Refrigeration in Flexography: Print Quality and Colors
The flexographic printing industry is extremely sensitive to temperature variations. Proper thermal control of anilox rolls, inks, and the printing environment is critical to ensure consistent quality and reduce waste.
Why Temperature is Critical in Flexography
Ink Viscosity
The viscosity of flexographic inks varies significantly with temperature:
- Warmer inks: lower viscosity, lighter colors
- Colder inks: higher viscosity, darker colors
A 5°C variation can alter viscosity by up to 20%, causing visible differences in printing.
Anilox Rolls
Anilox rolls heat up during operation due to friction. Uneven heating causes:
- Variation in ink transfer
- Color differences along the web
- Need for frequent adjustments
Drying
The temperature of the drying air affects solvent evaporation and ink adhesion to the substrate.
Recommended Temperatures
| Component | Temperature | Tolerance |
|---|---|---|
| Water-based inks | 20°C to 25°C | ±2°C |
| Solvent-based inks | 18°C to 22°C | ±2°C |
| Anilox rolls | 25°C to 30°C | ±1°C |
| Printing environment | 22°C to 25°C | ±2°C |
| Drying air | 40°C to 60°C | ±5°C |
Refrigeration Solutions for Flexography
Temperature Control Units for Rolls
Helioterm temperature control units for anilox rolls offer:
- Temperature control of ±0.5°C
- Heating and cooling
- High-flow pump for efficient circulation
- Quick connections for roll changes
Chillers for Inks
Ink refrigeration systems maintain constant viscosity:
- Stainless steel heat exchangers
- Easy cleaning for color changes
- Precise temperature control
Environmental Climate Control
Temperature and humidity control of the printing environment complements equipment control.
Success Story: Flexible Packaging Printing Company
A printing company specializing in flexible packaging faced problems with color consistency and a high rework rate.
Problems identified:
- Color variation between the beginning and end of the web
- Color adjustments every 30 minutes of production
- Rework rate of 8%
- Frequent customer complaints
Technical diagnosis:
- Roll temperature varying from 28°C to 45°C during production
- Inks stored at room temperature (18°C to 32°C)
- No temperature control in the printing environment
Helioterm Solution:
- 6 Temperature control units for anilox rolls
- Ink refrigeration system with 2 circuits
- 15 TR chiller for environmental climate control
- Centralized monitoring system
Results after 6 months:
- Roll temperature variation of ±1°C
- Color adjustments reduced by 70%
- Rework rate dropped to 1.5%
- Productivity increased by 25%
- Zero customer complaints for color variation
Benefits of Thermal Control in Flexography
Quality
- Consistent colors from the beginning to the end of the web
- Reproducibility between batches
- Less registration variation
Productivity
- Fewer stops for adjustments
- Faster setup
- Higher printing speed
Savings
- Reduction of substrate waste
- Lower ink consumption
- Reduction of rework
Conclusion
The investment in thermal control in flexography pays for itself quickly through waste reduction and increased productivity. Well-designed systems ensure consistent quality and customer satisfaction.
Helioterm serves flexographic printing companies throughout Brazil, with complete solutions for temperature control of rolls, inks, and the environment.