Knife Technical Information

Mario Cotta offer a range of holders to suit all types of slitting & cutting of a variety of webs. There are three main types of slitting methods to cut material: Shear Cut, Razor Blade and Score Cut (crush cut). The most appropriate slitting method used depends on a variety of factors including the type and thickness of the materials, speed of processing & quality of cut.

Shear Cut Knives

This slitting method uses two rotary knives to produce the same cutting effect as obtained by pushing a pair of opened scissors through a sheet of paper. It is used for slitting heavier gauge material such as thicker film/sheet, paper, foil, and most laminates.

Pros: The benefits of this method include accurate slit widths and close tolerances.

Cons: The setup for this method needs to be extremely precise, and requires achieving an ideal angle at the junction of the blades.

Score Cut Knives

Also referred to as “crush cut,” the score cut method involves crushing the material to sever one part from the other by using a dull knife making contact with a hard surface. This method is ideal for slitting pressure-sensitive adhesives, since it creates a “dry,” non-sticky edge.

Pros: Quick setup is a major advantage of this method.

Cons: When the score cut method is used to slit paper material, it creates dust that can accumulate and cause equipment malfunction. Also, if a defect appears when slitting plastic film and sheet, this can create film stretching and deformities (leading to rejects). When used on hard plastic, it may cause cracking.

Razor Cut Knives

Used primarily with light and non-abrasive materials, this method employs a simple razor blade slit in the air or in a grooved roll.

Pros: This is the most economical method, along with having a fast and easy setup.

Cons: This method is not capable of easily cutting through heavy, rigid, or abrasive materials. At high speeds, the razor blade method can also burnish film. If enough heat is generated, it will melt the film, creating a bead that is detrimental to achieving good winding.

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