Author Topic: static frames and patterns in halftones.  (Read 2199 times)

Offline Dottonedan

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static frames and patterns in halftones.
« on: June 19, 2015, 01:22:51 PM »
I've been noticing that static frames seem to often have what I think is a stretching issue. They con't seem to be that straight all the time.  Is this a common issue for outside companies that offer static frames and a re-stretching service?


I didn't see this non roller frames and manually stretched within the shop I guess due to not mass producing screens and they can focus more on the quality process. It's just seeming to be more common, when shops get them from outside sources and get them re-stretched, it seems its not always stretched very straight. Must be torqued a little tighter unevenly to cause patterns. Always most noticeable in high lpi in the low % rage of like 20% and below.


I imagine for the most part, if your a shop that predominately does flat spot color printing, you'd never notice an issue.


DO you have to pay a premium for more accurate stretching? I hear some charge extra if you want your specific screens back. Otherwise, if you send in 50, you get back 50 that are trade outs from other shops screen frames. So frame quality is random as well on those cases.



Artist & high end separator, Owner of The Vinyl Hub, Owner of Dot-Tone-Designs, Past M&R Digital tech installer for I-Image machines. Over 35 yrs in the apparel industry. e-mail art@designsbydottone.com


Offline starchild

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Re: static frames and patterns in halftones.
« Reply #1 on: June 19, 2015, 03:01:46 PM »
The question is how are they actually stretching the screens. How did they arrive at the finished product. (What guarantee do we have that the mesh is balanced? That the openings are squared or perfect rectangular and there is no isolated tension to cause an unusable degrade of tension)

If you expect to be paid a premium (fine but you shouldn't) then tell us summ'n. You don't have to reveal your procedural secrets but let us know you appreciate the screen printer's challenges and yes you did acquier the knowledge and not just the equipment, to address this particular concern.

Dude are you stretching the damn screens correctly?

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Offline Printficient

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Re: static frames and patterns in halftones.
« Reply #2 on: June 19, 2015, 06:53:43 PM »
We at Xenon pride ourselves on our techniques.  We are 5 days in house right now at between 1000 to 1500 screens made from scratch a day.  This does not include re-meshes.  We re-mesh your frame.  We do not use any kind of process that removes material from the frame itself.
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Offline jvanick

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Re: static frames and patterns in halftones.
« Reply #3 on: June 20, 2015, 08:04:43 AM »
Before we switched to S-Mesh we were using Xenon frames (resold by one of our suppliers), and were super happy with them.  I actually still have some 156's that are floating around the shop that have been through reclaim so many times that they're well ghosted that are holding 22N. 

Sonny, correct me if I'm wrong, but you guy's aren't doing any kind of S or LX mesh right?

Offline Printficient

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Re: static frames and patterns in halftones.
« Reply #4 on: June 20, 2015, 09:21:19 AM »
We are currently not offering S thread but I am not sure on LX.  I'll check Monday on the LX.
« Last Edit: June 23, 2015, 12:59:19 PM by Printficient »
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Offline ABuffington

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Re: static frames and patterns in halftones.
« Reply #5 on: June 23, 2015, 12:54:38 PM »
I doubt you are offering LX.  It is a Murakami Trade Mark Mesh Brand.  LX Mesh is another alternative.  It is a proprietary thread that is soft on the outside with a poly core that is similar to S Mesh.  It's advantage is in printing base plates and wb ink.  It is a softer mesh.  Minimal off contact is needed since it is a little softer thread.  The RZ or smoothness of the mesh is better than S mesh since the knuckles are welded more and requires less squeegee pressure to print.  Thick plastisols print a bit easier through this mesh.  Round off squeegee corners and sand glass smooth with this mesh to prevent excess wear where that squeegee starts.

The type of stretcher has everything to do with thread orientation on a frame.  A typical bar stretcher, or individual clamp method can distort the thread orientation and create distorted parallelogram  openings on the outer points of a 9 point tension area. Murakami Statics by Murakami are stretched on a proprietary Murakami Stretcher that we make ourselves and is designed for very accurate frame to mesh orientation.  It captures mesh very square to the frame, but more importantly pulls mesh in both directions and at all points in 90 degree angles to the frame to keep threads straight on all 8 frames in the rack, bar stretchers and individual clamp systems do not do this.  This also allows us to use metal guides to angle the frames and stretch at 22, 45 or 61 degrees to the mesh very accurately for half tone graphics and high end automotive printing.

The final key point is the mesh opening itself.  There is a measurement of mesh called the stress strain curve.  This graph shows how threads react to the forces of stretching.  If the threads in both the warp and weft direction react equally and are in balance to the forces of stretching the mesh opening has a better chance of staying square when stretched and registration is improved on sim process type printing. Murakami Stress Strain curves are identical, both the warp and weft react exactly the same to the squeegee force, no other mesh manufacturer can claim this. This is the case with all Murakami mesh.  Threads and heat sealing of the mesh knuckle are designed to produce accurate square openings in equal microns measurements in both directions.  This aids in preventing spot moire, aids in registration. 

Thread thickness can also affect moire.  Thicker threads are more prone to moire, thinner threads have more open area and capture more halftone data.

Al
Alan Buffington
Murakami Screen USA  - Technical Support and Sales
www.murakamiscreen.com

Offline Printficient

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Re: static frames and patterns in halftones.
« Reply #6 on: June 23, 2015, 01:01:59 PM »
I doubt you are offering LX.  It is a Murakami Trade Mark Mesh Brand.  LX Mesh is another alternative.  It is a proprietary thread that is soft on the outside with a poly core that is similar to S Mesh.  It's advantage is in printing base plates and wb ink.  It is a softer mesh.  Minimal off contact is needed since it is a little softer thread.  The RZ or smoothness of the mesh is better than S mesh since the knuckles are welded more and requires less squeegee pressure to print.  Thick plastisols print a bit easier through this mesh.  Round off squeegee corners and sand glass smooth with this mesh to prevent excess wear where that squeegee starts.

The type of stretcher has everything to do with thread orientation on a frame.  A typical bar stretcher, or individual clamp method can distort the thread orientation and create distorted parallelogram  openings on the outer points of a 9 point tension area. Murakami Statics by Murakami are stretched on a proprietary Murakami Stretcher that we make ourselves and is designed for very accurate frame to mesh orientation.  It captures mesh very square to the frame, but more importantly pulls mesh in both directions and at all points in 90 degree angles to the frame to keep threads straight on all 8 frames in the rack, bar stretchers and individual clamp systems do not do this.  This also allows us to use metal guides to angle the frames and stretch at 22, 45 or 61 degrees to the mesh very accurately for half tone graphics and high end automotive printing.

The final key point is the mesh opening itself.  There is a measurement of mesh called the stress strain curve.  This graph shows how threads react to the forces of stretching.  If the threads in both the warp and weft direction react equally and are in balance to the forces of stretching the mesh opening has a better chance of staying square when stretched and registration is improved on sim process type printing. Murakami Stress Strain curves are identical, both the warp and weft react exactly the same to the squeegee force, no other mesh manufacturer can claim this. This is the case with all Murakami mesh.  Threads and heat sealing of the mesh knuckle are designed to produce accurate square openings in equal microns measurements in both directions.  This aids in preventing spot moire, aids in registration. 

Thread thickness can also affect moire.  Thicker threads are more prone to moire, thinner threads have more open area and capture more halftone data.

Al
You are correct.  We at Xenon use proprietary methods and equipment as well.  Being one of the first three companies to stretch for the industry, over the years we have indeed created specific techniques for the screen making process.
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