Page 23 - MetalForming June 2010

Tooling Technology
Quick Die Change
The Process
Sure, suppliers aplenty stand ready to provide stampers with a slew of products designed to expedite die changes. But to ensure the money is spent wisely, first carefully plan the process and organize the shop floor.
BY LEE ELLARD
Quick die change is a snappy buzz phrase often associated with hard- ware including hydraulic clamps, die rollers, bolster extensions and die carts. However, also required to mini- mize downtime from the last good hit on one die to the first good hit on the next die is a well-formulated, efficient die-change process.
The beautiful thing about developing a successful quick-changeover process is that although it does require some intense thought and effort, most of the plan can be accomplished with minimal cost. Most shops can trim changeover time to less than 20 to 30 min. with lit- tle cost. Then, to get die changes done in as little as 5 to 20 min., capital invest- ment may be required.
Lee Ellard is national sales manager, Stamtec, Inc., a manufacturer of stamp- ing presses and a distributor of feed lines and quick-die-change apparatus: 931/393-5050, www.stamtec.com.
All job changeovers entail similar activities:
• Clear the press area.
• Unclamp, remove and store the die. • Retrieve the new die, and locate it
and clamp it in the press.
• Set up the workplace (coil line,
bins, conveyors, etc.)
• Achieve first part approval.
When planning a die-change pro-
cedure, entrust the people directly involved with changeovers—foremen, operators, setup people—with the responsibility of developing and imple- menting the plan. Put together a core team to:
• Analyze the current job-change process—Videotape a few job changes. • Identify the problem areas—Have the team watch the video and identify the problem areas, such as waiting 15 min. for a forklift to move a scrap bin or for someone to find and retrieve the
next die or the next coil. Breaking the process down into time blocks might look something like this:
Clear the press area Unclamp die
Remove die
Store old die and retrieve new die
Place die in press Clamp die
Adjust shut height
Adjust air counterbalance pressure
Set up workplace (conveyors, bins, feed-up coil stock, etc.)
First-piece approval Fully man the job Total
8 min. 4 min. 2 min.
10 min. 4 min.
14 min. 3 min. 1 min.
20 min. 10 min. 5 min. 81 min.
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METALFORMING / JUNE 2010 21
A good first step to quickening the pace of die changes: create an efficient press- room layout, and store dies close and convenient to the press area, with easy access to the dies by the transport vehicle. Photo courtesy of Green Valley Mfg.