The printing thickness of screen printing silicone is affected by many factors. The following are some of the main factors:
1. Printing stencil and squeegee factors
Depth of printing stencil ink line: The deeper the depth of the printing stencil ink line, the greater the ink thickness of the printed pattern.
Squeegee hardness and pressure:
Squeegee hardness: A harder squeegee can maintain a longer blade under greater pressure, and the quality of the printed thick film is better.
Squeegee pressure: When the pressure is moderate, the printed ink layer is symmetrical and flat, with clear contours; if the pressure is too light, the ink cannot fully contact the surface of the substrate; if the pressure is too heavy, the squeegee will deform, the ink layer thickness will increase, and the film layer will be uneven.
Squeegee speed: As the squeegee speed increases, the film thickness decreases.
Squeegee angle: When the angle between the ink contact surface of the scraper end and the screen surface changes, it has a significant effect on the thickness of the printed film layer. Usually, the angle between the scraper and the screen should be controlled within the range of 45°~60° during printing.
2. Silicone material factors
Silicone viscosity: Choose silicone with different viscosities according to the thickness of the printed lines. The higher the viscosity of the silicone, the greater the pressure required for printing, which may affect the printing thickness.
Silicone type: Ordinary silk screen silicone and single-component silicone that does not require baking may have different thickness performances during printing.
3. Silk screen factors
Silk screen type: Different types of silk screens (such as stainless steel, polyester, nylon mesh) may have different effects on the permeability and adhesion of ink during printing, thereby affecting the printing thickness.
Silk screen mesh: The mesh number of the silk screen (that is, the number of mesh holes per unit length) will affect the amount of ink permeability. Too high or too low mesh may cause the silicone to be unable to pass through the screen and adhere to the substrate, thereby affecting the printing thickness. Generally speaking, the mesh of silicone is more suitable between 80 and 120.
Photosensitive glue thickness: The thickness of the photosensitive glue will affect the adhesion and printing effect of the ink. The general thickness is between 0.1 and 0.5 mm, which needs to be determined according to the actual thickness of the sample.
4. Printing material factors
The surface state of the substrate (such as flatness, moisture content, surface tension, etc.) will also affect the printing thickness of the screen printing silicone. For example, a substrate with an uneven surface may cause uneven ink distribution, thus affecting the printing thickness.
In summary, the printing thickness of screen printing silicone is affected by a variety of factors. In actual production, it is necessary to select appropriate parameters and process conditions according to specific printing requirements and conditions to obtain ideal printing effects.