Problem Solving

Print is blurred or lines are not sharp

Possible causes of blurring in lines and text with imprecise printing and suggested solutions:

  • Pad based causes:
    • Pad may be too soft; use a pad harder.
    • The shape of the pad may be incorrect: different shaped pads should be tried.
  • ClichĂ© based causes:
    • Incorrect raster may have been used in the clichĂ©: the clichĂ© should be retried with different raster.
    • ClichĂ© is too deep: try printing again with a new clichĂ© with less depth.
    • Wrong type of clichĂ©: a suitable type of clichĂ© should be used, e.g. steel clichĂ© should be used instead of polymer.
  • Ink based causes:
    • The ink may be too thick: try printing again by adding some thinner.
    • The ink may be drying slowly: try again using a faster drying thinner or by reducing the printing speed.
  • Material based causes:
    • Surface of the material may be dirty; pre-cleaning should be applied to the material.
    • The surface of the material may be rough or chipped: another type of material should be used. If this is not possible, a harder pad is recommended.
    • If the material surface is uneven: a special shaped pad and pad connection should be used.
    • Print very close to the edge of the material; the device must be prepared to prevent the pad slipping.
  • Other causes:
    • The printing elements may not be stable enough; high speeds cause the pad to flicker. Anew mechanism must be created to reduce the speed. If necessary the pad must be stopped for a while before contacting the material.

Adhesion of the ink is not good enough:

This problem is usually seen when the type of product printed on is unknown or when the wrong type of ink is used. Possible causes and suggested solutions are as follows.

  • Pad based causes

    • Pad surface is greasy; the pad must be thoroughly cleaned before starting to print.
  • ClichĂ© based causes
    • ClichĂ© is too deep: prepare a new clichĂ© with less depth.
  • Ink based causes
    • The ink type may not be suitable for the material: an appropriate ink should be used according to the technical information card.
    • Double-component ink may need to be used instead of single: the use of dual component ink increases adhesion.
    • The ink-catalyst ratio may be incorrect: The ink and catalyst must be re-mixed at the correct proportions.
  • Material based causes
    • Surface of the material may be dirty; pre-cleaning with alcohol should be applied to the material surface.
  • Other causes
    • The material may not be pre-treated or insufficiently pre-treated; the pre-treatment procedure should be checked and repeated if necessary.
    • The required curing time is not met: the parts must be left for a longer time before the print quality is tested.
    • Final finishing is not done or insufficiently done; the use of heat tunnel and, in some cases, a flaming dryer for final finishing enhances adhesion.

Small pores are forming

If the pores are large and generally in the same area, the pad and the cliché should be checked for damage and replaced if necessary. Possible other causes and suggested solutions are as follows:

  • Pad based causes
    • Pad surface may be damaged: The pad must be replaced or the damaged area must be kept at outside of the print area.
    • Pad can be very flat: conical type pad should be used.
    • Pad can be very soft: hard type pad should be used.
  • ClichĂ© based causes
    • An error may have occurred due to bad pickling or contamination during clichĂ© preparation: the clichĂ© must be rebuilt.
  • Ink based causes
    • The ink may be too thick: try printing again by adding some thinner.
  • Material based causes
    • The surface of the material may be rough: a suitable pad for the rough surface should be used.
    • Surface of the material may be dirty; pre-cleaning with alcohol should be applied to the material surface.
  • Other causes
    • Ink may be contaminated with silicone or oil: the ink should be replaced.

There is a color transition between the pads in multicolor printing

In multi-color fast prints, the next printing pad can remove the previous color. This usually occurs in motifs in large print areas that have not been cleaned with thinner in advance. This is a problem especially when printing with slow-drying ink in multi-stage carriages and on turntable prints. For the solution of the problem, the time for cliché and printing can be increased. Possible causes and suggested solutions are as follows:

  • Pad based causes
    • Pad surface may be worn and porous: pad must be replaced.
  • ClichĂ© based causes
    • ClichĂ© is too deep: prepare a new clichĂ© with less depth.
    • Transmitter ratios and density values may be incorrect; a new clichĂ© should be tried with another transponder, if there are small areas or details in the design, high resolution should be applied.
  • Ink based causes
    • Ink may be too thin; printing should be retried with an ink prepared with less thinner.
    • The ink may be drying too slowly: a faster drying thinner must be used, airflow must be applied, or the pad printing speed must be reduced.
  • Material based causes
    • In glass and similar materials the surface can be extremely bright: surfaces that cannot be processed with thinner are generally a problem. Between colors, hot/cold air flow to the material may be applied or printing may be paused between the colors to allow the ink to dry.
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    • The material may be contaminated with oil: the parts must be cleaned before printing.

Ink thickness unstable

It is usually seen during printing with large surfaces. Possible causes and suggested solutions are as follows.

  • Pad based causes
    • Pad shape may not be appropriate, try different shaped pads.
  • ClichĂ© based causes
    • ClichĂ© type may not be suitable: use of steel clichĂ© causes less ink accumulation than polymer clichĂ©.
    • The clichĂ© depth may be wrong: a new clichĂ© should be prepared at the appropriate depth.
    • The transmitter type may be incorrect: a new clichĂ© should be prepared with a different transmitter.
    • ClichĂ© placement may be wrong: Printing of the long lines in the design should be tried by rotating the clichĂ©s in different directions.
  • Ink based causes
    • Ink may be too thin; the amount of thinner added to the ink must be reduced.
    • The ink may be too thick: the amount of thinner added to the ink must be increased.
    • The ink-additive ratios may not be appropriate: the ink mixture must be prepared at the correct ratio before being placed in the ink tray.
  • Material based causes
    • The surface of the material may be deformed: a suitable type of pad should be used.
  • Other causes
    • On open ink tray machines the stripping blade may be too soft: a suitable stripping blade and ink tray should be used.

Distortion-bending in print image

Distortion-bending in printing is often a problem encountered during the printing of deep or curved surfaces. Possible causes and suggested solutions are as follows:

  • Pad based causes
    • Pad shape may not be appropriate, try different shaped pads.
    • Pad may be too soft or too hard; a buffer of appropriate hardness must be used.
    • The image may be very close to the pad edge: the pad must be shifted or replaced with a larger buffer.
  • ClichĂ© and ink based causes
    • The clichĂ© can be very deep: it causes distortion and bending in the image with a fine ink.
  • Material based causes
    • Material may be moving or leaning during printing: A pad should be used with a hardness that will not tilt the material.
  • Other causes
    • The position of the material may not be suitable: the holder must be adjusted to support all areas of the material.
    • The holding device may be moving: the device must be fixed.
    • Proper printing can be achieved by changing the holding apparatus angle during angled prints.

Insufficient coverage in print

It is usually a problem when a single print is made on dark material. Mostly the second overprint solves the problem. If it is not solved in this way, it is possible to obtain the desired gloss print by making the white or according to the situation silver color background printing. Possible causes and suggested solutions are as follows.

  • Pad based causes
    • The pad surface may be porous and rough: the pad should be replaced.
    • The pad may not be suitable for ink transfer due to excessive flatness or softness: a more suitable pad should be used.
  • ClichĂ© based causes
    • The depth of the clichĂ© may be low: a deeper clichĂ© should be prepared and reprinted.
    • The transmitter type may not be suitable: a new clichĂ© should be prepared with a suitable transmitter.
    • ClichĂ© type may be wrong: the use of steel clichĂ© instead of polymer can solve the problem.
  • Ink based causes
    • Ink may be too thin; the amount of thinner added to the ink must be reduced.
    • The ink may not be completely transferred: the printing must be done by pausing air must be supplied for complete adhesion.
  • Material based causes
    • Due to the darkness of the material color, the desired gloss may not be obtained: a second print should be applied on the first print to create an additional layer.

Stained print

Usually occurs when the ink is too thin or the pad slides during the printing process. The pad sliding is due to the hard pad, the weak mechanism, the inclination of the mechanism, or the pad pressure is too high. Possible causes and suggested solutions

  • Pad based causes
    • Pad may be too hard; a softer pad must be used.
    • Pad may be too small for printing area: a larger pad should be used.
    • If the print exceeds the limits: pad pressure must be adjusted and/or a better holding device should be prepared.
  • ClichĂ© based causes
    • ClichĂ© is too deep: prepare a new clichĂ© with less depth.
    • ClichĂ© type may be wrong or transponder may be required: a new clichĂ© and transponder must be tried in conjunction or a different type of transponder must be used.
  • Ink based causes
    • Ink may be too thin: Ink without thinner should be added to thicken it.
    • The drying of the ink may be slow: try a new mix with a fast drying thinner.
  • Material based causes
    • Material surface can be extremely irregular: a special shaped pad must be used or the pad position must be adjusted
  • Other causes
    • Holder apparatus may not be suitable: a suitable apparatus must be prepared.
    • The working device may not be suitable: the device must be re-prepared.

Color differentiation in CMYK prints

This is a problem seen when the colors are not positioned correctly in CMYK prints. Possible causes and suggested solutions are as follows;

  • Pad based causes
    • Pads may not be positioned correctly: the positions of the pads must be checked and corrected.
    • Pads may not be evenly shaped and rigid: the same shape and hardness pad should be used for each color to prevent color shift.
  • ClichĂ© based causes
    • The images in clichĂ©s may not be as they were originally: the design should be redone and clichĂ©s should be renewed.
  • Ink based causes
    • Ink fluidity should be controlled and regulated if more than one image of an image occurs.
  • Material based causes
    • As in the case of plastic bottle printing, a holding device providing better support should be used in case of print breakage
  • Other causes
    • The work device may not be durable: it must be checked and a new device must be prepared if necessary.
    • The carriage, shuttle or rotary table may not be moving right, the feeder units should be checked and, if necessary, more sensitive units should be used.
    • The device must be connected improperly, check and correct.

Occurrence of drying stains in printing

The emergence of drying stains is usually due to the dried paint coming to clichĂ©’s image area. Possible causes and suggested solutions are as follows:

  • Pad based causes
    • Pad can be too flat: a more tapered pad should be used.
    • The pad may be worn and rough: the pad must be replaced.
  • ClichĂ© based causes
    • The depth of the clichĂ© may be low: a deeper clichĂ© should be prepared.
    • A faulty raster may be applied to the clichĂ©; a new clichĂ© with an appropriate raster must be prepared.
  • Ink based causes
    • Ink may be too thick, thinner must be added.
    • Ink in clichĂ© cavities may be dry: ClichĂ© should be cleaned with thinner.
  • Material based causes
    • Material may be contaminated with oil: Material surface should be cleaned with alcohol.
  • Other causes
    • The print speed of the machine is low; increase the speed.
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Adhesion of ink to the pad surface

Even the ink is transferred from the cliché to the pad, it is a problem that arises when you cannot successfully transfer the print onto the material. Possible causes and suggested solutions are as follows.

  • Pad based causes
    • The pad may be too soft: a harder pad should be used.
    • Pad shape may not be suitable: a more conical pad should be tried.
    • Pad may be worn, pad surface is rough and porous: Pad must be replaced.
  • ClichĂ© based causes
    • Inadequate clichĂ© depth can cause ink to dry on the pad ink pad: A new clichĂ© with proper depth should be used.
    • If the clichĂ© is too deep, it can cause the ink to dry also; the depth of the clichĂ© must be reduced or it has to be left to dry at certain time intervals.
  • Ink based causes
    • Ink can be fast drying: retarder or more thinner should be used.
    • The pad surface is very wet – The film is not clear. Use a fast thinner or slow down the print speed.
  • Material based causes
    • The surface of the material may be dirty (grease, oil, hand perspiration etc.): the printing surface must be cleaned and treated with alcohol according to the condition of the contamination. If the operator wears gloves it can help to resolve the problem.
  • Other causes
    • Room temperature may be too high: Room temperature should be 18-20 ° C.
    • Printing speed may be low: speed may be increased to prevent drying of the ink on the pad.

Pubescence on the print edges

It is caused by the static electricity on the material. In addition, inappropriate pad shape and ink fluidity can cause this problem. Possible causes and suggested solutions are as follows.

  • Pad based causes
    • Pad can be too flat: a more tapered pad should be used.
  • ClichĂ© based causes
    • ClichĂ© may be too deep; printing should be tried with a new clichĂ© with proper depth.
    • ClichĂ© may be without raster or with faulty type raster: ClichĂ©s should be prepared and tried with different raster.
  • Ink based causes
    • Ink may be too thick; thinner must be added.
    • Ink may dry too fast, fast thinner must be used.
  • Material based causes
    • Static load may accumulate on the material: de-ionizer should be used or the humidity of working environment should be increased.
  • Other causes
    • Humidity of air stabilizer may be low: humidity of the air stabilizer should be adjusted to 60-80%.
    • Conversion time can be very high: print time should be reduced.
    • The pressure of the pad on the material may be too high: the pressure should be lowered.

The intervals of lines in the print are closing

This problem is often observed on the pad surface also before printing on the material. Possible causes and suggested solutions are as follows.

  • Pad based causes
    • This problem can be caused by very hard pad: a soft pad should be used.
    • The pad may be worn, the surface may be rough and porous: the pad should be renewed.
  • ClichĂ© based causes
    • The depth of clichĂ© can be high: less deep clichĂ© should be prepared. Or the pause time of the pad on the clichĂ© and/or material should be increased.
    • During the preparation of clichĂ©, the first exposure time may be long: a new ClichĂ© with a shorter first exposure time must be prepared.
    • ClichĂ© image may be prepared without a raster, or with a raster which is not appropriate to the image: the design should be applied to the appropriate raster.
  • Ink based causes
    • Ink may be too thin, thinner ratio must be decreased.
    • Ink may dry slowly; fast thinner should be used or the pause time of the pad on the clichĂ© must be increased.
  • Material based causes
    • The surface of the material may be glossy (glass, etc.): the surface should be cleaned, or a suitable ink penetrating the material should be used.
  • Other causes
    • Pad pressure may be excessive: pad printing pressure on clichĂ© and material should be reduced.

 

Blurred or sharpness problem

Unsharp printing means blurred reproduction of lines or lettering.
Probable causes and possible solutions:

  • Pad-related causes
    • Pad too soft: use a harder pad.
    • Wrong pad shape: use a pad with different shape.
  • Cliche-related causes
    • Inaccurate etching of the cliche: make a new cliche.
    • Etching of the cliche 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-related causes
    • Ink is too thick: add more thinner.
    • Ink is too thin: reduce the amount of thinner.
    • Ink is drying too slow: use a faster drying thinner or cliche pause.
  • Material-related causes
    • 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 causes
    • 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.