Case Study
Flexible Packaging Printer Cuts Ink Rejection
Background & Challenge
A flexible packaging printer in East China, focused on BOPP film printing, suffered an 8% ink-rejection rate without surface treatment — frequent customer complaints and rising rework costs.
Diagnosis
On-site testing showed film surface tension of only 31 mN/m, far below the 40 mN/m required for water-based ink. The film had been stored too long and the line had no in-line treatment step.
Solution
We installed a 1.6 m in-line corona system at a power density of 15 W/(m²/min), with PLC auto-tracking of line speed (100–200 m/min) and dyne-level monitoring.
Results
- Film dyne level held steady at 40+ mN/m
- Ink rejection dropped from 8% to 0.5%
- Overall throughput rose about 20%