LED exposure units...what's out there and should I bother?

[Screen Dan]

So, I've been considering going LED.  I've currently got a Douthitt 5000w MH unit.  I have nothing but great things to say about the performance and support for both the exposure unit and both CTS units.

...but I have a narrow window where I could probably get my request for a new unit approved.  The space savings alone would be awesome (we have a DMZ...it's huge).  Not to mention the electricity savings, bulb savings, consistency improvements...and I imagine a reduction in the amount of heat they put off at idle and running, as well as noise? 

Please tell me if my expectations are wrong.

We coat with Aquasol HV (sometimes HVP) and HS for HD screens...so photopolymer, though we do add diazo sensitizer for added strength.

I also need it to accommodate 2 frame sizes, 23x31 MZXs and 32x48 M6s.  Douthitt does have a unit (water cooled!) but it is a conveyor and doesn't come close to handling our jumbo frames.

The CCI LED-EXP unit is interesting and very configurable, but I've not heard a peep around here about it...The same for the Light Speed Equipment unit.  Though this is understandable since these things seem to be coming out from all of the expected brands as well as out of the woodwork from all manner of manufacturer.

The first limiting factor will be what units can accommodate the 32x48 M6s...and I'm sure that will pare down my options significantly.  But what other units are on the market?

CCI
M&R
Douthitt
Vastex
Workhorse
Lightspeed
Anatol

...any I'm missing?

Assuming I can find one that accommodates my jumbos then we get down to the nitty gritty.   Are they really that great?  Assuming I stay with nothing but Aquasol (which I have no reason to think I won't) what can I expect for exposure times and cure compared to a 5000w MH?  Comparable?  Faster?  I'm fine if it takes a little longer to get a solid exposure given the many other benefits.  I've heard some rumbling suggesting super-fine detail might be a little worse, but practically speaking would a 55-60lpi screen print on your average commodity garment even reflect this?  Do we get solid cross-linking?  I only ask because we do a bit of DC and post expose for durability...would that be compromised?

I only ask all of this because I've been spoiled with a 5000w MH since I started here a forever-and-a-half ago...so I have no idea what other things I might have to look out for.

Thanks in advance for any advice.

EDIT:

Also, are all LEDs created equally?  I would imagine not.  If so, who has the best LEDs for the spectrum I need to nail for photopolymer+diazo...?

[TCT]

Saati has one also, and I think I remember Brown making noise about one too.

I can tell you for sure the Saati and Workhorse units are counterproductive at best for diazos.

[Screen Dan]

This is a concern of mine...curing the photopolymer but losing some of the durability the diazo gives me pause.

[Gilligan]

Anatol is at LEAST 10 weeks out.  That's what they have told me.  I've heard from a fairly recent customer of theirs that I should actually DOUBLE any lead times they give me!

[244]

So, I've been considering going LED.  I've currently got a Douthitt 5000w MH unit.  I have nothing but great things to say about the performance and support for both the exposure unit and both CTS units.

...but I have a narrow window where I could probably get my request for a new unit approved.  The space savings alone would be awesome (we have a DMZ...it's huge).  Not to mention the electricity savings, bulb savings, consistency improvements...and I imagine a reduction in the amount of heat they put off at idle and running, as well as noise? 

Please tell me if my expectations are wrong.

We coat with Aquasol HV (sometimes HVP) and HS for HD screens...so photopolymer, though we do add diazo sensitizer for added strength.

I also need it to accommodate 2 frame sizes, 23x31 MZXs and 32x48 M6s.  Douthitt does have a unit (water cooled!) but it is a conveyor and doesn't come close to handling our jumbo frames.

The CCI LED-EXP unit is interesting and very configurable, but I've not heard a peep around here about it...The same for the Light Speed Equipment unit.  Though this is understandable since these things seem to be coming out from all of the expected brands as well as out of the woodwork from all manner of manufacturer.

The first limiting factor will be what units can accommodate the 32x48 M6s...and I'm sure that will pare down my options significantly.  But what other units are on the market?

CCI
M&R
Douthitt
Vastex
Workhorse
Lightspeed
Anatol

...any I'm missing?

Assuming I can find one that accommodates my jumbos then we get down to the nitty gritty.   Are they really that great?  Assuming I stay with nothing but Aquasol (which I have no reason to think I won't) what can I expect for exposure times and cure compared to a 5000w MH?  Comparable?  Faster?  I'm fine if it takes a little longer to get a solid exposure given the many other benefits.  I've heard some rumbling suggesting super-fine detail might be a little worse, but practically speaking would a 55-60lpi screen print on your average commodity garment even reflect this?  Do we get solid cross-linking?  I only ask because we do a bit of DC and post expose for durability...would that be compromised?

I only ask all of this because I've been spoiled with a 5000w MH since I started here a forever-and-a-half ago...so I have no idea what other things I might have to look out for.

Thanks in advance for any advice.

EDIT:

Also, are all LEDs created equally?  I would imagine not.  If so, who has the best LEDs for the spectrum I need to nail for photopolymer+diazo...?

You are welcome to come here to M7R to do any type of testing you would like including cycle test on diazo based screens. A proper unit (and I say that for a reason) should perform better than your 5K unit both on photo polymers as well as diazo. Exposure times should also be faster, not slower and yes we can make the size you need.

[alan802]

I'll be completely honest and say that coming from a Richmond Solarbeam 10K watt unit, I'm a little bit disappointed  in a few aspects of LED but overall it's a good unit.  We have the Vastex unit.  The pros are the bulbs never losing intensity, no heat, and energy consumption, but when it comes down to it, it absolutely does not cross-link OUR SCREENS as good as our MH unit did.  On the surface it's a close match, but dig deeper, and we have had issues with screens breaking down, reclaiming problems, and a few other minor irritants that we're not used to dealing with, but I don't know that I'd not make the same choice had I had to do it again.  It's a toss up I guess.  The first DC screen I did with our LED lasted 5 print strokes, and I exposed it for about 90 seconds and we're doing our plastisol screens at around 40 seconds.  But it's nice to not have to worry about buying bulbs.  Our vacuum draw down is abysmal, but I've heard from numerous reliable sources that they've fixed that glaring issue that I still can't believe was ever an issue even on the first unit sold, but I digress. 

We can shoot screens for 5 seconds (305's) and they will hold up fairly well for plastisol, or for 100 seconds and they hold up very well, so exposure latitude is crazy good with the emulsions we've used on the LED...but they were also very good on the Richmond.  We've settled in on 25 seconds for high mesh, 40 seconds for middle mesh counts, and 50 seconds for low mesh. 

[244]

I'll be completely honest and say that coming from a Richmond Solarbeam 10K watt unit, I'm a little bit disappointed  in a few aspects of LED but overall it's a good unit.  We have the Vastex unit.  The pros are the bulbs never losing intensity, no heat, and energy consumption, but when it comes down to it, it absolutely does not cross-link OUR SCREENS as good as our MH unit did.  On the surface it's a close match, but dig deeper, and we have had issues with screens breaking down, reclaiming problems, and a few other minor irritants that we're not used to dealing with, but I don't know that I'd not make the same choice had I had to do it again.  It's a toss up I guess.  The first DC screen I did with our LED lasted 5 print strokes, and I exposed it for about 90 seconds and we're doing our plastisol screens at around 40 seconds.  But it's nice to not have to worry about buying bulbs.  Our vacuum draw down is abysmal, but I've heard from numerous reliable sources that they've fixed that glaring issue that I still can't believe was ever an issue even on the first unit sold, but I digress. 

We can shoot screens for 5 seconds (305's) and they will hold up fairly well for plastisol, or for 100 seconds and they hold up very well, so exposure latitude is crazy good with the emulsions we've used on the LED...but they were also very good on the Richmond.  We've settled in on 25 seconds for high mesh, 40 seconds for middle mesh counts, and 50 seconds for low mesh.

This is part of the problem with labeling LED as a generic system. None of our customers are complaining of screen failure in Diazo or photopolymer systems. All systems are NOT alike. Just a FYI.

[Admiral]

Yea, it's not fair to label them all into the same category like they perform the same.  Sure a MH bulb at a certain wattage would probably be predictable but not the LED exposure units.

We have done over 3K prints with a diazo emulsion for water based discharge printing with one set of screens, 7 or 8 color job just fine.  We did use hardener but if it was only 500 prints we probably wouldn't have.

[sben763]

As rich points out not all LEDs are equal.  I started out doing a DIY LED unit.  Most of the units just cant throughly cross link the emulsion before undercutting becomes an issue.  M&R has the strongest LED unit compared to all the other units that I've looked at the specs.  I had access to a M&R unit and it burns a nice screen.  I am only a manual printer so I can't say how it held up on a auto but the screens I tested I did just over 500 prints, some of the screens were a PFP.

I am not sure what spectrum range they are outputing but from my testing on my DIY LED I found that the spectrums are a very narrow band so I purchased the materials needed for the emulsion I'm using. 

The issue with the Vastex unit is the narrow band and the technology it's using.  If you can get them to give their output spectrum and use a emulsion that is best with that peak, things would be much better. There are a few other units that use the same technology and will have the same issues.

I ended up having a led built specificly for me.  What I am using is completely diffrent then any manufacture. 

[islandtees]

I'll be completely honest and say that coming from a Richmond Solarbeam 10K watt unit, I'm a little bit disappointed  in a few aspects of LED but overall it's a good unit.  We have the Vastex unit.  The pros are the bulbs never losing intensity, no heat, and energy consumption, but when it comes down to it, it absolutely does not cross-link OUR SCREENS as good as our MH unit did.  On the surface it's a close match, but dig deeper, and we have had issues with screens breaking down, reclaiming problems, and a few other minor irritants that we're not used to dealing with, but I don't know that I'd not make the same choice had I had to do it again.  It's a toss up I guess.  The first DC screen I did with our LED lasted 5 print strokes, and I exposed it for about 90 seconds and we're doing our plastisol screens at around 40 seconds.  But it's nice to not have to worry about buying bulbs.  Our vacuum draw down is abysmal, but I've heard from numerous reliable sources that they've fixed that glaring issue that I still can't believe was ever an issue even on the first unit sold, but I digress. 

We can shoot screens for 5 seconds (305's) and they will hold up fairly well for plastisol, or for 100 seconds and they hold up very well, so exposure latitude is crazy good with the emulsions we've used on the LED...but they were also very good on the Richmond.  We've settled in on 25 seconds for high mesh, 40 seconds for middle mesh counts, and 50 seconds for low mesh.

This is part of the problem with labeling LED as a generic system. None of our customers are complaining of screen failure in Diazo or photopolymer systems. All systems are NOT alike. Just a FYI.

Here I agree 100%.
 We recently received our unit and exposure times average about 10 seconds. No cross link problems and screens going 1000's of impressions.
LED units are not made the same.

[LuckyFlyinROUSH]

https://www.youtube.com/watch?v=UifJ3t6ziKs

Using Photopolymer 4ish seconds. - We used a dual cure...cant remember the name but it was around 30 seconds...but not dialed in.

[GraphicDisorder]

Been using our Starlight unit for about a year I believe now. Yet to see a single noticeable difference on press.  Now I am sure with some fancy tools you can tell me there are some. At what level is it just considered splitting hairs? For me its one of the better moves ive made in my shop.  But that was coming from a MH that was clearly having some issues after the years of use. Our exposure times with new bulbs even where several minutes.  So much faster now.

[Screen Dan]

Excellent info guys.  This is exactly the conversation I was hoping to have.

Rich, I think I'll be contacting you in the coming weeks.  Assuming you have the superior LED (and from all accounts in this thread alone, you do) and can build something to fit my jumbo frames I would have no hesitation about buying blue again...



...can mine be blue?

[alan802]

Sorry for using general terminology, but that's why I mentioned in the beginning we had the Vastex unit was so that everyone reading wouldn't confuse the fact that I was bundling every LED unit together even though I can see how it was interpreted that way.