QDC--Prestaging Can Cut Die-Change Time by More Than Half
That’s the message from QDC specialist Gary Zunker, president of Lightning Time Savers, Nicholasville, KY. Zunker spends much time traveling to metalforming operations and working with teams to analyze and correct die-change procedures, often cutting changeover times by 50 percent or more prior to any major QDC-equipment purchases.
He let MetalForming in on some relatively inexpensive die-change secrets.
Prestage, Prestage, Prestage
Prestaging is key, according to Zunker, noting that such common-sense approaches are not nearly as common as they should be.
“That’s the first step in successful QDC,” he says.
|This two-tier die cart placed near the press aids in quick die change by serving as a staging rack for a die waiting to run and at the same time can hold a die removed from the press. The setup saves on travel time for die retrieval.|
He suggests placement of a rack at the press as an inexpensive simple step metalformers can take right away.
“Instead of having a forklift travel long distances to obtain a tool or return it to storage, which a lot of stampers continue to do today, position a small two-tier rack at the press so that the forklift can remove a die from the press, place it on one tier and take another die, already staged on another rack tier, and place it into the press,” Zunker explains. “That saves a large amount of time usually taken by travel back and forth with the dies.”
Suppose space does not permit permanent placement of such a rack at the press?
“If that’s the case, what can I do to pull the die out quickly, take it somewhere and bring another die back?” he asks.
Rethink the Forklift
A forklift, especially one dedicated to the press, can take care of that, but it is not the ideal option.
Another reason to avoid forklifts for die transport, according to Zunker, has to do with forklift availability.
“Shop-floor personnel use forklifts all the time to move material, parts and equipment all over the plant,” he says. “So when it’s time to retrieve the die for the next job or pull the old tooling out of the press, personnel must track down the forklift or wait for it to show up. All of these things lead to inefficiencies and lost time.”
And one more thing: Forklifts routinely store dies in racks in a haphazard fashion, according to Zunker. Storing at odd angles or in extremely close proximity to other stored dies makes die retrieval from the racks difficult and time-consuming.
Die Carts Are Excellent Investments
The alternative? A die cart.
“A die cart solves the safety problem because it is designed to safely hold a die during transport, and it eliminates the ‘go fetch’ routine because the die cart can only do one thing—place the die into the press,” Zunker explains. “And a die cart protects the tooling and the press because it gingerly rolls the die into the press without dropping it, avoiding damage to tool components, sensors and the press itself. The die is under complete control during transportation.”
Die carts, when compared to forklifts, also add speed to the die-change equation.
Again, the key to successful QDC is prestaging, but that includes not only the dies but all of the tools—wrenches, clamps, etc.—needed to finish out a die change.
Huge Time Savings
“Given some simple steps such as these, we’ve seen 50 percent changeover-time reduction or greater without spending capital dollars,” says Zunker.
Another metalformer, Schlage Lock Co., was able to reduce average change-over on five 200-ton coil-fed presses from 55 to 15 min. after a QDC Blitz, according to Zunker.
Says Sean McDermott, operations manager at Schlage Lock: “We had invested heavily in the equipment required to perform quick die change, but had not realized many of its benefits. With no additional investment, the simple concepts of prestaging, team setups, and ownership enabled us to achieve an 80 percent reduction in setup times within two weeks.”
As a result of that effort, the company’s output increased by more than 40 percent. Such numbers make quite an argument for examining your die-change procedures.
Zunker notes that even greater time reductions are possible given implementation of the right equipment, such as multiple tier racks and turntables that can be positioned at the press and accept the old dies while rotating and supplying the press with a new prestaged die. MF
See also: Lightning Time Savers
Related Enterprise Zones: Tool & Die
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