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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