15 Most Common Water-Based Flexo Issues and How to Troubleshoot Them

1. Ink is drying too fast

The ink is drying on your plates, your ink rollers and maybe your anilox. It may even be failing to transfer to the substrate.

What it looks like

 Probable Causes

  • Too much heat from dryers or air blowing on print station
  • Slow press speeds
  • Improper ink pH

 Possible Solutions

  • Reduce dryer heat
  • Eliminate air flow on print station
  • Clean the plates and increase press speed
  • If pH is below 8.8, increase it with the recommended additive*

*Wikoff Color Technical Data Sheets list the recommended additives for pH adjustments

2. Ink is drying too slow

The ink is picking off, offsetting on the press idler and might be causing blocking issues.

What it looks like

 Probable Causes

  • Too much heat from dryers or air blowing on print station
  • Slow press speeds
  • Improper ink pH

 Possible Solutions

  • Reduce ink viscosity*
  • Increase warm air flow
  • Replace doctor blade and/or make sure chamber is parallel

*Wikoff Color Technical Data Sheets list the recommended solvents for viscosity adjustments

3. Pinholes

You’re seeing tiny holes in your print area, sometimes called fisheyes.

What it looks like

 Probable Causes

  • If ink adhesion is OK, add 0.5% pinhole additive under agitation
  • Add fresh ink to reservoir
  • Clean or change anilox roller
  • Slow the ink dry rate*
  • Use a harder mounting tape

 Possible Solutions

  • If ink adhesion is OK, add 0.5% pinhole additive under agitation
  • Add fresh ink to reservoir
  • Clean or change anilox roller
  • Slow the ink dry rate*
  • Use a harder mounting tape

*Wikoff Color Technical Data Sheets list the recommended additives for drying adjustments

4. Print is too strong

Print density is too high.

What it looks like

 Probable Causes

  • Ink viscosity is too high
  • Improper metering roller or doctor blade settings
  • Anilox cell volume is too high
  • Ink is too strong

 Possible Solutions

  • Reduce ink viscosity*
  • Increase metering roller pressure
  • Use lower volume anilox
  • Reduce ink with extender

*Wikoff Color Technical Data Sheets list the recommended additives for viscosity adjustments

5. Print is too weak

Print density is too low.

What it looks like

 Probable Causes

  • Ink viscosity is too low
  • Anilox roller is plugged
  • Anilox cell volume is too low
  • Anilox is worn
  • Improper metering roller or doctor blade settings

 Possible Solutions

  • Increase metering roller pressure
  • Replace doctor blade
  • Use higher volume anilox
  • Change anilox roller

6. Haloing

That pesky shadow, or line, is showing up on the outer edge of your image areas.

What it looks like

 Probable Causes

  • Plate cylinder is over impressed onto substrate
  • Plate mounting tape is too hard for the images

 Possible Solutions

  • Reduce impression
  • Remount plate with softer tape

7. Picking

You’re seeing spots or ink being lifted off your print area.

What it looks like

 Probable Causes

  • Ink is drying too slowly
  • Drying systems are insufficient
  • Ink viscosity is too high

 Possible Solutions

  • Contact your local Wikoff team for a faster drying formulation
  • Increase heat and air flow
  • Reduce ink viscosity*

*Wikoff Color Technical Data Sheets list the recommended solvents for viscosity adjustments

8. Mottled Print

Your solid print areas are spotted and/or speckled.

What it looks like

 Probable Causes

  • Ink viscosity is too low
  • Printing plate surface is uneven
  • Substrate surface is rough or uneven
  • Anilox is worn

 Possible Solutions

  • Add fresh ink to the reservoir
  • Mount a new plate
  • Contact your local Wikoff team for a primer
  • Change anilox roller

9. Adhesion Problems

The ink is having a hard time adhering to the substrate.

What it looks like

 Probable Causes

  • Ink system may not be optimized for your application
  • Inadequate substrate treatment
  • Ink viscosity is too low

 Possible Solutions

  • Contact your local Wikoff team to verify you have the right ink system
  • Check substrate Dyne level
  • Add fresh ink to the reservoir

10. Dirty Print

The edges of your print area are fuzzy and/or irregular.

What it looks like

 Probable Causes

  • Ink is drying too fast
  • Improper metering roller setting
  • Too much heat from dryers or air blowing on print station
  • Too much anilox-to-plate or plate-to-substrate pressure

 Possible Solutions

  • Contact your local Wikoff team for a faster drying formulation
  • Increase heat and air flow
  • Reduce ink viscosity*

*Wikoff Color Technical Data Sheets list the recommended solvents for viscosity adjustments

11. Foaming

Ink is foaming in the reservoir.

What it looks like

 Probable Causes

  • Ink pump is too vigorous
  • Ink viscosity is too high
  • Not enough defoamer in ink

 Possible Solutions

  • Reduce power/air to ink pump
  • Reduce ink viscosity*
  • Add defoamer to ink, small amounts at a time

*Wikoff Color Technical Data Sheets list the recommended additives for viscosity adjustments

12. Poor Trapping

The second-down ink doesn’t lay well over the first-down ink.

What it looks like

 Probable Causes

  • First-down ink is drying too slowly
  • Second-down ink is drying too fast

 Possible Solutions

  • Use lower volume anilox for first-down ink
  • Increase heat and air flow on first-down unit
  • Skip a unit between first-down and second-down ink
  • Reduce viscosity of first-down ink*
  • Slow down the second-down ink dry rate*

*Wikoff Color Technical Data Sheets list the recommended additives for viscosity and dry rate adjustments

13. Streaking

A continuous line is showing up in your print area.

What it looks like

 Probable Causes

  • Particles are lodged under the doctor blade
  • Anilox roller is scratched
  • Doctor blade is nicked

 Possible Solutions

  • Filter ink and clean behind the doctor blade
  • Replace anilox roller
  • Replace doctor blade

14. Blocking

The ink is offsetting onto the backside of the stock in rewind.

What it looks like

 Probable Causes

  • Ink is drying too slowly
  • Rewind is wound too tightly
  • Rewind temperature is too warm

 Possible Solutions

  • Increase heat and air flow in drying stations
  • Reduce rewind pressure
  • Reduce web temperature before rewind with a chill roller

15. Bridging / Filling in

The print is connecting in small type and screen areas.

What it looks like

 Probable Causes

  • Anilox cell volume is too high
  • Ink is drying to fast
  • Ink viscosity is too high
  • Rubber roller is too soft
  • Improper anilox roller settings

 Possible Solutions

  • Change to higher screen count, lower volume anilox
  • Slow the ink dry rate*
  • Reduce ink viscosity*
  • Change to a harder durometer rubber roller
  • Adjust anilox roller to “kiss” impressions

*Wikoff Color Technical Data Sheets list the recommended additives for viscosity and dry rate adjustments

Still not seeing the results you need on press?

Give us a call or send us a message and we’ll be happy to help you troubleshoot your water-based flexo issues. After all, happy customers are our number one priority!

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