Membrane switch screen printing special

Screen printing has been focusing on decorative effects since its invention. In addition to the common commercial features, another common feature is the requirement for good reproducibility of colors and patterns and the color rendering capability of the ink during screen printing in order to achieve the decorative effect.
1. Functional ink color design, color reproducibility, and color rendering of ink are important factors in evaluating the quality of membrane switches. However, the more important factor in evaluating the performance of membrane switches is the conduction function of membrane switches and the conductive circuit. reliability. Even if the Membrane Switch panel layer has a good color design, color reproducibility, and color rendering of the ink, if the switch's conduction function and the reliability of the conductive circuit are lost, everything is awkward.
The on-off function of the membrane switch and the reliability of the conductive circuit depend on the use of the functional ink and other treatment measures. The functional ink used in the membrane switch mainly guides the electric silver paste, conductive carbon paste, high-performance conductive silver, carbon ink and insulating ink.
The on-off function of the membrane switch and the reliability of the electrical circuit there are related not only to the quality of the functional ink, but also to the correctness and rationality of the circuit design in the production process, screen making and printing methods, and the like. For the control of the thickness of screen-sensitive material (photosensitive film or photographic film), an excessively thick photosensitive layer will result in wastage of expensive functional ink and increase the manufacturing cost; while too thin a photosensitive layer will seriously affect the film. The conductive properties of the switch.
2. The functional ink (silver paste) in the substrate processing membrane switch is printed on the polyester film (PET) by the method of screen printing. Because of the relationship between the characteristics of the silver paste and the PET properties, the ink must be printed before printing. Several treatments were performed on PET to ensure the smooth operation of screen printing and the strong adhesion on silver PET.
(1) Heat setting treatment The silver paste circuit printed on PET must be heated and dried in a tunnel-type drying tunnel or oven at 130 degrees for about 30 minutes to cure. Only after this process, the silver paste circuit has conductive properties. PET suffers film shrinkage after it is subjected to a high temperature of 130°C. PET must be heat-set before PET or PET that has been overheated.
(2) Surface Polarity Treatment The corona bombardment and other treatments give the PET surface a polar group of a functional ink, so that the silver paste has firm adhesion on the PET.
(3) Electrostatic protection treatment Due to the influence of static electricity, the PET surface can easily absorb dust in the air. Before the printing, the surface of PET is treated to eliminate static electricity, which can greatly improve the printing quality and ensure the electrical conductivity of the silver paste circuit.