Screen Tensions....???

[Rocfrog]

Ok I would assume that this has probably been beaten to death on here and most forums would just tell me to "search" (which I did) but being somewhat of a Noob I'm kind of lost......

So we are super dead here at the shop and I got bored and started surfing the forums and got into a few threads about Screen Tension and when I was cleaning the shop to make room for a our new exposure unit I found a Newman Meter. So I did a little research and think I figured out how to use it and decided to check a few of our screens. I now have a MAJOR concern, possibly.....

1st off we have static aluminum frames that we have rescreened out of house. So I went thru and checked a few of the ones we have had rescreened recently and then I checked a few of the older ones that have been here since I started (2yrs ago) and the newer ones barely registered on the meter, I think the higest one went up to just under 8n! While the older ones were closer to 14n. But none of them went above 20n, the only ones I checked that were above 20n were our brand new number screen for The Ultimate Number System that we just got in to try and get another set of numbers going and those were around 25n.

We have been having a lot of odd issues lately, not sure if it has been personnel or knowledge or anything like that, but now I'm starting to think this tension thing might be our problem. We have been getting the screens redone by a "local" company where before I believe they use to send them out of state (but I'm not sure) and these odd ball problems have kind of started about the same time as we started using this company now that I think about it.

With that said, what is a "typical" tension for screens? 85% of our screens are 156-160 mesh and then we have some 230's, 305's and maybe 3 110's. The Ultimate Number System screens are all 110's.

Nick

[ZooCity]

In a nutshell, about 20 n/cm is the min tension to avoid a host of printing issues.
Below that, you invite issues like image distortion, difficulty registering and peel/ off contact problems.  You can work around these, many have and still do and make great prints.

Higher than that, everything improves until about the 35 n/cm mark.  To reap benefits of going higher than that, 45 to 65 and beyond, you must pay closer attention to the calibration of everything and you need equipment that can hold these adjustments.  Plane issues are at the core here as higher ten = lower off contact and therefore less wiggle room all around.

To get up in tension you'll need:

Better statics, replaced regularly.

Retensionable frames, like Newmans

Hybrids like the shur loc EZ frames.

Last approach you might consider, if you want to stay with statics, is to find a skilled stretcher who can handle delicate mesh and properly stage tension it and have them stretch thin thread mesh like Murakami S mesh, which performs well at lower tensions.  Expect to pay more for this, presuming you can find someone nearby to do it.

[Printficient]

I agree.  20-25 ncm is recommended depending on mesh count.  We at Xenon get these tensions everyday.  What could be happening, is that you are not properly preparing the aluminum screen for re-stretching. To properly do this means removing the glue and any residue mesh from the screen frame without removing aluminum from the screen.  Also pre-tensioning the mesh is recommended as well. We at Xenon pretension all of our mesh before it is clear to the frame. We also put the frame through a multistep prep procedure to ensure proper adhesion of the mesh to the frame. If you have any more questions please call me at 404-895-1796.

[Rocfrog]

I agree.  20-25 ncm is recommended depending on mesh count.  We at Xenon get these tensions everyday.  What could be happening, is that you are not properly preparing the aluminum screen for re-stretching. To properly do this means removing the glue and any residue mesh from the screen frame without removing aluminum from the screen.  Also pre-tensioning the mesh is recommended as well. We at Xenon pretension all of our mesh before it is clear to the frame. We also put the frame through a multistep prep procedure to ensure proper adhesion of the mesh to the frame. If you have any more questions please call me at 404-895-1796.

I have no idea what or how the company does the rescreening....like I said before we send the screens out to be redone. For lack of better knowledge it looks like they "sandblast" the frames clean (on the screen side) before they put on the new screen anything beyond that I don't know. We haven't had any problems with screens popping or coming off the frames, they all seem good as far as that goes. This is just the first time I've checked the tension with something other than tapping on them with my fingers.....

In a nutshell, about 20 n/cm is the min tension to avoid a host of printing issues.
Below that, you invite issues like image distortion, difficulty registering and peel/ off contact problems.  You can work around these, many have and still do and make great prints.

If I'm reading this right, this seems like some of the problems we have been running in to. The prints seem to have more "texture" to them like they kind of "stick" to the bottom of the screens and some times no matter what you do to register some of them you just cant get them dead on, or sometimes if it's a hit/flash/hit on the same screen it looks double printed....

Last approach you might consider, if you want to stay with statics, is to find a skilled stretcher who can handle delicate mesh and properly stage tension it and have them stretch thin thread mesh like Murakami S mesh, which performs well at lower tensions.  Expect to pay more for this, presuming you can find someone nearby to do it.

I'm pretty sure the owner doesn't want to invest in more frames let alone a completely new style that he doesn't know anything about.

I've read a lot about this "S" mesh lately.....what is that?

Nick

[Gilligan]

We haven't had any problems with screens popping or coming off the frames, they all seem good as far as that goes.
Nick

Well, they won't bust or come off the frames without any tension on them. :p

[Admiral]

We run panelframes and newmans.  The panels we stick to 110s and 160s almost solely since other mesh counts just print crappy compared to our newmans.  Any jobs above 100 shirts I won't accept the panelframes on pretty much, their tension is much better than statics but still not what is recommended.  Even ink suppliers / manufactures recommend 25N minimum on every screen.

Our panel frames come out to 18-24N usually and work fine on the manual but I want to stick to rollers on the auto to not run into issues / slow downs.

I can't imagine what you are doing to get good prints out of those screens.  You are underbasing with a 160 at under 8N? I can't imagine trying to get that to work out..and wet on wet printing...

Anyway find a good supplier/restrecher for statics and you will be much better off, you want a minimum of 20-25N on standard mesh counts.

[Denis Kolar]

Nick.
I have not been in business that long, but I have bought from a few different screen suppliers.
My first order of screens was decent, I still have some 110 and 155 that are hanging around 18-20 (After 2 years).
Later, I wanted to make sure that I get all my screens at or more than 20 newtons (when I get them in, I understand that they will drop later) and I had that promised to me by 3-4 manufacturers. I returned every order I got, with some of the screens being around 13-14 newtons when they came in.

I still keep about 30 statics for a single color repeat jobs, but I have switched to Newman frames. I think that was my best decision since I started printing.
I bought 25 used Newmans, spent one evening cleaning them, and now have them in near new condition. Using them with Shur-Lock panels.

[Rocfrog]

We run panelframes and newmans.  The panels we stick to 110s and 160s almost solely since other mesh counts just print crappy compared to our newmans.  Any jobs above 100 shirts I won't accept the panelframes on pretty much, their tension is much better than statics but still not what is recommended.  Even ink suppliers / manufactures recommend 25N minimum on every screen.

Our panel frames come out to 18-24N usually and work fine on the manual but I want to stick to rollers on the auto to not run into issues / slow downs.

I can't imagine what you are doing to get good prints out of those screens.  You are underbasing with a 160 at under 8N? I can't imagine trying to get that to work out..and wet on wet printing...

Anyway find a good supplier/restrecher for statics and you will be much better off, you want a minimum of 20-25N on standard mesh counts.

I checked both our maunual frames and our auto press ones and they all seem to be around the same, new ones super loose and older ones somewhat ok. We do only spot printing, no wet on wet printing, everything gets flashed and usually gets hit twice. Most jobs take quite some time to put out, some of that is the fact that they don't higer screen printers here (just cheap labor) and the turn around is huge! In the past 6-8 months we've been thru about 8-10 new employees. So we do a lot of training but with these odd issues happening at random times I couldn't nail down if it was the new employee or something with the press (we have more issues on the auto vs the manual). We do ok for our shop, but even though this place is over 20yrs old I wouldn't say we are a very smooth running shop and the efficency out put is super low compaired to even some home based shops!

I guess my biggest question is....I need to know what the "standard" is on screen tension so I can bring this issue up to the owner and have facts/research to back up my claim because I'm pretty sure he's gonna go after the company that is doing the work, or have me call them and I want to have all the correct info before going down that road.

Nick

[JBLUE]

Nick you have quite a few problems you need to address beyond tensions and it sounds like you know that.  I would get a good collection of screens that are between 18-25 nm. You guys do not need to be messing around with higher tensions than that right now with the turnover of employees and improper printing practices.

From the sounds of it your low cost wages are costing you far more than you guys are saving. If you guys had a printer that knew what they were doing that press would only have to go around once. Flashing every color and hitting it twice is not the way to go as you already know.

It sounds like you have a idea of what's wrong and are pointing yourself in a good direction. You guys should really look at having someone come in for a few days and do some consulting or see if you can get some hands on at another shop.

[Gilligan]

Also, it is possible that your meter is way off.  Being that you "found" it laying around and don't really know it's calibration.

See if you can find another printer or have a supplier bring over one and A/B test them.  Not fool proof but it will give you an idea, it's unlikely they will both be off roughly the same.  One will likely be right and the other will be wrong.  But in that case it doesn't answer any questions as neither one of you will know which one is wrong.  Example, your meter could be low, or maybe your screen supplier's could be reading high.  Both would attribute to low numbers on your meter but neither answers what tension you actually have on your mesh.

[Rocfrog]

Nick you have quite a few problems you need to address beyond tensions and it sounds like you know that.  I would get a good collection of screens that are between 18-25 nm. You guys do not need to be messing around with higher tensions than that right now with the turnover of employees and improper printing practices.

From the sounds of it your low cost wages are costing you far more than you guys are saving. If you guys had a printer that knew what they were doing that press would only have to go around once. Flashing every color and hitting it twice is not the way to go as you already know.

It sounds like you have a idea of what's wrong and are pointing yourself in a good direction. You guys should really look at having someone come in for a few days and do some consulting or see if you can get some hands on at another shop.

I agree, there is a lot wrong with this shop. When I started this job two years ago I had no idea about screen printing and was hired as the Graphic Designer (which is my background) little did I know that I would have to learn all about screen printing and how wrong it was being done here. I have improved a few processes here based on my countless hours of research but all I can do is make suggestions to the owners based on my research and hope they listen. 98% of the time it falls on deaf ears. The main focus of this business is the sporting goods store, the screen print shop is two blocks away and is an after thought (or at least as we feel) so it is a very hard situation to make any real changes and make any true progress. In all reality if the shop was any more efficent than it is the three employee's (myself included) would be bored out of our minds and probably be dropped down to part time.

I would LOVE to have someone come in a "show" us how this is suppoused to run or at least get some more training via classes or visiting other shops, and I have suggested that to the owners but they don't want to "pay" for stuff like that, or they think it's a neat idea and then nothing happens. I know from this job the past two years that I want to be in Screen printing...that's what I want to do, unfortunetly I don't want to do it here. I hope to have my own business and make it great, because I now know what not to do. 

Also, it is possible that your meter is way off.  Being that you "found" it laying around and don't really know it's calibration.

See if you can find another printer or have a supplier bring over one and A/B test them.  Not fool proof but it will give you an idea, it's unlikely they will both be off roughly the same.  One will likely be right and the other will be wrong.  But in that case it doesn't answer any questions as neither one of you will know which one is wrong.  Example, your meter could be low, or maybe your screen supplier's could be reading high.  Both would attribute to low numbers on your meter but neither answers what tension you actually have on your mesh.

I kind of was thinking about that but I wasn't sure how to check that. It was in the origonal foam case but both the case and the instrument had spray tach residue on them, the case way more than the instrument. But I guess I could see if any of the other shops in the area have one and go from there.

Nick

[Gilligan]

Or ship it to someone relatively close that could check it against theirs.

I checked mine against Alan's when I went over to his shop for a few days.  We were within a newton or so of each other.

[Rocfrog]

And in case anyone is wondering here is the instrument I found....






Nick

[Rocfrog]

here's some shots of some of the screens.....

this is a 110 mesh and is the brand new screen for The Ultimate Numbering System


This is one of the newly rescreen 230's


This is one of the old origonal 156's


This is one of the newly rescreened 160's



Nick

[tpitman]

I've got the exact same meter. The first picture indicates that it's calibrated correctly. I don't measure tension on screens with emulsion on them, always on clean screens. I would think that emulsion would tend to give a higher reading since there wouldn't be as much deflection over the coated area. Others might know better.