Getting perfect white on black t shirts a record of my testing screen setups.

[shirtshack]

I hope you dont mind but I am going to spend the next few weeks dialling in and improving my white ink on a black t-shirts, and I thought I would post my results here as both a record that I can refer back to and maybe it will help somebody out.

First test is to get my emulsion over mesh set by adjusting my coating style.
Then dial in the exposure, test smart mesh vs T mesh, then onto static vs Newman roller frames and adjusting tension, then finally onto Ink squeegee choice ect.

Testing EOM on Screens

Equipment Used-

MHM X Type Plus 12 station, 10 Colour
2x Quartz Flash
Ryonet 110 White Standard Mesh screens
Manual Coating using Standard sharp edge, round edge coating trough- http://i574.photobucket.com/albums/ss181/ghettotige/Screen%20Printing%20Setups/IMG_1407.jpg
Emulsion Used- CCI Prochem TX Disharge-http://i574.photobucket.com/albums/ss181/ghettotige/Screen%20Printing%20Setups/IMG_1406.jpg

Measuring Device-
CM8802 Coating Thickness Gauge.http://i574.photobucket.com/albums/ss181/ghettotige/Screen%20Printing%20Setups/IMG_1405.jpg
Seally TA091 Paint thickness Tester.-http://i574.photobucket.com/albums/ss181/ghettotige/Screen%20Printing%20Setups/IMG_1404.jpg

So finally got around to purchasing a tool for measuring my EOM, so I thought I would have a play while its quite.

First test is to get several screens together, in this case I am testing New Static Frames from ryonet, mostly 110 and a couple of 156 mesh.

Up until now I have coated with the sharp side of the coater using a 1 stroke substrate side, flip screen one coat squeegee side, flip screen and repeat giving me 2+2 in total. I think I have been struggling with LOW EOM with this method so now I am going to test that.

Several different coating methods used-all 110 mesh
Screen 1,   Glisten method Sharp edge of Trough- took 5 coats substrate side to get the shine and then 2 coats squeegee side.
Screen 2, Glisten method Round edge of squeegee- took 2 coats to get the shine and then 2 coats on the squeegee side.
Screen 3, Original method sharp side, 1+1+1+1 ending on the squeegee side
Screen 4, As above but with 2 face coats added once dry using the sharp side.
Screen 5, As above but with the rounded edge of the coater
Screen 6, Original method 1+1+1+1 but with the rounded edge

First Thing I need to know is what my EOM is, Took me a few minutes to get my head around how to use the thickness gauge but I think I have it, but correct me if I am wrong..The guage came with 2 metal disks, remove the protective coat from those.. touch the prob to one of the disks and device reads NFe 0um/ 0.1mil- if not the calibrate by pushing the zero button 3 times, device then reads zero and is calibrated. Gauge also comes with clear shims of different thickness 48 micron, 99 micron, 257 micron, 497 micron. Place the shim over the metal disk and test, readings should be the same as marked on shims..

Onto the screens, I assume I place the metal disk on a flat surface and then place the screen ontop of that so the mesh is sandwiched between the metal disk and the probe to get the reading. Test an area of open mesh first to get the mesh thickness and then test an area with emulsion.

Results-Measurements in microns, hopefully my math is correct-
Screen 1, Glisten method Sharp edge             110/130= 20 =15.4% EOM    ((20/130)x100)= 15.4%
Screen 2, Glisten method Round edge of squeegee-      110/150= 30 =20% EOM   ((30/150)x100)= 20%
Screen 3, Original method sharp side,             108/122= 14 =11.5% EOM
Screen 4, As above but with 2 face coats          108/130= 22 =16.9% EOM
Screen 5, As above but with the rounded edge of the coater   110/135= 25 =18.5% EOM
Screen 6, Original method 1+1+1+1 but with the rounded edge   109/134= 25 =18.6% EOM

So looking at that it would seem I have been coating my screens at 11.5% EOM, funny that the Glisten method with a round cedge coater get bang on 20%..

Now onto stage 2- next batch of screens all with the glisten method, 2+2 in my case with the round edge to make sure my coating consistent.

Newman 83-71 at 30 newtons- 2+2 round edge = 84 mesh - 169 emulsion+mesh  =169-84 =85mu  ((85/169)x100)= 50%
new man 130s mesh- 30 newtons- 2+2 round edge = 52 mesh and 90 emulsion+mesh,  = 90-52=38mu  ((38/90)x100)= 42%
Newman 110t mesh - 30 newtons- 2+2 round edge = 105 mesh and 140 emulsion+mesh,  = 140-105=35mu  ((35/140)x100)= 25%
Newman 156t mesh - 30 newtons- 2+2 round edge = 86 mesh and 110 emulsion+mesh,  =24mu  ((24/110)x100)= 22%

[shirtshack]

Screens now 156 mesh
Screen 1- Original 1+1+1+1 coat                82/93= 11mu = 11.8% EOM
Screen 2- as above with 2 top coats with round edge    83/110 = 27mu = 24.5% EOM
Screen 3- Round edge Glisten method 2+2        80/110 =30mu = 27.2%

Once again looks like I have been doing it wrong, I will now try glisten method 2+1 see if I get closer to 20%

Few more screens tested for consistency-

screen 4-110 mesh- glisten + 2            106/138=32mu  23.2% Eom
screen 5- 110 mesh- glisten +1            108/125=17mu  13.6% Eom   
screen 6- 156 mesh- glisten +1            84/102=18mu   17.64% Eom
screen 7- 156 mesh- glisten +2            86/108=22mu   20.37% Eom

[Frog]

I applaud your effort to document these variables.

I do want to point out again that the whole point and inherent beauty of the glisten method is its visual cue rather than counting strokes, which, of course, will vary with mesh and technique anyway. btw, the way that I learned the glisten method, it's just round edge, two strokes substrate side, one stroke on the squeegee side, essentially pushing the predetermined emulsion deposit (as identified by the glisten) back through the screen to the "business" side. Sounds like you are going for a little more specifically for whites and I would be curious as to how much more you are now depositing with the second stroke.

[blue moon]

As Frog said, run glisten 2+1 on rounded side and dial in your speed so you get 20% on the low count meshes. Shoot for about 10% on the high counts. . .

pierre

[Frog]

As Frog said, run glisten 2+1 on rounded side and dial in your speed so you get 20% on the low count meshes. Shoot for about 10% on the high counts. . .

pierre

But, again to fine tune my answer, rather than specific number of substrate side strokes (two in this case) it's how ever many it takes to glisten on the squeegee side, then one to push it back. We just each learn from experience what it usually takes.

[Underbase37]

Nice work. It's testing like this that we came to realize we were way to thick on our S mesh, but a bit low on our T mesh.

Sent from my XT1585 using Tapatalk

[alan802]

I've measured thousands of screens and using the Glisten method and the round edge of the typical scoop coater will give you almost perfect results.  Most of our Glisten coated screens only need a 1/1 technique due to our current emulsion rheology so we're getting 15-20% EOM with 30 seconds of time to fully coat a screen.  It doesn't get much more efficient than that. 

[jvanick]

FYI -- we're getting 20% EOM on our S-Mesh screens with 1 coat on the shirt side due to the emulsion flowing through the screen mesh easier.

[ScreenFoo]

FYI -- we're getting 20% EOM on our S-Mesh screens with 1 coat on the shirt side due to the emulsion flowing through the screen mesh easier.

Hate to be dense here, but you are coating once on the squeegee side first, right? 

Cause if you aren't, I'm doing something wrong with S mesh. 

[jvanick]

Hate to be dense here, but you are coating once on the squeegee side first, right? 

Cause if you aren't, I'm doing something wrong with S mesh. 

nope... 1 coat, shirt side.

after having all kinds of wierd issues (getting nearly 60% EOM), Saati came in and worked through the issues with us, and we determined that 1 coat, shirt side was best.

Screens look great even on the squeegee side tho when we look at them with a loupe and even the microscope.

-J

[blue moon]

Hate to be dense here, but you are coating once on the squeegee side first, right? 

Cause if you aren't, I'm doing something wrong with S mesh. 

nope... 1 coat, shirt side.

after having all kinds of wierd issues (getting nearly 60% EOM), Saati came in and worked through the issues with us, and we determined that 1 coat, shirt side was best.

Screens look great even on the squeegee side tho when we look at them with a loupe and even the microscope.

-J

we coat the S mesh 1+1 with our thick emulsion. I can see how something thin or a really slow coat would be fine with just one swipe.

As it has been said, it is different for everybody . . .

pierre

[Printficient]

My question would be what is your starting parameter.  In order to truly dial in white on black you would need to use the white ink as your starting parameter.  Specifically the amount of possible picoliters per mm that could possibly be expended.  Then find a mesh count that allows at the least whatever the previous number is.  Then extrapolate the squeegee, tension and eom that does not encumber said number.  Also the substrate would either accept or not the amount of ink calculated in the above parameter.  My point is you need to understand the main parameters.

[ScreenFoo]

^^I was actually going to mention without screens with equal tension measurements the EOM figures aren't likely to be very repeatable.
Then I read Jvanicks post and derailed myself.

I'll have to try that out, I never tried coating substrate side once on the dull side and racking right away, and I know our EOM is rather excessive on  150S screens coated 1/1.

I bet you get a pretty killer Rz on the inside of the screen with that technique... 

[jsheridan]

Good stuff you're doing there and keep doing it, heck never stop experimenting as products are changing all the time.

Have fun with the testing and remember the times it didn't work so when it happens later, you'll know what's wrong. Having the why answers when the question arises is a big part of the problem solving that this biz is.

[alan802]

I know you're probably already doing this, but have a log book, journal, hell, call it a diary if you will, and write everything that you're doing down in that book so you can always look back at the progression and then you'll probably be able to see trends that will allow you to skip ahead and waste less time.  I try hard to write anything of significance down in my calendar book.  I have one of those calendar spiral notebooks that allows you to write down a good bit of info per day and it also has the old school calendar for each month that you can document things like employee absences and other smaller notations.  I've found this type of notebook to be the best for my needs, but everyone else's mileage may vary.