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 660 Views