Die Lifelines
Industry experts advise printers on maximizing die life before, during, and after usage.
by Jessica Millward, Associate Editor
COMMODIFICATION OF MUCH of the die industry has obvious drawbacks for die suppliers, who face intense price wars and shrinking profit margins. But viewing these precision instruments as expendable, interchangeable goods may be eating away at the printer's purse as well. Damage sustained to a die through improper maintenance procedures or careless handling tactics will shorten its life expectancy substantially.
Pre-purchase and set-up
There are a host of possible missteps in die handling/usage, but shortened die life usually can be chalked up to one of a few key factors. "The general causes [of short die life] are not having the right tool for the job; poor handling of the die on press; improper die maintenance and storage; or careless shipping when a die is returned for repair," says Gary Smith, VP/sales at RotoMetrics.
Matching the right die to a given application is paramount to the die's present and future performance characteristics. Such specificity dictates a close relationship between printer and supplier. Action Rotary Die's Production/Purchasing Manager Seth Albert specifically notes the necessity of open, thorough communication between customer and die supplier regarding run length and type of substrate to be used.
Consumables are always a very prominent consideration in die selection because their physical composition may contribute to wear of the die material. As Atlas Die Product Managers Tim Bussard and Marc Love explain, "Many converters now use recycled paper products that may contain a small percentage of non-paper contaminants, including abrasive particles." Bussard and Love insist the printer must also add potential ink complications into the equation. As with paper, some inks are more damaging to die material than others. "A classic example of this is Titanium white, which is among the most abrasive inks and contributes to premature die wear," they note.
An equally important factor in using flexible magnetic dies, Bussard and Love relate, is the precision level of the magnetic cylinder. "Any low or high spots on the cylinder surface can result in a loss of cutting or a smashed die."
Before the die is even on the press, printers can take several steps to ensure the die will perform well into the future. Albert recommends having the die tooled to strike the liner as hard as is feasible. Also, he says, "At the time of order placement, the substrate to be cut should be supplied to the die manufacturer for thorough inspection."
The application of specialty treatment coatings is very often a boon to die longevity, according to Bussard and Love. There is a broad range of these products available; Atlas reports success in employing an ion beam surface-hardening technique, and in freezing the die surface to reinforce a steel structure.
The complete diecutting picture is something to keep in mind when evaluating die cost-effectiveness and lifespan. Jim Riley, president of David K. Hart Co., advises examining the die and the diecutter being used. "Diecutting systems are not all designed the same," he reasons. "The same die may last 1,000,000 revolutions in one system but only 50,000 in another."
On-press particulars
After establishing the ideal die scenario for an application, press operators must be sure to handle dies carefully, and appropriately, according to press type. RotoMetrics' Smith illustrates: "On some presses, installing the assist roll backwards places one of the hold-down bearings on a die blade instead of the bearer, thus mashing the blade." Likewise, Albert warns against permitting the die to sit crookedly within the press-if the bearer rolls over the crescent of the base roll, blades will be crushed.
Once properly fitted, Smith stresses operators should avoid setting loose objects (such as razor blades) on the press, as they will most likely fall into the web and through the die station, causing serious damage. Above all things, printers should protect the cutting edge of the die. For flexible dies, this area is relatively fragile. Therefore, they should never be stacked on one another without a protective layer in between, state Bussard and Love. Also, operators should remove all jewelry before handling dies, and should shield the dies from any bumps to avoid nicks.
Long-term maintenance
Storage and post-press handling play a large part in the life expectancy of any die. Suppliers suggest a spray treatment following use, and then a return to a protected area. Riley suggests using a rust-preventative spray coating, and storing the die plate with a protective cover. "Suspend from hangers or lay flat, but avoid areas where weight may be placed on top," he concludes.
Albert reminds printers to check corollary items for wear and tear that might affect die performance. For example, he says, journal blocks and anvils should be checked regularly and replaced if necessary.
A final recommendation for die longevity is the creation of a die history file. Smith elaborates, "By reviewing these records, you get an indication of when it may be time to retool the die." With the history file's tracking of die usage/treatment, suppliers are better able to evaluate the printer's current and future die needs.
