What tools and materials are needed for a trace printing?
Answer: The most basic tool materials are the printing machine screen scraper, ink thinner, and net washing water.
What is the effect of the second screen distance on the printing effect?
Answer: The screen distance is the distance between the screen and the substrate, which is expressed by h. The function of the screen distance is to enable the screen to be printed with lines.
The method of contact or line separation is called off-screen printing, and h>0 is called off-screen printing. In general, h=2~3mr and appropriate adjustment according to the effect.
The larger the mesh spacing, the stronger the resilience of the mesh, and the faster the stripping speed, the better the clarity of the pattern. However, with the mesh spacing
With the increase of the screen, the tensile deformation of the screen will also increase, which will lead to the error of the printing pattern size and the error of the position accuracy.
The angle of the three scrapers is controlled at what angle.
Answer: The angle of the squeegee refers to the angle formed by the squeegee and the screen. The larger the angle of the squeegee, the smaller the squeezing force of the squeegee on the ink, so the ink is placed
The amount is small; the knife angle is small, the friction with the screen is large, the squeezing force of the scraper on the ink is large, and the amount of oil is large, but sometimes it causes oil filling
Too much, and the contact with the printing surface will be poor. The blade angle should be controlled at 60° ~80°
How to Control Pressure in Four Screen Printing
Answer: The function of pressure is to ensure full line contact between the screen and the printing surface. On this premise, the smaller the better, because the higher the pressure
Large, although the contact between the scraper and the screen is good, the degree of flattening of the screen and the degree of the scraper embedded in the mesh are high, so the amount of ink transfer is small, scraping
The larger the deformation of the knife, the greater the influence on the state of oil filling, and the increase in the deformation of the screen, and the scraping.
The friction between the knife and the screen will also increase, which not only increases the friction on the screen, but also affects the line scraping speed of printing.
What is the best knife speed in the five screen printing process?
Answer: The knife speed refers to the speed of the scraper during printing. The knife speed is too slow, although the ink filling is better, but the ink will appear on the edge of the pattern.
Penetration phenomenon, causing the pattern to expand; too fast knife speed will cause insufficient ink filling, incomplete printing, and also cause the ink release speed to follow.
If the printing speed is not high, the sticking section is too long, which affects the printing quality. The ink viscosity is large, and the fluidity is poor.
The same is true; the mesh number of the mesh is high, the mesh area is small, and the speed of the scraper can be slower when brushing. In the printing process, not only
Master the speed of the squeegee, and pay attention to the uniformity of the squeegee speed.
Several marks affect print quality
How to distribute ink (return ink) during six-screen printing? Answer: The function of ink distribution is to ensure that there is enough ink during printing.
And reduce the blocking phenomenon caused by the printing interval. This is because if the ink return is insufficient, the print will not be full enough, and even a phenomenon of virtual hair. The screen layout is very easy to dry if there is no ink to cover the remaining small amount of ink on it.resulting in the phenomenon of blocking the network .
screen blocking phenomenon in screen printing (clogging)
Answer: 1. The ink dries too fast. A considerable part of the screen printing ink is mainly dried by volatilization, so the drying speed is very fast.
When using this type of ink, it is easy to cause the phenomenon of blocking the network. At this time, add a slow drying agent to adjust the drying speed of the ink.
2. The ink viscosity is too high. The original ink is used directly when printing. The ink viscosity is often too high. At this time, it must be adjusted properly.
When mixing, it should be sufficient and even, and slow drying agent or viscosity reducing agent should be added while adjusting, so that the adjusted ink flows down from the ink mixing knife.
It is linear, it is appropriate to be thin and continuous
3. The printing process is too slow In the printing process, especially manual printing, due to alignment, input and removal of substrates, etc.
If the time is too long, the printing process is too slow, resulting in the drying of the ink and the blocking of the screen.
4. The environmental conditions are not good, and the printing environment is not particular. If the ambient temperature is too high or there is wind, the ink on the screen will be swayed.
Dry, and cause blockage of the net,
5. Poor screen production The screen is not transparent or there is a thin film that has not been washed off, resulting in blocking of the screen during printing.
Phenomenon.
The pattern is blurred during printing (missing lines)
Answer: 1. When the ink transfer is not normal, the ink dries too fast or the viscosity of the ink is too high, which causes the screen to block.
Phenomenon. For this purpose, you can clean the screen or add thinner
2. The printing method is wrong. When printing, the printing pressure is insufficient, the squeegee speed is too fast, and the printing squeegee angle is too large.
It can cause the pattern to be blurred. The printing pressure can be appropriately increased, the printing speed can be slowed down and the squeegee angle can be reduced
3. The stencil produces wet shrinkage. Due to the wet shrinkage of the stencil, the pattern becomes thinner and vacant. Therefore, it must be determined after printing.
Dry quickly to reduce wet shrinkage of the stencil.
4. The adhesion between the ink and the substrate is poor due to the poor matching relationship between the ink and the substrate, or the lack of contact with the surface of the substrate.
It may cause the poor adhesion between the ink and the surface of the substrate, resulting in the phenomenon of blurring.
5. The stripping force is too fast due to the excessive mesh distance, which makes the contact between the screen and the substrate worse, resulting in
virtual phenomenon
Nine pattern blur phenomenon during printing (fat oil)
Answer: 1. The fluidity of the ink is too large due to the low viscosity and fluidity of the ink
Large, the ink is easy to spread during printing and cause the pattern to be blurred. For this reason, the viscosity of the ink can be increased, or the indoor ventilation can be enhanced to
Increase the rate of solvent evaporation.
2. Excessive pressure Excessive pressure will also spread the ink and cause the pattern to be blurred. At this time, the printing pressure can be reduced.
3. The scraper is uncomfortable or improperly operated, the scraper used is not hard enough, too soft, or the scraper is not sharp enough, too smooth, and the printing
If the angle of the scraper is too small when brushing, it may cause the ink output to be too large and the pattern will be blurred. To this end, the angle of the blade can be adjusted, and the hardness can be selected.
Tall scraper or regrind it
4. The mesh spacing is too small, and the mesh spacing is too small, so that the sticking section is too long during printing and the pattern is blurred. At this time, the mesh can be adjusted appropriately.
distance.
5. The mesh number of the wire mesh is too low or the mesh number of the stretched mesh is too low, and the wire mesh is thicker, so the ink output is large and the pattern is easy.
Fuzzy. And sometimes the sticking phenomenon caused by the loosening of the screen will also cause the pattern to be blurred. At this time, the screen can be replaced.