Managing the flow of materials is critical to the successful operation of DaimlerChrysler's 2.9 million square foot Sterling Stamping plant in Sterling Heights, Mich.

At the facility, a fleet of 14 laser-guided tugging and towing AGVs (FMC Technologies, 215-822-4489) automatically transports finished metal parts from the production area to the shipping dock.

With a towing capacity of 30,000 pounds, each vehicle can pull three loaded carts. The vehicles not only transport products loaded onto racks by hand, they also interface with a robotic arm in a fully automated body side panel assembly line.

"We were able to improve overall driver efficiencies, reduce our leasing costs and improve the quality of our material deliveries," says Steven Brostek, director, production and material control, DaimlerChrysler. "That adds up to savings of up to $800,000 a year."

Brostek says DaimlerChrysler had several goals for the system, including a corporate-wide goal to improve safety by creating fork-free zones within every plant and to reduce product damage associated with handling.

The system was installed in phases. Two, four-vehicle systems were used to move racks from the end of a welding/assembly line to the shipping area. In those work areas, finished parts are loaded onto racks by hand.

In the final phase, six vehicles were added to automate the body side panel assembly line. In this system, body side panels are assembled by multiple robotic arms. A final robotic arm loads a shipping rack with 9 completed panels. A vision system enables the exact position of the rack so that the body side is securely held by the rack.

When the first rack is full, the robotic arm signals the vehicle to index forward so that the second rack can be filled. When the third rack is full, the robot control system sends a wireless signal, instructing the vehicle to return to the shipping area. A staged vehicle then moves into place to accept the next side panel so that production never slows.

In the shipping area, a lift truck is used to unload the racks, and the vehicle returns to the press line.