First, we should understand the characteristics of the silicone button
The hardness of the silicone button is generally about 45°. The single key surface of the printing has convex, concave solitary surface and plane, all of which are field line printing. In addition to requiring accurate position and clear graphics, printing ink is also required to be suitable for printing silica gel, the ink layer reaches a certain thickness, has strong adhesion and wear resistance, and does not change color or fall off after high temperature baking. Therefore, it puts forward special technical requirements for the screen printing process.
Two, the production method of screen printing screen
There are many methods of screen printing plate making, mainly using the photographic plate making method, that is, the sensitive adhesive is directly coated on the net, after drying to form a certain thickness of the sensitive film to become the graphic carrier, the process is:
Select net, select frame, stretch net, clean screen, dry, coating photosensitive adhesive, exposure, development, printing
The specific process is as follows:
1. Net frame
Generally use aluminum alloy, easy to operate, strength is not easy to deformation. Before the mesh with cyclohexanone wipe the mesh frame, remove the residual grease and dirt, and then wipe with industrial alcohol, after cleaning with water, and then dry the mesh frame. In the operation of the screen printing plate, it is necessary to dry several times, so the drying condition and cleaning should be strictly controlled.
2. Stretch mesh
The first selection of silk screen, rubber screen printing using nylon wire mesh, ink through the screen rate is good, constant tension, choose to cover the edge of the mesh frame and more than 6 ~ 10Cm mesh outside the mesh frame, using pneumatic mesh machine mesh, and tension meter for six point test, reach the required tension, coated with universal adhesive so that the screen stick to the mesh frame, with hot air blowing to speed up drying, After about 5mInR of bonding, you can turn off the mesh machine, the excess screen glued on the outside of the mesh frame, in order to maintain the bonding fastness of the screen. Cut off the excess screen, with cyclohexanone, industrial alcohol after cleaning the net surface dry. If the tension of the stretched net is unstable, it may cause the font offset and fuzzy, and there is a chord surface substrate resulting in the difference in the thickness of the ink layer. Flat orthographic printing requires a large tension screen, a camber printing surface requires a small tension screen, the process of the application of the screen tension range is 3N/Cm ~ 7N/Cm. Generally, the screen with large tension has a short service life. The process should be selected according to the needs: 100 straight yarn screen for printing conductive ink, 200 ~ 300 diagonal screen for printing positive characters and color blocks, in order to ensure the thickness of the ink layer and the integrity of the picture and text.
