Q: how does the multi-color overprint location?
A: in order to meet the needs of multi-color overprint overprint precision, is the key to master the positioning method in printing.In multicolor printing that is commonly used in positioning there are four.
Pull over positioning method is suitable for the straight edge artifacts printing;Hole positioning method is suitable for high precision puzzle of the same graphic calendar printing;Overlap positioning method is suitable for the transparent material printing;Edge localization method is suitable for special-shaped workpiece sets printing.In four color and network printing, regardless of the manual printing or machinery, precision error is equal to zero.In printing, can choose appropriate positioning method according to business requirements.
Q: how do you determine the screen tension and net?
A: a great influence on the transmittance of ink screen tension, such as 25 n/cm below the tension, does not work in the highlight areas of small branches.Increase the tension to after 5 ~ 10 n/cm, delicate branches can be printed.
By increasing network distance to improve screen tension method is not desirable.Increase from net has improve the effect of network version of tension, but increased the net distance, then will increase the squeegee pressure, printing dot increases.So can't adopt the method of increasing network distance to improve the network version of tension, should be in the network when the surface tension of the correct tense.
Q: mesh screen scraper in how to grasp?
A: 1. The role of the scraper, the size of the printing ink quantity, not only depends on the pressure of scraper, also depends on the Angle of scraping board and the layout of a printed, scraping board hardness, printing speed, the shape of the scraper blade, etc.
Master Japanese friends, scraper technology should have three years time, illustrate the importance of mastering scrapping printing technology.
2. The scraper blade shape: there are 7 kinds of the shape of the scraper blade, commonly used square and round mouth.Fabric printing multi-purpose round mouth scraper.
3. Print the perfect Angle: 45 ° Angle theoretically best, scraper blade in contact with the layout of the smallest.But in actual operation, scraping angles greater than 45 ° Angle, some even up to 65 ~ 80 ° Angle, Angle is 75 °.
4. The squeegee pressure and ink quantity control: printing pressure, printing ink layer thickness increases, mechanical seal, have special parts control pressure adjustment.Manual printing depend mainly on printing experience, stress the ink layer thick, mesh dimming level darker, 50% branch Angle of serious, 80% of the branches to the ground.Pressure is too small, ink layer thin, dark tone level can reproduce, and high-profile tiny points lost.Only moderate pressure, total pressure seal line straight, pressure to print out the color balance, rich layers of high quality print.
Q: how to master the ink layer thickness?
Answer: screen printing ink layer thickness for web plate 1/3 ~ 1/4 of film thickness.The size of the ink layer thickness by screen printing in the five elements (screen, scraper, printing ink, the material of substrates, screen printing machine performance) and five major variables (printing the perfect Angle, distance, printing pressure, printing speed, scraping ink viscosity) of the correct operation and material selection of high quality.In actual printing, to increase the ink layer thickness 3 ~ 4 times, relies on the membrane of increase plate thickness.Such as the requirement for printing ink layer thickness of 25 microns, the network version of the film thickness should be set to 75 ~ 100 microns.
Q: plate and the printer how to adjust?
A: to order according to the color of plate, plate printing position is determined, for debugging.
1. Mechanical adjustment: printing presses, version.Looking for a good line, determine the network distance.Network distance to determine the general requirements accurately, in order to achieve good accuracy, network distance to set lower, about 3 ~ 4 mm, small net frame 2 ~ 3 mm, large format can be a few taller, 5 ~ 6 mm.
Network distance parameters according to the tightness of screen size and stretched wide network to determine.
2. The scraper preparation: currently, multi-purpose soft hard moderate oil resistant rubber or polyurethane oil resistant silicone rubber scraper.Scraper hardness to shaw hardness is calculated.Generally for level 4, 40 ~ 45 degrees to the low hardness scraper, 50 to 55 degrees of hardness scraper, scraper, 60 to 65 degrees for medium hardness 70 ~ 75 degrees for hard scraper.Printing platform adopts the hardness of big scraper, scraper for 10 ~ 12 mm thickness.Scraper box size, length of miniaturization: a general than graphics on both sides of each are wide it is advisable to 20 ~ 30 mm.
Q: how to clean plate?
A: after downtime for screen printing plate processing, otherwise it will affect the printing quality.When printing, should immediately with the appropriate solvent clean layout clean, there shall not be ink, in order to avoid the residual ink dry solid plugging, reprint printing loss order.
Printing downtime for more than 15 h, shall be clean version after downtime.Your version to use paper or plastic covered good ink pad, flat plate.
1. Wash wash version flat on version release slot in the scrub gently, don't wash, lest affect network version of tension and loose network.
2. The color order printing should be continuous production, in multi-color printing, the color and the color overprint interval of not more than 1 d (days), so as to avoid substrates or glass printing ink, screen printing quality.