Impressions - February 2014 - 66

talking SHOP

Screen Printing Technique

Controlling Variables, Part 5
In the ﬁnal installment of this series, we address parameters
inﬂuencing ﬂashing and curing procedures.
By Rick Davis, Contributing Writer

n the last article of this series on controlling the variables of the textile
screen printing process, I will review
the factors surrounding ﬂashing and curing procedures.
The heat used in the ﬂashing and curing process is many times disregarded as
a controlled variable once a satisfactory
setting is achieved. There are numerous
aspects that require temperature alterations based on the products being used and
the apparel being printed. These include
low-temperature plastisols, which can cure
around 280˚F, whereas standard plastisols
require 320˚F to properly cure. Low-temperature plastisols often are used when
printing high-elongation fabrics, such as
Lycra spandex. In situations such as these,
you often must adjust the temperatures of
the ﬂash unit and dryer to properly cure
the ink ﬁlm based on the manufacturer's
recommendations.

Flash units can come with numerous
accessories and adjustments allowing for greater
versatility for printing on a variation of fabrics. The
Hopkins unit shown here swings in automatically,
and has hot forced air, and temperature and height
adjustments.

the ink/fabric's heat exposure to avoid
potential shrinkage issues. Every job that
comes to the press that has a ﬂash procedure built into it requires you to examine
the job parameters to determine if the
standard ﬂash settings are suitable for that
production run.

FLASH TYPES
In many cases, specialty fabrics like
Lycra spandex also can be sensitive to
heat, which will dictate that you decrease

Take Notice
Temperature alterations may be required during the ﬂashing and
curing process, depending on the following factors:
1. Ink Type
a. Standard plastisol
b. Low-temperature plastisols
c. Special-effects inks
2. Required ink-ﬁlm thickness being ﬂashed and/or cured
3. Fabric Type
a. Cotton - color and fabric weight
b. Polyester/blends - color and content
c. Specialty fabrics - Lycra spandex
d. Fleece
66

Impressions | February 2014

Two primary types of ﬂash units are
used today. The ﬁrst and most common
for manual printing applications is the
ceramic (black-body) ﬂash unit. The second -and more common for automatic
printing facilities - is the fused quartz
unit. Both work well for their respective
applications; however, fused quartz units
possess a higher wattage output, which
allows for a faster ﬂash and faster production speeds. This is critical for automated
screen printers.
Black-body/ceramic ﬂash units often
are preferred for starter facilities, as they
are less expensive and come in numerous conﬁgurations based on the manufacturer. These units will vary from a static
panel with no temperature adjustment to
automated units that will index over the
garment when triggered. They have adjustable temperature settings, as well as
hot air.
Quartz ﬂash units use a series of highwattage output quartz bulbs that can
impressionsmag.com

http://www.impressionsmag.com

Impressions - February 2014

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