To ensure the success of any glass-printing application, there are numerous factors that go under consideration such as the glass type, inherent tint of the glass, ink type, ink color, curing process, and environmental conditions. However, one crucial factor that needs to be determined is the print method. Glass can be printed on using one of the three techniques - screen printing, digital printing, or frit printing. While all these methods support different shapes, sizes, thicknesses, types of glasses, and allow the use of multiple colors, there are unique pros and cons that distinguish them.
1) Screen printing: Well-suited for a wide range of applications, screen printing is the most cost-effective and most dominantly used glass printing technique. It primarily utilizes two types of inks: enamel inks and UV-cured inks, both offering good opacity. UV-cured inks offer a larger color selection than enamel inks. Since every color requires a separate screen, the process can be time-consuming if the design has several colors involved. In most cases, the graphic features are printed on the rear side of the glass, which eventually gets sealed or bonded with a touchscreen or display. Except for the edges of the glass, the ink is almost never directly exposed to ambient conditions and corrosion. However, if the ink is not specially formulated for printing on glass, it can lose adhesion and begin to chip off very quickly.
2) Digital printing: Digital printing on glass works like a regular inkjet printer, where all you need is a digital art file to print. It offers greater flexibility in terms of changing designs at the last minute. Unlike screen printing, where even the smallest design variation requires the construction of a new screen, modifying an art file for digital printing is extremely quick and easy. This makes it a great choice for prototyping and achieving faster time-to-market products. But it is important to note that the inks utilized for glass digital printing are thinner as compared to the inks employed in screen printing. Hence, while working with light or pastel shades, multiple layers may be required to achieve a sufficient level of opacity. This can lead to increased thickness, posing challenges in the optical bonding process. In contrast to screen printing, where one color is printed at a time, digital printing also allows printing of all the different colors at once. Digital printing on glass is currently undergoing continuous developments to accommodate more types of inks.
3) Frit printing: Frit printing is very similar to screen printing with the exception of the ink utilized and the curing process. A unique powdered-glass ink is screen printed on the glass and then cured during the heat tempering process. It causes the ink to fuse to the glass, thus offering strong adhesion and making it extremely difficult to remove or scratch the ink off. Since frit printing offers the highest durability out of all the techniques, it is chosen for demanding applications where the glass is regularly exposed to challenging environmental conditions such as in the defense, heavy industrial and automotive sector. However, it is also the most expensive printing method and therefore, not as frequently employed. One of the limitations of this method is that while frit printing can be done on heat-tempered glass, it cannot be utilized for chemically-strengthened glass and the glass thickness is limited to greater than 2mm. Frit colors are also limited to black, white, and some grays.
Bringing together the right mix of functionality and durability for your custom application, the experts at GM Nameplate (GMN) can not only help you select the most suitable printing technique for your glass application, but also support your glass printing and bonding needs from prototyping through production. To learn more about GMN’s bonding solutions, visit our capabilities page here.