Common problems and solutions in the process of pad printing

Problem 1: the adhesive head absorbs less ink

Ink problems and solutions:

When the viscosity is large, diluent should be added for adjustment; If the ink on the steel plate is dry, wash the dry ink on the steel plate and put new ink again; The solvent of the ink is misplaced. Use slow drying or suitable solvent to mix the ink and control the temperature of the printing environment. Steel formwork: the etching depth of graphics and text is not enough, and the steel plate is remade; If you use the wrong film, replace the film so that the fineness of the line matches the etching depth of the steel plate; The surface condition of the steel plate after etching is not good, so replace it with a new one. Rubber head: the rubber head is peaceful, and the rubber head with a certain angle should be used; The rough surface of the rubber head makes it difficult to absorb ink; When the rubber head is deformed, the rubber head must be blown to maintain the original design shape. There is oil on the surface of the rubber head and the ink cannot be absorbed. Only cleaning or replacing the rubber head into the steel plate with too high strength can also cause the reduction of the amount of ink absorbed, so the strength should be adjusted.

Problem 2: the amount of ink released by the glue head is small

Ink: when the ink dries on the rubber head, use slow drying agent to adjust the ink; The viscosity of the ink is too low, and the glue head is too wet, so that there is too little ink adsorbed on the head. At this time, quick drying agent can be used to adjust the ink.

Steel plate: when the etching depth is not enough, the glue head cannot be dipped into more ink; When the etched image and text are too deep, when the image and text are too thin, the glue head cannot absorb too much ink. Therefore, the etching depth on the steel plate should match the fineness of the image and text. Rubber head: when the rubber head is normal, there is air flow that cannot be discharged when it contacts the workpiece during pad printing, so the rubber head should have a certain angle; If the surface of the rubber head is too rough, replace the rubber head. Other aspects: when the pad printing speed is too slow, the ink has viscoelasticity, so that the amount of ink released by the rubber head is small; When the ambient temperature of pad printing is much higher than 20 ℃, the solvent in the ink volatilizes too fast, and the ink on the glue head volatilizes too fast, so the best room temperature is 18-20 ℃.

Problem 3: insufficient cover

Ink: ink too thin or transparent will affect the covering, so we should choose ink with high color density and ink with appropriate viscosity.

Steel plate: when the etching depth is not enough, the amount of ink adsorbed on the rubber head is less; Pay attention to the depth and fineness of pictures and texts on the steel plate; Place the steel plate plane perpendicular to the rubber head to make the rubber head dip ink evenly.

For the rubber head: the rubber head is too flat to dip in ink, so the rubber head should have a proper angle and shape. The loose and too soft surface of the rubber head will cause less adsorbed ink.

Substrate: the surface is too oily, remove it with alcohol before pad printing; If the surface color is too black, it needs to be pad printed more than twice; If the surface is rough, you can replace the hard rubber head or replace the ink.

Other aspects: the doctor blade is too soft, so it should be replaced with a hard one to fill the slot of the steel mold with ink; Note that the template and doctor blade should be cleaned before pad printing.

Problem 4: the fineness of multicolor pad printing is not enough

In terms of steel templates: when several color steel templates are placed in the wrong position, the accuracy of pad printing chromaticity decreases, or the pattern on the steel template is not well made, resulting in insufficient fineness.

Rubber head: the rubber head is not installed in the center; The size of the rubber head is different or the hardness of the rubber head is inconsistent; The pressure of the rubber head on the steel template or substrate is uneven.

Substrate: substrate should have certain soft hardness and surface flatness.

Other aspects: positioning, fixture and workpiece fixation must be reliable.

Problem 5: pattern deformation

Steel template: when making, several color steel template patterns should be aligned and aligned reliably.

For the rubber head: select the appropriate rubber head and shape according to the pattern. The area is too large or too small. The rubber head is too soft and too hard, which is not suitable, and it should be adjusted. The pressure of pad printing should not be too large, and the cutting must be uniform, and the pressure on the steel template and the substrate should be consistent.

Substrate: the working material should not be too soft, and the pattern should not be too close to the edge of the workpiece.

Other aspects: the clamping fixture is reliable and the angle is appropriate, so as to ensure that the pattern is aligned with the highest middle position of the rubber head.

Problem 6: the color of the ink is wrong with the manuscript.

Ink: pad printing ink layer is too thick, color matching is improper, ink is too transparent or wrong ink is selected. Rubber head: wrong shape, too soft or rough surface.

Substrate: when the color of the workpiece itself is too dark, the number of pad printing should be increased, or pad printing should be done again after pad printing, or the material should be changed.

Problem 7: loss of outlets

Ink: use a quick drying diluent to make the ink layer too thick and eliminate the dot at the same time; Or dot visibility decreases when the ink layer is too thin.

Steel template: adjust the etching depth of the steel plate; Control the relationship between etching depth and graphic fineness; Select steel plate materials specially used for pad printing. In addition, check the quality of the manuscript and photographic film and the appropriate type of dot.

Rubber head: the surface of the rubber head should not be too rough. Choose a conical rubber head suitable for dot pad printing. Substrate: too rough surface will also affect the effect of pad printing dot.

Question 8: thin line set

Ink: adjust the dryness of the ink. Too slow drying is easy to cause the concentration of fine lines. In terms of steel plate: it is not allowed to etch too deep, and the fine graphic etching should be carried out in grades to meet the quality requirements of thin wires.

Rubber head: the surface should not be too rough, and the rubber head with some sharp shapes should be selected.

Substrate: it should be pre shaped to prevent shrinkage and deformation.

Question 9: bubbles (pinpricks)

Ink: the viscosity is slightly larger, and the ink layer is too thick. You should adjust the viscosity and add thinner.

Steel plate: the graphics and texts are not etched well. Check the graphics and texts with a magnifying glass.

Rubber head: the rubber head is damaged or too soft or the shape is wrong. Choose a sharp and hard rubber head.

Substrate: static electricity or dust.

Other aspects: the quality of negatives used in making steel plates

The surface condition of the steel plate, the sanitation of the environment around the pad printing, and whether there are stolen goods on the rubber head.