Design and implementation of discrete MES based on RFID technology

1.1 Discrete Manufacturing MES System

Manufacturing execution system is an advanced management technology for manufacturing workshops. It is located between the enterprise planning layer and the industrial control layer. It studies how to comprehensively consider the planning schedule, product process control, material management, quality monitoring, equipment management and cost management in the manufacturing process, and emphasizes the execution of manufacturing plans and the control of product manufacturing processes. It makes the information collection and feedback of the production site accurate and timely, and improves the transparency and agility of manufacturing management.

MES can optimize the management of the entire production process from order placement to product completion through information transmission. MES can respond quickly to real-time events in the factory and guide and process them with current accurate data. This rapid response to state changes enables MES to reduce non-value-added activities within the enterprise, effectively guide the factory's production operation process, and improve the factory's timely delivery capabilities and production return rate. This system uses radio frequency identification technology for data collection, which can effectively manage employees and work-in-progress resources. Improve management level and production efficiency and reduce production costs.

1.2 RFID Technology

Radio frequency identification technology is a non-contact automatic identification technology that emerged in the 1990s. It automatically identifies the target object and obtains relevant data through radio frequency signals without human intervention and can work in various harsh environments. With its unique advantages, RFID technology has been widely used in many fields such as supply chain management, identity recognition, transportation and military logistics. RFID technology is used to solve the real-time data collection of discrete manufacturing workshops. It has the following advantages: (1) non-contact, variable shape, small size, and reusable; (2) difficult to counterfeit and high security; (3) not afraid of pollution and suitable for various harsh environments; (4) data can be rewritten and has a large storage capacity; (5) tag recognition distance is long and fast.

2 Demand Analysis

As market competition intensifies and product life cycles shorten, discrete manufacturing is increasingly sensitive to market response speed. The most representative parameters related to response speed are response time and delivery time. To this end, enterprises must use information technology and advanced manufacturing technology to improve production efficiency while ensuring quality. This requires managers to strengthen production process management between the enterprise resource planning layer and the process control layer.

Applying RFID technology to the design of discrete manufacturing execution systems makes up for the information management gap and information feedback delay in the enterprise resource planning and control layers, and realizes the smooth transmission of workshop production data. It can greatly shorten the production preparation time and production cycle, improve product quality, make more effective use of workshop resources, rapidly improve workshop management capabilities and management efficiency, greatly improve the speed and accuracy of work-in-progress traceability, and make work time management more scientific and reasonable.

3 System Design Goals

The discrete MES system can make full use of the technical advantages of RFID to solve the information and management gap between the enterprise planning layer and the workshop site control layer, and realize the visualization and digital management of manufacturing and quality.

(1) Capacity analysis: It can conduct multi-faceted analysis of workshops, teams, equipment and personnel at the same time, so that managers can understand the progress of on-site production, dispatch resources and improve production efficiency.

(2) Real-time tracking of the entire production process: Accurately track the production status of each work-in-progress, understand the completion status of different orders, and provide strong support for managers to make decisions.

(3) Improve product quality: Establish a computer-aided quality assurance system to realize computer management of quality inspection records and quality statistical analysis, which can quickly find quality risks and effectively reduce the incidence of product quality accidents. The establishment of a quality system and the strengthening of management will further improve product quality and production quality, significantly reduce loss costs, and effectively save costs.

(4) Provide a basis for report printing: The summary of various production data and the generation and printing of various reports are all managed by computers, replacing the previous manual calculation, accounting, and manual reporting work, thus reducing the workload of relevant staff.

(5) Solve the problem of backlog of semi-finished products: It can provide the online quantity and online time of different workstations at any time. It helps enterprise managers to find out the links that affect the production progress in advance and provide assistance for balancing production.

4 MES system application solutions

Since RFID electronic tags are relatively expensive, their penetration rate in manufacturing and other fields is low, and there is no unified standard in various industries. The core idea of ​​the discrete manufacturing MES application RFID technology design proposed in this paper is to use RFID tags to track the product production process within the enterprise. RFID electronic tags are bundled during raw material processing. The electronic tags contain all the information of the work-in-progress, and the electronic tags can be reused. RFID electronic tag readers are set at each production process station to track the production of work-in-progress. The product controller at the station reads the electronic tag information through the RFID reader, enters key information such as product model specifications and production time into the factory computer, and tracks product production information.

The RFID card reader at the workshop station reads the electronic tag information of the work-in-progress and returns it to the database through the connection controller. Managers can not only track the quality and quantity of key parts in real time, but also issue corresponding production instructions through the factory workshop electronic board according to the real-time changing information, and give workers corresponding production operation plans. At the same time, the quality of each product component can be analyzed later.

5. Overall structure of the system

5.1 System network topology diagram

The topology of the discrete MES data collection network based on RFID is shown in Figure 1. The bottom-level workstation card reader is connected to the server with a control connector, and is connected to various WIPs on the production line. The application integration of the bottom-level production data collection and server communication is realized. The parking card reader collects the workshop field data in real time and feeds the data back to the server through the control connector. The management personnel analyze the field data in real time through the factory computer, make reasonable decisions, and inform the factory staff through the factory electronic billboard. The factory staff can complete the WIP according to the new instructions. The RFID card reader reads the WIP electronic tag information. On the one hand, it is transmitted to the factory computer as the basic information for production monitoring, and on the other hand, it is sent back to the parking card reader, and the workers are given corresponding production operation instructions through the electronic billboard.

Figure 1 RFID data collection network topology

5.2 System Architecture Diagram

The system structure adopts the ERP/MES/PCS three-layer structure, as shown in Figure 2. The system integration interface realizes the data and business integration of the MES system and the ERP system. The communication middleware adopts the C/S structure, extending the wireless data collector as the client of the system. The collector can directly connect to the database for real-time data exchange. In this way, the amount of information exchanged between the data collector and the server is small, the communication efficiency is high, the response speed is fast, and it has a strong data collection function, which can meet the factory's needs for data collection communication, and the burden on the server is also light.

Figure 2 System architecture

6 System Features

On-site paperless operation avoids errors in manual data copying, quickly collects and organizes data, reduces the overall cost of users, and can use the Internet for remote data query. Real-time grasp of on-site production quantity and quality status, accurate grasp of raw materials, work-in-progress, equipment and employee information. Use electronic billboards to provide on-site visual management, so that employees can accurately grasp the production progress. Maintenance personnel can determine the production staff of the product based on the collected information, clarify responsibilities, and establish production and quality data reports.

7 Conclusion

The system has been actually applied in a garment industry. It can well meet the requirements of discrete production and quality management, improve production efficiency, and has great promotion value.