What are photopolymer plates in flexographic printing?
Photopolymer plates are at the heart of modern flexographic printing, transforming the packaging industry’s approach to print precision and quality. These technologically advanced printing plates are made from photopolymers—materials that cure under UV light, creating a three-dimensional structure with precisely reproduced graphic elements.
The photopolymer plate production process begins with exposure through the master photomask, followed by exposure from the back side of the substrate film, which ensures the correct substrate thickness. The key step is exposure through the negative, which forms the actual printing elements. After washing out the uncured material and final exposure, a finished plate with elements of varying heights is produced, enabling the transfer of Printing inks with the graphic design.
Why photopolymer plates are revolutionizing print quality
The printing precision achieved with photopolymer plates stems from their ability to reproduce the finest graphic details while maintaining sharp edges and halftone dot stability. Modern photopolymers allow for the reproduction of line screens up to 200 lpi, which was unattainable with traditional rubber plates.
The control of Printing inks transfer Printing inks another groundbreaking aspect of this printing technology. Photopolymer plates feature a uniform surface structure, which eliminates the unevenness in Printing inks application Printing inks of older solutions. Thanks to precisely shaped printing elements, it is possible to achieve stable, repeatable print results with minimal Printing inks consumption.
How photopolymer plates boost production efficiency
Printing productivity increases significantly thanks to the extended lifespan of photopolymer plates, which can handle print runs of millions of copies without any loss of print quality. The reduction in prepress time is due to the plates’ improved dimensional stability, which minimizes the need for frequent adjustments during production.
Optimizing production processes also makes it easier to clean plates between color changes. The smooth surface of the photopolymer facilitates the removal of Printing inks residues, reducing production downtime. The modern water-washable plates we use in our washing systems further streamline the process by eliminating organic solvents from the regeneration process.
Selecting the Right Photopolymer plate for Specific Applications
The selection of the appropriate printing plate depends primarily on the type of substrate being printed and the quality requirements. For food packaging with high aesthetic requirements, plates with a thickness of 1.14–1.70 mm and a micro-relief surface are used, while standard plates with a thickness of 2.84 mm are sufficient for industrial packaging.
The technical specifications for the plates must take into account the line screen parameters of the anilox rolls, the type of ink, and the printing speeds. Hard plates (Shore A 68–73) are suitable for printing solid tones and text, while soft plates (Shore A 58–62) are better suited for reproducing halftones and gradients. Our many years of experience inflexography allow us to recommend the optimal solution for each specific application, taking into account the characteristics of the printing presses and the requirements of the final product.
