Flexo & Gravure Work Together to Delivery Even Higher Qualities, Synergies
Store shelves are crowded with lots of competing products. Each brand wants its offerings to break through the shelf clutter and grab consumer attention. That need to differentiate product and have it stand out at the “Moment of Truth” is driving packaging innovation. Many of what we think of as “traditional” packaging effects have become very recognizable on the retail shelf, and thus less desirable. Brand owners are increasingly seeking new unique alternatives that are more appealing. Additional factors that influence packaging are the growing need for brand security features, as well as end user desire for options that are convenient, easy to understand and use.
Inline flexo presses (narrow and mid web) are renowned for offering combination printing by incorporating numerous processes in a single pass:
• Cold/hot foil
• Screen printing
The combination of flexo and gravure in an inline process enables flexo printers to deliver innovative packaging solutions that add value, differentiate themselves in the market and deliver customers’ packaging requirements.
The advantages of flexographic printing are well known. But the combination of flexo and gravure, although not new, is not as well recognized or widely available. By adding a quick change gravure cassette to a narrow or mid web flexo press, converters can increase their capabilities in multiple avenues.
Gravure delivers superior print quality, and excellent ink laydown and consistency, because of its engraved copper cylinder. This makes the gravure process ideal for fine security type printing, white laydowns, metallic/fluorescent printing, and coating and adhesive applications using solvent or water based inks/adhesives at high production speeds. Flexo printing issues of pinholing, double hitting a white to get opaqueness or speed limitations are eliminated by using a moveable gravure cassette inline in a flexo press, where needed.
The ability to move the gravure cassette to where it is required in the process (first down, last down or in the middle) for each job gives the printer wide production flexibility. Yet changeovers of the entire inline combination flexo and gravure press can still be very quick. Utilizing gravure inking cassettes that can be prepared offline and easily slid into any flexo print station on the press can keep the gravure changeover time to minutes.
The applications for a combination flexo and gravure press platform are being used by printers of labels, flexible packaging, folding carton—even foil lidding. Examples include:
• Applying metiallic/fluorescent inks on labels, replacing costly hot or cold foils
• Applying white laydowns, coatings, lamination and cold seal adhesives for flexible packaging applications
• Applying coatings and laminations, for folding carton and medical blister pack applications
• Applying migration free coatings for lid or flexible packaging applications
• Printing/embossing micro security text on labels
• Printing very fine lines for printed electronic applications
FLEXO VS GRAVURE
Flexography delivers high quality printing for most common applications on a cost effective photopolymer printing plate. Current flexo print quality can rival gravure, yet offer a lower cost printing plate, better suited for the demands of today’s short to medium run market. Now, by adding one or two moveable gravure cassettes, printers can take advantage of the benefits of each process to offer unique, value added solutions by utilizing a cost effective inline process.
According to Ron Hengst, process engineer at MTS Medication Technologies, “To support our UV flexo printed pharmaceutical packaging conversion process, our utilization of the gravure station has been implemented to provide full flood coat and pattern coating for the permanent closure of our products. The gravure station has enabled us to expand our converting capabilities. Our processes now support reduced coating application requirements and the new ability to pattern repeat with the coating process.”
Hengst adds that, “The gravure unit has a high level of complementary process capability to the flexo units. Its functionality is easy to train across multiple production levels. The reduced changeover time opportunities increase with the Omet gravure station, allowing offline staging. The timeframe to implement the gravure station to the press line again is supportive of time reduction in job setups.”
The gravure print process does share some concepts with the flexo process, as the gravure cylinder can be compared to an anilox. Gravure print stations use a doctor blade to scrape the ink from the surface, similar to flexo. But gravure is a different process that has its own techniques. The main differences between flexo and gravure are:
• Doctor blade settings are more critical to gravure
• Traditional gravure cylinders are more costly
• The gravure cylinder etching is done by a prepress supplier—typically not in house, like flexo plates
• Larger dryers are often required on press, in addition to dealing with solvent ink VOCs if solvents are used
So how does a flexo printer learn to print with gravure? Many gravure and prepress suppliers are available to help flexo customers learn the gravure process. Additionally, the Sonoco Institute at Clemson University has a mid web combination flexo and gravure press, available for testing and training. According to Brad Gasque, research associate at the Sonoco Institute, gravure has the following features: “You can apply heavier coat weights since the ink is only split once (gravure cylinder to substrate) instead of splitting twice like flexo (anilox to plate, then plate to substrate). Compared to flexo, gravure is a totally different printing process. Gravure print quality is highly dependent on doctor blade settings, so training in that area is required. We mainly use gravure for testing coatings that require a very heavy wet coat weight. We have also used it for printed electronics, as well as combination jobs that require a continuous pattern, such as wrapping paper.”
SHORT RUN FLEXIBLE PACKAGING
One market that has great potential for combination inline flexo and gravure presses is flexible packaging. In addition to being able to print metallic inks, apply a white down first and/or a coat in the last station, a moveable gravure cassette can also be used for inline lamination of films. Further, one moveable cassette can be used for applying a water based lamination adhesive, while a second moveable gravure cassette can apply a cold seal adhesive, allowing highly efficient one step production. This can also be a good solution for indirect food contact applications, since the printing, lamination and cold seal steps can all be done using water based inks and adhesives. Additionally, producing laminated flexible packaging inline using a mid web flexo and gravure combination provides a highly efficient process for shorter runs. Are you interested in adding additional value to your flexible packaging offering? Why not include cold or hot foil to an inline flexo and gravure press to create eye popping packaging?
Brand owners’ desire for innovative solutions provides printers the avenue for higher profitability. Rather than competing by reducing costs, inline flexo and gravure combination printing enables printers to create innovative solutions that add value and profits. Combining flexo and gravure is a challenge but one that can easily be accomplished by partnering with proven suppliers that can assist you from concept to profit.