Why Sustainability Has Become a Business Imperative for Flexo Printers
A decade ago, sustainability in packaging printing was a marketing differentiator. Today, it is a procurement requirement. Brand owners including Unilever, Nestlé, and P&G have published binding supplier sustainability standards. The EU's Green Deal and Packaging Regulation mandate recyclability and reduced chemical impact. Converters who cannot demonstrate sustainable production are losing contracts.
Dimension 1: Transitioning to Low-VOC Ink Systems
Solvent-based inks release volatile organic compounds (VOCs) during drying. These emissions contribute to ground-level ozone formation, are subject to increasingly stringent regulatory limits, and carry significant compliance and abatement costs.
The Water-Based Transition Path
Transitioning from solvent to water-based inks on CI flexo presses involves three phases:
- Press assessment: Evaluate existing drying capacity. Water-based inks require higher drying energy than solvent inks at equivalent speeds. Identify whether drying zone upgrades are needed.
- Ink and substrate qualification: Water-based inks may require corona treatment of film substrates. Validate adhesion, lamination bond strength, and migration performance.
- Process standardization: Water-based inks are more sensitive to viscosity variation. Automatic viscosity control systems are highly recommended.
VOC Reduction Metrics
A full transition from solvent to water-based inks on a high-volume CI flexo press typically reduces VOC emissions by 85–95%, from several hundred kg VOC per day to under 20 kg per day for equivalent production volumes.
Dimension 2: Press Energy Efficiency
CI flexo presses are energy-intensive systems. The three largest energy consumers are the drying system, the drive motors, and the chiller/cooling system. Modern press design addresses each:
Drying System Efficiency
- Heat recovery systems recycle exhaust air heat to pre-heat incoming drying air — reducing gas consumption by 20–35%
- Variable frequency drives on drying fans adjust airflow to actual demand instead of running at fixed maximum output
- Optimized dryer zone geometry reduces the energy needed per meter of substrate dried
Servo Drive Efficiency
Servo motors with regenerative drives recover braking energy during deceleration and feed it back to the press electrical system. On a multi-unit CI flexo press, this can recover 5–15% of total drive energy consumption.
LED UV Curing
For UV flexo applications, LED UV systems consume 50–70% less energy than traditional mercury UV lamps, produce no ozone, and have lamp lives of 20,000+ hours versus 1,000–2,000 hours for mercury lamps.
Dimension 3: Substrate Waste Reduction
Every meter of substrate wasted in setup is a direct material loss. At $0.50–1.50 per meter for typical film substrates, waste reduction is both an environmental and financial priority.
Quantifying Waste Streams
Measure and classify waste by type:
- Setup waste (per job start): Target <150 m for servo CI flexo
- Defect waste (mid-run): Target <0.5% of run length
- Tail-out waste (end of roll): Minimized by roll splicing and full-auto rewinders
Press Design for Minimum Waste
Short web path between the last print unit and rewind minimizes the length of printed substrate that cannot be checked before winding. Web inspection systems with automatic defect detection stop the press immediately upon detecting defects, preventing extended defect runs.
Recyclability Compatibility
Modern packaging recyclability standards (How2Recycle, RecyClass in Europe) increasingly specify requirements for printing inks and coatings that do not impair the recycling stream. Key considerations for flexo printers:
- Wash-off coatings and inks that do not contaminate the recycled polymer melt
- Deinkability testing for paper-based packaging
- Avoidance of heavy metal pigments that contaminate recycled material
LISHG CI flexo presses support water-based, UV, and EB ink systems with drying and curing configurations validated for sustainable production. Contact our engineering team to discuss press configuration for your sustainability targets.
