An Ah Hah moment on tension.

[Dottonedan]

I've been reading up on the optimum mesh tension and came across an important factor that had always confused me.  The idea of why people see the need for soo many mesh counts. Some people (shops) have way too many mesh counts (like 15 or more) and now I know why. The main reason is due to low tension use. Contrasly, I've been to shops that only 3 mesh counts, a High like 309, medium like 156, and a low like 110.  Some even forgo low mesh all together.

The lower the tension across the board, the more you need a wider variety to achieve the various levels of ink deposit. Use a higher tension and you can reduce (streamline) your process and achieve a wider range ink ink deposit from your mesh that you do have.

For example, I tested this with Pierre once when I was at his shop and we printed white ink as an underbase on a 300 mesh. It didn't cover "heavily" as expected, but in sim process on underbased, you don't "need" 100% coverage, that's what your top white is for. So we "could" and did, but didn't actually use it in production. Just for experimenting. I knew that by adjusting off contact, print speed, pressure and angle, you can use a 300 to be able to, but often times not with great ink coverage. Now, I find that you can achieve more ink coverage "versatility" with the right tension. Higher tension. I'm not talking extremes but probably in the 35-45n area for a 300 mesh.

[ericheartsu]

but isn't that why we can use s-mesh?

Lower tensions, yet they allow for that greater range of ink deposit?

[jvanick]

but isn't that why we can use s-mesh?

Lower tensions, yet they allow for that greater range of ink deposit?

funny thing here is that thin thread/s-mesh actually does NOT put down as much ink as t-mesh.

you can test this yourself at home if you'd like:

coat up 2 screens:

160/64
160/48

(verify that you are indeed coating to 20% EOM or so -- just so they're not wildly different).

take 2 shirts and put them down the dryer to remove any residual moisture.

weigh the shirts on a .01g accurate scale and write the weights down.

print each screen (with the same art) on a shirt and re-weigh.

the one with the thin thread while LOOKING like it has more ink on it, actually has less ink when weighing.

I believe this to be due to the 'tunnel' effect of the mesh and thickness, and not so much the thread thickness.

[Dottonedan]

 Safar, Satti,  Newman, Murakami,  doesn't matter the type.  It's about the "high tension".  So how ever you get there with whatever brand,  it's the idea that high tension can help you streamline your mesh counts and keep. You more versatile with the selections you do have.   I'm sure S mesh was not designed for this specific reason but it's a good benefit no matter the brand.  Murakami is known for being able to get higher tension due to its thicker threads yet wider dispersion but you can aslo get extremely high tension with Newman roller mesh.

[Dottonedan]

jaVanick,  "Tunnel affect"?   Can you elaborate?

[jvanick]

jaVanick,  "Tunnel affect"?   Can you elaborate?

the total thickness of the emulsion and mesh is what creates the amount of ink deposit.  a thicker thread will build a thicker overall stencil.

the thinner thread diameter helps the ink release better from the screen, but the 'tunnel' created by the stencil (when properly filled/not smashed) is what actually is controlling your ink deposit.. not the open area of the thread.

I'm betting this will be one of the topics that Joe Clarke covers in a few weeks at Minds Eye.

[Dottonedan]

I have to correct myself. The Murakami mesh doesn't go that high on tension. I guess it's ideal for the shops that want more image and opacity but at a slight low lower production rate (probably more common also) than high tension mesh shops.

Murakami shows they have only three mesh counts that go over 30n by several at 29.  These are all lower than what I'm thinking of but to Eric's point, yes, seems like the Murakami is perfect to reduce mesh selections since you can reduce the numbers of mesh counts due to being able to be versatile in what you do have. The tension levels indicated for Murakami is typical. Most shops normally run at those levels or less anyways.

Still, this lower tension overall for Murakami is less than what I have been researching. I'm looking for the right mesh to get me up at a specific level of production and to be able to stay there as a normal. Low(er) tension in general, works against that idea.

[Dottonedan]

Understood and agree. Bro add to that, your tension (forcing up against the squeegee pressure) should be high enough or equal to  the force given in order to transfer an accurate dot on dot. Therefore, emphasizing the need for the proper tension. Too mush pressure on less than desired tension causes elongation or "gain".  As long as all mesh used are consistent in the lower tension, registration will look correct, but you can sacrifice on excessive buildup and gain. In many cases, I'd assume not to an extremely recognizable difference but it would be a contributor.

jaVanick,  "Tunnel affect"?   Can you elaborate?

the total thickness of the emulsion and mesh is what creates the amount of ink deposit.  a thicker thread will build a thicker overall stencil.

the thinner thread diameter helps the ink release better from the screen, but the 'tunnel' created by the stencil (when properly filled/not smashed) is what actually is controlling your ink deposit.. not the open area of the thread.

I'm betting this will be one of the topics that Joe Clarke covers in a few weeks at Minds Eye.

[abchung]

I think Murakami is produced by Nittoku Mills Japan. They do have thick threads and can stretch to50 Newtons.
The mesh chart can me downloaded with the following link.

http://www.nt-jp.com/en/products/screen/smartmesh.html

[abchung]

jaVanick,  "Tunnel affect"?   Can you elaborate?

the total thickness of the emulsion and mesh is what creates the amount of ink deposit.  a thicker thread will build a thicker overall stencil.

the thinner thread diameter helps the ink release better from the screen, but the 'tunnel' created by the stencil (when properly filled/not smashed) is what actually is controlling your ink deposit.. not the open area of the thread.

I'm betting this will be one of the topics that Joe Clarke covers in a few weeks at Minds Eye.

Wouldn't  the thread creates peaks and valleys. Where
Peaks Deposit = Emulsion + Thread diameter. (this is where ink deposit creates a hard hand feel).
Valley Deposit = Emulsion - Thread diameter (this is where ink deposit is minimal if thread diameter is increased).

I now coat 3-3 on thin thread to get a higher ink deposit, and the thin thread helps me fill stroke with ease.

[mimosatexas]

I'm a complete novice without any fancy tools compared to a lot of yall, but I can definitely say that the s-mesh does provide better coverage with less ink due to needing less pressure to clear the mesh so ink sits above the threads of the shirt vs being pushed into them. I think Alan has done a lot of testing related to this subject and I have tried to follow his lead in my shop. I have been getting fantastic one hit whites recently using thin thread mesh with higher eom and a super fast super light pressure push stroke. The eom provides the tunnel Jason mentioned, and the thin threads let me do a lower pressure stroke so more ink sits higher above the shirt and gives better print opacity. Increasing pressure or slowing the stroke dramatically reduce the opacity instead of increasing it. Tension is important of course, but I think logically that increasing tension means you must increase print pressure and or reduce off contact to keep the same light pressure, and the thin threads also max out lower than thicker threads, so all of the variables work in concert and simply increasing one or another as high as possible isn't objectively better than finding the ideal combination.

[ScreenFoo]

^^I think that's pretty spot on, higher tension can fix problems, but it can also create them if you don't have other variables in line.

Been playing with S vs. T on base plates a lot the last few months, and a couple things jump out at me about the implications described so far--as far as plastisol goes, at least.

High tension is relative--if you have a 150/48 and a 156/64 (like I have more than a few of here,) they will print in a reasonably similar manner if the S thread is at 22-24N, and the T thread is at 28-32N.  I haven't gotten into weighing printed samples, but my experiences on long runs with T and S threads agree with what Jvanick mentioned--that S threads consistently print more opaque with less ink, and that seems to be the major difference.  I know it's possible to run faster press speeds, say, with a 110 T at seventy newtons, but if I can get a base printing in one stroke with reasonable speed I find it to be pretty irrelevant in our situation whether I can cycle at 800/hr or 1000/hr.

The other thing about S thread mesh that is interesting to me is the idea that not only is the open area larger in the standard 2-D style of thinking, but the actual surface area of the threads is drastically reduced as well--going from 48 to 64 micron threads is a 33% increase in that surface area, and an even larger increase in volume, and especially white ink will make you notice that with the increased pressure or angle required to clear it. 

The 'tunnel effect' is pretty interesting in thread comparisons too, because if you think of an ideal stencil with a very smooth 90 degree wall, looking again at the S vs. T thread, I would think having more open area and less thread area and volume to interfere with the inks movement would make for easier ink transfer even with smaller details than you would normally print per the stencil thickness.  Not only is the thread area 'gripping' the ink less, there is more area for the squeegee to pump ink through, and speed can be increased similar to a thicker thread at a higher tension.

Just a few thoughts.

[GKitson]

jaVanick,  "Tunnel affect"?   Can you elaborate?

the total thickness of the emulsion and mesh is what creates the amount of ink deposit.  a thicker thread will build a thicker overall stencil.

the thinner thread diameter helps the ink release better from the screen, but the 'tunnel' created by the stencil (when properly filled/not smashed) is what actually is controlling your ink deposit.. not the open area of the thread.

I'm betting this will be one of the topics that Joe Clarke covers in a few weeks at Minds Eye.

You will win that bet, Joe Clarke will be talking about a lot more during his Ink Transfer Workshop presentation at Mind's Eye Graphics July 29-30 in Decatur, IN.  Just a few seats left and the early bird registration discount expires July 15th.

[Dottonedan]

All good deep conversation. I'm dig'n it.


Thanks for pitching in.

[blue moon]

we are running 150LX (S equivalent, but with fused knuckles) and can, and have, run our press at max flood and stroke speed with white ink. Final results is as good as any deposit I've seen. I think it can get just a touch better and deliver that elusive one stroke white on black shirts. We can do it on the royals in some cases, but blacks are not yet there. All our screens are S mesh and they are in 20-25 N range. We print regularly with 225S mesh for underbases and get a nice one hit deposit.

pierre