Choosing the Right Equipment
Focusing on your customers' application parameters—while keeping cost, safety, and simplicity in mind—are important factors in choosing the right slitter for the job.
ACCORDING TO "Slitting Techniques, Choosing the Best Method," produced by Tidland Corporation, it may be safe to say there are not many manufacturing industries that handle such a wide array of processed materials as package printing. Most of these materials need to be slit—cleanly, easily, and safely—in most converters' operations. There are three main slitting methods in use and Tidland has come up with a formula to best match the correct slitting method to the application.
Easy as 1, 2, 3
The 3-step procedure used by Tidland is: 1) Identify the important characteristics of each slitting method; 2) Identify the characteristics of the material to be slit; and 3) Match the material to the best slitting method.
These three slitting methods include sheer slitting, crush or score slitting, and razor slitting. Each has its own set of pros and cons.
Shear slitting, according to Brian Ivens, sales and marketing manager, Arpeco, can run at or faster than web speed, with the two blades acting in a scissor action to cut the web. This method generates minimal amounts of slitting dust. "This system is most effective for paper products," he added.
The second method—score or crush slitting—is a more complex method of separating the web, and although it is common, it involves the installation of a hardened anvil roll and wrapping the web over the roll, says Reiny Schable, application technology manager for Tidland. The slit occurs in the crushing nip between the anvil and the slitting wheel, and while changing widths is not hard, crush slitting has some downfalls.
"Changing slit widths is relatively easy, since only the slitter is repositioned over the fixed anvil roll," Schable said. One of its downfalls, however, is it is the most dusty of the slitting methods, delivering the poorest edge quality," he says.