Material Diversity in Focus: Windmöller & Hölscher’s Perspective on the Future of Flexo Printing
The push for more sustainable packaging is transforming the landscape of flexible packaging materials. Printers today must handle paper, polyethylene and a growing range of bio-based and compostable films, each behaving differently on press. Managing that diversity without sacrificing quality or efficiency has become one of the defining engineering challenges.
Achieving consistent print quality requires well-matched press settings and precise web handling.
Not long ago, press design centered on predictable materials and stable process windows. Today’s substrate mix demands systems that can compensate for widely varying mechanical and thermal properties. Paper absorbs moisture and changes dimensionally, while thin PE or compostable films deform under even minor tension or temperature shifts. Designing presses that handle both extremes reliably has become a decisive engineering challenge, one that Windmöller & Hölscher has addressed through continuous development in web handling, temperature control and automation.
Achieving consistent print quality requires well-matched press settings and precise web handling. W&H’s repeat control system continuously measures the print repeat length under tension, detects deviations over time and applies automatic corrections during production. To meet the specific demands of PCR films, W&H presses combine this control with advanced web transport technology. A harmonized system of web-tension sensors, super-grip idle rollers and a CI torque motor ensures stable web guidance, guaranteeing register accuracy and process stability at full speed.
EASY Setup minimizes operator intervention and reduces setup time and waste.
The growing use of post-consumer recycled (PCR) materials adds another layer of complexity, as their composition and mechanical stability can fluctuate from batch to batch, affecting tension control, drying behavior and ink adhesion. At the same time, regulations are accelerating this transition: by 2030, European legislation will require at least 35 percent PCR content in many plastic packaging formats, increasing to 65 percent by 2040. This shift is already influencing substrate selection and driving technical adaptation on press floors.
At Windmöller & Hölscher, sustainability is not only a goal but a foundation for innovation. The company focuses on improving equipment efficiency and reducing resource consumption across the entire printing process while preparing its technology for the new material landscape. PCR-based polyolefin films provide a clear environmental benefit but come with unique process challenges. They can contain tiny inclusions, typically one to two millimeters in size, that may be misinterpreted as surface defects by automated inspection systems. To address this, W&H’s inspection technology, such as the VISION system, is designed to account for the optical and structural characteristics of different materials. Through optimized lighting, image analysis and defect classification, it distinguishes true print errors from harmless irregularities in PCR content. This prevents unnecessary false defect alerts and waste to a great extent, ensuring stable quality control even on demanding substrates.
Beyond inspection, automation now extends to the broader press setup itself. Modern assistant systems are designed to interpret material data and automatically configure optimal parameters for each substrate. Windmöller & Hölscher’s EASY Setup is one such example. Using stored substrate profiles, the system determines the ideal web tension, drying temperature and light settings for inspection units, ensuring that every material, from thin PE and paper to high-PCR films, runs under stable, reproducible conditions. By integrating material intelligence into press control, EASY Setup minimizes operator intervention and reduces setup time and waste. In essence, it allows the press to adapt to the material rather than forcing the material to adapt to the press.
A key step in achieving the required mechanical and optical performance is the Machine Direction Orientation (MDO) process.
In extrusion, the shift towards mono-material structures is driving a similar transformation. To enable the recyclability of flexible packaging, today’s multi-material laminates must be replaced by monomaterial structures. A key step in achieving the required mechanical and optical performance is the Machine Direction Orientation (MDO) process, where stretching parameters allow extruders to fine-tune film behavior. Materials such as PET, long valued for its downstream processability, are increasingly being replaced by by MDO-PE or MDO-PP. While extrusion can tailor these properties during processing, differences between previously used PET films and new MDO films in stiffness, shrink behavior or optical properties still occur and must be considered by converters and printers.
Because Windmöller & Hölscher brings extrusion, printing and converting expertise under one roof, developments in these areas progress in a coordinated way rather than in isolation. This ensures that process requirements are aligned early in R&D and that downstream steps can reliably handle new mono-material structures. When extrusion delivers consistent film properties, automation on the press, such as W&H’s EASY systems, can fully support stable, high-quality production with minimal waste. This integrated approach strengthens the entire value chain as mono-material films and PCR becomes standard in sustainable packaging.
