Before You Went LED, What Were You Using?

[3Deep]

I've never really like the Vastex or Lawson equipment, for some reason it just don't seem right, but I know tons of people use there equipment and make tons of money.  I will say this the Starlight that Ron Hopkins brought to our shop was nice as F and If I get back in the market for an exposure unit it will be at the top of our list for sure.  The screens we burned where at 8 to 10 sec with HXT emulsion, I will say this a MH point light is going to do a better job because the light is going straight thru the unblocked emulsion cross linking it better.

D

[GraphicDisorder]

We keep seeing mention of better this or that with MH, has anyone printed the same exact artwork with each unit and seen any real measurable difference on press?  That's a honest question, haven't seen anyone say one way or another so I am curious. 

[alan802]

We keep seeing mention of better this or that with MH, has anyone printed the same exact artwork with each unit and seen any real measurable difference on press?  That's a honest question, haven't seen anyone say one way or another so I am curious. 

It wouldn't be that easy to see once you finally got a good enough screen on press. 

My biggest issue is with things like happened yesterday.  I had to shoot 5 screens of this one halftone image to get 1 good enough to go to press.  So I not only wasted 4 screens, but the extra time it took to shoot 4 more, then the biggest killer of time is to reclaim and coat those to get them back into the production loop. 

[ZooCity]

We keep seeing mention of better this or that with MH, has anyone printed the same exact artwork with each unit and seen any real measurable difference on press?  That's a honest question, haven't seen anyone say one way or another so I am curious.

Can't give you the scientific answer I would like to yet but yes, we have printed some halftone jobs, same films on both MH and LED and we didn't require any adjustments to the art or films.  This is for repeat, retail line merch so we have control print samples on hand and all matched up. 

What wasn't apples to apples however is our MH has a haggard old blanket on it.  LED is brand new with a pressure sensor.  I'm sure other shops are similar, by the time they upgrade to LED the old unit is probably lacking good vac pressure/draw down v. the brand spankin' new one.  This alone is going to make you equate the new machine with better, or on par, resolution.

Time never seems to be on my side for this but I do have the tools on hand to actually measure undercutting.  But maybe it's a moot point?  If the prints come out the same and the screens hold up, I have to wonder why bother measuring the difference.  There is undoubtedly a difference- point source light beats multiple point for fine detail, nobody's arguing that -but it really doesn't appear to be enough of a difference to matter for textile printers. Fully cross linked LED seems to be on par with fully cross linked MH expos.  Those printing other items like flatstock and circuit boards, etc. may have a different experience here.  We ain't printing 100lpi with 420tpi mesh.

[Dottonedan]

I think the point that some are overlooking is as people have mentioned before. Not all LED's are the same and with that, neither is the price. There is a place and a time for everything. Vastex is a good company and they make good products that fit your budget. That seems to be the kicker. It's a good product for many out there and maybe a better choice at the time than another one. There are plenty of 6 color manual press companies and you would all agree that each is a different level of quality.


You get what you pay for and you should be paying for what you need at the time. Vastex shines in many areas for what they specialize in and who they cater to in the industry. Maybe their LED unit is not designed to be reading mesh under a loop and looking at 2% in a 65lpi. It would work and save someone money in specific areas compared to other light sources I'm sure. Again tho, I might not try to compare it to a traditional light source aka 8k MH that is capable of holding 2% in a 65lpi  but the times might be much faster in other areas to compare to. That's a different side to look at.  Each of you do a thing called screen printing on apparel but each of you do something better than another and you all have different prices. Comparing a screen printer to another is not exactly apples to apples, well, more like Granny Smiths to Machintosh, apples but they are both round and both tasty to the right person. Same for LED units.

[blue moon]

I am gonna have to stand up for Vastex here. They make top notch  stuff in my book, the 2000 is a very impressive piece of equipment for example.

'not really sure what's going on with Alan's unit, there is a problem with it that should be taken up with the manufacturer and it should be sorted out.  But I will say that the Vastex unit we tested was top notch and in few ways better than the Starlight. This is not to knock on the M&R unit as it is impressive, but if I had to chose between the two, I would take the Vastex right now. In part because I ran some tests and Vastex had the most uniform light coverage amongst the units we tested. It also helps that I know what is going on with their light source and how it's designed including the light wavelength.

Going back to the measurements, yes, Richard and I took them and the difference between the MH and LED was very small and addressable in the RIP. The undercutting was about 2% and since it is adjustable with a curve, it would be hard to imagine anybody needing to use an MH to get a better dot.

The issue here is related to the LED unit's ability to penetrate all the way through te stencil and potentially the need to have multispectrum wavelength for full exposure*. It is possible that the Aquasol HV is more in tune with the wavelength Vastex unit is producing. It is the emulsion we tested it with and had really good results with. We were slightly underexposed at 9 seconds and had to bump up to 13-15, but after that we had no issues. We had no issues on the press at 15 seconds and I can honestly say that I wouldn't have any reservations with using their unit.

All that said and done, we did not buy one as it did not really solve any problems we have. Yes the exposure times would be shorter and the operating expenses would be lower, but we still have things much higher on the priority list.

pierre   


*emultions don't really crosslink completely as I understand, it is just a fraction of the total molecules that's needed for what we call full exposure.

[GraphicDisorder]

it would be hard to imagine anybody needing to use an MH to get a better dot.

That's pretty much was I was suspecting was the case but I am not smart enough nor have the free time to prove or disprove it one way or another. The only thing I just know that when we went to LED, we've not noticed any differences on press and that is where it really matters.  After all we aren't selling cross linking, exposure times, how easy it washes out and so on.  We are selling tshirts!

It wouldn't be that easy to see once you finally got a good enough screen on press. 

My biggest issue is with things like happened yesterday.  I had to shoot 5 screens of this one halftone image to get 1 good enough to go to press.  So I not only wasted 4 screens, but the extra time it took to shoot 4 more, then the biggest killer of time is to reclaim and coat those to get them back into the production loop. 

Vastex makes quality products and I am a fan of theirs. Are you certain at this point that you don't have something wrong with that unit? Have you discussed any of this with them?  Just being flat honest, outside someone dialing in the wrong exposure time for the screen being used and our first couple days of running the unit we haven't re-shot a single screen due to something with our LED unit. That's not me championing M&R either, I am just saying that I suspect regardless of brand you shouldn't be needing to re-shoot screens past the point where you have your exposure times figured out and such.

[tonypep]

The Sun

[Itsa Little CrOoked]

The Sun

I still do use the Sun, on screens that are too big for my exposure unit.  It takes a little adhesive spray and you lose your film. It's just that they can't easily be stored with spray adhesive on them

I'm still using a metal halide. A NuArc 2125 which is about an 800 watt unit, and its sloooow.

I need to upgrade.

[Underbase37]

*This is a long one*

I've been holding off a bit. As I wanted to do a bunch of testing before I gave my thoughts.

On the LED vs MH debate. I am only coming from the point of the unit we had ( Richmind Solarbeam, using a 10k bulb. ) To what we have now ( M&R I-image STE II with LED. )
There are a few other variables, like using film with the MH, as we were doing & not using film with the LED, as we are now.

As far as I can tell, the LED ( in our unit ) is having absolutely no problem fully curing/crosslinking, or zero slime/ residue on the squeegee side.....or how ever you want to put it. When I say fully crosslinked, I mean absolutely NO soft emulsion, except the image being rinsed out.

-Emulsion: Kiwo ONE-COAT : SBQ with Diazo
http://www.kiwo.com/polycol-one-coat
-1/1 coating
-20% EOM-on average, based on 156-110

-10k MH unit-
-156-T-white mesh : 48 sec.
-150-S-yellow mesh : 90 sec.

-M&R LED unit-
-156-T-white mesh : 27 sec.
-150-S-yellow mesh : 55 sec.

(*Thread jack*) Sorry

I also had the pleasure of doing some testing, pre-release of a new Kiwo emulsion, Multi-Tex that just hit the market this moth. Check it out!
http://www.kiwo.com/polycol-multi-tex
Its looking very promising....... I still need to do a bit more testing. ( tho I did get 2k DC prints with it on one image & another 2k DC prints with a second print, that I feel I could have gotten another 1k prints out of it......Without hardener, with out post expose, with LED exposure )

(*Back to it*)

I have exposed just over 600 screens in the month we have had our M&R unit. Many of these screens have been on reorders, jobs that were burned on our MH & now our LED. I see no compromise in quality exposure with our LED unit.
Many of these screens have also been, clean & save screens, ones we catalog & reprint ( some have already come back through the schedule ) cleaned multiple times. No problems. No lockups.
A large amount of them have gone through the full process of reclame/recoat/reprint, many times. No problem. No lockups.

I had screen up on press last week, it was a quick on the fly reburn for a DC job. The old screens were pulled off the shelf & had quite a bit of use on them already, but we went to press anyway. About mid way through the order one of the screens gets a heavy wipe-down & some of the small detail gets taken out. So I send the guys working on that press to an early lunch hoping to get as much time as I can before they get back for the screen to dry. It gets about an hour ( maybe ) I rush it along & get it on press. Not having that high of expectations, I'm expecting the worst, hoping for the best. Well that screen lasted another 800 prints being double stroked & when done with the order, I would say the screen had very little to no signs of breaking down. ( this was with Kiwo One-Coat emulsion, no hardener, no post exposure )

I have also done a few low mesh with a very thick EOM, 400 micron stencil, & after getting my time dialed in the screen was not under exposed at all & still I was kind of holding the reg marks ( we use .5 line width for reg marks )

I'm not saying it hasn't been without a bit of a learning curve, but nothing that didn't take 3 or less screens to get dialed in & this was just really the first few screens we shot of each mesh.
I would agree there are some differences in having a single point light source to having a multi point source, & I feel you may see the biggest problems with this if you have the need/want to underexpose.

Well maybe this all helps someone? 


   

Murphy37

[ericheartsu]

*This is a long one*

I've been holding off a bit. As I wanted to do a bunch of testing before I gave my thoughts.

On the LED vs MH debate. I am only coming from the point of the unit we had ( Richmind Solarbeam, using a 10k bulb. ) To what we have now ( M&R I-image STE II with LED. )
There are a few other variables, like using film with the MH, as we were doing & not using film with the LED, as we are now.

As far as I can tell, the LED ( in our unit ) is having absolutely no problem fully curing/crosslinking, or zero slime/ residue on the squeegee side.....or how ever you want to put it. When I say fully crosslinked, I mean absolutely NO soft emulsion, except the image being rinsed out.

-Emulsion: Kiwo ONE-COAT : SBQ with Diazo
http://www.kiwo.com/polycol-one-coat
-1/1 coating
-20% EOM-on average, based on 156-110

-10k MH unit-
-156-T-white mesh : 48 sec.
-150-S-yellow mesh : 90 sec.

-M&R LED unit-
-156-T-white mesh : 27 sec.
-150-S-yellow mesh : 55 sec.

(*Thread jack*) Sorry

I also had the pleasure of doing some testing, pre-release of a new Kiwo emulsion, Multi-Tex that just hit the market this moth. Check it out!
http://www.kiwo.com/polycol-multi-tex
Its looking very promising....... I still need to do a bit more testing. ( tho I did get 2k DC prints with it on one image & another 2k DC prints with a second print, that I feel I could have gotten another 1k prints out of it......Without hardener, with out post expose, with LED exposure )

(*Back to it*)

I have exposed just over 600 screens in the month we have had our M&R unit. Many of these screens have been on reorders, jobs that were burned on our MH & now our LED. I see no compromise in quality exposure with our LED unit.
Many of these screens have also been, clean & save screens, ones we catalog & reprint ( some have already come back through the schedule ) cleaned multiple times. No problems. No lockups.
A large amount of them have gone through the full process of reclame/recoat/reprint, many times. No problem. No lockups.

I had screen up on press last week, it was a quick on the fly reburn for a DC job. The old screens were pulled off the shelf & had quite a bit of use on them already, but we went to press anyway. About mid way through the order one of the screens gets a heavy wipe-down & some of the small detail gets taken out. So I send the guys working on that press to an early lunch hoping to get as much time as I can before they get back for the screen to dry. It gets about an hour ( maybe ) I rush it along & get it on press. Not having that high of expectations, I'm expecting the worst, hoping for the best. Well that screen lasted another 800 prints being double stroked & when done with the order, I would say the screen had very little to no signs of breaking down. ( this was with Kiwo One-Coat emulsion, no hardener, no post exposure )

I have also done a few low mesh with a very thick EOM, 400 micron stencil, & after getting my time dialed in the screen was not under exposed at all & still I was kind of holding the reg marks ( we use .5 line width for reg marks )

I'm not saying it hasn't been without a bit of a learning curve, but nothing that didn't take 3 or less screens to get dialed in & this was just really the first few screens we shot of each mesh.
I would agree there are some differences in having a single point light source to having a multi point source, & I feel you may see the biggest problems with this if you have the need/want to underexpose.

Well maybe this all helps someone? 


   

Murphy37

We just tried out the new KIWO emulsion to, and we were coating 1/1 sharp side. They told us that we should start coating 2/1 or 2/2 round edge, which we started doing with our PHU, and we are getting really really great screens now. On our STE II we are exposing at 14-20 seconds, and on our richmond solar beak with a 7K light, we are exposing at 22 LU.

We don't have an EOM meter, so can't chime in on our EOM, but i'm hoping to have one next month.

[Underbase37]

*This is a long one*

I've been holding off a bit. As I wanted to do a bunch of testing before I gave my thoughts.

On the LED vs MH debate. I am only coming from the point of the unit we had ( Richmind Solarbeam, using a 10k bulb. ) To what we have now ( M&R I-image STE II with LED. )
There are a few other variables, like using film with the MH, as we were doing & not using film with the LED, as we are now.

As far as I can tell, the LED ( in our unit ) is having absolutely no problem fully curing/crosslinking, or zero slime/ residue on the squeegee side.....or how ever you want to put it. When I say fully crosslinked, I mean absolutely NO soft emulsion, except the image being rinsed out.

-Emulsion: Kiwo ONE-COAT : SBQ with Diazo
http://www.kiwo.com/polycol-one-coat
-1/1 coating
-20% EOM-on average, based on 156-110

-10k MH unit-
-156-T-white mesh : 48 sec.
-150-S-yellow mesh : 90 sec.

-M&R LED unit-
-156-T-white mesh : 27 sec.
-150-S-yellow mesh : 55 sec.

(*Thread jack*) Sorry

I also had the pleasure of doing some testing, pre-release of a new Kiwo emulsion, Multi-Tex that just hit the market this moth. Check it out!
http://www.kiwo.com/polycol-multi-tex
Its looking very promising....... I still need to do a bit more testing. ( tho I did get 2k DC prints with it on one image & another 2k DC prints with a second print, that I feel I could have gotten another 1k prints out of it......Without hardener, with out post expose, with LED exposure )

(*Back to it*)

I have exposed just over 600 screens in the month we have had our M&R unit. Many of these screens have been on reorders, jobs that were burned on our MH & now our LED. I see no compromise in quality exposure with our LED unit.
Many of these screens have also been, clean & save screens, ones we catalog & reprint ( some have already come back through the schedule ) cleaned multiple times. No problems. No lockups.
A large amount of them have gone through the full process of reclame/recoat/reprint, many times. No problem. No lockups.

I had screen up on press last week, it was a quick on the fly reburn for a DC job. The old screens were pulled off the shelf & had quite a bit of use on them already, but we went to press anyway. About mid way through the order one of the screens gets a heavy wipe-down & some of the small detail gets taken out. So I send the guys working on that press to an early lunch hoping to get as much time as I can before they get back for the screen to dry. It gets about an hour ( maybe ) I rush it along & get it on press. Not having that high of expectations, I'm expecting the worst, hoping for the best. Well that screen lasted another 800 prints being double stroked & when done with the order, I would say the screen had very little to no signs of breaking down. ( this was with Kiwo One-Coat emulsion, no hardener, no post exposure )

I have also done a few low mesh with a very thick EOM, 400 micron stencil, & after getting my time dialed in the screen was not under exposed at all & still I was kind of holding the reg marks ( we use .5 line width for reg marks )

I'm not saying it hasn't been without a bit of a learning curve, but nothing that didn't take 3 or less screens to get dialed in & this was just really the first few screens we shot of each mesh.
I would agree there are some differences in having a single point light source to having a multi point source, & I feel you may see the biggest problems with this if you have the need/want to underexpose.

Well maybe this all helps someone? 


   

Murphy37

We just tried out the new KIWO emulsion to, and we were coating 1/1 sharp side. They told us that we should start coating 2/1 or 2/2 round edge, which we started doing with our PHU, and we are getting really really great screens now. On our STE II we are exposing at 14-20 seconds, and on our richmond solar beak with a 7K light, we are exposing at 22 LU.

We don't have an EOM meter, so can't chime in on our EOM, but i'm hoping to have one next month.

Yes, this new one is supposed to be a very fast exposer.
We use the round edge 1/1
I haven't spent enough time with this new one to say much about it. But its initial testing went very well.

Murphy37

[Maxie]

At FESPA I saw a LED that is sold by Saati USA, 300W and costs $500.
It will work like a spot light.
They say exposure for a pure photopolymer emulsion will be about 45 set at a lamp  distance of 36", at this distance I can expose two 23X31" screens.
I am ordering this unit.

[Itsa Little CrOoked]

At FESPA I saw a LED that is sold by Saati USA, 300W and costs $500.
It will work like a spot light.
They say exposure for a pure photopolymer emulsion will be about 45 set at a lamp  distance of 36", at this distance I can expose two 23X31" screens.
I am ordering this unit.

Need more info please.

I looked for this on saati sites. No joy....

[sqslabs]

Need more info please.

I looked for this on saati sites. No joy....

I think he may be talking about the same one Greg was testing in his setup at Mind's Eye.