Though still in the infancy stages in the woodworking industry, radio frequency identification already is helping companies improve tracking and production cycles.

By Tim Stiess and Earl Kline

What is RFID? Wal-Mart is using it. The Department of Defense is using it. Other woodworkers are beginning to use it. Should you?

Radio frequency identification is a way for computers to communicate directly with objects. If an object with an RFID tag comes within a certain radius of a reading device, a computer can identify the object, based on the information stored on the tag.

One of the most well-known uses of RFID is inventory management. RFID can be placed on parts or on locations within the inventory area to quickly direct a person to a specific part location and to verify that the correct one is in stock. If large objects, such as furniture or packages of lumber, are tagged, inventory could be performed by walking or driving by the tagged products with RFID scanners.

At the point of shipment, the RFID reader can record the exact moment a product was shipped, verify that the product was placed on the proper truck and identify any missing or partial orders. At the receiving end, RFID readers scan the orders as they are being picked up. On-board computers can then process the received orders and indicate where to take the orders.

RFID also can be utilized as an expeditor. If a product needs to make its way through a factory faster than others, an RFID tag can be attached to the product so that when it is in proximity to a work center, a reader can allow the worker to schedule production according to products with higher priorities. In addition, RFID can provide support for more automated manufacturing systems. An RFID tag can inform a conveyor as to an object’s size, weight, next process or previous process, and the conveyor will divert the object accordingly. An RFID reader can initiate a setup on a machine or provide the operator with the required information to complete the order.
Production analysis is another use for RFID. By putting RFID tags on products as they are being made, computer software can perform real-time analysis on the production process.

RFID Tags
The RFID tag is very simple. It is made up of a microchip that stores the required information and an antenna that broadcasts the information via radio waves.

Unlike a garage door opener, most RFID tags do not run on batteries. The RFID reading device, or sometimes a secondary unit, sends out a low energy field, which the tag captures and converts to an RFID transmission, which will be received by the reader.

The distance that a tag can be read by the reading device is a function of the relative strength of the signals. Signal strength depends on the strength of the energy field, the efficiency of the tags to change the energy wave into the RF wave, conditions that can block or interfere with the energy waves (i.e., metal, water) and the sensitivity of the antennas attached to the tag and the reading device.

Handheld devices have made RFID reading a fast and easy operation.

RFID tags can vary in shape and size. However, it is important to note that a small and compact tag means a small and compact antenna, which can result in smaller distance capabilities between the tag and the reader.

The most popular RFID tag is the inlay tag. It is very flat and contains a large antenna. This shape makes it possible to incorporate into a shipping label. For maximum application flexibility, the label on a product can then be labeled multiple ways: RFID, barcodes and alpha-numeric.

Special label printers can be purchased for inlay tags. Information typed into a form can be printed on the label, bar code and encoded in the RFID inlay tag — all in one step.

RFID Readers
RFID readers are the complementary equipment for the tags. As its name implies, this is the device that “reads” the information transmitted from the tags. In many cases, the “reader” is a combination of the reading device, the energy transmission device for the tag and, in some cases, a computer.

Handheld readers typically perform all three applications. At the pull of a trigger, this reader sends out an energy signal and any tag within its range will be identified on the small computer display. The downside to using this type of equipment is the battery, which limits the energy signal strength for shorter read distances.

In addition to the handheld models, RFID readers can be attached to a conveyor, forklift, or a work table. They are typically tied into a network so that current information can be obtained directly at the appropriate workstations.

Another popular form of RFID reading device is the portal, sometimes called a gate. The portal is a doorway or frame with RFID readers all reading toward the opening.

The orientations of the RFID readers minimize or negate places where tags can hide as they pass through the portal. Portals are very handy to have on each truck in the shipping department or between inventory and production, as a means of tracking material movement and identifying current locations of items.

Costs of RFID
In a manufacturing operation, each RFID implementation is unique. Determining the cost of RFID requires a consultant, or working closely with an RFID service company, to estimate the network of computers and software needed to make RFID an effective system.

Aside from the computer needs, RFID equipment is not necessarily an expensive technology. With individual readers’ costs ranging from $500 to $3,000, an entire shipping department can be set up with readers and a limited network for under $20,000, thereby giving companies the ability to monitor tagged orders as they enter trucks.

And while the cost for individual tags is not necessarily expensive, the cost of tagging each item can be prohibitive. Passive tags can cost between 10 cents and $1, while active tags can cost more than $20. Some companies try to reduce costs by buying more expensive reusable tags, which increases the initial cost, but can lead to savings over time.

RFID is a powerful tool, but it is only that — a tool. As with any implementation, a detailed analysis and feasibility study needs to be performed prior to any decisions. The cost of implementing RFID incorrectly may be far greater than not implementing it at all.

Tim Stiess and Earl Kline are associate and co-director, respectively, of the Sloan Forest Industries Center at Virginia Tech. The Center’s mission is to promote the global competitiveness and sustainable growth of America’s diverse forest industries. The RFID research was funded in part by the Wood Education Resource Center, Princeton, WV. For more information on this topic or the Sloan Forest Industries Center, contact Tim Stiess at (540) 231-3846, or at [email protected].