How is your tension from 305 down to 148 mesh?

[Dottonedan]

Do you keep the tension consistent in your shop for streamlining the process and keeping all mesh the same tension?

There are some different school's of thought on this. One camp says to tension at a good high that each mesh can handle. So lets say we use 25n across the board. This seems logical and should keep things easier to achieve.
The other camp says each mesh count should be tension at optimum for that mesh to get the best out of that mesh.So, lower mesh has a thicker/stronger thread and can stand higher tensions. The mesh in theory, should be at it's optimum to do it's job as well as it can.
So that brings me to the question, "does a lower mesh such as a 148 at 25n work as well as a 148 meh tensioned at optimum? I'm not even sure what optimum is for our 148 but lets say it's 35n. That's a 10n difference, but "both" are in a range that is considered a good tension. Would the 25 not work as well as the 35?  I'd think so, but others say no.

So where are you on this?  Consistent across the board, or different strokes for different folks?
The same subject can be asked about exposure and coating as well.

[Doug S]

I stretch optimum for each mesh ct.  For example, for sim process work, I usually use a 225 for the Ub and 280’s for the top colors.  The max tension on a 280 is 28n so I stop at 25 and the 225 the max is in the low 40’s but I stop at 36.  I never have registration issues with the different tensions.  I think that if I stretched the 225 at 25n that the mesh wouldn’t be open enough to easily allow the ink through.  That’s just my thought but I may be wrong.

[Atownsend]

All thin thread & rollers here so nothing ever goes past 30. 150/48 & 280/35 we shoot for 26N, 135/55 & 230/40 we will aim for a stabilized 28N. Sometimes we'll go up to 30N if the mesh is brand new to give it a little more room to relax. We try to keep everything + or - 2N, but we find it takes a quite a long time to actually workharden.

I think if you're running T mesh and you can stretch to the optimum for that mesh count then its probably best to do so. With standard T mesh I think the the higher tensions have much more benefit. As long as you don't have any screens that are below spec, I don't think you'd run into reg issues between a screen @ 25 & one a 32 or 35.

[Dottonedan]

Ah yes,  An optimally stretched mesh will provide more open area. Def something I want. Not for coverage, but more so for capturing more and more detail.

With standard T mesh I think the the higher tensions have much more benefit. As long as you don't have any screens that are below spec 

Agreed. Should enable you to achieve less off contact, less pressure, faster stroke, easier lay down with more open area.
I like high tension, and I don't know if I need to go (as high) as Mark Coudrey used to promote, but perhaps somewhere close.




So here's another question.

How many people document their tension and follow a mesh through it's history to see how fast your tension is dropping and to be able to hand select specific tensioned mesh?

Like is it lasting about 2 months, 6 months or a year before you need to re-tension?  Of course this will change up for different shops and use, but I'm wondering how many people document this?  I think we would like to.  We have too any older fames that don't see re-tentioning. They may get missed along the way and get used /mixed in with my favorite sim process jobs and could be causing issues on press and we might not even know why we have a problem.



One more.  How often do you re-tension?

[Colin]

Before I left my last shop, I was starting to document the screen tension records and the dates and the dates I did re-tensioning.

I was not cataloging number of impressions in between.... I had to much other stuff to do.

Thin thread can drop tension fairly quickly in the beginning and it tapers off  - I would say a little slower than normal mesh... But maybe I was just a lot more aware this time.

I would wait until my mesh tension got below 25n then tension up to 28n-30n.  I tried really hard to keep my 150/48, 180/40, 225/40 and 270 and 330 mesh counts between 25n and 28n.

If I was on top of tensioning a screen from the moment it was stretched, it would take maybe 2 months to get work hardened.  But that screen might go out 2-3 times one week then once the next week...

Hope this helps.

[tonypep]

If one has the ability to retension the question is where is the opportunity. Many do but many do not. Schedules and deadlines etc. IMO all tensions must be equal is bunk. Having worked with various ops with different limitationsI can comfortably say that; given the proper skill sets, the right people can produce excellent quality with what they have to work with. Trust me, I've been there, and am most likely going back.
Props and cudos to all that continue to improve the process so please do not take this out of context
best tp

[Colin]

Tp, as long as all tensions are above 25, I agree

And that's specifically referencing screen elongation while under squeegee pressure load.

[tonypep]

Agreed. At JNJ I had all mesh initial tension at 40....knowing that will go down to 25 depending on mesh and usage

[nicolas]

I've been slowly changing out my rollers to Shur-loc S mesh panels. They have tension recommendation for each mesh count on their site. So that is what I've been going by. So far so good, haven't poped a screen yet.