A woven mesh supports an ink-blocking stencil in screen printing. Silk threads, nylon, polyester, vinyon, or metal are used to make
flat or cylindrical screens. The printing paste or dye is placed onto the
screen and sprayed onto the fabric through the unobstructed spots. A design is
imprinted on a screen of polyester or other fine mesh, with blank areas coated
with an impermeable material, and ink is driven into the mesh gaps using a fill
blade or squeegee to impress the image onto the printing surface through the
squeegee stroke. Silkscreen, serigraphy, and serigraph printing are all terms
used to refer to this type of printing.
It's called 'Flat Screen Printing' or 'Rotary Screen
Printing,' depending on the type of screen utilized Printing Press in Dubai.
Choking of screens
is commonly caused by high viscosity printing paste, inappropriate squeeze
blade profile, improper screen cleaning, thickening agent deposition under or
over the screens, and frequent printing stoppages.
Misfitting of the
design: Improper screen tension, worn thermoplastic coating, deviations in
blanket guide controlling system, loose end rings, and pressure roll not
working, insufficient color in the screen, defective printing head, magnetic
clamps, and insufficient temperature are all common causes of misfitting of the
design.
Stains: A multitude
of circumstances might result in stains on the garment. The printer might
over-ink, the folders might have a Java meltdown, or the mill might leak a
little machine oil during the stitching operation. Stains are obvious flaws,
and any discoloration on the garment should be reported to the printer, even if
it is little.
Good work habits, such as washing the machine and floor
completely after oiling, ensuring that workers keep their hands clean, using
dry lubricants whenever possible, keeping the work environment clean at all
times, and covering materials with clean covers, are some of the solutions.
Conveyor Stain:
Improper conveyor drying, conveyor cleaning, machine-to-dryer speed
synchronization, and uncleaned nozzles and strainers are all causes of conveyor
staining.
Blanket stain:
This fault is usually caused by a failure of the water supply or the washing
pump, as well as an uneven thermoplastic coating or lines on the thermoplastic.
Misprint or no print
on selvedge: Improper setup, defective guiders, and unequal fabric width at
stitches are the causes of misprint on selvedge.
Improperly Washed Out
Design: Positive permeability to light rays, too heated drying before
exposure, insufficient contact pressure, too long a wait before exposure,
copying emulsion too cold, and exposure time too long are all factors for the
design not washing out properly.
Slippage on the
cloth: Frames were not adequately roughened, the adhesive was not evenly
applied, resulting in bubbles on the surface, and the cloth strip was not
correctly attached to prevent water or color penetration.
Pinholes are tiny
cracks in the emulsion that coats the screen, resulting in small specks of ink
where none should be. A spotting gun can be used to remove them (with the
exception of garment colored clothes). Pinholes are commonly caused by the use
of unfiltered photo emulsion, dust in the working environment, a lack of light
source, and a low hardener concentration. Before submitting the screen for
printing, double-check it.
Pilling of the lacquer
is most commonly caused by an emulsion coating that is too thick, inappropriate
degreasing, and an incorrect hardener percentage.
Placement: There
are some broad guidelines for placing an image on a garment, but because all
garments are different in size and proportion, exact placement is a matter of
taste. It is also influenced by the image's size and shape. The complete front
should be 3-4 inches below the collar, the full back should be 4-6 inches below
the collar, and the left chest should be lined with the sleeve's bottom seam.
All of these are general guidelines; however, the printer's
artistic judgment is crucial. Before printing; if there is a planned placement
that deviates significantly from the above criteria, make it apparent to the
customer.
Taking a full-size photocopy of the image and pasting it on
the shirt to see how it looks is standard procedure employed by printers in
Printing Press in Dubai to ensure that there is proper placement of image.
Send your ‘mock-up' to the printer if you decide it has to
be placed in an unexpected location.
Placement
consistency: Minor differences in placement can be seen from one shirt to
the next. The printer usually feeds the shirt onto the platen in the same way
every time, however shirts might vary in size. As a result, the printer is
frequently forced to make a call. If you have very strict placement consistency
criteria, you should state them right away.
Colour Correctness:
Process printing on clothing has a substantially lower color range than most
other printing technologies, thus colors don't always match well. A talented
inker and a well-engineered separation should be able to produce an attractive
print that captures the essence of the original's variety of tones and contrast
levels. To achieve out-of-range colors, touch plates are frequently employed.
On coloured shirts, the range of process printing is
substantially smaller than on white shirts. The variety of colors available in
spot printing is comparable to that of offset printing. The printer will
benefit from color specifications from any of the usual matching systems, such
as pantone, focoltone, and trumatch. It also helps if their printing and ink
departments are equipped with standard 5000k light source for colour matching.
Smearing of color:
When printing, deformed patterns smear the color. This difficulty can be
avoided by using the right color paste, printing with the right pressure, and
avoiding lateral movement of screens either laying them on the fabric for
printing or removing them afterward.
Dye migration is
a common occurrence with polyester-based garments. The color of the printed
area can be affected because garment dyes do not readily adhere to polyester
fibers. This effect can be noticed right away or weeks later. The most famous
example of this effect is red shirts with white ink, but many other
combinations might cause problems as well. It's critical to choose polyester-compatible
dyes and adhere to process parameters and timings precisely.
Scorching occurs
when the shirt is improperly heated between colors on the press during the
flashing stage or during curing in the main dryer. Scorching can appear in a
variety of colors, ranging from a barely visible yellow to a Cajun blackness.
The most durable inks are plastisol inks, however they must be cured with heat.
A burnt shirt is identified by large regions of yellow or
brown, as well as brittle fibers. To properly gel or cure the inks, a delicate
balance of temperature and time must be struck, and if careful measurements are
not observed, shirts can easily be burned. The size left in the shirts from the
mill might occasionally create this issue. This size can produce a light, airy
effect under normal curing circumstances.
Improper curing
is visible when inks lose a lot of their brightness or opacity following
washing. This is not the same as fibrillation. The curing process is one of the
most closely watched aspects of screen printing using plastsols. To cure
entirely, the ink must reach a specific temperature.
Fibrillation,
often known as icing, is a common side effect of light shirts that is sometimes
mistaken for faulty curing. The effect can be seen on prints that use
transparent inks to obtain particular brilliant hues by leveraging the
whiteness of the garment.
The lack of a strong plastic covering on these inks allows
some of the unprinted fibres to break through the ink layer and dull or
"frost" the picture when it is washed. This is becoming more of a
problem as the market demands heavier, smoother shirts.
These very heavyweight clothing' fibers are particularly
vulnerable to this effect. Because all of the inks employed, save black, are
transparent, process printing is prone to icing. To avoid this problem, it's
critical to follow the process exactly as it's written while producing the
sample and to properly train the staff.
Distortion: If
not loaded properly, the stretchy nature of fabric can result in a distorted
image. When the panel is being loaded, the glue used to secure it on the platen
can catch a piece of the garment and tug it out of shape. Although there are
loading procedures that can reduce this effect, particular shaped prints, such
as hard geometric boxes, will display significantly more distortion than
others. This difficulty can be solved by providing proper operator training.
Opacity: The term
"opacity" is used to describe the degree to which something is
transparent. Balancing dot gain and opacity factors is extremely difficult in
halftone printing. Especially under moderate stretching, the weave pattern of
light shirts should not be seen through the ink, even on light shirts. The
challenge is exacerbated on dark shirts by the necessity to cover the shirt
color with a thick enough coating of opaque lighter colors without making the
garment stiff. In most circumstances, the level of acceptability is a matter of
opinion, and poor coverage should be recognized when it occurs. Reduced
complaining can be achieved by properly training operators and educating
customers on fundamental ideas.
Poor Wash fastness
is affected by improper ink curing. To overcome this difficulty, careful
adherence to the method as specified during the sample development and proper
training of the workers are required.
Registration:
Screen printers employ a variety of presses, each with different registration
tolerances. Any color difference evident from more than a foot or two away is
usually considered unacceptable. A well-trained operator using good, well-tuned
equipment should be able to produce a product with little or no noticeable
error.
Printers in Printing Press in Dubai know that the easiest
technique to get a nice graphic image is to butt register the separations, which
requires near-perfect registration to print well.
Hand: The amount
of ink on a shirt is described by this phrase. A high deposit is permissible
and even anticipated in some printing styles, such as sporty. Any huge ink area
that stiffens the fabric is unpleasant in most other printing types. The weight
of the ink can be felt in severe circumstances, and the print will not breathe,
resulting in a sticky adhesive feeling on the wearer's chest on hot summer
days. It is suggested that you build a library of strategies to obtain adequate
coverage.
Colour out occurs
when the color paste in the reservoir becomes low while printing, causing blank
gaps in the print pattern. This problem can be solved by monitoring the level
of color pastes on a regular basis.
Scrimps are
unprinted lengthwise strips of fabric caused by a printing imperfection known
as scrimp. This might occur as a result of fabrics being folded lengthwise and
not properly fanned out on the printing table.
Every type of job has its own peculiar challenges and the
same is true for printing projects in Printing Press Dubai. However, it is
absolutely vital that to ensure that such projects measure up to the highest
standards; effort must be made to correct every printing problem that may dog
the screen printing process.
Jun 20, 2022 by Ashirasif48gmail.com 1K Views