Rail system helps robots maneuver in steel manufacturer’s tight quarters

Güdel TrackMotion technology helped a Kawasaki robot arm maneuver heavy payloads in tight quarters at ArcelorMittal.

Situation

Used to package everything from vegetables to lubricant to bug spray, steel cans are so common that few people give them much regard. But the manufacture of the thin-gauge steel and tinplate used to make these cans can be dirty, dull, and dangerous work—which makes it perfect for robots.

ArcelorMittal, a manufacturer of these materials, transports steel sheeting through the various stages of its West Virginia plant by winding it around cylindrical metal sleeves. These sleeves help prevent damage to the innermost layers of rolled steel when the material is raised on a crane’s lifting beam, or when the spool is slipped on and off mandrels during progressive processing steps. Without the sleeves, the first few inner layers of steel sheet would need to be a thicker gauge to prevent damage to the rest of the roll. But that would also make those layers unusable and produce a significant amount of wasteful steel scrap.

Maneuvering steel sleeves from a stack onto the first two mandrels in ArcelorMittal’s manufacturing process is dirty, dangerous, dull—and inefficient. The process requires the coordinated efforts of an overhead crane operator and a spotter located on the ground—or, more specifically, in a narrow pit with the mandrels. While they are moving each sleeve, the crane operator can’t be doing anything else, and when they are ready to move another sleeve, the crane operator might have already moved on to another task.

In addition, each sleeve weighs more than 500 lbs., and there is little room in the pit for a spotter to maneuver—and thus no room for error. If anything goes wrong, it could kill someone.

Resolution

To improve not only operator safety but also efficiency and cost-effectiveness, the company decided to automate the process. After speaking to several robotics suppliers, ArcelorMittal chose Kawasaki robotics combined with a Güdel TrackMotion Overhead (TMO) rail to maneuver heavy payloads in the tight quarters of its West Virginia steel processing operation.

The weight of the sleeves and the narrowness of the pit presented a challenge for robots. The application clearly called for a heavy-payload model. But the pit left little room to accommodate the bulk of most heavy-payload robot arms.

“There’s two mandrels in the pit, and they’re far enough apart that there’s no way to maneuver sleeves on them without using Güdel’s rail,” said John Weber, sales operations leader for Kawasaki Robotics. “The robot has to physically move side to side to hit both mandrels with a sleeve. Without a rail traversing the pit, we would have had to have used two robots.”

Discussions with ArcelorMittal also made it clear a rail would be needed to permit the robot in the pit to move completely out of the way on occasion and allow operators to access the machinery above and behind the unit.The components comprising the system are two Kawasaki robots, each with a payload capacity for 300 kg, and an 18-ft. TMO rail. One robot, mounted on the floor above the pit, pulls sleeves from a stack and hands them down to the second robot, which is suspended from a single-beam rail running lengthwise along the lip of the pit. The suspended robot employs a magnetic end-of-arm tool to hold each sleeve securely, even in the unlikely event of a power outage.

The single-beam track was instrumental in meeting several of the application’s criteria. In addition to supporting the weight of a heavy-payload robot as well as each sleeve it carries, the track allows the robot to make small lateral movements, enhancing its ability to articulate and maneuver the heavy sleeves onto each mandrel.

The TMO rail also doubles as a walkway along the length of the pit. This is possible because the robot carriage hangs from the bottom of the track, leaving the top of the rail clear for foot traffic.

“Güdel did something else with its track that was a first for me,” Weber said. “The rail has pins that mark its location on the floor. So ArcelorMittal can lift the entire traversing unit with the robot attached off of these pins and remove it to other parts of the plant for maintenance or just get it out of the way to maintain the steel-winding equipment. Then they can pick it back up with the overhead crane and set it down on the pins, and it goes right back into position. Since there’s no need to reprogram anything, away they go.”

By redirecting workers out of the pit and ensuring the initial mandrel-loading step proceeded at a steady tempo, the use of a rail-mounted robot not only improved safety but also efficiency for the steel manufacturer by helping to increase throughput.