Supercharged parts delivery

At DaimlerChrysler's Brampton, Ontario assembly plant, 61 guided vehicles have doubled parts throughput.

By Gary Forger, Editorial Director -- Modern Materials Handling, 12/1/2005

There's no doubt about it. DaimlerChrysler has three hot cars on its hands with the Chrysler 300, Dodge Magnum and Dodge Charger. In fact, the company built nearly 260,000 of the cars in the first 10 months of this year.

Fortunately, such popularity has not caught the automaker by surprise. In fact, the company planned for exactly this kind of success when it upgraded the parts delivery system at the Brampton, Ontario plant where all three models are built.

Automation had long been used in the plant. Automatic guided vehicles (AGVs) had brought some parts to the assembly line for nearly 10 years. In addition, an automated storage and retrieval system (AS/RS) had staged stamped parts for more than five years.

During the planning stages for bringing the Magnum, Charger and 300 to Brampton, it was clear the AS/RS was up to the new challenge, but the AGV system was not. Its computer operating system was woefully out of date and uptime was poor. The equipment was essentially obsolete, according to Steve Brostek, director of production and material control for procurement and supply.

The AGV system's shortcomings did not end there. "We needed a new level of flexibility as the complexity of moving materials in the plant was going to increase considerably with our new parts pull system," recalls Brostek. More frequent and precise parts deliveries would be required to support both a lean initiative and in-sequence production.

There are now 61 new AGVs (FMC) in the plant moving parts to the body shop and to trim and final assembly (see layout drawing below). In a typical day, they make nearly 2,700 parts delivery trips, covering roughly 4.75 million feet or 900 miles a day.

Not only is the new system more extensive (only 23 vehicles served the body shop before), but its daily throughput in terms of trips has doubled. Most important, "we now have a parts delivery system that works smart with the AS/RS using integrated controls for a very efficient flow of materials," says Brostek.

Cost of the AGV system exceeded $5 million and has an expected payback of 2.5 years, says Brostek.

Planning for the new parts delivery system started 24 months before the first AGVs went into operation in January of 2004.

As Brostek explains, materials handling is "a tool in a toolbox" that supports production at the plant. To determine which tools were best suited to producing the new models, "we first determined what were the materials moving through the plant, the flow of materials needed, pinch points and safety issues," he adds.

To produce enough cars to meet expected demand, flexibility in the plant needed to be improved without increasing overall plant size. Central to accomplishing that goal was the adoption of a parts pull system in the body shop and in trim/final assembly. That required a highly integrated parts delivery system that directly linked the call for parts at individual workstations all the way back to the actual stamping of parts.

While automation had been successful, it was only one of the handling approaches considered. But it didn't take long to decide that the existing AS/RS would be an integral component if it was better integrated into the flow of materials. Similarly, a new AGV system was clearly part of the plant's future. However, there would need to be other changes as well.

To begin, the AGVs only serviced the body shop, delivering racks of body panels to weld stations. Going forward, AGVs were going to have to be expanded to include the trim/final assembly line. That would require more and different types of vehicles.

There were also materials flow issues with the old system. Unfortunately, the paths mirrored how parts were previously brought to the body shop by lift trucks. As a result, there was congestion of vehicles that restricted parts flow. That also required constant monitoring of the vehicles, tying up human resources that could be better used elsewhere, says Brostek.

One other major issue was the lack of controls integration between the AGVs and other components of the parts supply system. Control systems were independent of each other, and unable to support the new pull model being adopted by the plant.

The system in place today came on line in two stages, January of 2004 and then one year later.

Coming on first were 27 reach vehicles that deliver stamped parts from the AS/RS to the body shop. Operating much like a reach lift truck to access the over/under conveyors at work-stations, these AGVs pickup racks of parts at automated storage and take them to the body shop. These 4,000 pound capacity vehicles make about 800 trips a day over the 200 foot roundtrip route. They deliver to the body shop parts such as fenders and hoods that were stamped at the plant, and return empty racks to the AS/RS.

When body shop operators need more parts, a signal is sent automatically over the plant's data highway to the AGV host computer, which then sends a signal to the AS/RS for more parts. The AS/RS sends a signal to the AGV host when the parts are ready for pickup.

In addition, another 10 masted vehicles make approximately a 2,000 foot roundtrip from receiving docks to the over/under conveyors in the body shop. They carry parts manufactured by suppliers to DaimlerChrysler and staged at the docks.

Five automatic guided tow vehicles also travel the same route as the masted AGVs. Each vehicle tows three dollies filled with racks of parts. All 15 masted and tow vehicles, which also came on line in 2004, are tied into the same data highway as the reach vehicles.

Nineteen pantograph AGVs feed parts from receiving docks to trim and final assembly. The vehicles, which came on line in January, 2005, destack large racks as well as bins from the dock lanes. Then the vehicles bring these parts, which tend to be relatively light weight such as headliners and exhausts, to designated workstations on the line. The pantograph maximizes efficiency of moves in the confined aisle widths of the assembly areas. The vehicles make nearly 400 trips a day over the 500 foot route with the same data highway directing the operation.

Looking over the new system, Brostek says all of the major goals have been achieved. The plant now operates on a pull system that has parts delivered in-sequence to workstations using a highly integrated controls and communication system that coordinates the AGVs and AS/RS. That information system also ties all the way back to the stamping presses, directing which parts need to be produced next.

Overall productivity is up 18%, he says, while operating costs have been reduced along with product and rack damage.

Another benefit of the new system is that storage of inventory in the body shop is negligible now, says Brostek.

Congestion has been eliminated and materials flow maximized. Better yet, people no longer spend time on process redesign but can now focus on efficiency improvements.

The finished system, Brostek says, may not look radically different than before, but the impact it has on operations certainly is.