Page 36 - MetalForming January 2011

Tooling Technology
A Heroic Die-Handling
Effort
A heavy-duty two-position die cart with a retractable bridge extension improves die-locating repeatability while enabling a 70-percent reduction in die-change time at a Metalsa (formerly Dana) automotive plant.
BY BRAD F. KUVIN, EDITOR
You won’t find too many presses as large as Press 25 at the Hop- kinsville, KY, Tier One automotive plant of Metalsa. It’s one big press—a 3000-ton Clearing with 300- by 72-in. bed, blank-loaded to stamp frame rails for pickup trucks and motor homes. The press hit the production floor of the 420,000-sq.-ft. plant in 2000, commis- sioned for manual transfer work. For ergonomic reasons—the large frame rails proved a challenge for workers to man-handle—in 2004 plant manage- ment added four robots to the press line to move parts in and out of the dies. But while the robots solved one issue, they created others.
“When we were manually transfer- ring stampings in and out of the dies at Press 25, precise die location was not a critical requirement,” says Barry West, a project engineer at the Metalsa Struc- tural Products facility. The plant sup- plies structures for light and heavy trucks, buses and passenger cars. Die locating via a groove machined into the bottom of each tool and a ball- shaped locator in the press bed pro- duced die-location repeatability to within 1⁄2 in. or so, accurate enough to accommodate manual parts transfer. However, when robots entered serv- ice, the half inch of die-position vari- ability required operators to reprogram
Automation abounds at Press 25 (3000-ton Clearing, 300- by 72-in. bed) at the Metalsa Structural Products (formerly Dana) facility in Hopkinsville, KY. Robots (right) move blanks and parts on and off the press, and a two-position die cart shuttles 80,000- to 100,000-lb. dies on and off the press bolster.
34 MetalForming/January 2011
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the robots with every die change—a regular occurrence.
“We’ve run anywhere from eight to 12 different tools on that press over the years, and we change the dies out at least once per shift,” says West. “Repro- gramming the robots added at least 30 min. to each die-change cycle.”
Overall, die changes would take an average of 200 min., West recalls, thanks not only to robot reprogramming but also in part to yet another issue pre- sented when the plant added the robots to Press 25: it had to add a blank feed- er to the front of the press. “Every time we went to change dies,” West adds, “we had to use a crane to move the blank feeder out of the way—there’s
no room (in the 100- by 200-ft. press bay) behind the press to accommo- date die changes.”
There’s Got to be a Better Way
When operators finally had had enough of completing 3-plus-hr. die changes using what West refers to as a flat-bed die hauler to move dies in and out of Press 25, West and the Hop- kinsville team went looking for a more efficient and accurate solution. Goals included improving die-locating accu- racy; enabling die changes without having to endure the time-consuming task of moving the blank feeder out of the way and then back into position with each die change; and the ability to