Label:Silkscreen Printing, Acrylic Sheet
Mar 13, 202410160
Tips for silkscreen printing on acrylic sheet
1. First, ink for printing, we choose high-gloss, friction-resistant organic glass ink. We don't use matte ink when printing on the surface, because this ink is not friction-resistant, and the color is not bright. Light boxes and signs outdoors should use inks with good light fastness to resist strong light, which extends the service life.
2. Printing films cannot be replaced by laser prints or sulfuric acid paper manuscripts. When printing, first fix the blank film on the glass plate with transparent tape. Films of other colors should be based on this, so that the position of the printed screen can be consistent.
3. To make fine screens, we use high-resolution photosensitive adhesive and high-tension, low-stretch screens. This will produce clear screens with neat edges of graphics and text. At the same time, it also ensures multi-color overprinting and position accuracy.
4. The color matching of silkscreen printing is generally carried out based on the experience of the printer. Since the mesh number of the screen in each batch is different, the thickness of the photosensitive film is also different. This always causes chromatic aberration in the printed product.
Therefore, each batch of work must be trial-printed with a pre-cured screen to produce a sample. Only after the customer confirms that the color is consistent with the original, formal printing can begin.
a. The distance between multi-color screens should be consistent.
b. The scraping speed remains consistent.
c. The scraping pressure remains consistent.
d. The Ink viscosity remains consistent.
e. The hardness of the large and small scrapers remains consistent.
f. The temperature and humidity in the printing workshop remain consistent.
5. When multi-color overprinting, to ensure the accuracy, the size of other plates can be appropriately scaled (the scaling size shall not exceed 0.1~0.2mm).
When printing, the dark plate is pressed against the shallow plate. The graphic plate is compressed and released. In this way, even when the organic plate is not cut accurately, or the plate and positioning block are poorly connected, the overprint can be accurate.
Cracks on acrylic sheet
Thermal expansion and cold contraction can cause cracking of acrylic sheets. For example, the environment temperature of printing is 20°C. After the silkscreen printing, the acrylic sheet is placed in the environment below 20°C. The ink and acrylic sheet will shrink and crack. If the silkscreen printing is completed, put the screen in the environment above 20°C to dry naturally, and wait for the ink to dry. The ink has tensile properties, it will not crack.
If the temperature of the acrylic panel is raised higher than the printing temperature before printing, the acrylic panel will slowly shrink with the ink after printing, which is not easy to crack. The hardness of the ink determines that the acrylic sheet will not crack. It will be more likely to crack when the hardness of the ink is high, but it won't crack when the hardness is low.
Conclusion: Two factors lead to cracking of acrylic sheet after silkscreen printing
1. Temperature
All temperatures are crucial: environment temperature, ink temperature, drying temperature and temperature difference before and after silkscreen printing. If there is a temperature difference, thermal expansion and cold contraction will occur, leading to cracks. The temperature of the central printing panel should be higher than that of printing environment.
2. Ink
The ink of silkscreen printing must pass the tests of ink adhesion and ink hardness. And we choose the ink with low hardness for batch processing.
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