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Troubleshooting Tools
Working with Daetwyler means that our entire 40+ years of top-quality print industry expertise is always right at your fingertips. Just like the products we create, we place a high priority on being your pressroom’s most valuable resource when it comes to precision output, and ultimately, your success.
Our extensive knowledge and first-hand experience includes solving all the most common printing problems faced by gravure and flexographic printers today, making us an ideal choice to help help with any challenge your pressroom is facing.
For help troubleshooting your issue, please select the printing method:
MDC doctor blades help avoid all manner of issues including ink spitting, bleeding, dot loss/gain, ghosting effect, uneven ink layer, streaks and chattering marks.
Anilox Wear
Anilox Wear
Causes
- Over-pressure of doctor blade
- Doctor blade contact area to large
- Incorrect blade material
- Blade holder/chamber in contact with anilox roller
- Excessive engraving recast
Solutions
- Look for reasons excessive pressure is needed and correct (see uneven metering)
- Install stops to limit over adjustment (pressure) of doctor blades
- Use filters and magnets in ink system
- Inspect anilox for recast on top of cell walls
- Use correct doctor blade to match anilox line screen
- Check new doctor blades for smoothness/roughness
We recommend
Back Doctoring
Back Doctoring
Causes
- Too much blade pressure
- Incorrect ink viscosity
- Containment blade is not correct
Solutions
- Reduce blade pressure
- Look for signs of extra pressure (i.e. wavy blades) and correct
- Check ink viscosity to ensure it is within specifications
- When using steel for both wiping and containment blades, the containment blade should be thinner than the wiping blade
- When using plastic, containment blade should not be more rigid than the wiping blade
- Containment blade width should be within specification of the chamber manufacturer
We recommend
Bleeding
Bleeding
Causes
- Humidity is too high – water is condensing in the sovent-based ink
- Amount of retarder used is excessive
- Ink viscosity is too low
- Pick-up volume is too high
- Print speed is too high
Solutions
- Mix fresh ink
- Use an ink with a faster solvent
- Adjust the viscosity
- Replace the anilox roller
- Reduce the print speed – increase the drying capacity
- Even though the doctor blade is not the decisive element, we recommend sharp doctoring
- Use bevel or lamella configuration
- Use coated doctor blades
Dot Gain
Dot Gain
Causes
- Excessive pressure between the plate cylinder and the substrate
- Volume of anilox roller too large
- Doctor blade contact zone is too large
Solutions
- Reduce pressure and adjust pressure setting
- Change anilox to lower volume roll
- Change blade to lamella stepped or bevel tip blade thus reducing the contact zone for a cleaner wipe and better control of the ink film thickness
We recommend
Excessive Ink Film Thickness
Excessive Ink Film Thickness
Causes
- Contact area of doctor blade too large
- Anilox cell count and volume does not match doctor blade selection
- Anilox line count and volume is too large
- Doctor blade is not set parallel to anilox and/or set incorrectly
- Blade pressure is too high causing blade to bend and wipe with back of blade
- Doctor blade wears too quickly/aggressively
Solutions
- See chart on FAQ to match blade tip to anilox line screen
- Check doctor blade set up to ensure blade is set evenly across the anilox and low pressure is used
- Look for reasons excessive pressure is needed and correct.
- Use a longer life, coated doctor blade
We recommend
Ghosting
Ghosting
Causes
- Volume of the anilox roller is too low
- Ink is drying in the cells
- Cells are inadequately filled
- Print speed is too low
- High amount of air flow or turbulence around plate
Solutions
- Change to anilox roller with a higher pick-up volume
- Change solvent blend to a slower drying solvent
- Increase the pressure in the chambered doctor blade system
- Increase speed or ink viscosity
- Check air flow around plate, fix if too much
We recommend
Haloing & Drop Effect
"Haloing" & Drop Effect
Causes
- Volume of anilox roller is too high
- Chamber pressure too high
- Plate cylinder to substrate pressure too high
- High pressure on the anilox roller to plate
- Worn blades or improper blade
Solutions
- Change the anilox roll to smaller volume
- Reduce pressure and adjust accordingly
- Reduce plate pressure to substrate
- Decrease pressure to plate
- Change blades to lamella tip for cleaner wipe
We recommend
Horizontal Streaks
Horizontal Streaks
Causes
- Pressure setting between the plate cylinder and the printing substrate is too high
- Print speed is too high
- Pressure setting between the anilox roller and the pressure plate is wrong
- There is a mechanical fault
- Plate layout – large gaps
- Wrong viscosity
- Too thin metering blade
Solutions
- Reduce pressure and adjust pressure settings
- Reduce the print speed
- Adjust the pressure setting
- Check the mechanical parts of the printing machine
- Add bearer bars, change plate layout
- Check viscosity
- Thicker blade
We recommend
Ink Density too High
Ink Density too High
Causes
- Volume of the anilox roller is too high
- Ink viscosity is too high
- Ink formulation in color matching is too strong
- Doctor blade contact zone is too large
Solutions
- Use an anilox roller with reduced volume
- Add solvent to adjust the ink viscosity
- Adjust ink formulation to match color
- Change blade to lamella stepped or bevel tip blade thus reducing the contact zone for a cleaner wipe and better control of the ink film thickness
We recommend
Ink Density too Low
Ink Density too Low
Causes
- Dirty anilox roller, dried ink in the cells
- Ink is too thin
- Ink is out of specification
- Anilox roller is worn out, volume is too low
- Low pressure on plate cylinder to substrate
- Low pressure on the anilox roller to plate Cylinder
Solutions
- Clean or change the anilox roller
- Check for proper viscosity
- Replace with new, fresh ink
- Change to good or new anilox roller
- Increase pressure to substrate
- Increase pressure to plate
We recommend
Leaking Chamber
Leaking Chamber
Causes
- Incorrect chamber alignment
- Incorrect end seals
- Wavy blades
- Re-doctoring of ink from the containment blade (back doctoring)
Solutions
- Verify chamber is parallel to anilox roller and both top and bottom blade are contacting the anilox roller at the same time
- Check with holder manufacturer for the correct end seal specifications and material
- Check blade settings to ensure the seal apex and blade width match
We recommend
Lines
Lines
Click here to download our white paper about working with white inks.
Causes
- Foreign particles trapped under the doctor blade
- Nick in the doctor blade
Solutions
- Reduce blade pressure
- Install ink filters and magnets
- Change doctor blade
- Check anilox for damage
- Send worn doctor blades to Daetwyler for evaluation
We recommend
Uneven Ink Layer
Uneven Ink Layer
Causes
- Ink viscosity is too low
- Too much retarder inside the ink
- Substrate surface is uneven
- Incorrect doctor blade pressure
Solutions
- Add fresh ink and fresh varnish
- Reduce retarder in your ink
- Use softer printing plates
- Check and adjust doctor blade pressure
We recommend
Uneven Metering
Uneven Metering
Causes
- Wavy blades
- Blade/chamber alignment
- Vibration
Solutions
- Clean holder and reset blade
- Check holder for damage and repair
- Tighten bolts from center out alternating sides
- Replace missing bolts
- Provide even tensioning on bolts
- Check end seal placement and height
- Ensure centerline of chamber is parallel to centerline of anilox
- Make sure containment and wiping blade in chamber contact the roller at the same time without adding additional pressure
- Check blade extension throughout entire chamber to consistency
- Check gear box of vibration
We recommend
UV Ink Spitting
UV Ink Spitting
Causes
- Doctor blade is worn or broke out on the anilox edge
- Surface of the anilox roller is damaged or dirty
- Wrong ink temperature
Solutions
- Replace the doctor blade
- Look for dried ink at the edges of the anilox
- Check the anilox radius
- Adjust the ink temperature
We recommend
Vertical Streaks
Vertical Streaks
Causes
- Doctor blade is worn
- Dried ink in the chambered doctor blade system
- Anilox roller is dirty or ink has dried on the anilox roller
- Particles in the chambered doctor blade system
- Anilox roller has score lines
- Waves in doctor blade from improper setup
Solutions
- Replace the doctor blade
- Put in new fresh ink or filter ink offline
- Clean the chamber
- Install an ink filter with magnets
- Change out anilox roller
- Change blade and check for flat blade, no waves
We recommend
Other Problems?
In combination with the right set-up, the MDC doctor blades can help avoid all manner of printing issues including hazing, unsmooth gradients, drag outs, flaws, chattering marks, ink streaks and cylinder wear.
Blade Chatter/Bounce
Blade Chatter/Bounce
Click here to download our white paper addressing chatter marks.
Causes
- Doctor blade angle is too steep
- Blade table oscillation gearbox/drive is not running out smooth
- Doctor blade pressure too low
- Doctor blade is loose in the blade holder
- Doctor blade holder is loose or vibrating in clamps/lockdowns not
- Ink volume too low in pan
- Back up/support blade not being used
Solutions
- Reduce the doctor blade angle
- Check oscillation bearings and drive gears for vibration
- Increase doctor blade pressure
- Check for loose bolts or clamps, tighten
- Tighten loose holder lock down clamps
- Increase amount of ink in pan
- Use proper back up blade
We recommend
Cylinder Wear
Cylinder Wear
Causes
- Not using proper doctor blade for application
- High blade pressure
- Flat blade angle
- Non-optimal surface roughness of the cylinder
- Using high opacity, highly pigmented inks
- Using waterbased inks
Solutions
- Do doctor blade audit for process
- Lower blade pressure
- Increase doctor blade angles – target 60 degrees +
- Increase cylinder roughness (Rz)
- Work with Ink supplier to reformulate inks
- Optimize process for proper ink usage
We recommend
Dragouts
Dragouts
Causes
-
Top side of the doctor blade tip is contaminated with dust or dried
ink particles - Ink viscosity is too low
- Blade angle too flat
- Contamination in the ink
Solutions
-
Clean the doctor blade top, use a slur stick or stop press and
wipe down - Increase the ink viscosity
- Increase blade angle
- Use an ink filter and magnets to remove contamination
We recommend
Drying In
Drying In
Causes
- Ink viscosity is high
- Ink temperature is high
- Cylinder temperature too high
- Solvents evaporating too fast
- Air gap too large
Solutions
- Check and reduce ink viscosity
- Check Ink temperature (70-75 degrees target)
- Check cylinder temperature
- Add slower drying solvent
- Decrease the air gap
Hazing
Hazing
Causes
- Blade angle is too flat
- Excessive blade pressure
- Ink not drying/flashing off cylinder in air gap
- Cylinder worn low roughness-Rz
- Improper doctor blade set up, wavy blade, long blade extension
Solutions
- Increase blade angle to 60-65 degrees
- Decrease blade pressure, reset blade, change blade
- Check viscosity, increase air gap, use a faster drying solvent
- Check cylinder roughness-Rz, dechrome/rechrome cylinder or remake cylinder
- Blade must lay flat in holder, blade extension past backup is 3-5mm max.
We recommend
Missing Dots
Missing Dots
Causes
- Cells are not emptying due to the electrostatic charge not working properly
- Impression roll too hard of durometer
- Rough paper surfaces and/or uncoated papers
- Too thin a doctor blade tip
- Too steep doctor blade angle
Solutions
- Check electrostatic assist system (ESA) working properly. Not used with metal composite or with metallized inks!
- Change impression roll to softer durometer
- Turn up ESA voltage
- Change blade to thicker lamella tip
- Reduce blade angle slightly
Streaks & Pin Lines
Streaks & Pin Lines
Causes
- Doctor blade contact zone is damaged, allowing ink to pass
- Ink is contaminated with hard dried insoluble ink particles
- Ink filter and magnets not being used
- Cylinder surface roughness (Rz) is too high
- Ink viscosity is too high
Solutions
- Hand polish cylinder or changed doctor blade
- Use ink filter and magnets
- Used a coated doctor blade
- Check the surface roughness Rz of cylinder
- Check and adjust the ink viscosity
We recommend
Unsmooth Gradations
Unsmooth Gradations
Causes
- High ink viscosity
- Incorrect screen or cell geometry
- Cylinder and ink temperature too high
- Substrate not corona treated, using wrong side of substrate
- No electrostatic assist system (or not working)
Solutions
- Check ink viscosity
- Discuss screen or cell geometry with cylinder manufacturer
- Check cylinder and ink temperature 70-75 ideal range
- Corona treater on, check substrate for proper Dyne level
- Check electrostatic assist system (ESA)
Other Problems?