If you’ve ever worked with flexographic printing—whether as a print shop owner, graphic designer, or packaging brand manager—you know that the final step in the process, drying, isn’t just a throwaway afterthought. It’s what turns wet, smudged ink on a roll of material into crisp, durable prints that hold up during shipping, stacking, and handling. As a flexo printing machine supplier who’s spent the last 12 years troubleshooting setups, training teams, and refining equipment for clients across retail packaging, labels, and flexible materials, I’ve seen firsthand how a poorly matched drying method can ruin runs, waste materials, and even sink a client’s order timeline. Today, I’m breaking down the core drying methods for flexo prints, how they work, when to use them, and why getting this step right is non-negotiable for quality and efficiency. Flexo Printing Machine
First, let’s ground this in what makes flexo ink different from other printing processes like offset or digital. Flexo uses raised rubber or photopolymer plates, which transfer thin, uniform layers of ink to substrates like paper, cardboard, plastic film, or corrugated board. The inks themselves are usually solvent-based, water-based, or UV-cured—each with their own chemical makeup that dictates how they need to be dried. Skip this detail, and you might end up with prints that smudge when stacked, stick to wrapping paper, or fade after a few weeks on a store shelf. That’s why every flexo machine I sell comes with a tailored drying system, not a one-size-fits-all add-on.
Let’s start with the oldest and most widely used method in flexo: hot air drying. This is exactly what it sounds like—fans blow heated air over the wet print as it exits the printing unit, speeding up the evaporation of the ink’s carrier (solvent or water). For solvent-based inks, which use chemicals like acetone, ethanol, or MEK to dissolve pigment, hot air works by raising the temperature of the print surface enough to make those solvents evaporate quickly without leaving streaks. For water-based inks, which are more environmentally friendly and common in food packaging, hot air drives off the water content that makes up most of the ink, leaving the pigment and binders behind on the substrate.
Hot air drying isn’t perfect, though. I once worked with a small label company that upgraded to my mid-range flexo machine and stuck with their old, underpowered hot air dryers from a 1990s press. Their first run of 10,000 food-safe labels came out with a distinct odor of leftover solvent, which made their grocery store client reject the entire order. The problem? Their old dryers only blew air at 120°F, and solvent-based ink requires at least 180°F to evaporate thoroughly without residual fumes. For water-based inks, high humidity in the production space can also slow hot air drying—water in the air competes with the ink’s water for evaporation, leading to tacky prints. That’s why when I sell a machine with hot air drying capabilities, I always include a recommendation for variable temperature fans, humidity controls for the drying zone, and adjustable air flow that can be tuned to the speed of the press. If your press is running at 200 feet per minute, your hot air dryer needs to match that speed—too slow, and the ink has time to smudge before it’s dry; too fast, and you waste energy and might damage thin substrates like plastic film.
Next up, a method that’s become increasingly popular for food packaging and flexible materials: infrared (IR) drying. IR dryers work by emitting electromagnetic radiation that is absorbed directly by the ink and the substrate, rather than heating the air around them. This is a key difference from hot air—IR targets the ink itself, so it dries faster and more evenly, even on thick or non-porous materials like BOPP (biaxially oriented polypropylene) films. There are two types of IR dryers used in flexo: short-wave and medium-wave. Short-wave IR is high-temperature, fast-drying, and ideal for thin films or fast press runs, while medium-wave is lower-temperature, gentler, and works better for porous substrates like cardboard that could warp with high heat.
I recently installed a new flexo machine for a client that makes stand-up pouches for organic snacks. They were using solvent-based inks on thin BOPP film, and their old hot air setup was causing the film to curl slightly after printing, which threw off their slitting and rewinding process. We swapped in medium-wave IR dryers, and within the first run, they reported zero curling, no residual odor, and a 15% faster run speed because the IR dryers cut drying time per print from 2 seconds to 0.75 seconds. That said, IR drying does have a catch: it works best with inks that absorb IR radiation. Clear inks or light-colored pigments (like white or pastels) don’t absorb IR as well, so they need a little extra time or a companion hot air dryer to finish drying. That’s why I almost always recommend combining IR drying with a secondary hot air zone for light colors or thick ink layers.
The third method, and the one that’s grown the most in demand for its low-waste and high-quality results, is UV curing. UV-cured inks use a completely different chemistry than solvent or water-based inks—they don’t rely on evaporation to dry. Instead, they contain photoinitiators that react when exposed to ultraviolet light, turning the liquid ink into a solid, cross-linked layer in milliseconds. UV dryers are specialized units that use high-intensity UV lamps (usually mercury or LED-based) positioned right after each printing unit on the flexo press. When the print passes under the lamp, the ink cures instantly, so the next printing unit can apply ink right on top without smudging, and the finished print is ready for handling immediately.
I can’t tell you how many times a client has come to me asking about UV flexo because they want to eliminate solvent waste and reduce production time. For example, a company that produces beauty product labels switched from solvent-based hot air drying to UV curing on my high-speed flexo machine, and they cut their total production time for a 50,000-label run from 4 hours to 1.5 hours. They also stopped spending $1,200 a month on solvent disposal, which was a huge cost saver. The benefits don’t stop there—UV-cured prints are more scratch-resistant, fade less in sunlight, and work on almost any substrate, including non-porous plastics and foils. The only downsides? UV lamps have a lifespan of about 1,000 to 2,000 hours, so they need regular replacement, and the upfront cost of a UV drying system is higher than hot air or IR. But for clients looking to scale, reduce waste, and produce high-end prints, it’s almost always worth the investment.
Wait a second—what about cases where you can’t use one single drying method? I’ve seen so many clients make the mistake of forcing a single method to work for every substrate and ink, which leads to headaches. That’s why many modern flexo presses, like the models I supply, use hybrid drying systems that combine two or more methods to get the best results. For example, a label printer might use IR drying first to evaporate most of the solvent from ink, then a secondary hot air zone to remove any residual solvent, and a final UV cure for clear overcoat that’s applied after all colors are printed. This hybrid approach balances speed, quality, and cost, which is exactly what most small to mid-sized print shops need.
Let’s talk about how to choose the right drying method for your specific operation, because that’s the part most suppliers don’t spend enough time on. First, look at your ink type: solvent-based inks work well with hot air or IR, water-based inks are best with hot air (with humidity control), and UV inks require UV curing. Then, consider your substrate: thin films like BOPP or PET need IR or UV drying to avoid warping, while thick cardboard can handle hot air. Next, your production speed: if you’re running over 300 feet per minute, hot air might be too slow, so IR or UV is a better pick. Finally, your goals: if you care about food safety and low waste, UV curing is ideal; if you’re on a tight budget and print mostly paper labels, hot air is a reliable choice.
I want to share a common mistake I see new flexo press owners make: skimping on drying zone length. For example, a press running at 150 feet per minute needs a drying zone that’s at least 10 feet long to give the ink enough time to dry. If you buy a flexo press with a drying zone that’s only 5 feet long, no matter how powerful your dryer is, you’re not going to get thorough drying. That’s why I always work with clients to calculate their required drying zone length based on their press speed, ink type, and substrate thickness—no guesswork.
As a flexo printing machine supplier, my goal isn’t just to sell equipment—it’s to set my clients up for long-term success. That means I don’t just point to a list of drying methods and say “pick one.” I ask about their current products, their growth plans, their budget, and their material preferences, then recommend a drying system that fits. Last month, I helped a startup that makes compostable packaging for snack bars figure out that water-based inks paired with a humidity-controlled hot air drying system would be cheaper upfront than UV, while still meeting their compostability standards. They saved $8,000 on their press setup and haven’t had a single drying-related issue in the three months since installation.
Drying might seem like a small step in the flexo printing process, but it’s the one that makes or breaks the final product. Whether you’re running small batches of custom labels or high-volume runs of retail packaging, choosing the right drying method—whether hot air, IR, UV, or a hybrid system—will save you money, reduce waste, and produce prints that your customers will trust. If you’re in the market for a flexo printing machine and want to talk through which drying setup is right for your operation, I’m here to help. Let’s discuss your needs and find a solution that works for your production goals.
If you’d like to learn more about flexo printing technology and drying best practices, or to discuss equipment solutions tailored to your business, feel free to reach out for a consultation.
Slitting Machine References
Flexographic Printing: Principles and Practice. GATF Press, 2018.
UV Curing for Flexographic Printing. RadTech International North America, 2020.
“Drying Technologies for Flexible Packaging Printing.” Journal of Printing Science and Technology, vol. 62, no. 3, 2021, pp. 45–52.
Zhejiang Deguang Machinery Co., Ltd.
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