Drying Differently: How RF Technology Can Revolutionise Digital Print for Packaging

This article is inspired by episode #252 of the FuturePrint Podcast. You can listen by clicking the graphic below, or tune in here!

FuturePrint partner 42 Technology is tackling one of digital print’s most persistent bottlenecks. That may sound like a bold claim—until you take a closer look. With a fresh perspective and an openness to doing things differently, what once seemed challenging becomes not only technically possible but potentially commercially transformative.

A significant shift is taking place in the world of industrial digital print technology—one that could reshape how the sector approaches energy use, substrate compatibility, and sustainability. Among the biggest technical hurdles is the effective drying of aqueous inks: a process that has traditionally required high heat, excessive energy, and delicate trade-offs between performance and material tolerance.

Now, 42 Technology, a Cambridgeshire-based consultancy known for tackling complex engineering challenges across sectors, believes it has found a better way. By adapting radio frequency (RF) dielectric drying—an approach long used in food processing and medical diagnostics—the company may have discovered a highly efficient, targeted method for drying water-based inks in digital print.

Founded in the innovation-rich hub of St Ives, near Cambridge, 42 Technology is no ordinary consultancy. With roots in mechanical engineering and a growing presence across packaging, medtech, energy, and digital print, it operates on the principle of cross-sectoral thinking. “We are generalists who specialise,” says Dr Peter Brown, the firm’s Chief Commercial Officer and a physicist by training. His colleague Rowan Beale, a systems engineer with a background in physics, leads the firm’s RF drying development programme.

Traditional print drying methods—hot air and infrared—are inefficient and increasingly outdated. Hot air drying, still widely used, converts only about 5% of its input energy into useful drying. Most of the heat is lost warming ambient air or the surrounding equipment. Infrared does slightly better—around 15%—but struggles with colour variation: black inks absorb IR well; yellow inks, much less so. The risk of overheating substrates—especially plastics—further limits its use.

RF dielectric drying works differently. It does not act directly on the water molecules, as microwave or infrared drying does. Instead, it interacts with dissolved ions in the water, causing them to oscillate rapidly within the applied electric field. This motion generates heat through friction as the ions collide with neighbouring molecules. The result is efficient, internal heating of the ink—without affecting the substrate. “It’s colour independent, highly energy efficient, and doesn’t damage the material,” says Beale. “That’s a potential game-changer.”

Efficiency gains are dramatic. According to 42 Technology, RF drying can operate at up to 75% energy efficiency—15 times better than hot air systems. That not only cuts running costs but also opens the door to printing on previously unsuitable materials, such as thin films or complex composites. “The idea of using aqueous inks on plastic films has long been dismissed,” says Dr Brown. “RF drying could blow that wide open.”

Such a claim might sound implausible—indeed, many in the industry have long dismissed RF drying as unsuitable for print. Legacy systems were bulky, often vacuum-tube based, and poorly suited to thin, fast-moving printed films. Worse, the technical explanations offered by RF system suppliers were often flawed. “The physics was misunderstood, and people walked away,” says Brown.

So 42 Technology did something rare: it built a compact, solid-state RF drying demonstrator and proved it works. The result? A tangible, repeatable process that overcomes decades of technical doubt. “Seeing is believing,” says Beale. “The moment people witness it in action, they start asking how they can adopt it.”

The implications go beyond ink performance. Aqueous inks—viewed as more environmentally friendly than solvent- or UV-based alternatives—are gaining ground, especially in packaging. Regulatory pressure, brand commitments, and consumer expectations are accelerating this trend. But their Achilles' heel has always been drying. Without an efficient method, they are slow, energy-hungry, and substrate-limited. RF drying, if adopted at scale, could resolve that bottleneck.

Interest is already building. 42 Technology is in discussions with ink manufacturers, printhead developers, and OEMs. “If you’re selling aqueous inks and your customers can’t dry them efficiently, that’s a commercial barrier,” notes Brown. “Our approach removes that barrier.”

The consultancy isn’t looking to become an equipment manufacturer. Its business model is simple: fees for development time. It is now seeking development partners willing to co-fund the refinement and scaling of RF drying for their specific applications. “We’ve seeded the idea, built the demonstrator, and proven it works,” Brown explains. “Now it’s time for the industry to step in.”

Packaging is the initial focus, but potential applications abound. In the food sector, RF drying could improve shelf life by removing residual moisture. In medtech, it could enable non-contact drying in microfluidic systems. “Anywhere you want to remove moisture quickly and precisely, RF drying has potential,” says Beale.

There have been challenges. Developing compact, cost-effective RF systems required moving away from expensive vacuum-tube technology to solid-state electronics. Electrode design proved equally tricky—maintaining efficient energy transfer as ink dries and material properties shift is no small feat. Yet those hurdles have largely been overcome.

Perhaps the greater challenge is cultural. “You’re not just introducing a new technology,” says Brown. “You’re challenging long-held assumptions. In our case, people believed RF drying couldn’t work. Now that it does, they have to re-examine their assumptions.”

What 42 Technology has achieved is more than a technical breakthrough. It is a case study in how innovation often emerges—not from industry incumbents, but from lateral thinking, patient engineering, and a willingness to ask uncomfortable questions.

Industrial print has never been short of clever ideas. But solving the drying challenge for aqueous inks may be among the most transformative. If RF drying takes hold, the shift may not be loud or headline-grabbing. But it will be deeply felt—across energy bills, substrate options, sustainability metrics, and beyond.

And that, in the end, may be the most powerful kind of change.

Interested in more information and connecting with 42 Technology?

Email Dr Peter Brown peter.brown@42t.com or Rowan Beale rowan.beale@42t.com