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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
rotary die cutting
Steel rule 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.
- 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
- The process of cutting selective layers of material.
This can be done very accurately with a rotary die in that
the height of the blade above the anvil is maintained precisely.
A typical application is a label that can be peeled off and
applied to a box. Scoring and butt cutting are special
cases of kiss cutting.
- Thru Cutting
- When all the layers of material are to be cut at the
same time, the blades cut completely through the material.
The shape of thru cutting blades is different than the shape
of kiss cutting blades. Slitting and sheeting are special
cases of thru cutting.
- 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 slitting
- 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 slitting
- 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.
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