Background
A leading Mumbai based converter, manufacturing flexible packaging laminates, has an 8 colour European CI flexographic printing press. Jobs include both surface and reverse printing on films that run at a maximum speed of 300 meters per minute; the maximum web width is 1350 mm. Solvent based inks with a viscosity of 18-20 secs (B4 cup) are used. The customer sought to reduce ink and solvent consumption to improve operating margins
Process
On each print station, an ink circulating pump delivers ink from the tank to the tray (pan) through a filter. As the print run progresses, temperature of the ink rises and then stabilises at a high temperature over time. The high ink temperature results in high solvent evaporation, which in turn results in higher top-up solvent consumption.
Solution
A heat exchanger was needed to reduce ink temperature to a level that reduces solvent consumed, without hindering the process. Critical design parameters included temperature and low rate of the ink, permissible pressure drop of the application and quantity of heat to be transferred through the heat exchanger. We evaluated the application data through heat exchange and CFD modelling to arrive at a compact design with optimal performance.
The Valflow ink temperature controller (ITS) uses water as the medium of heat transfer. It has a dependable (leak proof) construction and has a low pressure drop. It is sleek, easy to clean and simple to retrofit.
Result
Without a heat exchanger, temperature of the ink stabilised at 32°C when productivity was at an optimum level. With the help of the Valflow ITS, ink temperature during operation was reduced to 28°C. Lowering ink temperature by 4°C saw a reduction in top-up solvent consumption by 33%, while maintaining the same printing performance.
Conclusion
Annualised savings after installation of a Valflow ITS, with associated accessories, water chilling plant, etc. is significant, translating into a payback period of about 11 months!
AxisValence has extensive experience and expertise in various applications across industries, which we leverage to provide a suitable solution for your application.
