Silk screen printing on ceramic application methods and techniques

Ceramic infiltrating tile is a new product developed in the 1990s. It combines the high strength, wear resistance, corrosion resistance of natural granite and the rich decorative effect of natural marble and color glazed tiles. Its rich and colorful colors and exquisite The pattern is mainly achieved through the screen printing process, and most of the current use of direct screen printing method, fine print patterns, high production efficiency, the process flow is roughly as follows:

Production of bottom plate (positive drawing) → Screen printing (direct photolithography) → Printing → Enamel preparation → Proofing → Brick surface treatment → Screen printing

From the above process flow, we can see that the difference between the tile screen printing and the general screen printing process is the process of enamel preparation, brick processing and so on. In the production process, if the process is not properly controlled, the quality of the seepage bricks will have a greater impact. The following focuses on some issues that should be taken into account when applying the screen printing process on architectural ceramics.

Influence of the distance between screen and brick on the quality of printing

In screen printing, the spacing between the tile and the screen directly affects the accuracy of the printed pattern. With the movement of the scraper, the screen will undergo a certain deformation, the pattern printed on the brick and the pattern on the screen will not be exactly the same, so theoretically analyzed, the smaller the distance between the brick and the screen, the pattern on the brick The higher the precision. In the actual production control of building ceramic seepage tiles, the spacing can neither be too large nor too small.

In the screen printing process, when the squeegee scrapes through the screen, it is required that the screen must leave the surface of the tile before the stencil adheres to the mesh. Otherwise, the edge of the image may be blurred due to the infiltration of the enamel into the body. Moreover, if the speed of the wire mesh leaving the brick blank is too slow, as the moisture in the glaze is volatilized, the seed glaze easily adheres to the wire mesh, and the seed glaze particles continuously gather, resulting in blockage of the wire mesh mesh. The spacing between the tile and the screen has a direct effect on the speed at which the screen leaves the surface of the blank. When the distance is small, during the movement of the squeegee, the deformation of the screen is less, the upward tension generated by the screen is reduced, and the speed of the screen leaving the surface of the brick is decreased. If the viscosity of the stencil is large, it may be Attached to the mesh, the screen cannot leave the surface of the brick, causing serious printing defects.

Of course, the spacing between the screen and the brick cannot be too large. Excessive spacing not only reduces the accuracy of the pattern, but also imposes higher requirements on the strength of the screen material. Moreover, the speed of the screen leaving the surface of the brick is accelerated, and the amount of the penetrant impregnated into the body is relatively reduced, resulting in a light and blurred pattern. Therefore, the distance between the screen and the brick is an important parameter, and it should be comprehensively considered according to the requirements of the pattern precision and the performance of the enamel.

The effect of brick properties on printing quality

Different from the ordinary screen printing process, the properties of the brick (including moisture content and temperature of the brick) have a great influence on the color and pattern quality of the product. In actual operation, the body must maintain a certain humidity and temperature To adapt to the requirements of the screen printing process.

1. The influence of the water content of the brick on the printing quality

The moisture content of bricks refers mainly to the moisture content of the bricks after they enter the screen printing process through the drying process. The degree of moisture content has a great influence on the screen printing process. When the moisture content of the brick is too low, the permeated glaze will be quickly absorbed by the brick when it passes through the mesh of the mesh, which can easily cause aggregation of the glaze particles, dry knots, and clogging of the mesh, causing difficulty in printing. When the moisture content of bricks is too high, the absorption rate of the enamel glaze by the bricks is slow. If the spacing between the bricks and the wire mesh is small at this time, the screen may not be able to leave before the enamel is attached to the mesh after scraping. The surface of the brick, ie, the glaze, easily adheres to the screen, causing the mesh to clog. Therefore, in the actual production, it is generally required that the moisture content of the brick be controlled below 0.2%.

2. The effect of brick temperature on printing quality

If the temperature of the brick is too high (above 70°C), during the printing process, the water in the glaze will rapidly evaporate after encountering the high temperature body, so that the viscosity of the glaze will increase, and the viscous glaze will clog easily. Mesh mesh, causing printing difficulties. In addition, the coloring ions entering the green body will also migrate with the evaporation of water in the enamel glaze, and the coloring ions will be concentrated from the inside of the green body to the surface of the green body, resulting in deep flowering and blurred patterns. However, if the temperature of the brick is too low (below 30°C), the pores in the green body will shrink, and the resistance of the penetrating glaze into the green body will increase accordingly, and the coloring ions will hardly enter the interior of the green body, resulting in a glaze Spread across the surface of the green body, making the product pattern blurred, and the color is very light. Therefore, in order to improve the quality of printed products, the temperature of bricks should be strictly controlled, and it is usually controlled at 45-65°C.