Flexibility and change have become critical components for success in manufacturing. The concept of quick die change is basic: minimize the time from the last good hit on one die to the first good hit on the next one. The following are six common tool-changing challenges for stampers, and some tips to solve such pains.

Quick changeover is the practice of reducing the time it takes to change a line or machine from running one product to the next. One of the cornerstones of an efficient stamping operation is its ability to perform die changes in less than 10 minutes.

The successful implementation of quick changeover is the key to a competitive advantage for any manufacturer that produces, prepares, processes or packages a variety of products on a single machine, line or cell, according to Superfactory. Quick changeover allows manufacturers to keep less inventory while supporting customer demand for products with even the slight variations.

Put another way, die changeover is one of the few times when a press is not making money. Some die changeovers take five minutes, some take hours.

The following are six common challenges that cause stampers the most aggravation when changing a tool and tips to solve such pains, from Tecnomagnete Inc. magnetic die clamp sales manager Paul Van Every, as noted in TheFabricator.com’s STAMPING JOURNAL.

1. Different Die Sizes
If you’re working with different die sizes from job to job, and if you have a large number of dies, consider a die clamping system that works with a variety of die sizes. Some stampers locate dies with T-slots and simple spacers or locator pins on magnetic clamps to reduce the time it takes to locate a die.

When it comes to loading large dies, consider mounting line-up blocks to the press bolster or painting a red stripe on the center of the die and center of the press, as either of these can help operators line up a die more easily. Installing die lifters into existing T-slots can reduce the effort of lining up dies, without using up precious die space. Die lifters can be used in conjunction with hydraulic or manual die loading and hydraulic or magnetic clamping.

2. Locating Necessary Tools, Including the Next Die
A die clamp standard can save time by eliminating decisions such as which stud or finger clamp is needed, as well as clamp placement. “Shops that alter studs and clamps so they are similar save the most time,” according to Van Every. Creating a die change toolkit that contains everything needed allows for optimal use of time. Automated clamping mechanisms that require very little adjustment with as few tools as possible also can reduce set-up times.

Likewise, have a place for each die and label it to avoid wasting hours trying to locate a particular one. A die-labeling system is an inexpensive way to reduce changeover downtime, as it tracks where a die is at all times.

3. Changing Clamps
To reduce changeover times, look for clamps that can accommodate all die sizes run on a press. E.g., Hydraulic clamps that fit in existing T-slots can slide in and out easily. Magnetic clamps that cover the entire ram and bolster can eliminate all tools while accommodating all die sizes without standardization.

Similar, it should be noted that if a shop uses a hydraulic mechanical system to clamp dies, the shoe usually has to be the same thickness from die to die for the clamping system to work. Keep in mind that sometimes the cost of altering the shoe thickness is far greater than the initial clamp investment. This is not an issue for systems that can accommodate any die shoe thickness.

4. Making Ram Adjustments
Making ram adjustments is crucial and time-consuming. Altering die heights to a small window reduces the time needed to get the next die running, because some rams can adjust at less than 1 inch per five minutes. For example, running two dies back-to-back with similar shut heights can reduce ram adjustment times, writes Van Every.

5. Moving Dies In and Out
Reducing a dye’s total travel distance is a quick way to shave time from changeovers. For example, Van Every notes, “one stamper uses a die storage unit with multiple-height die racks. It has enough room to put all the dies on the same level as the bolster.” Then the stamper installed a simple roller system that extended all the way to the press, which eliminated a lift truck or die cart in the die-changing process. As the stamper then had 26 dies on four levels 12 feet above floor level assigned to a single press, he saved enough time to eliminate an entire production shift on two presses.

6. Recognizing Component Wear and Tear
Even the most organized plants can suddenly find themselves in a pinch when nuts and bolts, studs and clamps of all variety wear out over time and become unusable. Stampers that have a planned maintenance program or a clamping system with no wearable parts fare the best in reducing this element of changeover time.

Finally, keep in mind that the cleaner the pressroom, the more efficient the pressroom. So Van Every suggests cataloging non-inventory items at least once a year, and “if you find something that doesn’t belong, get rid of it.”

Let us know if quick changeover provides competitive advantage in your manufacturing process.

Resources

10 common quick die change problems
by Paul Van Every, Tecnomagnete Inc.
STAMPING JOURNAL (TheFabricator.com), Nov. 7, 2006

Superfactory: Quick Changeover – Single Minute Exchange of Dies (SMED)