Screen Printing UV coatings

[Seeking Knowledge]

Hello all,

Looking for some help, we are new to screen printing UV coatings and we are seeing an issue, at first we thought it was fisheye. But at closer look, it appears that our ink has tiny bubbles in it (I hear the song too), when you look in the 55 gallon drum you can see them. We reduced the ink, with UV reducer and they seemed to dissipate. However after printing for a while they came back and our thoughts are that we should probably try to keep very little ink in the screen an fill more ofter so the UV ink does not get aerated by the constant agitation. We are using Actega 9403, we tried Nicoat and that looked good without UV reducer but it is pricier. Lastly, it has been my experience when screen printing UV inks, that a cross hatch and tape test is the tried and true method for checking adhesion, is this true?

Thanks
SK

 

[HRoss]

Hi SK,
Since my business is specifically UV coatings, it seems you have 2 possible issues. 1. since you reduce or eliminate the problem by lowering the viscosity of the coating, you may have a product that is too high in viscosity (and the Nicoat product might be lower than Actega). 2. The flow control agents are not sufficient to break any bubbles created in the screen process. I'm sure I could assist, but I would like more information about your process, the substrate, etc. My email is [email protected] and yes, the scotch tape test has been the simple method of testing adhesion of coatings to ink (not only screen). Let me know if I can help you.

 

[Seeking Knowledge]

Hello Ross,

I was out of town for the past two weeks, thanks for the response. I think we have a a lot of variables that we need to get handled. We currently are using a third part vendor for our screen making. They brought to our attention that the diamond chases we are using are not true diamond chases. The Frame depth is significantly thinner and this is due to the screen clamping on this press. They were telling me that they could not get the mesh up to 18-20 newtons when stretching, when they did the frame itself started to warp. I think they ended up going with 10ish newtons, I think this could be causing us some grief too. Another item I found interesting is that they were using 420 Twill weave, I have never used twill weave in my years of screen printing but also I am not familiar with this type of screen printing, I used to do it on a much larger scale.

Thanks again,
SK

 

[HRoss]

Hi SK,

I've been off the system for a while and finally read your comments. Sound like you have the equipment issue well understood now. If I can assist in the future, you have my email. Best of luck moving forward.

Kind regards,
HRoss

 

[Seeking Knowledge]

Thanks HRoss,