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Screen printing machine silk screen tension and net margin, overprinting, ink, squeegee principle

Addtime：2015/7/4 11:16:46 Hits：1797

Screen printing machine silk screen tension and net margin, overprinting, ink, squeegee principle
What tension?
Tension is defined as when the screen by the action of the tension, there is a screen on both the internal and the vertical portion of the contact with each other in adjacent traction force.
Relationship between tension and network distance
Surface from the bottom of the screen version of substrates called network distance, network distance plays an important role in the printing process. Elongation mesh adjustment to ensure that the ink transfer effect. Network distance should not set too high or too low, as too high screen at the blade pressure, or super elastic limit repeatedly stretched friction, easy to break and cause the screen to produce a permanent plastic deformation, so that the screen prematurely relaxation, the impact of its life and printing quality. If too low, the screen does not have enough elasticity, causing the substrate and screen breaking Sriracha, make screen separating the ink and ink transfer rate and clarity are affected, but there will be quality problems.
Distance network is based on the level of tightness screen size and screen to decide, under tension to achieve the required conditions, the general network from 2-4 mm. High-strength wire mesh, tension 20N / CM from the network in general 2MM less.
Relationship between tension and squeegee
Three squeegee in the printing process:
1. The ink is directly extruded into cell and transferred to the substrate.
2. squeegee pressure and screen printing effect extending the length and in control, the squeegee pressure infinitely large friction resistance generated when the forward movement on a large, if not enough squeegee hardness, squeegee will produce large deformation. In the case of a large squeegee hardness, but also may cause loose mesh deformation.
When the tension, squeegee pressure is large, the friction and drag produced is also large, will shorten the life of the screen version, if the tension, squeegee pressure, the ink will produce slippage, resulting in the printing section can normal, resulting in thicker lines, distortion.
So one fine print, will need to maintain the desired tension and squeegee pressure has the best screen, the only way to achieve excellent printing results.
Relationship between tension and overprint
The tension of the screen version has a lot of influence on the overlay precise, in the color printing, printing of resilience and its elongation different strains vary, which can cause overlay errors. When the elongation, the printed version of the graphic size and the size of the printed copies will be obvious bias, so precise chromatic tension plate must be consistent with a network version of tension must be uniform.
Of course, to do silk screen version of the tension are absolutely uniform, consistent there is a certain difficulty, in fact, have allowed a certain margin of error, the experts mistaken for precise register, tension error should be less than 0.5N / CM, but generally overprint error of plus or minus 0.5 / CM is acceptable.
Metastasis of tension and ink
In the screen printing process, the printing plate with ink and substrate separation is mainly due to the adhesion of ink cohesion (ie prevent ink separation force), and the transfer function of the ink depends on the tension of the screen, from the network point of view and adhesion of the ink on three factors. Since the printing of the attached suction bearing ink than the ink adhesion to the screen to be much stronger, so the ink will be able to return by the elastic tension of the mesh under the separation and screen, quickly transferred to the substrate top.

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