Today's lean manufacturing environment is not dissimilar to the scenario of an old English nursery rhyme that goes, "For want of a nail the shoe was lost; for want of the shoe the horse was lost; for want of the horse the rider was lost; for want of the rider the battle was lost; for want of the battle the kingdom was lost; all for the want of a horseshoe nail." At the moment, the need to quickly and cost-effectively identify, monitor, track, locate and predict the flow of raw materials, components, finished goods, processes, and people in manufacturing environments is more critical than ever -- and there are radio frequency identification (RFID) solutions that accomplish these tasks.
RFID has been called the only automatic identification technology because reading of RFID tags typically does not require any action on the part of employees. This simple statement is the fundamental building block to understanding the ways in which RFID can work in manufacturing.
In its simplest form, RFID can be used to identify, count, locate and track raw materials and components from receiving through the facility. Tags can also be affixed to returnable containers, totes, trays and other devices to track components through manufacturing. RFID can be used to locate and monitor equipment and cutting tools, personnel and manufacturing or maintenance data.
Inventory
Maintaining an accurate inventory -- not only what and how much, but where -- is essential to efficient manufacturing.
Ford Motor Co., which needs to track thousands of items in its supply chain to ensure that assembly lines are furnished with the right components at the right time, utilizes a real time locating system (RTLS) for bins and components to ensure not only accurate inventory of components, but also to keep assembly locations properly supplied.
Today's RFID systems can rely on a wide variety of reader configurations -- mounted on lift trucks or hand carts, in "tunnels" or gateways, on stretch wrapping equipment -- to automatically read the identity of items as they are put into, or removed from, inventory, or as they move through the facility.
Process Control
An early application of RFID in manufacturing was to identify cutting tools for automated equipment in a flexible manufacturing environment. The button-sized RFID tag not only assured that the correct tool was selected, but also allowed the system to keep track of the type of material cut and hours of use for each tool. This approach facilitated the development of an accurate and efficient preventative maintenance program that utilized the tool for its effective life, and called for it to be changed before it broke and damaged the piece being processed.
RFID tags on trays and other devices used to convey components through flexible manufacturing and batch processing have also been used to record each machine tool and process for later review, if needed. For continuous batch processing, as in food, raw materials can be recorded on the tag as the product moves from station to station. Such use reduces communications burdens and carries the information on the components to quality control (QC) where it can be reviewed, archived or discarded as appropriate. If there is a problem, the data on the tag provides instant access to the entire process.
Harsh Environments
Because RFID is not affected by overlying paint, chemicals, or other contaminants, they can be used in some of the most extreme manufacturing process environments.
For example, Texas Instruments uses RFID tags to track cassettes of wafers as they move through an ultra-clean semiconductor fabrication facility. While the facility is ultra-clean, the fabrication processes would be destructive to bar code labels. Similarly, RFID is used to identify and track printed circuit boards through manufacture and the QC process.
Griva S.p.A., an Italian textile manufacturer, uses RFID to track over 300,000 rolls of fabric annually and 500 pieces shipped daily. While textile manufacturing may not initially seem like a harsh environment, the dying, washing, drying and handling of fabric presents real challenges to tag survivability -- challenges the tag supplier met -- thanks to RFID.
RFID is also used to track beer kegs which are exposed to scrubbing and sterilization prior to filling, and to hard use once they leave the facility.
Asset/Returnable Container Tracking
One of the fastest-growing applications of RFID is asset location and tracking. Whether it is the presence and maintenance history of required emergency equipment, test equipment that must be calibrated on a specific schedule, or tools and jigs that belong to the customer, RFID tags facilitate locating and tracking of not only the item but data pertinent to its ownership, maintenance, and inspection certification.
Returnable containers such as gas cylinders, beer kegs, and other containers that must be certified for use on a routine basis are also being identified by RFID. Ensuring that the correct containers are returned results in significant cost savings, and may have implications in limiting liability. Even as products leave the four walls of a facility, active RFID is being used to track shipping containers as they cross the ocean or travel down the highway.
Personnel ID
In many manufacturing facilities, personnel may be the most critical and, at the same time, unpredictable asset. RTLS tags can identify and locate key personnel within a facility. More importantly, however, an RFID tag can be used to record qualifications and clearances. Workers who have not been checked out or certified to operate certain machines or perform specific processes can be instantly flagged and prevented from harming themselves or others.
Personnel ID can also play a key role in disaster planning. Knowing which employees are still in a facility -- and where they are -- can be the difference between life and death.
Conclusion
RFID tags come in many shapes, sizes, form factors, frequency ranges, memory capacities, and read or write ranges. No one solution is likely to fit all of a company's business requirements. However, it is important to understand that RFID has historically been, and will continue to be, a viable solution in manufacturing environments for improving efficiency, safety and profits. Automatically.
Daniel P. Mullen is president of AIM Global, the worldwide industry association for automatic identification and mobility. As an industry advocate, Mullen strives to present a balanced view of the technologies, including their strengths and limitations. He serves as chairman of the U.S. Technical Advisory Group for ISO/IEC SC31, and the international standards committee for Automatic Identification and Data Capture. Under his guidance, AIM Global bar code symbology standards and RFID implementation guidelines have moved from industry documents to internationally accepted standards.
