"RFID is a sensing technology," says Alex Stuebler, business manager, Siemens Energy & Automation Inc. (Norcross, GA), which supplies readers, antennas, tags, printers, and software. The company recently introduced the Simatic RF600 family of RFID products for production, warehousing, and retail store applications, and offers RFID consulting services via its Siemens Business Solutions Group.
RFID makes it possible for manufacturers to automatically sense a part or asset's proximity, and gather information about its location. Collecting this data at critical points in the plant improves visibility within the four walls, and can serve as the basis for quality assurance and product genealogy documentation.
On the asset management side, RFID can help improve the maintenance and repair process and minimize equipment downtime. Because RFID collects information without human intervention, it also boosts labor productivity by automating manual data collection tasks.
RFID tags used in factory floor applications are typically passive rather than active, or self-powered, and use a variety of frequencies. Having read/write capability makes it possible to add information to a tag at each step of the process. Read-only tags and tags that read/write once simply serve as a "license plate" linking to data in a manufacturing execution or other enterprise system. Manufacturers use battery-powered active tags when they need to store large amounts of data or require a long read range.
DEPLOYMENT CONSIDERATIONS
When deploying RFID, it's essential to consider the meaningful information the technology provides, such as support for lean manufacturing or Six Sigma programs.
"Return on investment is associated with the business process changes RFID enables," says Vivek Bapat, director of marketing, Rockwell Automation Inc., which offers hardware, engineering, and business services as well as the resources of its RFID pilot lab in Milwaukee. When implementing a factory floor RFID system, it's essential to determine "how, where, and what type of information will be added to the tag," Bapat says.
Not surprisingly, practical considerations abound. Read distance -- or how close the tag must be for the reader to scan it -- is one major consideration. Other basic questions manufacturers should answer include: How much data must be communicated to and from the tag? What environment will the tag encounter? Will it be submerged in paint, baked in an oven, surrounded by metal?
"Factory equipment can cause interference," warns Greg Edds, manager of global operations at Hewlett-Packard (Palo Alto, CA), an RFID user. "A lot of equipment today emits high-frequency energy. It's easy to map process flow, but testing is needed to understand how tags and readers interact with various systems." In addition, RFID on the factory floor inevitably requires some capacity for filtering data. Manufacturers often accomplish this via middleware, but data filtering may also be performed at the device or network level. RFID information typically streams into the programmable logic controller, which may filter the data before passing it on to higher software layers such as manufacturing execution and enterprise resource planning systems.
Rockwell, for example, builds a filtering capability into its Allen-Bradley ControlLogix controllers via a product extension called EWEB. The EWEB module also transmits data from the controller to RFID printers and readers. This bi-directional communication and data filtering helps eliminate the need to install new hardware/ software.
HP relies on middleware to filter RFID data in some of its operations. The company has already implemented UHF technology at the warehouse level to provide supply chain visibility; however, tags are applied on HP's manufacturing floor rather than in its warehouses, which are run by 3PL partners.
At some HP facilities, a shop floor system sends data to middleware from OATSystems Inc. (Waltham, MA) or Shipcom Wireless (Houston). The middleware, in turn, transmits tag commissioning information to RFID-capable printers from Printronix (Irvine, CA) and Zebra Technologies (Vernon Hills, IL). These printers output paper labels with the serial number, part number, and universal product code in bar code and human-readable formats and encode the 915-MHz tags. Most tags are supplied by UPM Rafsec (Westmont, IL) as 3 x 3-inch, self-adhesive labels. At other locations, the shop floor system communicates directly with the RFID-enabled printers.
As each product tag is commissioned with electronic product code information, the data is associated with the item?s serial number in HP's database. This helps HP track the movement and flow of goods. For maximum flexibility, HP uses RFID hardware that is multiprotocol and handles 13.56-MHz as well as UHF frequencies. In a test underway at a printer manufacturing facility in Brazil, HP is attempting to push the tagging step further upstream. For this evaluation project, HP encodes 13.56-MHz tags with unique identifiers and applies them at the start of the manufacturing process. Then it reads and updates the tags at various assembly and quality control points. "When the printer is complete, there?s a full manufacturing history on the tag," says HP's Edds.
Best of all, HP can access this data virtually anywhere without linking to the factory system, and it is available to service personnel and subcontractors. Some security and privacy issues are inherent in this scenario, but Edds is confident the evaluation program will confirm the technology's capabilities as it currently stands, as well as point out necessary improvements. Capital investment requirements for a factory floor RFID project span a wide range, from a few hundred thousand to several million dollars. With few exceptions, hardware and tag costs are overshadowed by expenses related to project management and network integration.
Niche applications are most likely to show quick return on investment. Closed-loop deployments also accelerate ROI, especially if tags can be used multiple times.
Look for process points, such as quality checkpoints, where real-time identification is useful. It?s also important that calculations are made together. "You can?t separate manufacturing ROI from supply chain ROI," notes Bapat. Because RFID collects information at a highly granular level and increases visibility in the plant, "the deeper you are able to push RFID in the production process, the higher the ROI," he explains.