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screen printing => Screen Making => Topic started by: Gilligan on December 09, 2015, 05:05:46 PM
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So this screen was sitting in the screen rack for a few days and my screen guy had cleaned a couple of screens above it but I watched and he never touched the screen that is on top of the stack (at the bottom of the rack) at all.
All of a sudden we heard an odd sound in the shop, didn't think anything of it till my production manager walked in the back and I heard him cursing. I walked back to find a busted screen. I went into the security camera system and found when it busted.
https://youtu.be/ct0Z2YzxsyQ
It's about the 1:08 min mark.
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Weird. I thought I saw the pants leg on the coveralls in front of the screen rack move at the moment the screen ripped.
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We heard it on the other side of the shop so I'm guessing there was some force behind that bust.
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It happens.
Usually when we see it there's been a big temperature swing.
Kind of terrifying seeing it on film. Like a screen printers Blair Witch or something.
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not unusual especially if you recently retensioned the screen. I have busted a lot of screens some will scare the crap out of me because they will be just sitting there and out of thin air it goes BANG.
My guess is a thread or two got damaged and over a period of time a thread next went then another then bang.
I have even heard immediately after re-tension the mesh start to go you can hear a thread or two going they make a small snap sound then another sound then another sound then BANG.
If you post a picture of the tear i bet it will be pretty indicative of where the break started.
mooseman
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We are climate controlled so, no big temp swings.
Moose, this was freshly printed with! LOL
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Wonder if he got to close with PW and put a pinhole/small tear in it right there.
Seems to cause our screens to rip like that.
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We are climate controlled so, no big temp swings.
Moose, this was freshly printed with! LOL
Gilly, you know I am crazy, I have actually, purposely, watched screens blow out. Why to undertsand what initiates and accelerates a blowout situation.
I can go on about a slow process to break, starts with the thinest loss of a thread or two and watched the opening in the mesh slowly scarifice the next thread and the next thread to the kind of loss you describe. In one example I had a small loss of mesh fabric from a retension. The blowout process took more than 30 minutes to result in a blowout failure.
There is absolutely no doubt in my mind and experience , given the screen was just sitting there when it blew out, that you experienced what i define as a slow process break. Starting with very slight damage to a small area in the mesh from handling, or from the action of printing where some debris in the ink may have scratched the mesh in the print field .
As I said I could go on but the bottom line is you somehow damaged or degraded the fabric and it failed under load. And if it was S mesh the degree of initial damage can be a lot less to the same result.
mooseman
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Who you gonna call?
Pierre
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It was S mesh.
It had been carded by the "new guy" so that's a possibility. But he does card off ink with a business card so that should be unlikely.
It had been printed on a WEEK before as my production manager took some personal time for most of the last week and it busted after he got back. At least 5 days since use.
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weird you might start thinking about a seance ::)
mooseman
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S-Mesh on a newman will do that all the time man. It just takes the slightest microscopic nick or someone banging down and you can't see the crush under the tape where the locking strip is. It is freaky to just have one sitting there and hear that pop sound. I've had it happen with 150 S more than any other for some reason. Sucks too, those panels ain't cheap!
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It's the forces of darkness for sure...
Steve
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The flipside of thinner threads stretched at very high tension for sure. Heck, I've had it happen with conventional mesh at 20n (or lower)
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Yeah, it probably wasn't high tension... not sure when the last time we took that one up was... we need better tracking on that.
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Try dropping the tension 1-2 newtons in the narrow direction of the screen. The location of the rip could have been caused by a medium sized squeegee that did not have the corners rounded off. Also avoid having the squeegee wider than the pallet you print on, probably not the case, but it just crushes the threads and wears them out over the edge of a pallet. Lower tension slightly overall. Avoid putting S mesh in the sun for too long, especially in summer, the expansion of the frame can raise tension as well.
Soft brushes, or sponges to apply chems. Softened plastic goop scoops or softer plastic cards. Move up to 200S, or 225S for a stonger screen.
Al
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Who you gonna call?
Pierre
I don't think, I will call the Ghost busters.
I believe the mesh is "Force Sensitive" (sorry, just been waiting for the Star Wars movie for the past few months).
I have given up on the path of extreme high tension. I now stretch all my thin thread to 20N then tighten the nuts and the tension will go up to around 25. No problem ever since. I retention before applying mesh prep.
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Who you gonna call?
Pierre
I don't think, I will call the Ghost busters.
I believe the mesh is "Force Sensitive" (sorry, just been waiting for the Star Wars movie for the past few months).
I have given up on the path of extreme high tension. I now stretch all my thin thread to 20N then tighten the nuts and the tension will go up to around 25. No problem ever since. I retention before applying mesh prep.
What mesh prep?
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oops. Sorry. proper name is Degrease... I use "Macdermid Mesh-Prep" for my halftone work.
http://www.macdermidautotype.com/products/70-universal_mesh_prep (http://www.macdermidautotype.com/products/70-universal_mesh_prep)
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oops. Sorry. proper name is Degrease... I use "Macdermid Mesh-Prep" for my halftone work.
[url]http://www.macdermidautotype.com/products/70-universal_mesh_prep[/url] ([url]http://www.macdermidautotype.com/products/70-universal_mesh_prep[/url])
Whew, I was afraid that you meant the abraders from the days of old. They would be deadly on these thin-threaded meshes!
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Whew, I was afraid that you meant the abraders from the days of old. They would be deadly on these thin-threaded meshes!
I have used the SAME wooden handled shoebrush for 7 years. I read about using them in Sign Business Magazine close to 20 years ago. Rick Williams was writing in his column about setting up to screen print signs on a budget. I even made my own scoop coaters! (not very good, but they worked...sortof) I had sheet metal tools for my sign building. Used the sun for my exposure unit, and cut vinyl on clear plastic sheeting for film positives, sprayed with spray tac instead of a vacuum table.
I mostly use static S-mesh screens and if they break, I figure did it myself with a corner, or too long with dehaze on the mesh. No ghosts in my shop. And I've never had a screen break on press either, but I rarely use my roller frames.
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I had a screen pop the other day that had been sitting coated undisturbed for probably a month. Then all of a sudden, POP!! It happened when I was in the screen room coating screens. Startled me so much I dropped the coater, emulsion all over the floor, also dropped the screen I was coating, landed on the coater and popped that screen too! :(
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Wow what a bummer!
Alex, your story is better, but I did 3 static S-meshes once, all in one swell foop. O had my press indexing under flash one morning, to warm up the platens. I had laid my platen spacing "stick"...a chopped off 1 1/2" X 1 1/2" wooden baluster....on the top of the control panel, and my Gauntlet doesn't run smooth enough to do that.
I left the room for a minute, and when I returned the stick had dropped onto a platen and rode around popping each screen. I grabbed the emergency stop button just before it crashed the last screen or it would have broken the entire set, a job of 4 screens. :o
Stan The Doofus
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Try dropping the tension 1-2 newtons in the narrow direction of the screen. The location of the rip could have been caused by a medium sized squeegee that did not have the corners rounded off. Also avoid having the squeegee wider than the pallet you print on, probably not the case, but it just crushes the threads and wears them out over the edge of a pallet. Lower tension slightly overall. Avoid putting S mesh in the sun for too long, especially in summer, the expansion of the frame can raise tension as well.
Soft brushes, or sponges to apply chems. Softened plastic goop scoops or softer plastic cards. Move up to 200S, or 225S for a stonger screen.
Al
I'll see what my guy THINKS the tension was, but I doubt it was very high.
We ONLY use natural sponges on our screens. We don't touch anything to the screens but business cards when carding ink on or off. We are printing on an auto and this screen hadn't seen any youth or sleeve plattens in a while if at all. I forgot what mesh this was, but my guy will likely remember.
We do leave them in the sun for extended periods but this one had been inside for over a week.
I'm not arguing with anything you are saying, it just doesn't apply to this particular screen is all.
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I had a screen pop the other day that had been sitting coated undisturbed for probably a month. Then all of a sudden, POP!! It happened when I was in the screen room coating screens. Startled me so much I dropped the coater, emulsion all over the floor, also dropped the screen I was coating, landed on the coater and popped that screen too! :(
Omg... Gotta find some amusement in that right? ;D