CRC Technical Notes

Here you will find a few definitions which will help to clarify the converting jargon

Click on the terms highlighted in blue for detailed articles..

Die Cutting

Die Cutting:
	A process of cutting materials, in either roll or sheet form. The cuts can be either partial or complete. Die cutting is often combined with other processes such as laminating, printing, and forming. If the material is cut all the way through, then the process is called thru cutting. Typical applications for thru cutting are gaskets.

Rotary die cutting Steel rule die cutting

Web

Web:
	If a sheet is a rectangular piece of thin material, a web is a sheet which is long enough in one dimension to be rolled up. In the converting business, any material on a roll is referred to as a web. A common phrase might be: 'first the web is unwound, then it is laminated and scored before being sheeted'.

Kiss Cutting

If a kiss cut rectangular piece of thin material, a web is a sheet which is long enough in one dimension to be rolled up. In the converting business, any material on a roll is referred to as a web. A common phrase might be: 'first the web is unwound, then it is laminated and scored before being sheeted".

Thru Cutting

Thru cutting is a cut that goes all the way through all layers being cut.

Slitting

Slitting is the process of making a straight cut, parallel to the edge of the web, through all the layer(s) of material. A typical slitting operation is taking a 60" wide master roll and slitting it down to 10 6.0" wide rolls.

Razor Slitting

Razors are ideal for slitting certain materials such as thin plastic films. For these material, the special carbide razors we use leave a clean edge with little distortion or dust. Razor cutting is less viable for thicker materials and papers which tend to generate dust and rip.

Pressure Cutting

Pressure rollers squeeze the material between blunt round blades and a hard cylindrical anvil. This is a very efficient method of slitting most materials, though the edge quality can suffer when cutting papers and thin films. In most cases, pressure slitting is the best process for cutting felts and foams.

Shear

Shear slitting uses a scissors action to cut thin materials between two overlapping circular blades. This process is the most expensive and the hardest to set up, but is ideal for papers and thin membranes.

Scoring

Scoring is similar to slitting in that it is one or several cuts parallel to the edge of the web, but scoring involves cutting only selective layers of the material. A typical application would be foam weather stripping where several strips are left side by side on the backing paper of the adhesive for ease of handling. Scoring is also a partial cut or weakening of the material to create a fold line as you might find in a box or envelope.

Sheeting

Sheeting is the process of making a straight cut across the web. The idea is that the roll of material is being converted into sheets. The term is some times used to define the process of making individual parts as opposed to rolling up the output of the converting process.

Laminating

Laminating simply means combining two or more webs and bonding them. There are many ways to laminate materials: pressure, heat, adhesive coatings, and surface activation with flame or corona treatment. The most common method of lamination is to use a thin roll of precoated adhesive, often referred to as PSA (pressure sensitive adhesive). Some materials come already coated with adhesive for lamination such as clear laminate overlays.

Core

Most webs are rolled up on a tube called a core, usually made of cardboard or plastic. Most materials are wound on core that have a 3 inch inside diameter, though it is not unusual to find materials on 1", 5", 6", 12", or 16" cores. The larger cores are usually used for materials that have memory. That is, materials such as thicker plastics and heavier papers which take on the shape in which they were stored. This can be a problem if the material comes wound on a roll and the final product must be flat. While there are decurling processes, these materials are often wound on larger cores to reduce the problem.