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screen printing => Screen Making => Topic started by: Prōdigium on July 23, 2016, 11:08:31 PM

Title: LED Exposure Units - Emulsions
Post by: Prōdigium on July 23, 2016, 11:08:31 PM
Not that I want to get into a "whats better", "this sucks" or my exposure unit is better...or whatever debate. But after reading a painfully long thread about the issues of LED exposure units, I thought it would be interesting and helpful to gather some basic data from real shop users. Compiling some basic real world data may even help existing users resolve some complaints or address some performance issues with their own units. I believe it would be helpful, to many people to have some feedback on emulsion. As with ANY exposure unit emulsion choices will play a huge part in perceived and real performance of an exposure unit.

There are tons of emulsions on the market every shop will pick one or more based on THEIR needs alone and there is no wrong or right choice....its about what works for your shop, ultimately that is all that matters. This is not a contest, there is no need to embellish results or try to make a case for faster is better because for some shops, clearly too fast IS the problem.

Now we all know, or should know that there are a gazillion variables at play when it comes to "proper" exposure of a screen but for the sake of making this an easy thread to reply too ans assimilate lets keep it down to the basics. Giving members some real data here will prove a huge resource for future members as well so lets keep it on topic. Each member can take what they want from it later and use it...for whatever reason in a new thread where the merits of any brand of whatever can be debated.

For now, lets just compile some data.


Lastly any foot notes about what you believe is the quality of the stencil such as breakdown issues, poor halftone resolution or even problems with reclaiming..which may indicate improper/under exposure.
Title: Re: LED Exposure Units - Emulsions
Post by: jvanick on July 24, 2016, 08:34:14 AM
I think a few additional fields should be added for those know/can provide the data.

- EOM
- "Positive type" CTS or Film or Velum (does anyone still use that here?)
- Stouffer Strip results.
- Ink type (plastisol, waterbase, discharge, hsa?)


For us:

M&R Starlight 2331 with the glass removed
positive source - I-Image (epson based unit)
Saati PHU + diazo11 (To slow it down)
20 screens per day
coating method 1/0 on Thin-thread mesh
screen room is climate controlled at 72-76 degrees, 25-30% RH 24x7.
all screens exposed to a solid '7' on the stouffer strip.

exposure times:
150/48Y - 30 sec
160/48W - 24 sec
225/48Y - 18 sec

Approximate EOM across the board is 17%.

production run can be anywhere from 12 pieces to 20,000 pieces.
Title: Re: LED Exposure Units - Emulsions
Post by: Gilligan on July 24, 2016, 11:03:23 AM
You could just use/hi-jack this google docs sheet I started a long time ago.

https://drive.google.com/open?id=1DQahuQ2WivbJJ9aGp7zyIxmMSWJitNNvipFsX4ajaFE
Title: Re: LED Exposure Units - Emulsions
Post by: screenprintguy on July 24, 2016, 01:56:25 PM
I think a few additional fields should be added for those know/can provide the data.

- EOM
- "Positive type" CTS or Film or Velum (does anyone still use that here?)
- Stouffer Strip results.
- Ink type (plastisol, waterbase, discharge, hsa?)


For us:

M&R Starlight 2331 with the glass removed
positive source - I-Image (epson based unit)
Saati PHU + diazo11 (To slow it down)
20 screens per day
coating method 1/0 on Thin-thread mesh
screen room is climate controlled at 72-76 degrees, 25-30% RH 24x7.
all screens exposed to a solid '7' on the stouffer strip.

exposure times:
150/48Y - 30 sec
160/48W - 24 sec
225/48Y - 18 sec

Approximate EOM across the board is 17%.

production run can be anywhere from 12 pieces to 20,000 pieces.

Jason, only 1 swipe of emulsion one only 1 side of the mesh?
Title: Re: LED Exposure Units - Emulsions
Post by: jvanick on July 24, 2016, 01:58:17 PM
I think a few additional fields should be added for those know/can provide the data.

- EOM
- "Positive type" CTS or Film or Velum (does anyone still use that here?)
- Stouffer Strip results.
- Ink type (plastisol, waterbase, discharge, hsa?)


For us:

M&R Starlight 2331 with the glass removed
positive source - I-Image (epson based unit)
Saati PHU + diazo11 (To slow it down)
20 screens per day
coating method 1/0 on Thin-thread mesh
screen room is climate controlled at 72-76 degrees, 25-30% RH 24x7.
all screens exposed to a solid '7' on the stouffer strip.

exposure times:
150/48Y - 30 sec
160/48W - 24 sec
225/48Y - 18 sec

Approximate EOM across the board is 17%.

production run can be anywhere from 12 pieces to 20,000 pieces.

Jason, only 1 swipe of emulsion one only 1 side of the mesh?
That's correct .. a 1/1 builds 50% eom
Title: Re: LED Exposure Units - Emulsions
Post by: screenprintguy on July 24, 2016, 03:23:23 PM
So you use this method for both wb, and plastisol? Just curious man. I always thought you had to have the coat on both sides for a true crosslink. I'm not using phu but I wonder if I'm hurting our printing with a 2/1
Title: Re: LED Exposure Units - Emulsions
Post by: jvanick on July 24, 2016, 04:07:13 PM
So you use this method for both wb, and plastisol? Just curious man. I always thought you had to have the coat on both sides for a true crosslink. I'm not using phu but I wonder if I'm hurting our printing with a 2/1
We've looked with microscopes with Ross Balfour from saati and confirmed that the emulsion is completely encapsulating the mesh.

A 1/0 from the print side actually results in a perfect glisten method as well.
Title: Re: LED Exposure Units - Emulsions
Post by: Frog on July 24, 2016, 04:50:29 PM
It's not always as easy as just counting strokes, or even which side of the coater is used.
As pointed out, some can apparently lay down enough emulsion with one stroke while others may need more.
Pressure, speed, viscosity, mesh count, and maybe even how the stars are aligned seem to all affect the end result.
Title: Re: LED Exposure Units - Emulsions
Post by: Dottonedan on July 24, 2016, 06:37:30 PM
The perfect coating all depends on the technique.  J Vanic may be very slow but sure or evenly coated (while going slow).  Thats extremely hard but he may have a knack for it. Most need several coats and need to coat semi faster to eliminate any studders. That's why for him, a 1/1 would be too much.

The trick to getting the correct thickness is using a gauge to measure EOM.  Doesn't matter how you get there.
Title: Re: LED Exposure Units - Emulsions
Post by: jvanick on July 24, 2016, 06:44:52 PM
The perfect coating all depends on the technique.  J Vanic may be very slow but sure or evenly coated (while going slow).  Thats extremely hard but he may have a knack for it. Most need several coats and need to coat semi faster to eliminate any studders. That's why for him, a 1/1 would be too much.

The trick to getting the correct thickness is using a gauge to measure EOM.  Doesn't matter how you get there.
We are installing an auto coater in a few weeks hwre, it's going to be interesting to dial it in and see what a 1/1 delivers.   To be honest I'd much rather be coating 1/1, but it is what it is for now.

A thickness gauge, to me, is as important as a stouffer strip of tension meter.

If you can't measure it, you can't track it, if you can't track it, you can't improve it.
Title: Re: LED Exposure Units - Emulsions
Post by: rusty on July 25, 2016, 08:04:48 AM
We just got a starlight unit and haven't dialed in all the numbers yet but we have also been doing mainly spot colors as of late.

     - starlight 2331
    - emulsion we are currently using is Chromalime
   - 5 screens a day on average
   - Coating method is a bit different. I coat once with an oversized coater to cover complete screen and the use a smaller coater to scoop up excess and give an even coat. I do this to eliminate using tape and quicken    setup and reclaim. it would probably qualify as a 1/0 coating method
    - room is not climate controlled yet.
    - as of now my exposure time is 15 seconds across the board. We are mainly using S-mesh except when doing flatstock then we are using 230 mesh only. We are currently a manual shop  for t-shirts (we have an automatic for glass printing) and are not doing any sim process at the moment.
     - average production runs are about 100 shirts (anywhere from 48 to 144)

Sorry this isnt as detailed and specific but figured you might want to know what some smaller shops are doing and as we grow and dial everything in I will add in more specific numbers.

Title: Re: LED Exposure Units - Emulsions
Post by: Prōdigium on July 25, 2016, 09:47:15 AM
We just got a starlight unit and haven't dialed in all the numbers yet but we have also been doing mainly spot colors as of late.

    - emulsion we are currently using is Chromalime
   - 5 screens a day on average


It might be enough to help others figure out how to get a better exposure, or make them think about changing emulsion for a better exposure. Speaking of emulsion, what product name from Chromaline...they have lots of versions of emulsion.
Title: Re: LED Exposure Units - Emulsions
Post by: Prōdigium on July 25, 2016, 09:54:15 AM
I think a few additional fields should be added for those know/can provide the data.

- EOM
- "Positive type" CTS or Film or Velum (does anyone still use that here?)
- Stouffer Strip results.
- Ink type (plastisol, waterbase, discharge, hsa?)

Well, to be honest I think that in the majority of shops...even ones that do good printing, they do not have a clue what EOM they have. As for film types, well again way to many variables and ink types are actually not relevant. The idea of this thread is to get some data that would allow people who are using, or considering LED exposure units to see if maybe the emulsion choice they have is appropriate and if they are getting satisfactory exposures. 
Title: Re: LED Exposure Units - Emulsions
Post by: rusty on July 25, 2016, 09:54:56 AM
We just got a starlight unit and haven't dialed in all the numbers yet but we have also been doing mainly spot colors as of late.

    - emulsion we are currently using is Chromalime
   - 5 screens a day on average


It might be enough to help others figure out how to get a better exposure, or make them think about changing emulsion for a better exposure. Speaking of emulsion, what product name from Chromaline...they have lots of versions of emulsion.

the emulsion from chromaline is called chromaLIME.

https://www.chromaline.com/product/chromalime/ (https://www.chromaline.com/product/chromalime/)
Title: Re: LED Exposure Units - Emulsions
Post by: Frog on July 25, 2016, 10:18:06 AM
Speaking of emulsion, what product name from Chromaline...they have lots of versions of emulsion.


Lance, the Chomalime is Chromaline's new emulsion tuned for use with LED

http://www.ikonics.com/pdf/user-guide/chromaline/ChromaLime_140904.pdf (http://www.ikonics.com/pdf/user-guide/chromaline/ChromaLime_140904.pdf)
Title: Re: LED Exposure Units - Emulsions
Post by: Prōdigium on July 25, 2016, 10:21:32 AM
 :-[...sorry, my eyes are getting bad. Working 15+ hours a day.
Title: Re: LED Exposure Units - Emulsions
Post by: Homer on July 25, 2016, 10:22:06 AM
CCI Blue HXT w 2oz diazo to slow it down
S mesh statics.
1/1 sharp edge.
DTS
Starlight 2331 / no glass
average time: 30 seconds (some counts are around 22 seconds, other in the 40's)

w/o diazo AND WP film AND glass we had anywhere from 3 - 8 seconds with other pp emulsions

IMO, an LED unit really "shines" with paired with a DTS. We had it for a year with our film set up and it was really, really fast and beat the pants off our 1k unit. But that glass became so incredibly hot after 10 screens, we had to stop exposing for 20 minutes or so to let it cool down. Find a way to get the heat out and keep that glass cooler...
Title: Re: LED Exposure Units - Emulsions
Post by: Prōdigium on July 25, 2016, 08:49:40 PM
IMO, an LED unit really "shines" with paired with a DTS. We had it for a year with our film set up and it was really, really fast and beat the pants off our 1k unit. But that glass became so incredibly hot after 10 screens, we had to stop exposing for 20 minutes or so to let it cool down. Find a way to get the heat out and keep that glass cooler...

I have heard this complaint a number of times about a few brands of units...not sure why a problem like this would not have been noticed during development? Maybe it was tested in an air conditioned room....either way, whats the sense in a 10 second burn time if your wasting 20 minutes later to let the thing cool down. But I can certainly see where having it paired with DTS would solve that problem.

Your like the 10th person that has posted here, or elsewhere I have read that adds diazo to slow your exposure....seems rather a waste to me. Why have you not simply switched to a dual cure emulsion with a naturally slower exposure?
Title: Re: LED Exposure Units - Emulsions
Post by: ebscreen on July 25, 2016, 08:57:03 PM
Unless I'm mistaken, dual cure emulsion is essentially a photopolymer with diazo added.

Our MSP3140 is woefully under-cooled as well. The Photosharp next to it has double the fans and none
of the heat problems.
Title: Re: LED Exposure Units - Emulsions
Post by: alan802 on July 26, 2016, 10:13:54 AM
The new Starlights don't have any issues with getting too hot.  It gets to 90 by 10am and it's over 100 for about 4 hours of our production day and I've yet to feel the glass to be any warmer than the ambient air.  I've shot 30 screens one after another within a span of about 45 minutes with very little time between exposures and I didn't notice any heat issues with our Starlight.  I was specifically looking for it too since I had read a few posts about it.  I'm sure Rich can elaborate further on this but I do know our unit is very new and they may have done a few things to curb the heat issue inside the unit. 

I'm almost ready to do a more comprehensive review of our Starlight and I've done a few videos but I haven't had a chance to review the vids and get them on youtube.  Maybe once it slows down later next week I'll get a window to get the info out there.
Title: Re: LED Exposure Units - Emulsions
Post by: Admiral on July 26, 2016, 10:34:03 AM
The new Starlights don't have any issues with getting too hot.  It gets to 90 by 10am and it's over 100 for about 4 hours of our production day and I've yet to feel the glass to be any warmer than the ambient air.  I've shot 30 screens one after another within a span of about 45 minutes with very little time between exposures and I didn't notice any heat issues with our Starlight.  I was specifically looking for it too since I had read a few posts about it.  I'm sure Rich can elaborate further on this but I do know our unit is very new and they may have done a few things to curb the heat issue inside the unit. 

I'm almost ready to do a more comprehensive review of our Starlight and I've done a few videos but I haven't had a chance to review the vids and get them on youtube.  Maybe once it slows down later next week I'll get a window to get the info out there.

That's one of the wonderful things about LEDs, very efficient so they don't put off a ton of heat.  Incandescent light bulbs are only like 3% efficient at putting out light, that means 97% heat...I have actually used a bulb for fermentation temperature control before.  This is also why I have been updating bulbs at home to LED bulbs (even got 5 free from my energy company).

We never had crazy film sticking problems like some people but we did have some sticking when we used glass and our MSP 3140.  Sure is nice being off of glass and using a Starlight.
Title: Re: LED Exposure Units - Emulsions
Post by: mk162 on July 26, 2016, 10:42:29 AM
LED don't put off heat, the 12v converters do.  the bases of LED bulbs will get warm, but the tops stay cool
Title: Re: LED Exposure Units - Emulsions
Post by: Homer on July 26, 2016, 10:54:17 AM
well whatever it is, my glass was getting HOT.

Title: Re: LED Exposure Units - Emulsions
Post by: jvanick on July 26, 2016, 11:00:33 AM
well whatever it is, my glass was getting HOT.

on both my starlight AND saati multi-300, the surface of the screen will get hot (glass or no glass).

I believe it to be radiated heat.  you can actually prove this for yourself by putting your hand in there while it's on (you may need to bypass the safety with a magnet on the starlight -- I didn't tell you that tho)... your hand will feel warm, but the glass will be cool.
Title: Re: LED Exposure Units - Emulsions
Post by: kingscreen on July 26, 2016, 11:40:02 AM
We have a Starlight and have never had an issue with glass getting hot. 
There are days we burn 15-20 screens back to back; no issue.