Flexo Plate Troubleshooting – Part 3

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 3 of flexo plate troubleshooting series that explores some of the most frequently encountered problems, their causes, and the technical solutions to overcome them.

Blocking

• Problem: Ink transfer from one print to the next.
• Causes: Ink drying problems, web tension issues, or substrate humidity problems.
• Solutions: Optimise ink, substrate, and dryer parameters.

© Mary Anne Enriquez

Ink Splashing

• Problem: Ink splashing.
• Causes: Low ink viscosity or incorrect anilox specification (high volume or low line count).
• Solutions: Adjust ink viscosity; optimise anilox specification.

Misregistration

• Problem: Misalignment in print registration.
• Causes: Plate mounting issues, equipment problems during plate making, plate orientation on imaging system, or separations from different raw material batches.
• Solutions: Ensure plate making equipment functions correctly; image separations consistently; use plates from the same batch.

© Anyflexo

Element Edges Start to Print Early

• Problem: Element edges print prematurely.
• Causes: Cupping issue or high impressions between anilox and plate or plate and substrate.
• Solutions: Optimise plate making parameters (e.g., dry times); adjust impression settings on press.

© Anyflexo

Unsharp Printing

• Problem: Blurred printing with high dot gain.
• Causes: Plate swelling from unsuitable solvents/cleaners causing softening during printing, high impression settings, cupping issue, or ink issues.
• Solutions: Use appropriate solvents; reduce impression settings if necessary.

© Anyflexo

Ink Transfer Issues

• Problem: Poor ink transfer.
• Causes: General ink issues, ink drying on anilox roller, or plate surface contamination.
• Solutions: Check ink condition; clean plate surface and anilox roller.

Filling-In of Fine Elements

• Problem: Fine elements filled with ink.
• Causes: High anilox to plate impression or incorrect ink viscosity.
• Solutions: Confirm anilox settings; adjust ink viscosity as needed.

© Anyflexo

Ink Bleeding

• Problem: Ink bleeds, obscuring screen structures.
• Causes: Improper pigments in ink or pH imbalance in water-based ink.
• Solutions: Consult with your ink manufacturer.

© Anyflexo

Dirty Print in Transitions of Flexo Plates

• Problem: Dirty printing in screen transitions.
• Causes: High anilox to plate impression, low ink viscosity, high anilox volume, or shallow intermediate depths or plate relief.
• Solutions: Optimise press and ink parameters; correct plate making issues.

© Anyflexo

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