Faster, higher quality, cheaper and more flexible: single-pass digital printing in coil coating is an innovation that is revolutionizing the coil coating process. As an integral part of the coating process, this printing method enables photos, computer graphics and samples to be printed directly onto steel or aluminum sheet.

Coil coating is a continuous, automated process for coating metal before fabrication into end products. Therefore the metal coil is positioned at the beginning of the coating line, and in one continuous process, the coil is unwound, cleaned, pretreated, primed, and painted or printed before being recoiled on the other side of the line and then packaged for shipment. All of this happens at up to 180 meters per minute!

The coil coating process (c) HELIOS

HELIOS develops and formulates sol-gel printing inks for coil coating design with digital printing. They are based on environmentally friendly solvents and show good outdoor durability and excellent mechanical properties. The specific “coil coating” printing system consists of a polyester primer, a sol-gel ink and a HD PE clear coat. This fine-tuned system allows easy passage through the printing machine for the highest level of productivity. They dry in a few seconds and allow a wet-on-wet application of the clearcoat.

Sol-gel printing inks are already successfully used in various industries, including glass printing. For the future there are many possibilities. The manufacturers of digital printers receive inquiries from many other sectors and already supply them with printers.

The printing technologies currently used to enhance prepainted metal are mainly Rotogravure printing, Flexographic printing, and hot lamination with printed plastic films. Digital printers in contrast spray the ink directly onto the substrate and the printer can adjust the size and quantity of the ink drops. Each parameter can be set with the printing software in the same way, so that only the exact amount of ink needed for printing is used. Due to its advantages, digital printing is already used in many industrial sectors.

With single-pass digital printing, finally a printing process was developed that can be integrated into the coil coating process without interference. This means that any digital image can be printed. The printing process can be programmed as required, patterns can be printed several times and while one job is being printed, the next job can already be programmed.