Active RFID Tracks Kit Carts Through Assembly

By Claire Swedberg

The system links each loaded cart as the kit is assembled, then is staged for shipping, shipped to the assembly plant and received, thereby reducing the amount of time workers previously spent searching for missing carts required for assembly.


Wave Reaction has developed a solution that marries bar codes or passive radio frequency identification with active RFID technology, in order to enable manufacturers to track kitting carts and the components on those carts as they are moved from one facility to another, and throughout the assembly the process.

The system, known as the Wave Reusables Kit Cart Solution, has been used by one heavy equipment manufacturer for approximately one year, according to Wave Reaction, and has reduced the costs related to kitting cart loss by 83 percent. The manufacturer has asked to remain unnamed. Wave Reaction is currently in discussions with several automobile manufacturers that aim to use the technology as well.

A rack with a Wave Reaction tag at the bottom left

For the past decade or more, Wave Reaction, located in Galena., Ill., has offered its customers solutions to track the movements of reusable containers between their facilities or from suppliers. The technology is used as an inventory-management system to ensure that containers can be accounted for. Wave Reaction makes its own active RFID tags and adapts hardware from a variety of RFID reader vendors, according to its clients’ needs.

More recently, says Charlie Daoud, Wave Reaction’s development director, the company has been providing the RFID technology and software to manage a kanban system of parts or materials used at manufacturing sites. In addition, Daoud says, one of the company’s largest customers—which makes heavy equipment—asked if Wave Reaction could provide a solution that would not only track the reusable kitting carts that move from a kitting facility to product assembly, at a separate location, but also link each cart to the items loaded onto it.

The Wave Reaction solutions are tailored around three concepts, Daoud says: communication, automation and translation. When it comes to communication, he explains, a solution needs to help all parties understand the same information. By automating the collection of data, the system eliminates the need for tribal knowledge from personnel at each point at which a cart is handled. Translation consists of presenting information to each separate party in a way that is intuitive. “Our software is scalable,” Daoud states, “so we can make small changes to the software,” so that users can interact with information in the way they want.

Traditionally, Daoud says, the equipment manufacturer, like many such companies, had to rely on the organizational skills and methods of multiple parties who may handle a given cart. For instance, one individual builds the cart with the appropriate components at a kitting site, and the cart is managed at a staging area where it is shipped on a truck and then sent to the assembly site. At that site, it may be unloaded immediately, or it may sit in short-term storage.

The cart is then moved to the assembly process. At each location, the individuals handling that cart tend to have their own system of managing information, including spreadsheets, phone calls or e-mails. Often, there is confusion regarding who might have misplaced a particular cart, which can lead to it being unnecessarily replaced when it is likely to turn up again.

Wave Reaction built a system that would enable all parties involved with the cart to use a single software platform. Each of the thousands of carts comes with an active 433 MHz RFID tag attached to it. Trucks that transport the carts are also tagged with the same active RFID tags. Wave Reaction installed readers at staging areas and dock doors to track the tags’ movements through those zones.

Wave Reaction’s Charlie Daoud

When a new cart is loaded, the operator opens the Wave Reaction software residing on the company’s server, which captures information regarding what should be loaded onto each cart from the company’s existing SAP software. A user scans a bar code on each item as it is loaded onto the cart; a passive RFID tag read can be used as well. The item’s bar-code number is then linked to that cart. The Wave Reaction software confirms that the appropriate items are loaded onto that cart, or displays an alert in the event that an item is missing, or if one is present that should not be included.

The cart is then moved to the staging area to be shipped to assembly. As a truck pulls into the loading dock, the reader at that location interrogates the tag on that truck, as well as those on all carts being loaded into the vehicle. Once the truck is fully loaded, the software automatically issues a text message to the driver, indicating that the vehicle is loaded, or which carts it contains. As soon as the truck pulls out of the dock—at which time the system stops reading the vehicle’s unique ID number via RFID—the software sends an e-mail message to receiving personnel at the assembly site.

If no loading docks are available when the truck reaches the assembly area, it can be redirected to the short-term storage area, where the vehicle’s tag is then read by another Wave Reaction RFID reader. The software updates that data so that employees at the assembly site can not only view which trucks are awaiting unloading in short-term storage, but also determine which carts are on each truck.

Wave Reaction customized the system for the multiple parties that use it, in order to make it intuitive for use. For instance, the kitting site had utilized a white board on which was listed information regarding staging and loading. Now, workers can view the data on a large screen that displays the Wave Reaction software in a format similar to how it was displayed on the white board. They can then glance at the screen to see what has been loaded, what is in staging, and when a particular truck arrives and leaves.

At the assembly facility’s receiving area, workers had previously used a television monitor to view information about expected shipments. The new large screen installed there shows Wave Reaction software data about what has arrived, as well as when and where, in a similar format on a dashboard in the software.

Supervisors can use the system to receive a notice for each shipping or receipt of a cart, or they can set the system to send only specific notices—or none at all. Alternatively, they can access the software directly to view each cart’s status and location, and thus the items loaded onto those carts.

To date, the heavy equipment manufacturer has used the technology to track the carts as they are loaded, shipped from the kitting facility and received at assembly. In the future, the firm could opt to deploy additional readers to capture the kits’ movements throughout the assembly process.

In the meantime, the information the solution provides has managed to reduce not only the incidence of lost carts, but also the labor costs incurred as a result. What’s more, it decreases the number of carts that are ordered, since the company knows exactly which carts it has and where they are located. In addition, it helps to ensure that assembly lines never come to a halt due to a specific kit not being available.

To develop solutions such as this, Daoud says, “We have long-term customers come to us with challenges. We have a core software platform that never changes, but we add modules on the periphery,” to solve problems using customers’ existing system, and the language and format to which the users are accustomed.