FAQ

FAQ
factors_affecting_print

What Factors influence obtaining Quality Print?

From the facts mentioned so far, it becomes evident that the result of printing is influenced by a multitude of factors. Experience shows that the root cause of a faulty print is virtually never to be found in the mechanics of the printing press.

Defects in the Pad Printing Machine itself are nearly always obvious, clearly definable and can be remedied by the technicians of the manufacturer. Hence, this issue can be ignored. To eliminate problems connected with printing, it is of greatest importance to describe deficiencies in as detailed a way as possible.

Any Pad Printing technician has difficulties on the telephone when a customer makes statements which are only general in nature. Not even the best technician can be of assistance when simply told “the press won’t print” or “the quality of the print is poor.”

Sources of Deficiency in getting Optimal Printing Results

Deficiencies most commonly found in printed material:
– no opacity
– misregister
– motif distorted
– blurring
– poor leveling of ink
– problematic overprintability in multi color prints
– color does not correspond with artwork
– spiderweb effect on contours
– screen dots are visible/are not visible
– fine lines run together
– large areas not completely covered
– small bubbles (pinholes) visible
– motif smudged
– ink does not adhere to substrate
– desired grade of gloss cannot be achieved

During printing operation:
– pad does not pick up ink
– no deposit or only partial deposit of ink by pad

A number of additional problems arise, which are, however, very particular to the individual areas:

Pre-operational deficiencies, e.g.:
– inadequate pre-treatment
– no or only partial deposit of ink on substrate

Post-operational deficiencies, e.g.:
– ink/color turns after some time
– ink cannot be lacquered
– ink does not adhere to substrate

Containment of Deficiencies

In order for any problems which arise to be contained quickly, the individual components (e.g., substrate, pad, cliche and ink) should be systematically changed or replaced.

The settings of the Pad Printing Machine and the ambient conditions (humidity!) should be checked. Making individual sample prints at a higher or lower printing speed or blowing on the pad can also be helpful.

Description of Problems and Proposed Solutions

Spots of poor ink pickup by pad during Pad Printing Process?

Potential Problems in Printing – Description of Problems and Proposed Solutions

If ink pulls on pad fibers during pickup, it is too thick and needs thinning.

Poor (spotty) release of ink by Tampon in during Pad Printing Process?

Potential Problems in Printing – Description of Problems and Proposed Solutions

ncomplete or spotty deposit of ink by pad is referred to as “splitting.” It plays a minor role in a continuously running process. The problem only arises when cycle times fluctuate or after short breaks. The pad deposits the dried ink all at one time, producing an inconsistent image. Using fast thinners will decrease ink build-up and improve ink deposition.

Insufficient opacity of ink during Pad Printing Process?

Potential Problems in Printing – Description of Problems and Proposed Solutions

This problem very often occurs in pad printing, and cannot always be solved satisfactorily. Due to the low degree of ink transfer in pad printing, 100 % opacity cannot be achieved on many objects with only a single printing, especially in the case of dark substrates. Increased hiding power can be attained by double or triple printing or preprinting with white.

Misregister in multi color prints during Pad Printing Process?

Potential Problems in Printing – Description of Problems and Proposed Solutions

The simplest way to contain these deficiencies is to produce a new cliche with precisely registered film.

Distortion of motif during Pad Printing Process?

Potential Problems in Printing – Description of Problems and Proposed Solutions

Distortion means that a printed rectangle, for example, does not show any right-angled corners, and has more the shape of a cushion. Distortion occurs primarily in very curved motifs or in motifs which are in proximity to an edge of the area to be printed or of the substrate. It is often impossible to achieve a 100 % correction. It is possible to make a wraparound print, but improvements with this method are also limited.

Blurring of Print during Pad Printing Process?

Potential Problems in Printing – Description of Problems and Proposed Solutions

Blurred print is understood as the indistinct, hazy reproduction of lines or letters. This deficiency is often confused with distortion.

Poor leveling of ink/poor wetting during Pad Printing?

Potential Problems in Printing – Description of Problems and Proposed Solutions

Overprintability in multi color prints in Pad Printing?

Potential Problems in Printing – Description of Problems and Proposed Solutions

During high speed printing operations, the last ink printed may be removed by next pad. This occurs particularly on larger surfaces, where material cannot be dissolved by thinner, or with slower inks in connection with carree or rotary indexing tables and linear belts. The problem hardly ever arises when adjustable tables are used. The best solution is to pre-heat objects or dry them with cold or hot air at intervals during the printing run

Color of ink does not match artwork after Pad Printing?

Potential Problems in Printing – Description of Problems and Proposed Solutions

This problem occurs frequently in pad printing. It is, however, often impossible to achieve the original shade, as it cannot be mixed from the colors available in pad printing. To lessen the influence of the substrate color, the options are to: pre-print using white, double print, or triple print to increase the opacity. Each method does, however, have its drawbacks, and should be tested beforehand.

Splotches or spiderweb effect on contours after doing Pad Printing

Potential Problems in Printing – Description of Problems and Proposed Solutions

Improvement can be achieved by grounding press. Splotches or spiderwebs most often occur with materials such as polystyrene, polycarbonate, or acrylics.

Screen dots are (not) visible after Pad Printing?

Screen dots are desirable for some prints, but not for others. Some photopolymer cliches cannot be produced without a screen, or only with a certain type of screen. With steel cliches, the screen is only exposed in for support of the doctor blade, to allow printing of larger motifs over an entire surface.

Blurred print is understood as the indistinct, hazy reproduction of lines or letters. This deficiency is often confused with distortion.

Fine lines converge after Pad Printing?

Potential Problems in Printing – Description of Problems and Proposed Solutions

This problem occurs with cliches having both a large surface and fine lines in one motif, because the surfaces should be etched deeper and with screen, but the lines are to be etched flat and without screen.

Surface of the printed product appears to be patchy after Pad Printing?

Potential Problems in Printing – Description of Problems and Proposed Solutions

This deficiency is easily observed in prints where peripheral areas are acceptable, but coverage (hiding) worsens progressively toward center. See also “Insufficient Opacity.”

Small air bubbles (pinholes) are visible on the product after Pad Printing?

Potential Problems in Printing – Description of Problems and Proposed Solutions

This deficiency can be contained easily. If bubbles always appear in same place, problem will be found in cliche or pad. If position of bubbles shifts, problem is caused by dust particles or electrostatic charges.

Motif (design) appears to be smeared (smudged) after Pad Printing

Potential Problems in Printing – Description of Problems and Proposed Solutions

This deficiency often occurs when thinner is added during printing run, where ink and thinner are not properly mixed.

Ink peels/flakes off substrate after Pad Printing?

Potential Problems in Printing – Description of Problems and Proposed Solutions

This problem frequently occurs because the type of plastic material is unknown, or unsuitable ink systems are used. The requirements for adhesion and scratch proofing are very different due to the respective demands placed on the finished products.

It is expressly recommended that the printing material be checked under the respective conditions of use before printing any production run.

Desired grade of gloss not attainable after Pad Printing?

Potential Problems in Printing – Description of Problems and Proposed Solutions

Due to the thin layers of ink inherent in pad printing, it is generally not possible to attain as high a grade of gloss as with screen printing.

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