Flat screen curved surface screen printing refers to screen printing with flat screen on cylindrical or conical curved surface. Under certain conditions, screen printing can also be carried out on elliptic surface, drum surface and arc surface. Dry screen curved surface screen printing machine is a machine which uses flat screen to print the curved surface. Working principle of flat surface silk screen printing machine: a - roller support, B - axis support, C - inlay support. When printing, the flat screen plate and the substrate move, while the scraper is still.
The flat screen printing plate is clamped on the screen frame, and the flat screen curved surface screen printing machine moves uniformly. Due to the friction of the screen plate, the substrate placed on the supporting device rotates accordingly. In the imprint line, the linear speed of the curved substrate is consistent with the moving speed of the flat screen plate, so as to realize the ink scraping printing. In theory, the embossing line should be at the highest bus of the curved substrate to increase the off screen angle and ensure the printing quality. For the convenience of adjustment, the top angle of the scraper is generally 60 °± 15 ° and it is required to be able to adjust the vertical degree and the upper and lower dimensions. The purpose of vertical adjustment is to ensure that the edge line does not shift laterally during the up and down adjustment, and is always aligned with the highest bus a. the scraper with a top angle of 60 °± 15 ° is used to ensure that the scraper inclination angle α is formed after vertical installation. In the actual adjustment, in order to ensure that the plane screen printing plate and curved substrate can be separated in time, the embossing line can be slightly forward, especially when the substrate diameter is large, the embossing line must be forward. The supporting device of curved surface printing is a special device of various forms, which is designed and manufactured by users according to the product requirements.
Two pairs of roller supports can be used for curved surface printing of cylindrical or conical containers, and sleeve supports can be used for covers and cups whose ratio of length to diameter is less than 1.5, and inflatable devices can be used to support soft hollow containers. Elliptic surface is a part of cylinder surface, which can be supported by cylinder inlay. The principle of printing on the surface of a cone is basically the same as that on the surface of a cylinder, but the difference is the graphic shape of the screen plate and the motion form of the screen plate. When making screen printing plate for cone surface printing, it is necessary to draw the unfolded drawing of cone surface, find out the center of fan according to the unfolded drawing, and then select appropriate screen frame to make screen printing plate. On the plate efgh which can completely hold the sector abed, the plate corresponding to the sector is made. A right angle bar is fixed on the plate efgh, and a fan-shaped plate is installed on the O-axis. Then, just like the surface printing of the cylinder, four rollers are used to support the substrate under the plate. The scraper is fixed. Move the plate frame according to the fan shape, and the scraper can press the pressure to carry out the surface printing of the conical plate.
When printing, the conical bearing plate is in line contact with the screen plate under the pressure of a certain scraper; when the screen plate moves horizontally around the axis of the fan-shaped development drawing, the substrate rotates synchronously on the support device; the ink is squeezed by the scraper and missed to the surface of the substrate to complete the printing.