Net frame and taut net
1) Selection of screen frame
Frame is the most basic element in screen printing.The printing plate in screen printing is a screen image with a template, and it is of no use if the screen cannot be fixed on a smooth frame.
The screen frame should have enough strength to resist the tension of the screen.The net frame is required to have sufficient tensile strength, no flexure and deformation after stress to print high quality products;
Screen frame should be in contact with water, bath agent. L and affected by temperature change.This requires that the screen frame does not corrode, skew, ensure the repeated use of the screen frame;
Under conditions of guaranteed strength.Screen frame as far as possible to choose durable, light weight, corrosion resistance, not deformation, easy to operate and use.At the same time, the screen frame and screen binding surface must have a certain roughness, strengthen the adhesion of screen and screen frame;
In optical disk screen printing, the size of a 3 10mmX210mm steel mesh frame and aluminum alloy mesh frame are commonly used.Screen frame should be handled before use.Glue coated side must be cleaned, grease removal, remove ink and glue residue;Wear off sharp edges and corners of mesh frames.Regular horizontal calibration and use of grinding wheel or sand process roughening mesh frame surface.L to improve the adhesion of the mesh, etc.
2) net
Before the silk net. First clean the screen frame and the screen adhesion surface.Rub lightly with fine sandpaper.Roughen the surface.Easy screen frame and screen adhesion.If there are previous residues of glue and residues.It should be cleaned, then precoated with adhesive and let dry.
Accurate tension net method, the vertical clamp wire | countries of warp/weft wire stretched to flat mesh machine chuck., startup nephews net machine to strength, make the nephews network step by step slowly pull zhong, flattening, ‘close to the regulation of tension, first pull stretched mesh machine width, or tension, draw in the other two sides, let it all consistent tension, avoid by all means DouRan give force to the peak.This will cause uneven purple force, warp and weft twist, will form a plate – making moire.
In order to keep good printing, the tension of tension network should be controlled.Continent tension is too large easy to tear the screen.Caries mesh sheet j is too small and the silk is loose.Easy to overprint or harm dot.Moderate tension can ensure print, printing dimension accuracy.Overprint accuracy, screen in the process of scraping good resilience.Dry point and long printing life.
In order to make the screen to get uniform tension, the method of gradual drawing is used.The tension of the first stretch was about 18~ T9 Nicm, and the tension was about two to three times.Each interval was l0. 15 minutes.Because the tension will drop after staying for 15 minutes, — hour or so stretch the fourth month.The tension was about 23~25 Ncm, and the aging treatment lasted for more than 24 hours.Make the tension uniform and stable.If time is limited.Aged for at least 2 hours to reduce rebound.The tension will decrease within 48 hours after stretching the net, and it will be basically stable after 3~5 days.Therefore, the silk net should have a certain reserve, conducive to the release of stress, prolong the service life of silk country.When using tensiometer to measure the tension, generally using the five-point test method, in the center of the screen frame and four corners of the selection point.Each point of longitude and latitude measurement once, to ensure that the difference between each point is the smallest.
The taut network of optical disc silk screen adopts the taut network method, that is, the warp and weft of the screen is at a certain Angle with the edge of the screen frame. The taut network is conducive to avoid the moire of the orthogonal taut network, which helps to increase penetration and improve the printing quality.
In high printing precision and color printing, the choice of tension and mesh Angle has a direct impact on the printing quality.Network Angle selection is not appropriate, there will be moire printing.The commonly used Angle is 20R~35°, when the number of awards used is high.The mesh Angle of 22.5° is more suitable.Of course, the selection of stretch network Angle and color base version of the Angle match, in order to effectively prevent moire.