THE BUSINESS OF VISCOSITY BLOG



4 Flexographic Printing Issues and What to Do to Solve Them

Posted by Mark Portelli

Feb 22, 2018 4:33:39 PM

When it comes to flexographic printing, maintaining consistent quality is paramount to the success of your operation — and profitability.ink_colors.jpeg

Yet riding that thin line of consistency is easier said than done, as any number of issues can crop up in your process.

However, every issue has a solution.

Here are four common problems that can occur with your ink, including known causes and how you can potentially correct each one.

 

#1 — Adhesion issues

When you have issues with adhesion, ink will flake off your substrate when crinkled — or it will be easily removed in the “tape test” — which can easily lead to customer rejections.


CAUSE

SOLUTION

Viscosity too high

Reduce viscosity consistent
with acceptable printability

Viscosity too low

Add virgin ink to fountain

Ink surface tension
too high

Consult your technical
sales representative

Incorrect ink system for
substrate

Ensure that the correct ink for
the substrate is being used

Poor film treatment

Check surface of film for adequate treatment; if possible treat in line

Ink drying too slow

Check driers for heat and airflow; consult your ink manufacturer or reduce with faster solvent blends

Substrate surface
contamination

Apply primer before printing,
use in-line treater

Insufficient web
temperature

Increase temperature settings of driers, check drier balance

 

#2 — Bleeding or smearing issues

Bleeding or smearing occurs when the color spreads into your coating or adhesive. While some may not view this as the most dire of issues, it still affects your quality and can lead to waste and possibly rejections.

CAUSE

SOLUTION

Improper pigment use

Reformulate ink, consult
with ink supplier

Coating or adhesive may be rewetting ink

Reformulate ink, consult
with ink supplier

Ink viscosity too high

Reduce viscosity or
film thickness

Incorrect solvent
formulation

Use faster or slower
drying solvents

 

#3 — Color strength issues

When your color is too strong, your printed colors will not match the expected target. This is a problem especially in today’s world where consumers expect perfection when it comes to branding images.

CAUSE

SOLUTION

Viscosity too high
(solvent-based inks)

Reduce viscosity consistent
with acceptable printability

pH too high
(water-based inks)

Check & adjust pH, reduce
viscosity to acceptable level

Ink pigmentation
too high

Reduce colorant strength
with extender

Anilox roll cell volume
too great or cell count
too low for application

Replace with higher line count
or lower volume anilox roller

Pressure roller setting
inadequate

Adjust impression to
improve print

Plate or ink metering
roll durometer (hardness)
too low for job

Consult your plate or
roll manufacturer

Inadequate doctor blade
impression

Adjust doctor blade to recommended pressure

 

#4 —Ink consumption issues

When you’re using too much ink, you’re getting fewer impressions per ink volume. Ultimately, it will eat away at your bottom line and damage your profitability.

CAUSE

SOLUTION

Viscosity too high

Reduce viscosity

Ink color too strong

Use extender to weaken color
to acceptable level

Weak/old ink

Check ink to original standard, check date and usage; consult
your ink supplier

Excessive anilox volume

Replace with appropriate anilox

Metering roll too soft for job

Check metering roll durometer, reduce ink

Ink loss on startup
or shutdown

Review ink handling setup & shutdown procedures

 

Ink management…

Whatever issue you may be experiencing, it’s clear that consistent print quality requires effective ink management. However, ink management can be a difficult process.  There are many different elements to be held in careful balance as can be seen in the issues discussed above, including pH, viscosity and evaporation (both of which are related to temperature), etc.

Fortunately, printers can simplify this delicate balancing act through ink control automation.

Norcross’ StablINK system is designed to improve ink performance by continuously monitoring and making adjustments in solvent-based or water-based printing applications. To learn more, download our brochure or contact Saint Clair Systems directly to discuss your application.

Click to get your StablINK brochure

Topics: flexographic printing, ink management

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