Pad Printing Trouble Shooting
- Blurred or sharpness problem:
Unsharp printing means blurred reproduction of lines or lettering. - Ink does not meet adhesion requirements
This problem frequently occurs because the material of the product is unknown or the wrong type of ink is used. - Small pinholes are apparent
If they're large and consistently in the same place, check the pad and cliche for damage. Replace if necessary. - Colors transferring between pads on multi-color jobs.
In fast multicolor printing sequences a subsequent pad can remove a previous color.
This happens most often in larger print motifs on substrates not etched by the thinner. This usually occurs in connection with multi-station conveyors or turntables when using slow drying inks. This problem can be eliminated by initiating print and cliche pauses. - Uneven ink thickness
Usually occurs with larger areas of ink coverage. - Distortion in printed image
Distortion usually occurs when a printing on deep or curved surfaces. - Opacity of ink is poor
This is usually a direct result of printing on dark substrates with a single print. In these situations a second "hit" will usually bring the image up to a desired opacity level. Otherwise, a background print in white, or sometimes silver, will lay down a sufficient level of ink to make a brighter image. - Smudged image
This occurs when ink is too thin or pad slips during print. Slippage of pad during printing can be caused by too hard a pad, poor fixtures, angle of part in fixture, or excess pad pressure. - Mis-registration of colors multi-color print
- Image appears blotchy
A dry appearance or voids in the print is usually caused by ink which had dried in the image area of the cliche. - Ink sticks to pad surface
If the pad picks up the image cleanly but does not drop-off entire image during print stroke, voids will appear in image. - Hairs on edges of image
This can be caused by a static charge in the part, but can also be due to other factors such as pad shape and improper ink viscosity. - Fine lines begin to close up
This problem usually occurs in reverse images where copy has dropped out of the artwork.
Blurred or sharpness problem:
Unsharp printing means blurred reproduction of lines or lettering.| Probable Cause | Possible Solution |
| Pad | |
| Too soft. | Use a harder pad. |
| Wrong shape. | Use a different shape. |
| Cliche | |
| Inaccurate etch. | make a new cliche. |
| Etching is too deep. | Etch a new cliche with less depth. |
| Wrong type of cliche. | Use the suitable cliche type(e.g. steel in place of polymer). |
| Wrong type of screen. | Test a new cliche 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 faster drying thinner or cliche pause. |
| Material | |
| Dirty surface. |
Pre-clean. |
| Rough, grainy surface. | Switch over to other material, if possible, or try a harder pad. |
| Large differences in height. | Use special shaped pads and pad mounting devices. |
| 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 at front position before releasing the ink film to avoid vibrations of the pad during printing. |
Ink does not meet adhesion requirements
This problem frequently occurs because the material of the product is unknown or the wrong type of ink is used.| Probable Cause | Possible Solution |
| Pad | |
| Too much silicone on surface. | Clean new pads with alcohol beforeuse. |
| Cliche | |
| Etched too deep. | Remake cliche deeper. |
| Ink | |
| Wrong type of ink. | Use the suitable ink according to thetechnical data sheet. |
| Bi-Component? | Use bi-component ink with hardener. |
| Incorrect ratio of ink to hardener. |
Remix ink with correct ratio by weighing ink and hardener. |
| Material | |
| Dirty surface. |
Preclean with alcohol. |
| Other | |
| No/insufficient pretreatment. | Check pretreatment procedure. If necessary, repeat. |
| Required cure time is not met. | Leave parts for longer period of time before testing. |
| No/insufficient after-treatment. |
Use heat tunnel and in some situations flame parts. |
Small pinholes are apparent
If they're large and consistently in the same place, check the pad and cliche for damage. Replace if necessary.| Probable Cause | Possible Solution |
| Pad | |
| Surface is damaged. | Replace pad or adjust so that damaged area won't interfere with image. |
| Pad is too flat. | Use pointed shape pad. |
| Too soft. | Use a harder pad. |
| Cliche | |
| Bad etching due to error or dust during exposure stage. | Remake. |
| Ink | |
| Ink is too Thick. | Add more thinner. |
| Material | |
| Rough surface. |
Use a firmer pad. |
| Parts dirty. | Clean. |
| Other | |
| Ink contaminated with silicone or oils. | Replace with new ink. |
Colors transferring between pads on multi-color jobs.
In fast multicolor printing sequences a subsequent pad can remove a previous color.This happens most often in larger print motifs on substrates not etched by the thinner. This usually occurs in connection with multi-station conveyors or turntables when using slow drying inks. This problem can be eliminated by initiating print and cliche pauses.
| Probable Cause | Possible Solution |
| Pad | |
| Porous, worn surface. | Replace pad. |
| Cliche | |
| Etching is too deep. |
Etch a new cliche with less depth. |
| Wrong percentage and LPI of screen. |
Test a new cliche with a different screen. (higher DPI screen for smaller areas & detail) |
| Ink | |
| Ink has too much thinner. | Add more pure ink to cup or inkwell. |
| Ink is drying too slow. |
Use a faster drying thinner, blow air, or use pad delays/ pauses to give inks time to dry. |
| Material | |
| Very smooth surface. Substrates which cannot be etched by the thinner (e.g., glass) are especially problematic. | Use hot/ cool air blown onto part between colors, or use pauses before printing. |
| Substrates contaminated with oils. | Clean parts prior to printing. |
Uneven ink thickness
Usually occurs with larger areas of ink coverage.| Probable Cause | Possible Solution |
| Pad | |
| Wrong shape. | Use a different shape. |
| Cliche | |
| Wrong cliche type. |
Use steel cliche to prevent ink "scooping". |
| Wrong etching depth. |
Make a new cliche controlling depth. |
| Wrong type of screen. | Test a new cliche with a different screen. |
| Wrong orientation. | Turn long lines at an angle. |
| Ink | |
| Too thin. | Reduce the amount of thinner. |
| Too thick. |
Add more thinner. |
| Insufficient mixing of ink andadditives. | Mix the ink thoroughly before puttingit into the ink tray or cup. |
| Material | |
| Odd shaped surface. |
Use suitable pad. |
| Other | |
| Doktor blade too soft. | Use firmer doktor blade or convert to inkcup system. |
Distortion in printed image
Distortion usually occurs when a printing on deep or curved surfaces.| Probable Cause | Possible Solution |
| Pad | |
| Wrong shape. | Use a different shape. |
| Too soft or too hard. | Use different hardness. |
| Image too close to pad edge. | Move or replace pad. |
| Cliche | |
| Etched too deep. |
Coupled with thin ink, the smudging caused isoften mistaken for distortion. |
| Ink | |
| Etched too deep. |
Causes smudging (see above) |
| Material | |
| Moves or collapses. | usare supporti speciali o tamponi |
| Other | |
| Unsuitable work piece fixtures. | Modify the fixtures to achieve supporton all positions of the product. |
| Fixtures move. | Check fixtures. |
| Printing on angle. | Change fixture angle. |
Opacity of ink is poor
This is usually a direct result of printing on dark substrates with a single print. In these situations a second "hit" will usually bring the image up to a desired opacity level. Otherwise, a background print in white, or sometimes silver, will lay down a sufficient level of ink to make a brighter image.| Probable Cause | Possible Solution |
| Pad | |
| Porous and rough. | Replace pad. |
| Too flat and soft causing insufficient inkrelease. | Use a firmermore pointed pad. |
| Cliche | |
| Etching depth is too low. |
Etch a deeper cliche. |
| Wrong type of screen. | Test a new cliche with a different screen. |
| Wrong type of cliche. | Use a different type of cliche. |
| Ink | |
| Ink too thin. |
Thicken ink. |
| Ink not transferring completely. | Use print pause or air blower to partially dryink for proper release. |
| Material | |
| Image not brilliant enough due to darkness of parts. | Use double hit to lay down additional layer. |
Smudged image
This occurs when ink is too thin or pad slips during print. Slippage of pad during printing can be caused by too hard a pad, poor fixtures, angle of part in fixture, or excess pad pressure.| 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 use fixture with more support. |
| Cliche | |
| Depth too deep. |
Make a new cliche. |
| Wrong type of cliche, may need screen. | Test a new cliche with a screen or use a different type of screen. |
| Ink | |
| Too thin. |
Add pure ink to thicken. |
| Slow drying. | Use a faster thinner. |
| Material | |
| Very uneven surface. | Use special shaped pads or adjust pad positions. |
| Other | |
| Fixtures are unstable. | Remake. |
| Work piece fixtures are not stable enough. | Remake. |
Mis-registration of colors multi-color print
| Probable Cause | Possible Solution |
| Pad | |
| Pads are not mounted correctly. | Adjust pads to pick up images in the exact same place. |
| Unequal shapes. | Use equally shaped pads. |
| Different hardnesses. | Use pads of the same durometer. |
| Cliche | |
| Images are not in registration. | Re-register artwork and etch new cliché's. |
| Ink | |
| Image spreads more in one color than in another. | 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, shuttle or turntable moveinaccurately. | Establish more accurate control of indexing. |
| Fixtures are insufficiently attached. | Fasten fixture screws. |
Image appears blotchy
A dry appearance or voids in the print is usually caused by ink which had dried in the image area of the cliche.| Probable Cause | Possible Solution |
| Pad | |
| Too flat. | Use a more pointed shape pad. |
| Porous, worn pad. |
Replace pad. |
| Cliche | |
| Etching depth is too shallow. | Make a new cliche with deeper etch. |
| Wrong type of etch. | Make new cliche with screened areas. |
| Ink | |
| Too thick. | Add thinner. |
| Ink dried in etching. | Clean the cliche with thinner. |
| Material | |
| Contaminated with oils. | Clean with alcohol. |
| Other | |
| Machine speed too low. |
Increase speed of the machine. |
Ink sticks to pad surface
If the pad picks up the image cleanly but does not drop-off entire image during print stroke, voids will appear in image.| 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. |
| Cliche | |
| Etch is too shallow. |
Etch a deeper cliche if ink is drying on pad. |
| Etch is too deep. | Etch a new cliche with less depth, or use cliche pause to allow ink time to partially dry on cliche. |
| Ink | |
| Dried on the pad. | Use retarder or more thinner. |
| Too wet on the pad -does not film well. | Use a faster thinner or pause on the print stroke. |
| Material | |
| Dirty surface (grease, oil, releaseagents, hand sweat). | Preclean. Depending on the grade ofdirtiness, with alcohol, if necessary.Wear gloves during printing. |
| Other | |
| Room temperature is too high. |
The room temperature is best at 64-68 °F. |
| 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/hotair. |
Hairs on edges of image
This can be caused by a static charge in the part, but can also be due to other factors such as pad shape and improper ink viscosity.| Probable Cause | Possible Solution |
| Pad | |
| Too flat. | Use a more pointed shape. |
| Cliche | |
| Etch is too deep. |
Remake a cliche 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 high speed thinner. |
| Material | |
| Static charge. | Use a de-ionizer or increase humidity in shop. |
| Other | |
| Air moisture is too low. |
Increase air moisture up to 60-80%. |
| Cycle time is too high. |
Reduce printing speed. |
| Pad pressure too high forcing ink outward. | Decrease pressure. |
Fine lines begin to close up
This problem usually occurs in reverse images where copy has dropped out of the artwork.| Probable Cause | Possible Solution |
| Pad | |
| Too hard. | Use a softer pad. |
| Roughened porous surface. | Use a new pad. |
| Cliche | |
| Etch depth is too deep. | Make a new cliche with lower etching depth.or use pause to allow ink set/drying time in cliche. |
| First exposure of plate-making process is too long. | Make new cliche with lower exposure times. |
| Wrong type of etch. | Use a different type of cliche with screened image area. |
| Ink | |
| Ink too thin. | Reduce the amount of thinner. |
| Too slow; ink smears out. |
Use a faster thinner, or pause above cliche. |
| Material | |
| Too smooth (e.g. glass) |
Clean thoroughly, to aid in "catching" the ink. |
| Other | |
| Pad stroke is adjusted too high. Causes ink tobe forced out of etched areas. | Reduce pad stroke. |