Screen printing technology

In screen printing, screen mesh, wire diameter and screen textile pattern and the selected material directly affect the tension and the network of tension, the tension and the network, is on the basis of these parameters on the screen tension measurement, measurement of tension, detected tension point from the inner edge of the frame should be 10 cm, otherwise the measured tension is not accurate. SEFEN PET 1000 each mesh can achieve maximum Zhang Guo values shown in the table below. In the table refers to the maximum tension value is the given mesh strength display, namely, all kinds of mesh, different wire diameter can bear and resilience of maximum force value, more than if the table given in tension value, mesh will lose elasticity, become the plastic deformation, which in the tension and the network should pay attention to in the. Tension unit: n / cm ( N / CM ), available Newtonian tonometry measurements. The tensiometer can detect the warp and weft tension. The so-called mesh warp tension, is the entire volume mesh winding direction of tension, namely edge typing direction on the tension of weft tension; the screen is the screen, the width direction of tension. The tension can be seen, the same material to create a different wire diameter, different mesh screen, its tension is different, is the same mesh screen, its tension is different, which is the same number of mesh, mesh of different diameters, the tension is different, because the tensile Zhang Du and wire diameter is proportional relationship. For example: B A is the wire radius 2 times, A wire tensile strength is 4 times of B wire. Table in the tension value of side length of about 1 meters below the high strength frame network effective, when the edge length of 2 meters of net frame, then the tension value should be reduced 15%-20%, if the net frame length of 3 meters, the tension and the network, according to the table given tension reduction of 20-25%. In order to ensure that the processing and printing, silk screen without being torn risk, so the tension and the network, tensile stress than the table of the low tension point is necessary.

Two, tension requirements
1, different uses of the web templates tension is different. For example: color printing outlets, in order to ensure the tone value accurately and reductive, required tension 20-30N / CM. The fine print, dial scale, tension for 12-18N / CM. General graphic printing, tension for 8-12N / CM. Manual printing, rough printed products, or to the size precision, no requirement, tension > 6N / CM, notably color color overprinter, in order to make the printing position accurately, requires not only the screen tension should be greater than 10N / CM, and set several stencil must reach a consistent tension, for printing outlets more important, otherwise it will cause a moire and hue deviation.

2, printing outlets why higher tension net template? This is because the A, high tension network templates can get lower network distance, when the network distance is doubled when, will make the printing graphic deformation increases three times, therefore, when the screen stencil tension is low, ink is not uniform and dot enlargement and distortion, effects of hue. B, the lower the net margin, silk screen can use a smaller pressure, so that the net template reduced wear and prolong the service life of net template. C, smaller scraping pressure, helps to avoid ink dot perimeter, deformation, improve the network edge sharpness, ensure the printing effect.