screen build up help

[ericheartsu]

We are printing an 8 colored simulated process tee for a client. We set it all up, shirts ran fine. about 25 shirts in we noticed that the print was completely different than the first print.

it seems the culprit seems to be ink buildup on the screens....but how do we get around this?



Top part of the image is how it's supposed to look. the bottom part is how it's looking now!

[alan802]

Well, unfortunately there are several dozen variables that directly affect buildup so troubleshooting buildup can be tough if you're not doing many things right, but easy if you are doing almost everything the right way.  Higher mesh counts, higher tension, proper eom, quick print stroke, etc.  But most often times it's simply the ink that is not suited to print wow.  On sim process, you do expect to get dot gain and the print should begin to look right after a half dozen or so prints and should remain there for the duration of the print run.  With excessive buildup, you see a huge shift in color and it is happening so quickly that I'm thinking that you have one or two really tacky inks that cannot, under any circumstances perform wow.  I've been having good results with qcm 1030 wow base and Lee's is carrying it so you might run down and see Mitch or Robert and pick up a gallon of it and mix it in with your inks for this job and see how much it helps. 

You can adjust for dot gain and maybe some of the sep gurus will chime in on that and you can get through this job with current inks or you can get some of the 1030 and see if that helps.

[ericheartsu]

Screen mesh is 230 and 305, on pretty tight newman frames, although they are about to be tightened after this job.

i think ink is the culprit too, as we are using union mixopaque orange, mixed with some other low bleed inks to get the color.

[alan802]

From what i've experienced, the low bleed colors do build up heavily.  I don't know if that's because of their extra opacity or something that helps with bleed resistance.  The maxopaque series from union doesn't print wow worth a damn, and neither does the qcm xolb line.

[Gilligan]

I know my opinion don't mean ish... but I think the bottom print looks better.

[blue moon]

MIXO and MAXO are notoriously bad for WOW and Union makes an additive to fix some of the issues. You will need the Flow Additive they sell specifically for this purpose. Also, as mentioned before, it takes 10-20 prints for your screens to build up and settle. If you received the approval on the first shirt off the press, it will look different from the rest of the production. Your only option now is to go and adjust the seps and burn new screens that will let less ink through. If you can't find the flow additive, I have it here and can send you some if need be. . .

FLOW CONTROL ADDITIVE
MIXO/MIXE-9020, PLUS/PLUE-9020
When printing wet-on-wet, ink buildup on the back of the
screens can reduce printing speeds and degrade the
sharpness of the printed image. Flow Control Additive will
reduce or eliminate this problem. This product lowers ink
viscosity and dramatically reduces or eliminates the amount
of ink that adheres to the back of the screen when printing
wet-on-wet. Use no more than 1-2% by weight.

pierre

[mk162]

I agree with pierre, it takes a few prints to get ink flowing and I bet that is what happened.  You could thin the ink out a little to drop the opacity or lighten the color itself if that won't effect the rest of the print.  If the orangeish color has no solid areas, you could drop it a shade to compensate.

[tonypep]

Personally I wouldn't use the mixo for sim process and try to stay away from modifying inks for this. RFU Wilflex, QCM, Rutland, etc work very well without modifying assuming everything else is dialed in. I think Pierre likes them though.

[blue moon]

Personally I wouldn't use the mixo for sim process and try to stay away from modifying inks for this. RFU Wilflex, QCM, Rutland, etc work very well without modifying assuming everything else is dialed in. I think Pierre likes them though.

we use Union's Unimatch series which is specifically designed for sim process. It is thin, translucent and will run WOW very well. I bought some MIXOs and did not like them so they are still sitting on the shelf. Using them for transfers only now.

pierre

[tonypep]

Aahhh  that splains things!

[Dottonedan]

Sounds like your using all plastisol on this one. If I remember correctly, you like to use a discharge base, correct?


If using a  plastisol base, you may also want to check your pallets to see how hot they are. Your first few test prints may have been just right (having the base ink slightly tacky), allowing the wet inks to adhere more so. Now that the pallets might be hotter, you might be over flashing or curing the base causing the ink to be more of a sheet of plastic and allowing the top wet inks to move around a bit/causing dot gain says Dot-Tone.  Just another thought.


Keep the off contact close as well. It may have started out looking good, but the more ink that builds up, can cause this. Now that I think about it, I'm headed down the road that Alan mentioned. Way too many variables that can cause that. Hard to tell.

[ZooCity]

I think the bottom looks better too.  If it's not too late, get approval on that one and go for it. 

Definitely avoid anything formulated for high opacity here, or flash it.

It does take quite a few go-rounds for wow to stabilize it seems but 25 seems excessive to me. 

What really chaps my nuts with WOW printing is when it gets on this arc where the first dozen are building up, it stabilizes and looks good for 50 or so and then all of the sudden one screen gets muddy.  Wipe down, build up again, get another 50 out that are on spec, then the muddiness again, repeat...grrr.

This is where process control starts to really pay off I'd say.  It might seem silly to nitpick all the variables but when you can lock and load and run hundreds of pieces WOW without any stoppage or stress, you're winning. 

[tonypep]

Sounds like your using all plastisol on this one. If I remember correctly, you like to use a discharge base, correct?


If using a  plastisol base, you may also want to check your pallets to see how hot they are. Your first few test prints may have been just right (having the base ink slightly tacky), allowing the wet inks to adhere more so. Now that the pallets might be hotter, you might be over flashing or curing the base causing the ink to be more of a sheet of plastic and allowing the top wet inks to move around a bit/causing dot gain says Dot-Tone.  Just another thought.


Keep the off contact close as well. It may have started out looking good, but the more ink that builds up, can cause this. Now that I think about it, I'm headed down the road that Alan mentioned. Way too many variables that can cause that. Hard to tell.

Not sure why any base would be needed on this white shirt.

[ericheartsu]

Thank you guys very much for all the amazing feedback. You guys helped point out alot of things i was over looking.

In the end, we lightened our orange, then we called the client showed her a proof of what we had, and she was thrilled with it.

she is picking them up today, so hopefully she is still thrilled with them!

And Dan, we do like using Discharge bases, but we didn't use a a base on this tee!

[ZooCity]

Tangental ?:

You cats running lots of WB, how is the WOW printing with them?  I would assume it's badass but we've yet to do anything but single color so I wouldn't know.  I'm bringing wb/discharge into the house gradually and keeping our full lineup of plastisol but I look at a job like this and think WB right away.