Figure 2.11 is effective for integrating independent ERP and PDM systems through file transfer, but this conflicts with the principle that data must be stored in the same location to keep the owner clear and avoid data inconsistencies. Because the bottom layer of ERP and PDM systems are relational databases, the data about products are also stored in their respective domains of the database. The so-called pass-through mode is that the same data model and data are used in ERP system and PDM system. Both systems directly operate on the data of the database and exchange data.

Figure 2.11 straight-through type

The PDM system generates the intermediate text or intermediate data table from the information needed by the ERP system, and the ERP system directly reads the information from the intermediate file or intermediate table and writes it into the database. The PDM system and the ERP system in this way are relatively independent, the interface does not involve the internal structure of both sides, and the responsibility of the interface is very clear, and the security of the data is guaranteed.

The problem is that the data network synchronization of the two systems is slightly poor, but as long as the time for reading and writing intermediate files or data tables is reasonably specified, the data synchronization will not affect the use. What needs to be mentioned in particular is how to adopt the intermediate mode to ensure the consistency of PDM and ERP information.

There are two common ways: one is guaranteed by the ERP system, that is, the PDM system periodically writes three types of information needed by the ERP system in the intermediate file or data table, and when the ERP system reads the information, it analyzes the information already in the ERP system to determine which is new, which is modified, and which is deleted, and finally writes the updated information into the ERP system: the other is when the PDM system generates an intermediate file or data table. Compared with the existing data in the ERP system, it is judged that the data has been updated, and the updated data is written to the intermediate file or data table.

In this mode, PDM system and ERP system have a unified data model. The data is fully shared. The problems of "different views", "different languages" and "different controls" are solved. The three views of EBOM, PBOM and CBOM are operable in both PDM system and ERP system, and are completely seamlessly integrated.

PDM system and ERP system have a unified data model, and the data work together completely. This situation is usually the result of the PDM system and the ERP system provided by the same vendor and after the overall CIMS data planning for the enterprise. For example, PDM and ERP systems provided by SAP or BAAN. The PDM function is embedded in SAP's Rhamp3 system, and BAAN purchased the PDM software of one company to integrate with the original ERP system.

The main problem of this integration is users' satisfaction with PDM system and ERP system. If the supplier initially provides ERP system, and then extends to the PDM field, its PDM system function is relatively weak. When users require a truly seamless PDM function, this integration may not be able to meet the requirements of users. And vice versa. It should be said that at present, the mainstream ERP and PDM software manufacturers are getting closer to each other, but the real bound commercial software of ERP and PDM systems is still some time away.

● bridge integration mode

As shown in figure 2.12, when PDM and ERP systems have their own databases and do not have a unified information model, this model is often adopted, but most PDM suppliers and ERP suppliers provide API interfaces, so according to the focus, the interface can be placed on one side of the PDM system or on the side of the ERP system, and the data of both sides can be manipulated through the interface.

For example, when the engineering BOM (EBOM) is generated in the PDM system, it can be released, and the manufacturing BOM (PBOM) and cost BOM (CBOM) are generated in the ERP system. However, in order to view the complete engineering BOM in the ERP system, you have to call the interface of the PDM system, so the problem of "different views" is solved through such secondary development.

The two-way transmission of information between PDM and ERP systems, and the integration of two-way transmission makes designers and manufacturers work on their own familiar information platform. Through the efforts of ERP and PDM system software manufacturers, today's PDM systems can seamlessly transmit product data and related documents to ERP systems, protecting the exchange of product data between the two systems: when designing new products or modifying old products, the relevant data will be automatically transmitted and presented in the ERP system. At the same time, the relevant details of the ERP system can be transmitted to the PDM system in a consistent and up-to-date format.

Evaluation of four integration modes of table 2.1ERP and PDM

Evaluation of four integration modes of I=RP and PDM

In order to evaluate the three modes of PDM and ERP integration, according to the previous analysis, nine indicators are determined for the two categories of integration performance and integration cost. The following rough evaluations are made for the three integration modes:

According to Table 2.1, the integration performance is described in three scales: good, medium and poor. The integration cost is described in three scales: low, medium and high. The regional range of the performance / price ratio of the following four integration modes can be obtained, as shown in figure 2.12.

Figure 2.12 Integration pattern comparison

From the figure above, we can see that the pass-through mode is better than the bridge mode, and the bridge mode is better than the active and passive mode: therefore, we will use the pass-through mode to implement the integration of ERP and PDM.

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