Short Run Clichés
There are basically three types of cliché’s: steel, mid-run, and short-run.
Steel clichés are the most durable of the three types, capable of
lasting more than one million impressions. They
can be anywhere from .250" to .390" thick depending
Mid-run cliché’s are made of thin steel. (.026"
to .040") Also referred to as "record" cliché’s,
mid-run cliché’s can last anywhere from 35,000
to 150,000 impressions, depending upon the application.
Steel and mid-run cliché’s are coated with a
photoresist, dried, then imaged by exposure
to UV light. After exposure they are developed,
touched up, then chemically etched using either
nitric acid or ferric chloride. Due to the complex
nature of this process, most steel and mid-run
cliché’s are made by pad printing equipment
Short-run clichés are also referred to as polymer or plastic clichés.
Short-run cliché’s are the least expensive,
least durable, and easiest to make. Some types
of short-run cliché’s are developed in water,
while others are developed in an alcohol and
water solution. While the alcohol developed
short-runs are typically more durable, the durability
and image resolution of both water and alcohol
developed cliché’s can vary significantly depending
upon manufacturer. For example, some water-developed
cliché’s last only a few hundred impressions,
while high quality alcohol cliché’s can last
20,000 impressions. Ask your supplier which
cliché is best for your application.
When mounting any mid-run or short run cliché
to a spacer or dummy plate, be sure that there
is no debris between the back of the cliché
and the spacer plate. Debris the thickness of
an eyelash can result in a bump in the cliché
which will be shaved off by the ink cup or doctor
blade later, possibly rendering the cliché
Etch depths are usually about .00085" to .001"
(18-25 microns). After the image is picked up,
transferred, and dried, the finished ink film
thickness will be about 20% of your etch depth.
Many people reason that in order to compensate
for such a thin ink deposit all one needs to
do is make the cliché] deeper. Actually,
the best way to increase ink film thickness
is to multiple print the image, since etch depths
in excess of .00115" (or about 40 microns) result
in blurry, smeared images and incomplete transfer.
Screened images are necessary in certain applications.
Large open areas need to be screened to support
the ink cup or doctor blade so that it doesn't
dip into the image during the doctoring stroke.
The screen exposure is a second exposure which,
once developed, results in a fine pattern of
dots or "bumps" in the bottom of the etch. In
addition to support, these dots help provide
resistance to ink flow when the pad compresses
to pick the image up, preventing the ink from
forming a wave that results in an inconsistent
Rotary clichés are often referred to as "drums", since they are
cylindrical. These can be solid steel, mid-run
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