Impressions - February 2014 - 68

Screen Printing Technique

Another aspect
to consider is
the fact that once the
platens are hot from
exposure to the ﬂash
unit(s), you now are
sending into the dryer
a printed garment that
may be as hot as 125˚F
when entering the
chamber.

In the ﬂashing process, the objective is
to properly gel the ink ﬁlm. The gel point
of plastisol ink can be between 150˚F and
250˚F, depending on the ink being used.
The potential result of curing the underbase
with the ﬂash is poor intercoat adhesion
between the underbase and the overprint.
This, in turn, will result in poor washability.
The overprint simply will not adhere to the
underbase when cured in the dryer.
Another aspect to consider is the fact
that once the platens are hot from exposure to the ﬂash unit, you now are sending
into a dryer a printed garment that may be
as hot as 125˚F when entering the chamber. Remember that you have the dryer set
to cure the ink on a garment that is supposed to be at room temperature.
The objective is to bring the printedand-ﬂashed ink ﬁlm up to 320˚F for a sufﬁcient amount of time to properly cure.
Should the ink ﬁlm be hot going onto the
dryer chamber, you easily could exceed
the cure point of 320˚F and potentially
damage the ink ﬁlm. This is dependent
on the ink's sensitivity and is more apt
to occur on a radiant heat dryer than on a
gas-ﬁred, forced-air dryer.

Fast Flashing
HD and HD Clears
Puff Inks
X
Suade Puffs
X
Metallics
Shimmers
Glitters
Crystalinas
Stretch Inks

FLASHING SFX INKS
Special-effects (SFX) inks offer a special challenge with respect to the ﬂashing
process. The parameters are as varied as
the number of SFX inks offered on the
market today.
The ﬁrst aspect to consider is that, in
the past, 99% of all garments with SFX
graphics added required only one SFX ink.
This greatly simpliﬁed the process because
with a majority of the graphics that possessed SFX ink, that ink would simply be
printed last in the color sequence.
Today, more and more graphics on the
market possess multiple special effects.
The combinations are endless, as are the
ﬂashing variables involved. The trick in
the separation process is where the SFX
ink belongs in the print color sequence
and how to ﬂash that ink, if needed. SFX
inks were not intended to be printed weton-wet. Thus, should you hit a SFX ink
once it is printed onto the fabric, you will
deter its desired effect.
Now that bling apparel is more popular, you can ﬁnd more shirts than ever possessing multiple special effects. The ink
products with the greatest appeal are clear

Medium Flashing

Slow Flashing
X

X
X
X
X
X

Different special effect inks require different ﬂashing parameters. Here is a chart to help
you decide on ﬂashing times, depending on the ink being printed.

Impressions | February 2014

overcoats, crystalline and high-density, as
well as modiﬁed puff inks and ﬂuorescents. These SFX inks are being mixed and
added into graphics in very creative manners to achieve one-of-a-kind effects.
Garments featuring these graphics demand a high retail dollar due to the work
that goes into decorating them. One of
those costs includes not only the SFX inks,
but also the fact that the garment must
be ﬂashed for each special effect that appears on the garment. The only exception
is if there is an SFX ink that can be run
last in the printing sequence. Although
any screen printer with a press and a ﬂash
unit has the capability to execute multiple
SFX graphics, those with the expanded
printing capabilities (14-plus-color automatics) and multiple ﬂash units will have
the greatest efﬁciency and versatility.
The ﬂashing process possesses more
variables than many people consider. Identifying those ﬂash cure-related variables
within your own facility will only improve
your efﬁciency, quality and productivity.
Rick Davis is a screen printing veteran
with more than 30 years in the industry. His
background spans contractor management,
plant management, consulting, international
sourcing and sales. He is currently the southeast regional sales manager for the Triangle
Ink Co. and is a member of the Academy of
Screen and Digital Printing Technology. Rick
also is a speaker at industry trade shows
and a regular contributor to industry trade
magazines. For more information or to comment on this article, email Rick at rdavis@
triangleink.com.

Suggested

Reading

Like this article? Read these and
other screen printing articles at
impressionsmag.com:
* "Controlling Variables, Part 1"
* "Controlling Variables, Part 2"
* "Controlling Variables, Part 3"
* "Controlling Variables, Part 4"
impressionsmag.com

http://www.impressionsmag.com http://www.impressionsmag.com

Impressions - February 2014

Table of Contents for the Digital Edition of Impressions - February 2014