Aniloxes: The Beating Heart of Flexo
IN the world of flexographic printing, the anilox roll is both an unsung hero and a critical linchpin. It dictates ink transfer, defines print quality and determines efficiency. As converters push the boundaries of speed and precision, the role of anilox technology has never been more scrutinised. The stakes are high – every miscalculated volume, inconsistent ink laydown and improperly matched cell geometry could mean wasted substrate, failed colour accuracy and production downtime. ‘With today’s manufacturing advancements, we can achieve finer screen rulings and deeper cells, allowing for precise control over ink volume,’ explains Darrion Crowie, business development manager at Sareltech, a leading South African supplier of printing and laminating solutions. ‘This translates into smoother ink laydown, reduced pinholes and improved opacity – especially for challenging applications such as white inks or high-density process work.’
These advancements are driven by multi-impact laser engraving, which produces cells with smoother walls and flatter bottoms. The result? Enhanced ink release, reduced dot gain and innovative new cell structures, such as elongated or S-shaped configurations, that optimise ink flow. ‘The geometry of anilox cells is crucial – everything from shape to depth and angle matters. While the 60° hexagonal pattern remains a staple for its ink release efficiency, newer channel engravings are proving even more effective in improving uniformity and minimising inconsistencies.’ Nowhere is precision more critical than in expanded colour gamut (ECG) printing. By replacing spot colours with a fixed ink set – typically CMYKOGV (cyan, magenta, yellow, black, orange, green, violet) – ECG enables more consistent branding and reduces ink waste. But it also demands absolute control over volume tolerance to ensure repeatable colour accuracy. ‘ECG is an exciting evolution, but it introduces new challenges in maintaining consistency,’ says Darrion. ‘Printers are leveraging sophisticated colour management systems, ICC profiles and real-time monitoring tools such as the BST IPQ inline spectrophotometers developed together with X-Rite. These technologies measure colour accuracy during production and allow for instant adjustments to maintain target values.’ Anilox rolls play a critical role in this equation. ‘Precise engravings and tightly controlled volumes are non-negotiable.
We work closely with printers to match anilox specifications to ink requirements, ensuring predictable transfer rates. Regular press maintenance and cleaning schedules further safeguard against deviations in performance.’ Choosing the right anilox for the job isn’t a universal formula. Substrates – from absorbent papers to non-porous films – demand tailored ink transfer strategies. ‘Water-based inks, for example, require coarser line counts and lower volumes to balance pigment load,’ Darrion notes. ‘Non-absorbent materials like foil or certain plastics, on the other hand, call for finer engravings to ensure sharp detail without flooding.’ Successful printers, he says, don’t rely on guesswork. ‘They rigorously test anilox configurations on sample substrates before committing to full production. There’s no room for trial and error when high-value jobs are on the line.’ Even the most advanced anilox roll is only as good as its maintenance routine. ‘Dirty or worn-out aniloxes kill efficiency and print quality,’ warns Darrion. ‘That’s why we advocate for laser cleaning technology, such as the Inelme Laser Anilox Cleaning System, which removes ink and residue without damaging the ceramic surface. Unlike chemical-based cleaning, this method is safer for operators and far more sustainable.’ Sareltech also champions predictive maintenance tools, such as 3D microscopes, to monitor cell wear and volume loss. ‘It’s about preventing problems before they happen. Cleaning schedules based on real-time data extend roller lifespan and maintain peak performance.’ Where does anilox innovation go from here? Darrion envisions a future where flexo closes the gap with gravure in terms of quality and efficiency. ‘We’re already seeing advances in ceramic coatings, such as Linde’s AMT technology, which enhances durability and ink transfer. There’s also growing potential for even more customisable cell geometries tailored to specific applications.’ Sustainability will also play a defining role. ‘Eco-friendly cleaning methods, reduced chemical usage and anilox materials designed for recyclability will become industry standards. As hybrid printing grows – integrating flexo and digital technologies – anilox rolls will need to evolve to support seamless transitions between processes.’ Ultimately, the demand for precision, efficiency and sustainability is shaping the next generation of anilox solutions. ‘Flexo printing isn’t standing still,’ Darrion concludes. ‘And neither is anilox technology.’
Written by Anton Pretorius – Packaging & Print Media