Faq

Among the FAQ listed below you have not found what you were looking for? Then write us your question and we will reply as soon! info@comec-italia.it

Q?
Blurred print or sharpness problem
A.
Probable Cause Possible Solution
Pad  
Too soft Use a harder pad
Wrong shape Use a different shape
Cliché  
Inaccurate etch Make a new cliché
Etching is too deep Etch a new cliché with less depth
Wrong type of cliché Use the suitable cliché type (e.g. steel in place of polymer).
Wrong type of screen Test a new cliché with a different screen
Ink  
Ink is too thick Add more thinner
Ink is too thin Reduce the amount of thinner.
Slow drying Use a fast drying thinner or cliché pause
Material  
Dirty surface Pre-clean
Rough, grainy surface Switch over to other material, if possible, or try a harder pad
Printing near edges Fixtures must support the pad to prevent slippage
Other  
Work piece fixtures are not stable enough

 

High speed causes pad vibration

Make new fixtures

 

 

Decrease speed. If necessary, pause the pad at front position before releasing the ink to avoid vibrations of the pad during printing

Q?
Ink does not meet adhesion requirements
A.
Probable Cause Possible Solution
Pad  
Too much silicone on surface Clean new pads with alcohol before use
Cliché  
Etched too deep Redo a deeper cliché
Ink  
Wrong type of ink Use the suitable ink according to the technical data sheet
Probable need for two-component ink Use two-component ink with hardener
Incorrect ratio of ink to hardener Remix ink with correct ratio by weighing ink and hardener
Material  
Dirty surface Pre-clean with alcohol
Other  
No/insufficient pretreatment Check pretreatment procedure. If necessary, repeat it
Polymerization time not respected Let the pieces stand for longer time before testing
No/insufficient after-treatment Use heat tunnel and in some situations do the flame treatment
Q?
Small pinholes are apparent
A.
Probable Cause Possible Solution
Pad  
Surface is damaged Replace pad or place it so that damaged area won’t interfere with image
Pad is too flat Use pointed shape pad
Too soft Use a harder pad
Cliché  
Bad etching due to error or dust during exposure stage Redo the etching
Ink  
Ink is too thick Add more thinner
Material  
Rough surface Use a firmer pad
Dirty parts Clean them before printing
Other  
Ink contaminated with silicone or oils Replace with new ink
Q?
Color transfer between pads on multi-color jobs
A.
Probable Cause Possible Solution
Pad  
Porous, worn surface Replace pad
Cliché  
Etching is too deep Etch a new cliché with less depth
Wrong percentage and DPI of screen Test a new cliché with a different screen (higher DPI screen for smaller areas & details)
Ink  
Ink contains too much thinner Add more pure ink
Ink is drying too slow Use a fast drying thinner, blow air, or use pad delays/pauses to give inks time to dry
Material  
Very smooth surface. Substrates which cannot be notched by the thinner (e.g. glass) are especially problematic Use hot/cool air on part during the print, or use pauses before printing
Substrates contaminated with oils Clean parts before printing.

 

Q?
Uneven ink thickness
A.
Probable Cause Possible Solution
Pad  
Wrong shape Use a different shape
Cliché  
Wrong cliché type Use steel cliché to prevent ink “scooping”
Wrong etching depth Make a new cliché controlling depth
Wrong type of screen Test a new cliché with a different screen
Wrong orientation Change cliché orientation
Ink  
Too thin Reduce the amount of thinner
Too thick Add more thinner
Insufficient mixing of ink and additives Mix the ink thoroughly before putting it into the inkcup.
Material  
Odd shaped surface Use suitable pad
Other  
Doctor blade too soft Use firmer doctor blade or convert to hermetic inkcup system
Q?
Distortion in printed image
A.
Probable Cause Possible Solution
Pad  
Wrong shape Use a different shape pad
Too soft or too hard Use different hardness
Image too close to pad edge Move or replace pad
Cliché  
Etched too deep Coupled with thin ink, the smudge caused is often mistaken for distortion
Ink  
 Too thin + etched too deep Causes smudging (see above)
Material  
Moves or collapses Use special fixtures or appropriate pads
Other  
Unsuitable work piece fixtures Modify the fixtures to achieve support on all positions of the product
Fixtures movement Check fixtures
Printing on angles Change fixture grade
Q?
Fine lines begin to close up
A.
Probable Cause Possible Solution
Pad  
Too hard Use a softer pad
Roughened porous surface Use a new pad
Cliché  
Etch depth is too deep Make a new cliché with lower etching depth or use pause to allow ink drying in the cliché
First exposure of plate-making process too long-lasting Make new cliché with lower exposure time
Wrong type of etch Use a different type of cliché with screened image area
Ink  
Ink too thin Reduce the amount of thinner
Too fluid; ink smears out Use a fast dying thinner, or pause above cliché
Material  
Too smooth (e.g. glass) Clean thoroughly, to aid the ink cohesion
Other  
Pad stroke is too fast. Causes ink to be forced out of etched areas Reduce the speed of the pad stroke

 

Q?
Ink sticks to pad surface
A.
Probable Cause Possible Solution
Pad  
Too soft Use a harder pad
Wrong shape Use a more pointed shape
Roughened porous surface Replace with a new pad
Cliché  
Etch is too shallow Etch a deeper cliché if ink is drying on pad
Etch is too deep Etch a new cliché with less depth, or use cliché pause to allow ink to partially dry on cliché
Ink  
Dried on the pad Use retarder or more thinner
Too wet on the pad, does not film well Use a fast dying thinner or pause on the print stroke
Material  
Dirty surface (grease, oil, release agents, hand sweat) Preclean. Depending on the grade of dirtiness, with alcohol, if necessary. Wear gloves during printing
Other  
Room temperature is too high The room temperature is best at 18 – 20 °C
Pad speed too low Increase speed in the case of ink drying on the pad
Pad speed too high Use pause on print stroke in case of ink too wet to allow more drying time, or use cool/hot air
Q?
Smears on edges of image
A.
Probable Cause Possible Solution
Pad  
Too flat Use a more pointed shape
Cliché  
Etch is too deep Redo a cliché with less depth
Wrong type of screening or no screen Use a different screen
Ink  
Too thick Add more thinner
Ink is drying too slow Use a fast dying thinner
Material  
Static charge Use a ionizer or increase humidity
Other  
Air moisture is too low Increase air moisture up to 60-80%
Cycle time is too fast Reduce printing speed
Pad pressure too high forcing ink outward Decrease pressure
Q?
Opacity of ink is inadequate
A.
Pad  
Porous and rough Replace pad
Too flat and soft causing insufficient ink release Use a firmer and more pointed pad
Cliché  
Etching depth is too shallow Etch a deeper cliché
Wrong type of screen Test a new cliché with a different screen
Wrong type of cliché Use a different type of cliché
Ink  
Ink too thin Thicken ink
Ink not completely transferred Use print pause or air blower to partially dry ink for proper release
Material  
Image not brilliant enough due to darkness of parts Use double hit to lay down an additional ink layer
Q?
Smudged image
A.
Probable Cause Possible Solution
Pad  
Too hard Use a softer pad
Too small in relation to the image Use a larger pad
Prints over edges Adjust the pad stroke and/or secure the fixtures
Cliché  
Depth too deep Make a new cliché
Wrong type of cliché, may need screen Test a new cliché with a screen or use a different type of screen
Ink  
Too thin Add pure ink to thicken
Slow drying Use a fast dying thinner
Material  
Very uneven surface Use special shaped pads or adjust pad position
Other  
Fixtures are unstable Redo them
Q?
Mis-registration of colors in multi-color print
A.
Probable Cause Possible Solution
Pad  
Pads are not correctly assembled Adjust pads so as they pick up images in the exact same place
Different shapes Use equally shaped pads
Different hardnesses Use pads of the same hardness
Cliché  
Images are not in registration Re-register artwork and etch new cliché
Ink  
Image spreads more in one color than in others Correct ink viscosity to prevent incorrect dot gain
Material  
Parts collapse (e.g. plastic bottles) Use a more supportive fixture
Other  
Work piece fixtures are not stable enough Control. Make new fixtures if necessary
Conveyor, feeder or turntable move inaccurately Set carefully the devices movement
Fixtures are insufficiently attached Fasten fixture screws
Q?
Image appears blotchy
A.
Probable Cause Possible Solution
Pad  
Too flat Use a more pointed shape pad
Porous, worn pad Replace pad
Cliché  
Etching depth is too shallow Make a new cliché with deeper etch
Wrong type of etch Make new cliché with screened areas
Ink  
Too thick Add thinner
Ink dried in etching Clean the cliché with thinner
Material  
Contaminated with oils Clean with alcohol
Other  
Machine speed too low Increase the machine’s speed