Screen Tensions....???

[Screened Gear]

What duro is your squeegee? If its a 60 or lighter (looks like a clear 50 duro or something) that maybe an issue also if your ink is thick. Soft squeegees can't put the pressure down enough for thick sticky inks.

[ebscreen]

Hang in there buddy, you'll get it!

What duro squeegee are you using by the way?


Personally I would never have tried to do the back in one screen one color.
Halftones fills up against smallish text isn't going to give you much contrast. Beside
the point now, but something to think of for the future.


My guess is something in your squeegee/angle/speed/pressure/ink. A 110, even with poor EOM,
should have no problem with opacity at P/F/P.

Set up the front again, medium pressure, slow speed, slightly steepish angle, 70 duro squeegee, hard flood,
1/8" off contact. Make sure you're flashing correctly as well. that will get you in the ballpark and you can finetune
from there.

[Rocfrog]

What duro is your squeegee? If its a 60 or lighter (looks like a clear 50 duro or something) that maybe an issue also if your ink is thick. Soft squeegees can't put the pressure down enough for thick sticky inks.

That's our "new" one and if I remember right it's a 70.

Nick

[inkman996]

Also watching your video after the second stroke you can see the substrate peel away that means not enough tack, when that happened the print will look like crap every time. But like Jon said some more angle a bit slower and try to get the inside of that screen scraped almost clean after a stroke.

[alan802]

Ok, I can see a few things here.  Jon mentioned something that many people don't really pay much attention to, and that is the amount of ink left on the screen after the squeegee passes, not just in the open stencil area.  What I'm seeing is the squeegee doing a poor job and unlike Jon, I actually like the angle you have it set to.  We tend to print with more straight up angles than some shops.  Now a reason there could be that much ink left behind the squeegee could be the squeegee buckling due to excessive pressure and losing that blade edge contact with the mesh.  Another reason that happens is because of the ink itself and too soft of a blade for the rheology of the ink, essentially the ink is overpowering the squeegee blade.  If you can wipe your finger on the inside of the screen after the print stroke and a bunch of ink is on your finger, you've got to change your blade settings or your blade, meaning your angle, which I think is ok, reduce squeegee pressure, slow the blade down or go to a harder duro blade.  The ink is the ink at this point and I wouldn't mess with it if it's a decent brand of ink it's likely not the issue.  Also I would slow the print stroke down a little and see if that helps your blade's edge make better contact with the mesh.  You're printing at 12-14"/sec from what I can tell, and with low tension and the looks of that ink, it's too fast.  We can print thick white at 12-15" on many jobs but we are also using much higher tension and honestly a much better squeegee blade.

It's not HD video but it sure looks like the blade is flexing too much.  I can't tell if your off contact is too high or too low, but I would assume that if the blade is buckling and there is still some ink left in the stencil that the OC is too low.  And if your OC is low, tension is low, ink is very tacky then that's just a terrible combination.  You've got an older sportsman with no squeegee pressure regulators so to take pressure off you have to raise the blade.  Jon is a hell of a printer but I can't say I agree with him from what I can see.  I think the 15 newtons or less maybe is really holding you back from your main goal here.  I would bet you money I could bring one of my screens to your shop and get a one hit white on that pellon with that blade and angle by backing off the pressure and adjusting OC.  I'd back off pressure, keep the angle the same, maybe slow it down and see how the ink reacts with those changes.  Hopefully this time of year you have time to tinker, cause I spent hundreds of hours after work and between jobs trying to get this thing right and it's not something that just happens.  When your adjusting things, do one at a time and print.  And once you start noticing a lot less ink left over after the print stroke, and more importantly in the stencil, you'll know you're going the right direction.

I'll have some more info on the new blades I've been using maybe tomorrow.  Joe Clarke has added some different duros and a few changes to the original smiling jack blade and I've got to say I love the new blades, especially for printing white on darks.

[Screened Gear]

Jon is a hell of a printer

Alan makes a great point here.

I am not even close to where I need to be. I am still learning everyday. I had a really hard time printing white in the beginning so I know what your going though. Its frustrating and just makes you want to cry. I was lucky enough to have guys on here help me. Int he end, you will have to put in the time. I have tried other printers settings and still had no luck. There really is a ton of variables. I got to the point that nothing made sense. What made sense to me was a few tests.

Is the stencil clearing? If it is then back off the pressure until it does not clear. Now you know how much pressure is needed. Ounce it doesn't clear then add just a little pressure so it clears again. Now your set.

If it is not clearing then add pressure until it does clear.

There is a ton of ways to get the screen to clear.  Angle, speed, air pressure in the choppers, up and down adjustment, off contact, ink, duro of blade. Its a dance you have to do to get it to work. As Alan said adjust one at a time until you see what it does.

[Inkworks]

Also watching your video after the second stroke you can see the substrate peel away that means not enough tack, when that happened the print will look like crap every time.

Good eye! That sure looked like the screen didn't release from the substrate until the platens lowered. That'll cause huge problems with print opacity and probably leave nasty release puckers in the ink coat.

[Screened Gear]

I went back and watched the video again. Alan is right the blade is bending alot. Inkman is also right that you need more tack on the shirt. That blade has to be a 60 duro to bend that much and not clear the screen. Change it out with a 70 or better a 65/90/65. Add a little more angle and slow it down to half the speed your at. Your ink is not worked up enough yet to go that speed. I know that because of the way it picked up the shirt. You also will need to bring the squeegee up so your not smashing it into the pallet. You just want a little bend in the blade. Do that then make small adjustments until the screen clears. If its clearing from the beginning then back off the pressure or speed up until it does not clear. Then adjust it back just a little until it clears again. Then your set. As you run and your ink gets worked up you can take off some pressure or speed up the print speed. (both of these do about the same thing: lessen pressure.) You will want to do this so the print stays nice and bright.

[tonypep]

Good thread indeed. I'll let the young turks continue the discussion but it looks like we are beginning to understand the importance of realising the almost infinite outcomes when we change even one of the interdependant variables. It might be important to note that it can be difficult to understand the impact of change if we change too many things at once.

[Rocfrog]

Sorry guys I was off for the weekend, painting my sons Boy Scout Troop trailer.

But thank you for the great responses! As far as the Duro of the blades I'm not real sure what we have here, we have probably 7 auto squeegees but I have no idea what duro they are the only reason why I kind of remember that this one is 70 is because it broke and we recently replaced it.

So I think I'll lessen the pressure and slow down the squeegee speed and do another test print and video it. As far as "clearing" the screen goes what am I actually looking for? Is it supposed to be actually clean or just relatively clean? When I print on the manual I can get it really clean and most prints I can pull of in one pass, am I looking for something similar?

As far as the pellon sticking....I had just sprayed down the pallet with spray tac so it was pretty tacky and I don't think I saw it come off...maybe I don't understand what you mean or maybe I jsut didn't catch that....?

Nick

[Screened Gear]

Sorry guys I was off for the weekend, painting my sons Boy Scout Troop trailer.

But thank you for the great responses! As far as the Duro of the blades I'm not real sure what we have here, we have probably 7 auto squeegees but I have no idea what duro they are the only reason why I kind of remember that this one is 70 is because it broke and we recently replaced it.

So I think I'll lessen the pressure and slow down the squeegee speed and do another test print and video it. As far as "clearing" the screen goes what am I actually looking for? Is it supposed to be actually clean or just relatively clean? When I print on the manual I can get it really clean and most prints I can pull of in one pass, am I looking for something similar?

As far as the pellon sticking....I had just sprayed down the pallet with spray tac so it was pretty tacky and I don't think I saw it come off...maybe I don't understand what you mean or maybe I jsut didn't catch that....?

Nick

If that is a 70 then its worn out. Find a blade you have that is a little stiffer. (get some new blades on order And mark them so you know what you have) Don't print on a pellon. I never understood why people use them. They are more expensive then a shirt (you can use a shirt many more times) and why dial your press into print on them then print on shirts. They don't print the same. Get an shirt to print on. Do your tests on shirts. You want all the ink in the open stencil area so clear. That means not even a tiny spot of ink in the open mesh. Just like you would when printing manually. Its really the same just on an auto you can't feel what your doing to be able to adjust. For tack you really need the shirt to stay down. It should be the same as you do on your manual.

[inkman996]

Trust me your pellon peeled away from the screen, and that is not good for quality not to mention registration. In essence you're trying to get the mesh to just kiss the substrate and quickly snap away and leave the ink behind.

You say the squeegee broke? Seriously I hope you do not mean the rubber, god that should not break unless you are really printing with some serious pressure, even then its would take a lot to brake squeegee rubber.

You are correct as well as your manual screen looks when you clear it is what you should see on the auto, but unlike the manual you cannot feel the print and adjust on the fly it takes tinkering and understanding. Eventually you will get it, I came from printing on a Javelin for many years and clearing a white screen in the cold winter months was next to impossible and a science all in itself. To be honest we couldn't always get white screens to clear in one stroke on that press but that never made me stop trying. Going from that to a chopper A/C head machine brought the fun back in to printing, previously I hated it and did not really realize it till stepping up in the press department.

[Inkworks]

As far as the pellon sticking....I had just sprayed down the pallet with spray tac so it was pretty tacky and I don't think I saw it come off...maybe I don't understand what you mean or maybe I jsut didn't catch that....?

Nick

Watch the video over and over from 15 seconds to 20 seconds. you'll see the screen sticks down in the center and then pops off the print. There is a sound right then too that might be the screen popping off.

Basically it looks like the screen stays in contact with the pellon until the platens lowered.

Either:
1 - The pellon lifted and stuck to the screen.
2 - The off contact is too low for your screen mesh tension.
3 - Your mesh tension is seriously low, like well under 15.
4 - It was a trick of the camera angle

The screen should release from whatever you're printing on, following 0.5 - 3" behind the sgueegee, as it does it's print stroke. not stay stuck down in the center and then pop off.

[inkman996]

As far as the pellon sticking....I had just sprayed down the pallet with spray tac so it was pretty tacky and I don't think I saw it come off...maybe I don't understand what you mean or maybe I jsut didn't catch that....?

Nick

Watch the video over and over from 15 seconds to 20 seconds. you'll see the screen sticks down in the center and then pops off the print. There is a sound right then too that might be the screen popping off.

Basically it looks like the screen stays in contact with the pellon until the platens lowered.

Either:
1 - The pellon lifted and stuck to the screen.
2 - The off contact is too low for your screen mesh tension.
3 - Your mesh tension is seriously low, like well under 15.
4 - It was a trick of the camera angle

The screen should release from whatever you're printing on, following 0.5 - 3" behind the sgueegee, as it does it's print stroke. not stay stuck down in the center and then pop off.

Good point about the tension, that would be extremely low tension if the mesh itself is sticking to the substrate.

[Rocfrog]

Ok 1st off, once again I would like to thank everyone for their time and great feedback!!! And second off I want to say that I understand this is a very time consuming complicated process and I'm not looking for a "quick fix" I just want to be able to understand the process better and how what I'm doing affects the out come in which way.

So with that said.....

As far as the squeegees go, I want to say that these are the same squeegees that came with the press, as far as I know. In the two year I've been here we have only ordered one replacement squeegee (the one in the video because it's a different color) and that was because it broke. We have another one up there that is broke and one more that is starting to.....

Here is a pic of said "broke" one...


Now I slowed down the speed and lessened the pressure and took another video....

http://smg.beta.photobucket.com/user/Rocfrog/media/Screen%20Print/New%20coatings/IMG_8547_zps823401ec.mp4.html

Don't print on a pellon. I never understood why people use them. They are more expensive then a shirt (you can use a shirt many more times) and why dial your press into print on them then print on shirts. They don't print the same. Get an shirt to print on. Do your tests on shirts.

Pellon's are what we have here for test prints. I've never really understood it myself, I'll do a test print on the Pellon and it looks GREAT and then it hits the shirt and looks like crap! But we only get test shirts if we mess up one. So our test print shirts are VERY limited!

Nick