Flexo Plate Troubleshooting – Part 2

Achieving high-quality prints in flexo printing relies heavily on the quality of the flexo plates used. Technicians must possess a thorough understanding of the common technical issues that can arise with flexo printing plates and the appropriate solutions. This article is part 2 of flexo plate troubleshooting series that explores some of the most frequently encountered problems, their causes, and the technical solutions to overcome them.

Curling

• Problem: Plate curling potentially leading to “plate lifting” issues
• Causes:
  • Differential shrinkage of polymer and polyester carrier film
  • Insufficient main exposure
  • Excessive plate processing time
• Solutions: Review and optimise all plate making parameters

© Anyflexo

Insufficient Plate Hardness

• Problem: Reduced print quality, high dot gain, and lower durability due to insufficient plate hardness
• Causes:
  • Prolonged washout time
  • Inadequate drying time or temperature
  • Low UVA intensity during main or post-exposure
• Solutions: Verify correct plate making parameters

© Anyflexo

Dirty Plate Surface

• Problem: Plate surface contamination and residual slip sheet layer
• Causes:
  • Polymer residue redeposition from processor
  • Dried solvent droplets
  • Lint from cleaning towels
• Solutions:
  • Ensure solvent saturation
  • Check washout processor condition, especially final wiping brushes
  • Use lint-free towels or soft brushes for plate surface cleaning

© Anyflexo

Insufficient Solid Ink Density

• Problem: Low solid ink density in print samples
• Causes:
  • Ink condition
  • Anilox roller condition and specification
  • Plate and tape hardness combination
• Solutions:
  • Verify and adjust ink viscosity and overall condition
  • Confirm anilox roller condition and specification
  • Consider alternative plate types, tapes, and surface patterns

© Anyflexo

Pin-Holing and Ink Lay-Down

• Problem: Pin-holing and inconsistent ink lay-down
• Causes:
  • Anilox specification
  • Ink rheology and viscosity
  • White ink print quality
  • Substrate preconditioning
• Solutions:
  • Verify anilox condition and specification
  • Test different plate and tape combinations
  • Consider surface screening

Dirty Printing

• Problem: Dirty print results in some colours with high dot gain
• Causes:
  • Suboptimal ink condition, especially drying speed
  • Incorrect anilox specification
  • Missing dots on plate
• Solutions:
  • Confirm ink condition
  • Verify anilox specification

© Anyflexo

Slurring

• Problem: Blurring and smearing of printed image
• Causes:
  • Excessive impression settings
  • Cylinder rolling condition issues
  • Mismatched surface speeds of cylinders
• Solutions: Verify and correct all printing press parameters

© Anyflexo

By familiarising themselves with these common issues and their respective solutions from part 2 of flexo plate troubleshooting series, technicians can effectively fix flexo printing plate and maintain high-quality print results. Stay tuned for Parts 1 and 3 of this series, which will delve into additional problems and their remedies.