Is Spectar compatible with UV-cured inks?
YES! Spectar has a high dyne level (40–42); therefore, it prints well with both traditional and UV-cured inks.
Following are step-by-step instructions for screen printing with UV-cured inks on Spectar:
- Remove protective masking from the sheet and clean with a mild soapy solution. If no masking is present, follow the same procedure. Rinse and dry before printing.
- Apply ink per your standard procedure. Follow the ink manufacturer’s recommendations when using any reducers. In some cases, a different durometer bar may be needed for optimal print quality.
- Know the type of light source, bulb intensity, and belt traverse speed that is being used. Follow the manufacturer’s recommendations for the appropriate number of passes. All of these factors affect the total amount of UV exposure that the ink receives to be properly cured. Note that the number of passes can change with different ink colors; for example, black ink often requires more passes under the curing lamp than other colors. Also, note that lamp output can decrease with age—older light bulbs may require additional exposure to achieve a full cure.
- If you have any trouble, check the bulb output across the web using a calibrated light meter. For uniform curing, the light output needs to be constant across its width.
- Spectar has a high dyne level; therefore, it prints well with most UV-cured inks. If you have trouble with adhesion, either switch ink brands or corona treat the surface of the Spectar sheet. (This is typically not necessary.)
- Perform your own testing to make sure the article meets fitness-for-use criteria. Suggested ink manufacturers are Nazdar, Gans, Toyo, Sericol, Sun Chemical, and Flint.
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Watch out for:
- Inks are typically cured via light exposure directly to the ink side. However, some customers need to cure the ink through the sheet, also known as second-surface printing. In these cases, make sure the Spectar sheet that you are using does not have a protective UV cap layer. The UV cap layer on that side of the sheet will block the lamp light from reaching the ink side, resulting in ink that may be only partially cured.
- If your project requires thermoforming after printing, make sure the inks chosen are designed for thermoforming. Inks that are not flexible could contribute to part failures due to cracking.
- For applications that may be exposed to incidental sunlight or output from an interior light, make sure to test each color for fading.
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