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Safer, Faster Die Changes

By: Brad Kuvin

Saturday, March 01, 2008
 
The pressroom at the Price Industries manufacturing plant in Suwanee, GA, had grown accustomed to sharing a forklift with other plant departments every time it needed to change out its single-stage stamping dies. Press operators tending to the firm’s 15 medium- to high-tonnage presses (45 to 500 tons) would call on
This 11,000 lb. capacity die cart serves three straightside presses
This 11,000-lb.-capacity die cart (top) serves three straightside presses and seven three-tier die racks at Price Industries. To extract a die, the cart operator raises the die table to the height of the die, then extends the arms of the lift (bottom) out to the die far enough to slide the hooks at the end of the arms over die handles. Retracting the arms then slides the die onto the cart’s die table.
two toolroom employees to leave their posts and head into the pressroom to change dies as needed, typically at least once per shift. If and when the die-change duo could even locate a forklift, die changes then would take at least 60 to 90 min.

In addition, the firm’s line of air-distribution products (grilles, registers and diffusers) has developed over the last 10 to 15 years to larger products, and at the same time those overseeing Price’s 45,000-sq.-ft. pressroom were tasked with improving productivity. Part of the solution came by moving away from single-stage dies and toward fully progressive dies. While forklifts could safely move the smaller dies, the die-change procedure proved unsafe when, in 2000, large 10,000-lb. progressive dies began showing up on the floor.

“To remove a die from a press,” explains tooling engineer Billy Googe, “the tool-change team would have to catch the edge of the die with a fork, pick the edge of the die up and then slide wood or steel blocks under the die plate so that the team members could slide both forks under the die. They then would tilt the forks back in order to move the blocks underneath the back of the die to move the fork lift as close as possible to the die. They’d then pick up the die and back away from the press, then move to the die rack. With the bigger and heavier progressive dies, the procedure became not only slow and tedious, but very unsafe. Blocks could slip out, or the die could slide off of the forks.”

Die Cart to the Rescue

In 2005, with a substantial inventory of progressive dies, Price invested in a 11,000-lb.-capacity die cart with 71 in. of lift, to serve its three biggest presses—150-, 300- and 500-ton straightside models. Along with the cart came seven three-tier die racks with docking, roller and locating pins to handle some 15 progressive dies. The cart—a walk-behind self-powered model—and racks came from Lightning Time Savers, Nicholasville, KY, with installation assistance provided by Price’s local industrial distributor, Southern Industrial Equipment, a supplier of pressroom equipment and automation.

“The presses run at 25 to 30 strokes/ min., and we easily can get a typical production run out of a die in one shift, sometimes less,” says Googe. “But we needed a better process to switch out our dies, since each end product requires a set of three dies to supply parts for our assembly lines. Thanks to the die cart and racks, we’ve improved our die-change process from where we required two toolroom people and as long as 90 min. to change out a die to having the press operator change out dies in as little as 5 min. A dedicated cart for die changes has improved our pressroom productivity immensely. And, the toolroom guys can continue to service our dies, rather than leaving the toolroom to perform die changes out in the pressroom.”

Rollers on the die racks and lift rails on the dies that slide into T-slots on the press bolster plates prevent damage to the dies during changes. Mounting plates have location slots machined into them that match locating pins mounted to the bolster plates of the presses.

And the floor-mounted location blocks also have locating pins to line up with slots at the front of the die cart, to ensure that the operator locates the die cart precisely and repeatably each time, and picks up and drops off dies in the same location. “There’s no bumping around, and no alignment issues with the feeders at the presses,” says Googe.

To extract a die, the cart operator raises the die table to the height of the die (whether in a press or rack), then extends the arms of the lift out to the die far enough to slide the hooks at the end of the arms over die handles. Retracting the arms then slides the die onto the cart’s die table.

A Second Cart Coming, and Maybe a Third

Price has enjoyed notable sales growth, so much so that it’s building a second plant nearby. It’s also launching a new product line that requires even larger dies, which will run on a 400-ton hydraulic press—blank-fed using pick-and-place robots. For this line and its accompanying dies, Googe, along with Mike Wise, the plant’s manufacturing engineering manager, decided to invest in a second die cart from Lightning Time Savers, similar in design but with more capacity—16,000 lb.—and wider to accommodate an additional two sets of rollers on the die table. It arrives at the plant in May.

“Once we get our new plant up and running,” says Wise, “we might move the original die cart to the new plant and purchase a third cart to replace it.”

MF

 

See also: Lightning Time Savers, Southern Industrial Equipment

Related Enterprise Zones: Tool & Die


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