The Die is a cutting tool designed to cut a repeat pattern and can be manufactured in either a flat or cylinder profile.

Flat Bed Dies are sharpened steel rule fastened in a movable chase. The chase is lowered to a stationary anvil as the web stops momentarily and then returns to the ready position.

Magnetic Dies are machined or etched from thin flat sheets of metal which are wrapped around a magnetic cylinder on a rotary press. The depth of blade is significantly less than with an engraved die however the costs can and the durability are also less.

Rotary Engraved Dies are manufactured from a solid cylinder where the cutting edge is formed by removing material from the surface of the cylinder, creating a raised sharpened cutting surface. Engraved dies are typically more expensive however will normally last longer and can be used on more intricate shapes and designs. An additional portion of engraved dies is the addition of bearers which is a collar on either side of the cylinder which positions the cutting surfaces at the precise distance from the anvil roll, thus controlling the depth of cut.

Die Bearers

Bearers are precision ground surfaces on each end of an engraved die or magnetic cylinder that maintains a specific distance between the cutting blade and the anvil surface. This clearance is determined by the caliper of the liner to be used. (40# = 2.5 mils, 50# - 3.2 mils target, etc.) The caliper of the release liner is critical since the proximity of the die to the anvil roll surface is controlled, the liner becomes an extension of the anvil roll, supporting the facestock and adhesive so they can be cut.

If the release liner varies in thickness, the facestock and adhesive will be pressed either too far into the die or not far enough. Materials with high liner caliper could result in liner breaks during automatic label application because of cuts in the liner, or could cause label dispensing problems due to adhesive flow through cuts in the silicone layer. Materials with low liner caliper could result in problems with label matrix breaks or label predispensing during converting due to the label surface or adhesive insufficiently cut.

Anvil Roll

The anvil roll is a precision ground roll of hardened steel that the bearers ride on. The anvil roll as in the analogy of a blacksmith's anvil, is the surface that supports the material that is to be hammered or in the case of label converting, supports the material to be cut.

In some operations the cutting surface is pressed directly against the anvil roll, cutting the material all the way through. "Steel to Steel die cutting as it is called is not normally used in the pressure-sensitive industry. In some cases the anvil may be ground to have slightly larger or slightly smaller diameter to the ends, where the bearers ride, so as to move the liner paper closer or further away from the cutting edge of the die. These are called stepped anvil rolls and can be used to compensate for materials with either thicker or thinner liners.

Die Blades

Die blades which is the sharpened cutting edge are ground in a variety of configurations based on the requirements of the die. Single bevel, single taper are common in flat bed steel rule dies. Single bevel, double taper and Double bevel, double taper are other types. The taper is generally determined by the die manufacturer based on what the die will be used for. Typically, die blades for paper will be set to a 28 degree angle while films will have a 21 degree angle. However, this can change slightly from die manufacturer to die manufacturer, and from one film to another.

Die Pressures

Most die manufacturers recommend die pressure of 120# per lineal inch of blade width. That is a combined pressure for each side of the die. In other words, each jack bolt should have 60# pressure for each inch of cross web blade.

Die Life

Die life will vary depending on the material being cut. Any material containing fillers and/or abrasive coatings will reduce die life. This would include heavily filled ink coating such as opaque white screen inks.

Die manufacturer will not commit to a minimum number of impressions before the die needs to be retooled. They will recommend coatings to help prolong the life of a die.

Film dies require a sharper edge than paper dies due to the conformability of the film. The cutting edge must cut the elastic films as compared to the bursting operation when cutting paper. When cutting attempting to cut papers with an overlaminant, the dies must be tooled to the film overlam. Improper tooling will stretch the film and burst the paper and or liner before the film is cut. In some cases, films will cut easier if a larger wrap is made on the anvil roll.