One Stroke Printing

[Inkworks]

Okay, I'm interested in doing more one stroke printing, right now we double stroke a lot of stuff on the auto to get a good coat of ink down/clear the screen. For those of you regularly single stroking bases and other non-top coat prints, I've got a few questions.

I Understand a heavy/hard flood coat is a big part of being able to clear the screen in one print, but with limited off contact doesn't flooding that hard cause problems with the floodbar pushing the screen down and contacting the shirt? Or are you flooding before the carousel raises the platens?

I would think that even if you are flooding before the platens raise, that you are really committing to clearing the screen with one stroke as two are ruled out with the floodbar pushing down so hard, if I run too much flood pressure and double stroke then I get ghosting from the flood deflecting the screen forward and contacting the shirt. I believe I can set my press to flood before the table raises.

Are you running "S" mesh for this? I'm going to bring some in to try, right now everything is normal mesh at good tension on Hix retens.

Are you going with coarser meshes to facilitate one stroke? I'm having trouble thinking I'm going to clear a 230-300 that's not underbased with one stroke.

I've heard a good fast stroke is good for one-stroke, that seems counter-intuitive, although I guess it's all about shear, not driving the ink into the shirt to get the screen to clear.

Any words of wisdom on off contact? Are you running extra to help the heavy flood from not touching the platen? Bare minimum? We are generally at ~1/8" give or take on regular T's

thanks for any input.

[Colin]

First question is:

How thick is the stencil of the mesh you are printing through?  That will now be your maximum deposit.

All those tricks will help.... but if your stencil is really thin.  You have maxed out the amount of ink you can physically lay down in a single pass.

Answer the aboce, and we can help you from there

[Orion]

Lots of variables here. Screen tension, off contact distance, blade durometer, pressure and angle, plus ink rheology. If your white ink is to stiff to push through your mesh count, you might consider either reducing the viscocity of the ink (by no more than 5 percent reducer to ink) or employing less of an angle on the squeegee blade. Just my guess?

[Orion]

...and if you feel bringing in "S" threads for your under base is the right thing to do, well then.. you would be right.

[tonypep]

It all comes down to one of my favorite phrases......."interdependant variables". Fix one problem and two or more pop up. You'll get good advice here but the best learning comes from good old fashion experimentation and observation. Thats how you can best determine the "why"of things.

[sweetts]

It all comes down to one of my favorite phrases......."interdependant variables". Fix one problem and two or more pop up. You'll get good advice here but the best learning comes from good old fashion experimentation and observation. Thats how you can best determine the "why"of things.

So true what works for some may not work for you. I had all kinds if issues getting started then visited some shops and learned my ink was way too thick to clear the screen. I started to play around found a good viscosity then went out and purchased different ink with similar viscosity. The point here is I tried everthing ppl suggested but until I put time in focusing on that one problem and playing around the resolution eluded me.

Sent  from samsung gem(the worst smart phone ever)

[Frog]

Years ago, this issue was addressed by the folks at Union on their site in a very simple easy-to-understand way.

Something like

"Won't reducing my white make it less opaque than using it straight"?
"Not if the straight ink isn't clearing the screen anyway."

[Inkworks]

We coat with the glisten method, usually 3/2 I don't measure EOM, but we get a nice gasket.

I do adjust  mesh selection and EOM depending on the desired outcome.

One of my stumbling blocks was with the flooding hard enough to be able to clear the mesh in one stroke, and the interference with the platen when using low off contact. We use triple durometer Squeegee 65/85/65.

Generally we're using QCM WOW inks, and usually adding some softee base, not just to give a softer hand to the print, but to help fight the ink from climbing the floodbar and to help it clear the screen. I do battle to keep squeegee pressure as low as possible, but right now we still probably double stroke 1/2 or heads on any given job.

I have a feeling i just need to flood much harder, and see if I can set the machine to flood before the platens rise.

[ebscreen]

It's one of those things that will come with time and experience, much as Tony said.
You can sit there and figure out how to get one screen, one design, one ambient conditions
situation figured out and then the next time be back at square one.

Several pointers:

Yes, flooding hard will help, though not always as hard as you think.

Mesh is important, but we can single stroke up to 230 underbases.

Backing off squeegee pressure will actually help more than increasing it.

70 duro is probably your go to guy.

Sometimes you will clear in one stroke and then you make that second one out
of habit and ink will actually pick back up in the open areas of the mesh.

If you get really really close, as in there's only a tiny bit of ink left in the mesh,
you're probably got all of the physical aspects down (pressures/angles/speeds, etc.)
and the ink is likely all that's left. Typically a few more test prints will get it
flowing, but it does depend on the ink.

Somehow after awhile this all becomes like a third sense and you can just do it.
I know, weird, but it does.

[Inkworks]

Sounds like pad-printing Lol.

[ebscreen]

Sounds like pad-printing Lol.

Yeaaaahhhhh, I tried that once.

Once.

[ZooCity]

Just curious, do you guys actually use the metal floods on the autos to fill the stencil with the flood edge contacting the screen?  I always figured I would prefer another squeegee for the flood bar given my manual technique with plastisol.

I've only used an auto setup with WB for flatstock so I'm clueless on this and only know what I've read on it.

I imagine that if you have the flood very low and in good parallel there's a hydraulic effect that naturally fills up the stencil without dragging a metal edge up your screen every print stroke (that doesn't sound good to me). 

My line of thought here is that I easily clear most mesh counts in one stroke on the manual with a good fill and yes, S mesh but I doubt thin thread mesh is a must for one stroking plastisol on an auto, I'm sure it helps to a degree though.

[Inkworks]

Yes metal floodbar. Winged Action engineering floodbars to be exact. I don't know why companies even sell non-winged floodbars or include them on their presses any more.

They really don't have a negative effect on the screens, in fact a sharp squeegee is probably harder on the mesh/emulsion than a floodbar is.

I'm looking forward to playing with the S meshes.

[alan802]

I've been chasing this dream of "one hit white" or whatever color, doesn't have to be white for a while now.  I have tried many different kinds of mesh from 83/70 to 150/48's for one hit applications.  I can give some of my thoughts and results and it might help some of you, others might even be further along on the subject than me.  I've found that all the factors/variables need to be in order for this to work, when some think that doing a one hit white is possible for everything.  The art cannot be huge blocks of ink, like the "stop sign" example.  Overall stencil thickness has to be high, which means a simple glisten method will likely not get you to the finish line.  We use the glisten method plus 1,2 or 3 strokes on the squeegee side.  Each additional coat will give you an additional 20-30 microns from the measurements I've taken.  Some of you might see more or less depending on your coating technique but only a thickness gauge will confirm that. 

According to mesh manufacturers a 135/64 will give you a 48 cm3/m2 theoretical ink volume and a 135/48 will give you 43.  If the artwork allows, you can increase the TIV of the 135/48 with a thicker stencil while maintaining the more open area that the thinner thread mesh gives you.  But that surface tension you have to overcome with the thicker stencil can increase the amount of print pressure needed as well so you have to find the fine line.  You can reach a certain point in stencil thickness where you'll have to start adding more print pressure so be careful.

Print speed is important.  Squeegee blade is important.  The right blade can allow you to print the same ink at twice the speed and therefore get more opacity from an ink since the ink is on top of the shirt.

I've found that most people fail at this because they refuse to use a low enough mesh count because it's looked down upon to have low mesh in the shop by many these days.  You can try all day long to get a one hit print through a 180 and you'll fail.  Put that same design on an 83/70 and you might actually have a chance.  Most think that printing with 110's or lower will give you too thick of a print but if you can get a one hit print with an 86/100 the ink deposit will be the same thickness as a 158/64 that is print/flash/print. 

It's really simple if you break it down, it takes a certain volume/thickness ink deposit to cover the shirt fibers and look opaque.  The ink deposit from a 180/54 is not going to cover most darker colors with one stroke, a 230 might take 2 strokes, flash and 2 more strokes to give you a truly opaque print on black shirt, when a really good, light pressure and fast print stroke through a 90/100 will give you the same deposit of ink.  Of course all of this info on the mesh spec sheets is "theoretical" based on having like stencil thicknesses between mesh counts so you can change those TIV's by adding or subtracting stencil thickness.  But reading those TIV's will give you plenty of information on what mesh will work best.  If you did a sample print and you got a print that was 90% opaque with a 110/71 then you can look at the mesh chart, see what mesh count will give you approximately 10% more ink deposit and use that.  The 110/71 is at 55 cm3/m2 and a 90/71 is 66 cm3/m2 so there is your 10% that you lacked in the 110/71.  Or you could add one more coating stroke to that 110/71 and see where that gets you.

Gilligan was here and we printed a few things on the manual so I could show him what I am speaking of above, and I think we were test printing a design on 50/50 red shirts and we were accomplishing a one hit white.  If I remember correctly it was on a 110/71 murakami smartmesh.  Red isn't black or navy but it's pretty close.   

[alan802]

I've got 2 new mesh counts in recently to help me in the one hit department, Sefar E'mesh in 83/70 and 123/70.  I've stretched up 3 of the 83's and used them but I haven't done the 123's yet.  This thread has inspired me to go out and put two of them together and put them into production tomorrow or Friday.