SCREEN PRINTING
Screen printing is the oldest and most widespread printing technique. Today, it is among the highest-quality and premium printing methods, allowing designs to be printed on almost any type of surface. The printed motif can range from a simple, single-color design to a full-color photographic image.
The most common and well-known use of screen printing is on textile materials, such as T-shirts. Screen printing belongs to the category of stencil printing techniques. The printing form consists of a frame with a stretched mesh. Using a squeegee, the ink is pressed through the mesh onto the chosen material or substrate. Frames can be made of wood, plastic, or metal (aluminium). The aluminium frame is the most durable and long-lasting, resistant to chemicals, corrosion, and easy to clean.
The meshes can be made from natural, metallic, or synthetic materials. Synthetic meshes are the most commonly used for making stencils, with polyamide (nylon) and polyester meshes being the most popular types.
A stencil represents the design to be printed. A photosensitive emulsion is applied to the mesh and dried with warm air in a darkroom, away from sunlight. A positive film of the design is then placed on the mesh and exposed to UV light, which hardens the emulsion. This process creates open and closed areas on the screen: the open areas (printing elements) allow ink to pass through onto the substrate, while the closed areas (non-printing elements) block the ink.
After exposure, the screen is rinsed with water to remove the unexposed emulsion, then dried. Once dry, the screen is ready to be mounted on the printing machine. The screen must be precisely aligned to ensure the print appears in the correct position; for multi-color prints or photographs, color separation or halftone processing is required. Images can be reproduced in four colors using the CMYK system (cyan, magenta, yellow, and black).
The printing ink is prepared just before printing. If necessary, water or thinner is added to the original ink to adjust its viscosity. The ink must not be too thick to ensure it spreads evenly across the stencil using the squeegee. Additionally, drying retarders, accelerators, or surface varnishes can be added to the ink as needed.
Drying tunnels fix the applied ink onto the substrate as it passes through. The finished print emerges dry, durable, and long-lasting. Both manual and automatic (carousel) screen printing machines are used.
In manual printing, the operator places the T-shirt on the platen, lowers the screen, spreads the ink, and presses it through the mesh with the squeegee. The screen is then lifted, and the shirt is removed and placed into the drying tunnel.
In automated machines, most steps are simplified and faster. The operator loads the shirt onto the platen, and the machine automatically rotates it to the printing position, applies the ink, and presses it with the squeegee. The printed shirt is then passed to another operator who places it into the drying tunnel. The tunnel, typically 3–6 meters long, dries the shirts with hot air at 150–165 °C. At the tunnel’s exit, another operator collects the dried shirts, folds them, and packs them as needed
Advantages of Screen Printing on Textiles:
- High printing speed
- Long-lasting prints
- Excellent resistance to machine washing, drying, and ironing
- Resistant to boiling and roller ironing (hospital linens, pillowcases, covers, surgical garments)
- Ability to achieve various layer thicknesses for different effects (from smooth, embedded prints to raised, textured, fluorescent, metallic, or glow-in-the-dark finishes)
Disadvantages:
- The preparation process is time-consuming; washing and drying screens, preparing files, printing films, applying and drying photo emulsion, exposure, rinsing, re-drying, and mounting on the press. The costs and preparation time are considerable, which is why this method is not commonly used for short production runs or multi-color printing.
- The printing surface should be flat and free of obstructions that could damage the screen, such as zippers, seams, cuffs, plastic or metal fasteners, drawstrings, or thick hems.
At Dinsar, we use an automatic M&R Sportsman screen printing machine with 10 colors, enabling us to produce high-quality prints with large production capacities. We can print designs up to 55 cm in size, using eco-friendly inks that are safe for both people and the environment.
