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Die stations with brains adjust changing

July 18, 2006

A US die manufacturer has introduced a new diecutting station that uses electronics and hydraulics to automatically correct many of the problems that plague the cutting process. The new system is described by the developer as “a unique approach to eliminating the most common headaches among converters in the narrow web industry, including material wraps, damaged dies, inconsistent cuts, waste, and short die life.”
The closed loop diecutting control system from American Die Technology is the result of a marriage between the basic principles of hydraulics and sophisticated electronics, according to Area Sales Manager/Engineer Sevki O. Ergun. Here is Ergun’s description of how the technology works:
“The system, on its own, will automatically compensate for changes in diecutting pressure; it relieves pressure when there is an increase due to heat build up, and it adds pressure if there is a loss. The system will detect material wraps and stop the press in milliseconds, and it will automatically maintain the pressure equally on both sides of the web throughout the entire run. This minimizes the amount of time spent on setup, replacement tooling and material waste while maximizing the life of cutting dies, bearing blocks, anvils, and hot stamping cylinders.

Pressure changes
“The concept of equal pressure is similar to keeping an automobile’s front-end aligned to get even tread wear and maximize the life of the tires. The experienced press operators also do their share to quickly catch pressure changes and realign both sides of the web with equal pressure as conditions change throughout the run. However, unless you have a rather tall operator with long arms who is dedicated to monitoring changes who can safely reach over a 16" wide running press to manually adjust the pressure screws to maintain equal pressure at all times, the tools frequently do run under uneven pressure before they are caught. The result is premature and uneven die wear and increased spending in tooling.
“By the same token, broken webs wrap around dies so rapidly that even the quickest of operators are not fast enough to minimize such wasteful occurrences and potentially damaged tooling. There are optical web break detectors which have been available on the market for a long time but there is no advanced technology there. An optical web break detector is simply a camera pointed at the web from about an inch away; if it sees nothing (meaning that the web breaks) it will stop the press. This type of camera does nothing related to diecutting pressure. In fact, it relies solely on what it sees or does not see; so if the lens is blocked by dirt, or if a piece of the waste gets stuck on the camera, it could behave as if the web were still in front of it, when it’s not.
“The closed loop control system is designed to empower press operators of all skill levels to achieve optimum conditions for longest die wear with minimum effort. All the operator has to do is set the desired optimum and the maximum allowed pressure — nothing else! Pressure changes that occur during the run across the web are automatically corrected. Since the entire system is directly linked to diecutting pressure via hydraulics, the electronics that come with this system simply allow the regulation of the pressure applied by this system: They keep it at the desired pressure level automatically throughout the run; they keep it equal on each side of the press and relieve diecutting pressure; and they stop the press immediately if the preset maximum allowed pressure level is exceeded. The pressure settings also can be wired remotely so that they can be set at someone’s desk in an office away from the press.

Digital controls
“The complete unit comes with a digital control panel, bridge plate and an internal pump. Depending on the specs of the materials being converted, the pressure ranges and the design of the product are custom-made so that it is a perfect retrofit as an add on to existing machines. The pressure ranges available are from 25 pounds of down force to 15,000 pounds of down force (for really thick materials).”
Ergun adds that while the pricing of the complete system increases with the web width of the press, the prices for the most common widths — 7", 10", 13", 16", and 20" — are all under $10,000.
American Die Technology is based in Suwanee, GA.