FLEXO vs. OTHER PRINTING METHODS Web: www.luminite.com Phone: 888-545-2270 As the printing industry moves forward into 2020 and beyond, let’s take a fresh look at the technology available, how flexo has changed to meet consumer demand, and how 5 other popular printing methods compare. CONTENTS ● A History of Flexo Printing ● How Flexo Printing Works ● How Litho Printing Works ● How Digital Printing Works ● How Gravure Printing Works ● How Offset Printing Works ● What is Screen Printing? ● Corrugated Printing Considerations ● Flexo Hybrid Presses ● Ready to Get Started with Flexo? 2 A History of Flexo Printing The basic process of flexography dates back to the late 19th century. It was not nearly as refined, precise, or versatile as the flexo process today -- and can be best described as a high-tech method of rubber stamping. Printing capabilities were limited to very basic materials and designs, with other printing methods greatly outshining flexo. Over the past few decades flexo technology has continuously evolved. This is largely thanks to the integration of Direct Laser Engraving technology, advancements in image carrier materials, and in press technologies. These innovations, among others, have led to increased quality and precision in flexo products. These technological improvements have positioned flexography at the helm of consumer product and flexible packaging printing. Flexo is growing in popularity in a variety of other industries, too, including medical and pharmaceutical; school, home, and office products; and even publishing. How Flexo Printing Works Flexo typically utilizes an elastomer or polymer image carrier such as sleeves, cylinders, and plates. The image carrier is engraved or imaged to create the design for the final desired product. Ink is transferred from the ink pan via an anilox roll onto the image carrier, where it is then printed onto the substrate. Flexo printing is most commonly associated with uses in flexible packaging and labels, utilizing a variety of substrates including film, paper, foil and non-woven. Producing these products generally takes 3 steps: 1. Artwork The first step in flexographic printing is designing your artwork. Creating a design that fits the specifications needed to produce the final desired print can be challenging. Failure to thoroughly proof your artwork can result in costly mistakes. Image carriers cannot be changed once they are produced. When mounted to a printing cylinder, image carriers created flat stretch and distort your image. You can learn how to calculate and compensate for the distortion -- or opt for In-The-Round, continuous print image carriers that are distortion free. 2. Web-Fed Substrate Materials The rolling design of the flexographic printing press allows for continuous substrate materials (in roll-form) to be fed through the machine. This feature of flexography is what allows for the continuous printing process that can achieve high speeds, maintain accuracy, and efficiently produce large print runs. 3 3. The Flexographic Printing Press ● Unwind and Infeed - A roll of substrate is fed into the printing press. Tension must be kept taught to prevent slack which can cause wrinkling, misregistration, web breaks, and other print defects. ● Enclosed Doctor Blade Inking System - A continuous cycling pump fills the enclosed chamber with ink. The ink is transferred onto the anilox roll with any excess removed by the doctor blade. The ink cycles in and out of the enclosed system during printing. ● Inking Anilox Roller - The anilox roller contains microscopic cells which carry a thin layer of ink from the inking system to the image carrier. ● Image Carrier and Impression Cylinder - The image carrier transfers the image to the substrate. The flexographic press pulls the substrate between the image carrier and the impression cylinder. Simultaneously, the impression cylinder holds exactly the right amount of pressure on the substrate for even ink distribution. ● Drying - The substrate winds through roller-less and plate-less sections to dry the ink. Depending on the number of colors used, the substrate might pass through multiple image carriers, impression cylinders, and drying sections in a single print run (one per color). ● Outfeed and Rewind - The final step on a flexographic printing press is the outfeed and rewind, where a substrate is rolled up again in preparation for a cutting die, which will separate individual prints. 4 How Litho Printing Works Litho printing is an offset process which uses a printing plate. The ink is first applied onto the printing plate and then transferred to a rubber blanket through multiple ink rolls, and finally applied to the substrate from the blanket. This means the image is not printed directly onto the substrate from the plate. What is the Difference Between Flexo & Litho Printing? Both flexo and litho printing can produce reliable prints in very high volumes. They can be used to produce quality product packaging, labels, and a wide variety of printed paper materials. While lithographic printing might dominate some markets, flexo printing has increasingly gained popularity since the 1970s with the introduction of direct laser engraving. COST: Litho can accommodate foil stamping, spot gloss, embossing, and other embellishments, but these options also come at a higher cost. Additionally, since the only way to print with litho is through an indirect pre-print, this guarantees an additional step in production and thusly raises costs. Both processes can be very cost-effective when printing large runs with basic needs. With proper maintenance and storage, as well as an investment in durable image carrier materials, flexo image carriers can be reused many times before they need to be replaced. SUBSTRATES: Litho is generally limited to printing on smooth, flat surfaces as the image must be pressed onto the substrate. Printing on corrugated substrates requires an additional step in production where the images are first printed onto linerboard, which is then attached to the corrugated substrate. Flexo can print on both porous and non-porous surfaces, making it ideal for a wider variety of substrates, including coated linerboard and paper. INKS: Litho generally uses oil-based inks, and printing usually consists of the four process colors, each requiring a dedicated printing station. Flexo also utilizes one image carrier per color and can use oil-based inks; it additionally accommodates printing with a wide variety of other inks -- including water-based, solvent-based, and UV inks. Curable inks, such as UV, afford faster drying times. Faster drying can lead to faster production runs. IMAGE QUALITY: Flexo is noted for producing superior print with fine line and text detail. Making the final decision whether to print using the flexo or litho process depends on the substrate, budget considerations, and a number of other production requirements. 5 How Digital Printing Works Digital printing presses function similarly to the printers we use at home. Unlike the other printing methods, digital printing does not require the creation of printing plates because a digital press uses electronic files to print images. Digital printing is capable of rendering high resolution images. This method costs more per print than the other methods and moves more slowly, but without the need for printing plates, set up is less expensive. This makes digital printing a great option for small volume printing, samples, or test marketing. What is the Difference Between Flexo & Digital Printing? COST: Flexo is a more cost effective option than digital for high-speed and high-volume printing needs. Being a continuous printing solution, there is little to no press downtime. However, for short runs, digital printing is considered more cost effective due to the comparatively minimal initial investment in materials and quick set-up time. INKS/SPEED: Due to the fast-drying inks that are compatible with flexo printing image carriers and presses, flexo is a great option for applications where speed is of utmost importance. QUALITY: For some industries, digitally printed final products may be less durable than ones printed with flexography. This is a particular consideration when printing products intended for outdoor use, or needed to withstand many years of display. 6 How Gravure Printing Works Gravure printing works by applying ink to a substrate with the use of a metal plate that is typically mounted onto a cylinder. This plate is often made of copper or chrome. The image or text that is intended for printing is typically laser etched into said metal plate, a process that often delivers high quality and precise results with good repeatability. What is the Difference Between Flexo & Gravure Printing? COST AND LEAD TIME: Gravure image carriers are typically much more expensive than Flexo, making the number of prints required to break even much higher. Gravure, however, has a longer press run time as the cylinders do not require as frequent changing as Flexo. Gravure lead time is usually 3-4 times that of Flexo in the time it takes to manufacture the image carrier. SUBSTRATES: One of the limitations of gravure printing is that it generally better suited for porous substrates. This is one of the reasons that gravure is best suited for high detail printing on applications such as magazine covers. That isn’t the case with flexo printing, which is able to print on both porous and non-porous substrates, making the technology ideal for everything from film to paperboard. INKS: Another key differentiator is the range of inks Flexo is able to print with. Gravure is more limited in the inks that it works with, often making Flexo the superior choice due to the ease of printing with a wider variety of inks. Gravure requires much more ink per print, which can drive up the cost of printing. ENVIRONMENTAL CONSIDERATIONS: Due to the fact that Gravure is traditionally associated with solvent based inks, although water based ink capabilities have been evolving, Flexo is commonly considered the “greener” options.