CTS users - Exposing screens

[TCT]

Thought this question was covered before but couldn't find it anywhere...

For CTS users that don't have a integrated exposure device- When you made the switch from films and glass exposure unit to CTS and no glass, how did you determine your new exposure times/units? I don't seem to remember hearing(not that it hasn't been talked about) about a exposure test or a step test you can print on your screens. Just trial and error?

[Alex M]

Start with 50% of what you were doing if you glass was 3/8 thick


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[TCT]

Start with 50% of what you were doing if you glass was 3/8 thick


Sent from my iPhone using Tapatalk

Johnny on the spot there Alex! Don't think I barely finished pushing "post"!  Let me guess, your kids are just done trick or treating now also?

Good starting point, thanks!

[jvanick]

Tape a stouffer strip to the screen before exposjng.

[dirkdiggler]

All the above and lots of trial and error, I have the 1st starlight with the CTS conversion no glass, so I have probably been doing it the longest.  Still testing as matter of fact!

[GraphicDisorder]

We still use glass on our starlight, we have a constant loop basically 2 guys, one outputting screens / exposing. The other taking the exposed screen and washing it out. I assume removing glass would speed up burning but not much point as it takes about the amount of time to burn it as it dose to rise.

[jvanick]

We still use glass on our starlight, we have a constant loop basically 2 guys, one outputting screens / exposing. The other taking the exposed screen and washing it out. I assume removing glass would speed up burning but not much point as it takes about the amount of time to burn it as it dose to rise.

are you just 'shimming' the screen above the glass?

[LuckyFlyinROUSH]

Trial and Error.

Taped a calcluator to it and exposed, then went from there. We are still tweaking, but that's due to no automatic coater yet.

After a 4-5minute soak in water, screens should rinse out very easy in 30 seconds or less...if you loose dots quickly add half a sec and repeat.

[GraphicDisorder]

We still use glass on our starlight, we have a constant loop basically 2 guys, one outputting screens / exposing. The other taking the exposed screen and washing it out. I assume removing glass would speed up burning but not much point as it takes about the amount of time to burn it as it dose to rise.

are you just 'shimming' the screen above the glass?

Correct.

[jvanick]

I may have to give 'shimming' a try... might help with the over-cure on one side, raw on the other side, as the screen will expose slower....

hmm...

[GraphicDisorder]

I may have to give 'shimming' a try... might help with the over-cure on one side, raw on the other side, as the screen will expose slower....

hmm...

We use paint sticks, so not super thick. We have zero issues.

[mk162]

we shoot through the glass as well.  it gives us a bit larger window to nail times....and the metal fab guy never got me a quote back.  It's a small job for him anyway.

[Zelko-4-EVA]

I may have to give 'shimming' a try... might help with the over-cure on one side, raw on the other side, as the screen will expose slower....

hmm...

We use paint sticks, so not super thick. We have zero issues.

we do something similar on our Douthitt DMZ  - we went with yardsticks.  zero issues as well

[jvanick]

yesterday, I tried shimming the screens about 1/8" 'higher' than the glass would have been (but left the glass out as I have my homemade cts conversion kit on my starlight)

interestingly enough, the times changed a touch, but more importantly, the stouffer strip results and resulting screens seem better... I need a few days of HSA and discharge jobs before I'll be willing to say that my old problems are licked, but I'm guessing that I was a fraction of an inch too close to the LEDs.

I cut up some various sets of blocks in 1/16" increments so I can play with the screen height a bit more... I'm shooting a halftone grid on the edge of the screens where I can, and I haven't noticed any differences in the halftones when looking with a loupe.

[Screen Dan]

This shimming idea is pretty fascinating to me.  But couldn't this potentially result in hot-spots, cold-spots and potentially undercutting from the change in what I'm sure was a carefully engineered distance/angles to account for the extremely multi-point nature of LED exposure units?

I'm curious if Rich has anything to chime in with.