Jul 18, 2011Agriculture equipment manufacturer John Deere has increased efficiency in the way it replenishes welding material as well as the way it carries out processes at its assembly stations at a factory run by its Seeding Group in Moline, Ill. That's due to a Wi-Fi-based real-time location system (RTLS) provided by AeroScout and integrated by Prime Technologies, a Michigan company that acted as general contractor for the system's installation.
Since the system went into full production in March of this year, the company has seen a 10 percent increase in efficiency in welding due to improvements in material replenishment and fewer delays caused by waiting for materials in its welding areas, says Shay O'Neal, John Deere Seeding Group's project manager. He adds that replenishment of kit carts, which are loaded with welding materials used by workers, is 40 percent faster. On the assembly line, the system provides a view into work in process (WIP), which thus far has reduced the cycle time (Takt) it takes to assemble a single product by about 5 percent. AeroScout's tags and software were integrated by Prime Technologies into John Deere's SAP, reporting and programmable logic controller (PLC) systems, says Dennis Kubica, Prime Technologies' president. Prime Technologies' Phizx Takt Management System provides the interface with SAP and AeroScout software, so that workers on the assembly floor can access the data.
The factory assembles John Deere's MaxEmerge XP row-crop planters, machines that are used by farmers to deposit a variety of seed in soils and seedbeds. At its welding station the company employs a staff of six people dedicated to replenishing materials for welders to ensure there are no delays in the welding process. The plant has about 50 welding stations, for which each has two replenishment kit carts—one to be filled at the kitting area, the other one for use at the welding station. The kitting area, where the carts of material are loaded with welding materials, is approximately 150 feet from the welding area, and therefore staff spent a great deal of time walking back and forth between the areas, looking for empty containers and refilling them accordingly.
John Deere was seeking an automated solution to improve on its manual system, opting to deploy 100 AeroScoutT2 battery-powered RFID tags. Each tag transmits a 2.4 GHz signal that can be received by Wi-Fi access points, enabling the company, O'Neal says, to use the existing Cisco Wi-Fi nodes that it had already installed throughout the facility and avoid the expense of installing RFID readers.
When a kit cart is close to being empty, staff in the welding area press a button on the AeroScout tag to indicate it will soon need replenishment. The tag transmits that event to the Wi-Fi nodes, sending the request to the back-end software, which then displays the kit cart's ID number, contents and need for replenishment on an LCD screen located in the kitting area. Staff see the display on the screen and walk to the welding area to retrieve the cart.
The company also wanted to use the system to manage work in progress at its assembling lines. Many of the products the factory makes are unique, and therefore the assembly process varies according to each piece of equipment that passes down the line. Because assembly steps and quantity of pieces for each upcoming product was often unknown, there was little preparation possible for staff in the assembly area. The Wi-Fi system was designed to resolve that.
In this case, a tag is attached with a magnet to each piece of seeder equipment that is being assembled (typically about 30 seeders are on the assembly line at one time). Each tag's unique ID number is linked to the product information, such as what kind of piece is being assembled, its serial number and the date. The software stores the details of what assembly process each kind of equipment must go through, and where the appropriate assembly stations are located, through which the equipment must pass.
The Wi-Fi nodes read the tag of each seeder as it passes from one assembly station to another, indicating where it has been and what its next assembly location will be. In this way, management can see at what point the equipment is in, as well as how much time it spends at each station. At each station, an LCD screen displays exactly what pieces of equipment are going to be arriving from another station, and how many of them there are. In that way, staff can prepare for coming tasks, and even request more assistance, or offer assistance elsewhere based on the volume of equipment on its way to the station.
Altogether there is one LCD screen in the kitting area, eight on the main assembly line and 11 in various subassembly and welding areas throughout the factory.
"Our goal was to improve Takt time," says O'Neal, who expects the reduction to increase from what he estimates may be about 5 percent improvement in Takt time thus far. He reckons there has been a 40 percent reduction in cycle time because of the improvement in replenishment. He has also seen a decrease in overtime work undertaken by kitting staff at the welding station.
"I was pleasantly surprised to see how well the system met our needs," O'Neal says.
