[机械模具数控自动化专业毕业设计外文文献及翻译]【期刊】基于RFID的制造业与库存革命-外文文献

46 CADDM Vol. 15 No.1 (2005)The RFID-Based Manufacturing and Inventory Revolution HAMIDULLH Khan Niazi, SUN Hou-fang, RIAZ Ahmed, SHAHID Ikramullah Butt (School of Mechanical and Vehicle Engineering, Beijing Institute of Technology, Beijing 100081, China) Abstract: Radio frequency identification (RFID) is a contactless form of automatic identification and data capture (AIDC) technology. This paper explores the use of RFID in the new field of manufacturing automation and quality control. This paper consists of five parts. The first part gives a brief background and introduction of technology. The proposed use of RFID technology in the field of manufacturing automation and quality control is discussed in second part. The third part covers its use in the field of warehouse management system. Part four is a local review and analysis of RFID technology in manufacturing and warehousing which would support the potential use of this technology locally at China. The last part of paper gives concluding remarks about the RFID technology with recommendations of RFID use in these areas. Key words: RFID; EPC; manufacturing automation; warehousing; AIDC CLC number: TH 166 Document code: A Article ID: 1003-4951(2005) 0046-06 1 Introduction RFID is an Automatic Identification Data Collection technology that uses radio-frequency waves to collect the data between reader and tagged items to identify, categorize and track these items. RFID is fast, reliable, and there is no requirement of physical sight or contact between reader and the tagged items. The other advantage of the tag is its ability to work under harsh environmental conditions such as snow, fog, ice, paint, dirt, and high temperature up to 250C. _ Received: January 10, 2005 Biography: HAMIDULLH Khan Niazi (1963-), male, born in Punjab (Mianwali), Pakistan, Ph D student, main research fields are manufacturing and automation Historically, RFID technology was employed first time by the British in World War II, to identify friendly and foe (IFF) aircrafts. The present day commercial and private aviation traffic control is still based on this system1. It was the first obvious use of RFID. In the late 60s and early 70s, the need for security and safety surrounding the use of nuclear arsenals drove further the development of RFID tagging of equipment and personnel. Around 1977, this technology, which had been developed in government labs for these applications, was transferred to the public sector. From here to onward, a lot of new application areas have been explored in various sectors. The biggest boost to this technology came when an Auto-ID Center for RFID was opened at the Massachusetts Institute of Technology (MIT), Cambridge, in 1999 and began field tests in 2001. The Centers self-described mission was to “assemble the building blocks to create an Internet of things. The center accomplished its task and transferred its technology to EPCglobalTM (). In the simplest form of RFID, an integrated circuit on a small silicon chip is attached to a small, flexible antenna, creating a tag. The integrated circuit provides data storage to record and store The RFID-Based Manufacturing and Inventory Revolution 47 information. The tag can hold many types of qualitative data about the item, such as its serial number, configuration instructions, what time the item traveled through a certain zone, even temperature and other data provided by sensors. A reader sends a signal to the tag (active or passive). The tag absorbs some of the RF energy from the reader signal and then reflects the RF energy as a return radio signal containing information from its memory depending upon the type of tag. The tags can be categorized as passive and active tag according to their responding ability, and can also be categorized as read-only (RO), write once read many (WORM) and electrically erasable programmable read-only memory (EEPROM) tag according to their functions. Read-only tags, the least expensive, are programmed by the manufacturer and user. The EEPROM tags can be effectively used in manufacturing applications where qualitative data can be displayed and updated at required location. Read-write cards, the most expensive, allow users to write to and read from their memory contents2. The passive tags are cheaper and operate without any internal battery source, deriving their power from the energy generated by the reader. Passive tags are smaller and lighter than active tags and they have a virtually unlimited life. Some disadvantages include their shorter read ranges compared to active tags, their limited storage capacity, and their inability to perform well in electromagnetically noisy environments. Passive transponders (tags) also require higher-powered readers. Active tags, which are more expensive and generally larger than passive tags, contain an internal battery for power. They reduce the power requirements of the reader but have a finite operating life3. Active tags can allow greater communication range and better noise immunity than passive transponders. Active tags can also result in higher data transmission rates when used at higher radio frequencies. The network of RFID (Fig. 1) comprises of six fundamental building blocks: the Electronic Product Code (EPC), the RFID tag, RFID Reader, Object Name Service (ONS), Physical Markup Language (PML) and Savant. The EPC is stored on a RFID tag4. The EPC number is a unique number that identifies a specific item in the RFID Network. EPC is currently represented as just 64 or 96 binary digits or bits and serves as a lookup key for retrieving additional data about the object from a networked database5, in a similar manner to the way in which we all use Uniform Resource Locators, URLs6or web addresses as a pointer to further pages of information on the World Wide Web (WWW). This reduces the amount of memory capacity required by the tags, thus lowering their production costs7. Once the EPC is retrieved from the tag, it can be associated with dynamic data such as from where an item originated or the date of its production. The reader then sends the data to computer running middleware (savant). The middleware, after filtering the reader data, passes the number to a computer or local application system, known as the ONS for retrieving data about the item / product. The company application server is also closely linked with savant. The ONS tells the computer systems where to locate information from the PML on the network about the item carrying an EPC e.g. the item production date, batch number, ingredient, or other information like what action is required next. Savant PML ONS ApplicationReaderEPC carrier Tag sFig. 1 Building blocks of RFID technology Unlike bar code-based tracking systems, an RFID system can read the information on multiple tags without necessarily requiring line of sight and without the need for a particular orientation. That means RFID systems can be largely automated, greatly reducing the need for manual scanning. In addition, RFID tags hold much more data than Universal Product Code (U.P.C) in bar coding. This paper explore the use of RFID technology 48 HAMIDULLH Khan Niazi, SUN Hou-fang, RIAZ Ahmed, SHAHID Ikramullah Butt in the present day manufacturing environment to cater the problem of work in progress (WIP) determination, safety hazards in high speed machining, production process and quality control. This paper also discusses the use of RFID in warehouse management system (WMS) with the use of passive tags. 2 RFID in Industrial Manufacturing The RFID can be used extensively in manufacturing and production control. The tracking of product and determining WIP status on shop floor, making quality control checks and avoiding safety hazards are few areas in manufacturing sector. The modern CNC machines operating at around 20,000 rpm can cause major accidents by simply inserting wrong tools in the tool magazine / tool holders during the tool initialization and tool selection process. The RFID tag fitted in the taper shank or retention bolt of tool can reduce not only setting time but also can avoid major accidents due to wrong selection of tool or tool setting. The CNC machine initialization can automatically pick the right read sequence of all tools in the tool holder positions and then all geometric and technical data for the tool can be transmitted correctly to the tool management system of CNC control unit. There is no need of manual entry and it eliminates the possibility of human error. The danger of accidents due to excessive speeds, the selection of wrong rotational direction or the incorrect positioning of the tools in relation to the work piece will thus be eliminated. The rewritable transponder coded tools can improve a lot of cost saving in the production and service cycles. Even the latest details of tools regarding radius, length tool offset etc can be updated for sharpened tool in real time during service cycles. The monitoring of process in centralized and decentralized system may be accomplished in real time in central database of the enterprise due to transparent image of process data. The latest information of the product can be seen in the right place at all manufacturing stages. This is the most significant step in the virtual control of object or product. The option of changing data in the EEPPROM transponder at each processing station means that it is possible to create information flow between the individual work stations, which takes the pressure off the control system. This will increase the speed of production and processing operation in making the timely decisions. 2.1 System Security Management Shifting object data from the central computer to the object significantly increases system security in the network based manufacturing system. Sometimes, despite software crashes or failures of the central computer, the relationship between object and its current data can be established anywhere and at any time because of RFID based networked manufacturing system. If necessary, objects can also be withdrawn from production process without affecting the central data. If necessary the object is subsequently put back into the process, work can continue without problems or faults occurring8. 2.2 Production Process Monitoring Data capturing problem under harsh environmental conditions was one of the limitations of bar coding or manual data entry, which is now possible with the RFID technology. The BMWs Dingolfing factory (South Germany) has replaced its bar code with transponder fitted to bonnet of car bodies of series 7 and 5 to cut down cost and optimize the production process. As the car body moves through different production departments, the 32 K bytes EEPROM transponders with read / write features and with a range of 4 m, communicate important data (e.g. chassis number and serial number) with the production process9. The factory has installed 3000 tags and 70 readers in the assembly area. The transponder works equally well even during painting process in oven and at any stage data related with certain process can be tracked in seconds. This is the most important step in the production process monitoring specially in the harsh environment. 2.3 RFID System in Quality Control The quality and status of product during different production processes at various checks can be monitored with writable transponders. These quality checks and the current status of the product can be monitored in real term at each stage of production. The quality data of products remains visible and back tracking of quality problem at any stage can be done at will. The tolerances control and assembling of precision components can be accomplished with RFID based system at different The RFID-Based Manufacturing and Inventory Revolution 49 work stations. The individual tolerances can be selected and assembled by a robot equipped with a RFID features. The assembly fitting of individual components in the assembly environment can be recorded as data to transponder and thus quick assembly can be ensured with accuracy. 3 RFID in Warehouse Management System (WMS) Implementing an RFID compliance tagging system with low cost passive tags may seem daunting, but is quite manageable once you have clear understanding of requirements and options. The present requirements of WMS at pallet and cases level are being investigated for successful and consistent communication among the customers, supply chain partners, technology providers and internal departments. Presently a lot of systems testing and refinement are being carried out all over the world. The RFID based WMS offers business performances in the most precise and effective manners for identification and virtual tracking of items in the stand alone, distributed network or completely networked based WMS. The potential areas of benefits of RFID and cost reduction over the bar coding are indicated in Table 1 for short term, mid term and long term basis. The short term cost reduction benefits in the WMS and inventory reduction are 28% and 55 % respectively. The mid term and long term benefits in the areas of Retail and Distribution Centers (RDC) are also worth mentioning. The working principle of RFID in WMS is same as mentioned earlier. The store related RFID data can be retrieved and passed to a companys inventory or supply chain applications. The RFID provide complete visibility of each items location, state and context throughout the entire supply and demand chain. It will also increase data quality and speed and prevents incorrect and incomplete orders. The current problems in the visibility of advanced shipment notice (ASN), back ordering and other bottlenecks in the WMS can be solved in the real time at all concerned locations. The RFID based WMS will improve the management of all other store related activities. The real benefits of RFID, however, will be realized by re-engineering processes around RFID. In most environments, RFID can achieve 99.5% to 100% first-pass read rates. Further, with no moving parts or optical components, maintenance is not an issue10. Table 1 Source: e FORCE (RFID solution to life cycle management)11Activity Area Benefits of RFID % of Cost ReductionStorage Warehouse Automated, accurate Inventory management 28% Dispatch supplierAutomated checking process 26% Claims ManagementHub Automated, accurate data records decrease claims generated 18.5% Cross Docking ADC Automated checking, reduced paperwork decrease admin 18% Receipt ADC Automated checking 9.4% Claims ManagementADC Automated accurate data records decrease claims generated 20.8% Dispatch ADC Automated checking process 5% Storage ADC Automated accurate inventory 21.7% Inventory Cost All Reduced Inventory due to visibility through chain 55% Asset Utilization All Improvement in asset Utilization 30% Receipt Retail Reduced paper work 2.8% Storage Retail Automated inventory management 16.3% Replenishment Retail Improved efficiency 4.5% Losses Retail Reduced loss (not of code, overstocking) from inventory visibility 11% Total saving from RFID linked supply chain cost compared to barcode driven supply chain cost structure 8.1% Potential Prioritization of Opportunities: Short Term Mid-Term Long Term 4 Local Review of RFID Technology in Manufacturing and Warehousing The following local survey at China, in Fig. 2 and Fig.3 shows that RFID technology has a lot of potential to support the Chinese companies with an adaptive and visible supply chain at a lower cost and faster response promises. Today, the RFID has a bright future in China along with the fastest growing and most promising market in the world. The RFID 50 HAMIDULLH Khan Niazi, SUN Hou-fang, RIAZ Ahmed, SHAHID Ikramullah Butt has vast potential applications in manufacturing automation, tracking of pallets, cartons and cases in the warehouses at China. On the manufacturing side, WIP status can be checked through RFID instead of Job cards and other conventional methods of routing sheets. The quick up-to-date progress on WIP and other qualitative data will result in enormous saving of time and considerable improvement in the efficiency of enterprise. The applications of the RFID in enterprise resource planning (ERP) and product life cycle management (PLM) are in consistent with the data format and structure making it the most suitable due data capturing technology in these future technologies in the network based environment. The read / write features of EEPROM tag make it most suitable to the nature of jobs in WIP and other uses in manufacturing enterprises. The passive tags, being cheaper may be effectively used in tracking pallets, cases and individual products in warehousing applications. The energy received by the passive tag is generally less than 100W12. The survey conducted by Auto ID center Futan, Shanghai for 52 China based companies in Fig.2 and Fig.3 illustrates the approaches and potential of RFID technology adoption in China. It reveals that only 9 % of the participants had a deeper understanding of RFID application in manufacturing, logistics, retail and etc. Market education and promotion about RFID technology are highly desirable in China. It could be achieved by promoting activities like: workshop, seminar, websites and pilots12. The survey results to another