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screen printing => General Screen Printing => Topic started by: Dottonedan on April 04, 2017, 10:26:23 AM
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So, the (one stroke white) definition seems to be a little vague and I'm looking for clear definition.
Some (one stroke people) have said they are doing (one stroke) but when I see them doing it, it's actually two strokes wet at the first station (then a flash) and colors.
I imagined a (one stroke) to be just that. You hit it once, and then flash.
Now, I'd be happy with a P F P. (two hits) and I could see that being brighter than stroke, stroke flash.
Our people are printing some jobs with 110 mesh, coated 2/1 open solid art for example.
1/16" off contact,
The squeegee is a M&R green standard 70. We just got in the 75/90/75.
The angle on that 70 is out a little like 10-15 degrees. I suggest standing it up...and backing off the pressure that is at 50lb.
So, we just got our 75/90/75 in.
I think there is just too much pressure, the squeegee bends over a tad as they print.
Should we be applying more pressure on the flood to fill the screen better maybe? How much is too much pressure on that without causing wear on the screen?
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110? Most shops moved away from the 110 as a standard screen some years back when white inks became more print-friendly and folks learned about EOM. (add also that really thick prints also were generally shunned)
I know that I switched to 160's for almost all white jobs except for fleece which I may go as low as 125, but usually 140.
Now, add to all of this that I am still printing manually, and autos generally can easily go up one count.
Our auto experts here should certainly be able to help your guys get into the 21st century
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You may want to look up "One Hit White" I think it's more commonly referred to as.
We print manually, but when we switched over to thin thread mesh, it made a world of a difference for our printing...
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One hit or one stroke. I figured I was saying the same thing (but not to be confused with the inks (One Stroke).
I forgot to toss in the fact that they do this on one screen (for the reason that most all of our orders are 40 shirts or less). If it were a higher quantity, they say they would add another white screen...but I think they would still PPf PPF each of those.
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I run an odd shop LOL, but I still use 110 mesh for my whites, why because I can hit it twice wet on wet and have a nice white print, now that angle your talking about straight up is not going to get you very much ink down IMHO for a one hit white your going to need an angle to lay down more ink in one pass. I find that S-mesh 135 is one of the best mesh you can use to get a one hit white print, because it has more open area which you can do with a regular 110 mesh if the screen is good and tight 20n or higher. Oh the white ink your using also makes a difference, some cover better than other's if your looking to hit it one time. Now all this is just my opinion and what works for me in my shop and what I've picked up from some on here.
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if it's an issue with clearing the screen, have they tried slowing the squeegee speed down?
Rarely do we double stroke anything on the auto.
If it's not real thick ink, a 70 duro should work...if it's bending in half, they have too much pressure.
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The white ink they are running could be problematic and making things worse. If you have posted which white you are using, I do not remember.
We use Rutland Street Fighter cotton and low bleed. We have just started re-using Rutland silky cotton. All of these inks are shorter bodied. The Silky has more umph/heavier body but still clears very nicely.
We use a 65/90/65 blade - sharp - 150S mesh at 25 newtons+, squeegee angle is 10-15 degrees and we print with 25-35 pounds of pressure when everything is warm. Squeegee speed is typically 30-40. Good solid flood, but not to heavy.
We typically 2 stroke our white base. With where our pressures are, we do not get a full clear on one squeegee pass. 90% gets deposited, but not all, typically the top of the print image has a little left behind. Print is very bright.
When we single stroke the ink, we will run 35-45 pounds of pressure. Same speed. We usually prefer the brighter underbase 2 strokes will give us.
The above is for our 14 color Sportsman. On our 12 color, the arms are much shorter and we can print with up to 15 pounds of pressure less.
Our second screen for a print flash print white, we will use 150S or 180S. Either a 65/90/65 blade or 70/90/70. Same angels and much lighter pressure, usually faster print speed. You just need enough pressure to make good contact. We will then typically 2 stroke the top color. Very bright clean white prints.
We do also use a smoothing screen 95% of the time.
Hope this helps some.
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We run 110S all the time. We also use an 81 from Saati, which also has a very fine thread, so a lot of open area, but not an overly thick stencil. But all of those strokes and flashes? Seems like a lot or overkill to me.
Steve
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Just walked out into production..... White ink on our small press, not a huge image area but some pretty solid areas of the print. This is 110 mesh on base - single stroke, and 150 mesh on top white single stroke..... Sorry for the small crappy video but you get the idea..... If your guys are double stroking, flashing, double stroking, etc probably have some issues.
https://www.youtube.com/watch?v=M7Q7UMWtlrk&feature=em-upload_owner (https://www.youtube.com/watch?v=M7Q7UMWtlrk&feature=em-upload_owner)
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Will a air driven head differ than a electric head when talking about how much pressure you run on press?
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Will a air driven head differ than a electric head when talking about how much pressure you run on press?
Most definitely.
Murphy
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Dan.
That does sound excessive.
We almost never use 110 anymore( haven't in many years), we almost never double stroke.
We print at an average of 40-45psi.(much less alot of the time)
Many of the other variables will be unique to your shop.
Murphy
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Just walked out into production..... White ink on our small press, not a huge image area but some pretty solid areas of the print. This is 110 mesh on base - single stroke, and 150 mesh on top white single stroke..... Sorry for the small crappy video but you get the idea..... If your guys are double stroking, flashing, double stroking, etc probably have some issues.
https://www.youtube.com/watch?v=M7Q7UMWtlrk&feature=em-upload_owner (https://www.youtube.com/watch?v=M7Q7UMWtlrk&feature=em-upload_owner)
Danny, Thanks for the vid. PROOF is in the pudding.
Once question tho. I hear often now days,that you don't want your squeegee bending over. It's either too soft or too much pressure. You did get a great white, so its working, but I thought I saw tow different results there.
The first squeegee was not bending at all. The 2nd squeegee did look like it was bent over a lot.
Again, not saying it's not the right thing to do, (since it works) but was wondering if it's the difference of a base and a top white on pressure and angle? Seems like the most ink is being laid on that top white.
Thoughts on that?
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IMHO: Almost no one cares whether you stroke once or twice for a base white, unless it's your arms or press.
Also: It's impressive in some instances to get a one hit white, in others it's nearly guaranteed (think smooth poly vs. potato sack.)
Pretty sure Alan802 dropped the link on here long ago, but there was a great article on the web by Mr. Clarke about force vectors.
The interplay between pressure, squeegee angle, and print speed have just enough variables to confuse one utterly. :)
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When i consider whether an underbase in one hit or two hit white, what i am thinking in my situation is clearing the mesh. Some whites if I print at over 50% speed take two hits to completely clear the mesh, two hits on our press gives a max speed of around 550 an hour, so if we want to go faster than that we need a white that will clear the mesh with one hit preferably at 70% speed or faster. I dont notice any difference in the number of hits once the mesh has cleared as far as opacity is concerned. Almost all of our underbases are printed on a 150S mesh, with one hit. On our next batch of screens we will be ordering a lower mesh count for underbases to be able to clear at full speed. From my perspective the one hit two hit is solely based on overall print speed of the press and not opacity. And there are many factors to be considered in getting the results, ink being a small factor as a lot of printers on this forum can get the majority of white inks to clear on one pass with the proper technique.
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Dan to answer your question that was just an auto operator setting up the jobs on that press that is real green. It's the smallest press I have only three colors although we do inline foil and 3 color with 2 flashes on that machine. I start all new press ops there and my guy has only been on press for less then 20 jobs solo. He was running waterbase black on that last head the job before so I assume that's why he had more pressure on that head just not checking like he probably should lol. I was working on seps taking a break reading your post and went to take a quick video as he came to have me approve the print shortly before but usually we run a bit more pressure on the base and a touch less with a much faster stroke on the top white/colors. I have four presses and they all have their ideal settings for each type of print. Screen printing takes good front end but there's still a big art form in screen making and printing on press imo but starting with the best tools like proper mesh/blades is key for good prints.