Bubble Formation with and without heat curing
Posted: Tue Jan 10, 2017 2:02 pm
Hello,
I have noticed that there isn't a specific topic on bubble formation while screen printing.
I have been working on industrial screen printing for a handful of years. 90% of the time, on any given day, I can come in and find the ink we print with prints clean and without problems. But that other 10% of the time when we print (using the same inks as the other 90%) bubbles will form on the substrate after a print. There is no determinable pattern for why this happens. It will sometimes occur when the weather is hot and humid, cold and dry, and everything in between.
The emulsions we use are mixed over a day, left to rest for at least a day, and then prior to being poured out on to the screen they are quickly stirred slightly and kept in climate controlled temperatures.
This happens for a range of our inks, some of which use solvents and some of which use resins.
From everything I am mentioning I have a feeling that the onus falls not specifically on the ink (though I am not ruling it out) but on the handling of the print. If all the variables for the ink are constant (viscosity, mix, settling time, and so forth) what possible variables are at play on the print side?
I have read up on amount of ink put on the screen, sharpness of the squeegee, angle, pressure level, and a few others. Bubbles seem to form while under the oven curers, but still do (though at a much less frequent rate) when air dried.
Defoamers are also not an option as the ink formulation is quite sensitive and we really cant change it.
I am thankful for any suggestions or answers.
I have noticed that there isn't a specific topic on bubble formation while screen printing.
I have been working on industrial screen printing for a handful of years. 90% of the time, on any given day, I can come in and find the ink we print with prints clean and without problems. But that other 10% of the time when we print (using the same inks as the other 90%) bubbles will form on the substrate after a print. There is no determinable pattern for why this happens. It will sometimes occur when the weather is hot and humid, cold and dry, and everything in between.
The emulsions we use are mixed over a day, left to rest for at least a day, and then prior to being poured out on to the screen they are quickly stirred slightly and kept in climate controlled temperatures.
This happens for a range of our inks, some of which use solvents and some of which use resins.
From everything I am mentioning I have a feeling that the onus falls not specifically on the ink (though I am not ruling it out) but on the handling of the print. If all the variables for the ink are constant (viscosity, mix, settling time, and so forth) what possible variables are at play on the print side?
I have read up on amount of ink put on the screen, sharpness of the squeegee, angle, pressure level, and a few others. Bubbles seem to form while under the oven curers, but still do (though at a much less frequent rate) when air dried.
Defoamers are also not an option as the ink formulation is quite sensitive and we really cant change it.
I am thankful for any suggestions or answers.