Impressions - April 2024 - 22

harder. Don't worry, this is one of the cheapest upgrades you can do
in a shop; yet it's one of the most overlooked ways to improve the
overall quality of your prints.
Ideally, a selection of different durometer squeegees should be
available for each of the print stations you have.
Mesh, Mesh & More Mesh
Not all mesh is made the same. If you do thorough research, you'll
find that " you usually get what you pay for. " Get some screens from
a reputable source that uses rebuttable mesh. Check that the mesh
is a low elongation type. Keep in mind, some mesh comes from another
industry-like the filtration industry-and is not specifically
made to be stretched to such a high level. Rip resistance is the main
factor they avoid.
Meshes that are specifically made for screen printing are designed
to be stretched and printed through. This means the mesh is more
stable under tension, and when stretched properly, has a greater mesh
opening or percentage of open area. A larger open area will allow ink
to flow through more easily and under less pressure, thus giving you
a better image.
Be aware that different manufacturers may use different thread
thicknesses for their mesh. Some use thicker threads, maybe to avoid
frequent ripping. Others use thinner threads that may rip easier but
are worth every penny. Think of a mesh made of rubber bands. Now
imagine the rubber bands getting thinner when they are stretched out.
When the mesh is stretched properly the threads become thinner, it
opens the area of the mesh that the ink passes through, making it
easier to print using less pressure.
In this zoomed-in view, you can
see the detailed emulsion coverage
on the screen being used. Image
courtesy of International Coatings
Let's briefly discuss mesh tension. Earlier, I mentioned mesh tension
as one of the key ingredients to a quality imprint. Have you ever
used a cheese cutter that uses a thin tight wire? Well, imagine trying
to slice the cheese with a thick, loose wire. Not easy. Now, imagine
slicing cheese for a living, and you want to make more money. The
only way you could make more cash is by slicing faster. Screen printing
through a tight mesh simply makes it easier and faster.
Remember the big shop I mentioned? They really do not like to
double stroke any of the colors. Why? Because doing so can cut the
rate of the prints per hour by 30 percent or more. Less prints per hour
means less income. They will adjust everything (squeegee, mesh type,
emulsion, etc.) to perform at peak level to achieve the maximum rate.
I have often been contacted and asked for help to assess a problem
at a shop. The first thing I like to do is to check the quality of the
current screens they are producing. Is the mesh tight? Is there enough
EOM or thickness of the emulsion? Are there too many pinholes?
Can I see the edges of where the film was? Like in medicine, there
are symptoms or signs of an unhealthy screen.
Correcting Curing
I often get complaints regarding ink not curing. Plastisol-based inks
(which can also include water-based inks) need heat for the ink compounds
to fuse and " cure. " Regularly test your prints during a production
run to assure that the ink is truly cured.
To do so, stretch the " cured " print to see if it cracks too easily. Sometimes
there is simply not enough ink. Otherwise, check the dryer
settings. Is the temperature high enough or is the belt speed too fast?
Check whether the temperature is set at the correct setting for the
type of ink you are using, either standard cure or low cure.
I often find that the temperature is set high enough, but the dryer
belt speed is simply too fast. Plastisol inks need to be cured at
the suggested temperature for at least one minute. Water-based inks
P.22
ImpressionsMagazine.com April 2024
The white underbase for the
design on the facing page.
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Impressions - April 2024

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