AGVs Help Old DaimlerChrysler Plant Compete

Automated material handling made this 45-year-old stamping plant more efficient — therefore, more cost-competitive.

When DaimlerChrysler asked its plant managers for ideas on how to modernize stamping operations in the year 2000, Conrad Hawley saw the writing on the wall of his 45-year-old Twinsburg, Ohio facility. He knew he had to find a way to make these operations more cost-competitive or the company would lose ground to competitors investing in new facilities. At the same time, as the plant's production control manager, he also saw an opportunity. By automating material handling, he figured the company could improve efficiency and increase the plant's longevity at the same time.

Much of the savings would come from eliminating lift trucks and making better use of their operators. Since the plant opened in 1959, lift trucks have been its primary form of material handling. A fleet of 138 vehicles fed the hungry stamping lines. Strict safety guidelines demanded that operators with full loads drive in reverse. This directive resulted in many sore backs and necks, as well as accompanying medical claims.

As Hawley and material handling engineer Jim Petruna considered different automated material handling solutions, they soon learned this would not be an easy project. They’d have to overcome several constraints to achieve success in this building.

The plant’s age was the first constraint. The location of the equipment, width of the narrow aisles, and irregular woodblock floor (including in-plant railroad crossings) was set and could not be changed. “We don’t change layouts in our assembly area other than when model years change,” Hawley explains. “That means you have to wait every four to five years before you can make any major changes. You can’t make the aisles any wider.”

That fact alone made choosing an automatic guided vehicle (AGV) system seem a foolish notion. But Hawley and Petruna saw opportunities that the naysayers in the company didn’t.

“Jim and I started benchmarking some Ford facilities which had older AGVs,” Hawley recalls. “We decided we could do this in an existing facility. The alternative would be to continue how we’ve been moving material since the plant opened — with lift trucks. The safety standpoint also drove what we wanted to do, because injuries slow down the whole plant. We saw AGVs work with old systems and said there isn’t anything we’re doing that’s not repeatable. We know it will take the same path, so there’s no reason it shouldn’t work at our place.”

Clearing obstacles

When Hawley got authorization to start the project, he had a big wish list.He got authorization for only two AGVs.

That made the case for tugger vehicles, because they can transport a maximum amount of material per vehicle.

“Our business is different from assembly plants,” he explains. “We move a lot of big sheet metal at line speeds of 500 per hour. An assembly plant moves much smaller items at 40 an hour. Our challenge was moving big parts and big quantities on a regular basis.”

Even though the AGV project won authorization, those who knew the building were nervous. They knew the turns alone would be a challenge.

“You couldn’t look from one end of our plant to another without seeing something in an aisle,” Hawley adds. “But we thought if AGVs could work at an old plant like Ford Chicago, they could work here.”

But a second major obstacle centered around the labor force. After doing things the same way for many years, there was resistance to change. There was the general perception that automation is the enemy because it eliminates jobs. As you would expect, the 2,300 employees at Twinsburg represent a force with considerable power, and a project will “die” without their support. The challenge for Hawley and Petruna was to gain acceptance by the labor force. Knowing that, they sat down with the union that handles lift truck maintenance and agreed that they would maintain the AGVs.

“The skilled trades guys in this department eventually saw this as their future,” says Hawley. “They knew that most plants outsource the service on AGVs, so they saw this as an opportunity. If they’re not fixing these, they knew they wouldn’t have a future with us.”

A third major obstacle involved providing an acceptable ROI or payback by not only keeping pace with increased production, but by reducing costs in areas (labor and damaged material) while maintaining high safety standards and ergonomic issues.

Phased implementation

A key element was to break the project into small phases, prove the concept and expand. Using this methodology, the project developed momentum. As one phase was successfully completed, there was an emotional lift which increased support for the next phase.

“We focused on multiple stage projects in all departments,” explains Jim Petruna. “We wanted everyone, including management, the union and the safety department comfortable with the solution. This phased implementation approach becomes more beneficial as the system price increases and as the potential effects on production increase. You limit risk by ‘walking before you run.’”

Following this implementation model, the Twinsburg project team divided the project into four basic phases.

In the first phase, a two-vehicle self-guided vehicle system was installed to haul full racks from certain press lines to the shipping department. The effect on throughput as a result of this change was demonstrated using simulation software, then actual values were benchmarked against historical numbers at Twinsburg and against the other DaimlerChrysler stamping plants.

The two-vehicle system was run for six months to develop estimates of longer term operation vs. what could be learned in very short duration testing .

In the subsequent three phases, an additional 29 AGVs were installed, along with over/under racking and turntables. Payback during these phases varied, depending on the labor involved in the operations.

“In the first two phases, because we didn’t have people in certain places, payback was probably a year,” Hawley calculates. “The next phase was a six-month payback because I had lines where there were four drivers and we went down to one. That’s across multiple shifts. When we ordered our last lift truck fleet, we used most of them two or three shifts. We reduced the fleet by 35 lift trucks on the first, then eight on the next one and 16 on the next.”

Results

The safety and productivity gains Hawley and Petruna expected were achieved.

“We met all the cost savings goals we forecasted,” Hawley testifies. “Throughput has increased by 25 percent because of reduced downtime in the pressroom and assembly areas.”

In addition, Twinsburg has become the benchmark stamping plant for DaimlerChrysler, and its other two stamping plants are now implementing similar programs. Engineering teams from Daimler’s plants worldwide have visited to learn from what has been accomplished in Twinsburg.

This project also resulted in some industry firsts, according to Mark Long- acre, of FMC Technologies, suppliers of the AGVs.

“In developing this program, Conrad and Jim asked for features and capabilities that exceeded what was currently available,” he says. “A major decision was the type of bumper to use. Mechanical bumpers had been traditionally used on guided vehicles, but a new laser bumper [Sick] had become available. Because of the reduced maintenance requirements and programmability of the laser bumper, there were advantages to replacing the traditional mechanical bumper with the laser bumper. Twinsburg was the first major guided vehicle installation in the North American automotive industry that took advantage of the laser bumper technology. This was a major advancement and nearly every guided vehicle installation since Twinsburg has used laser bumpers in the same arrangement that was perfected at Twinsburg.”

But the modernization at Twinsburg is not finished. It has transitioned to a “continuous improvement mode.” By the end of the year, Twinsburg will install forked AGVs.

“Our sister plant, Toledo assembly, has fork style vehicles,” Hawley explains. “That was a big bold step in that we usually move multiple racks while they’re moving one rack at a time. We’ll be loading up door inners and outers on the lines where we now use a manual lift truck to put racks on and off turntables. We want as much direct labor as we can focused on manufacturing. Customers don’t want to pay for material handling.”

Another reason this project has been so successful for Twinsburg is that the company didn’t lay anybody off. In fact, it went into this program short of manpower, with Hawley and Petruna hoping that this project would be successful enough to reduce the workforce through attrition, as people retire. The system is also making good use of the existing labor.

“Instead of having one guy worry about one line, and maybe we’re getting 50 to 60 percent utilization because he can’t do another line, now he can handle multiple AGVs coming at him and his utilization can go up,” Hawley concludes. “That’s what we call playing center field because he’s out there handling the whole area. We also get suggestions from our people on the floor to improve operations. For the lines where we don’t have AGVs, when there’s an AGV right next door and it’s not being fully utilized, they’ll say, ‘why don’t we look at using the last dolly every hour and start supporting that line also?’ Once you get used to what these vehicles can do, you get people discussing these possibilities. That way you keep making it better.” MHM

Editor’s Note: In our November issue, Conrad Hawley will be honored, along with several other material handling professionals, in Material Handling Management’s first Material Handling Innovation Awards program. These awards will be distributed during an awards banquet in Cleveland next year, held concurrently with the Material Handling Industry of America’s NA/2004 Material Handling Show. For more information, contact MHM at (216) 931-9346.

System Suppliers

FMC Technologies (AGVs) www.fmcgvs.com

Orchid International (Turntables) www.orchidinternational.com

SailRail (over/under racks) www.sailrail.com

Sick (laser bumpers) www.sick.com

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