Before You Went LED, What Were You Using?

[blue moon]

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.

I have two of their units here and we are testing them. One is the 300W prototype and the other is the 450W water cooled single point light source. Give me few weeks to get some results. We  burned few (3) screens with the 300W unit, but that was just preliminary testing. We were at 2 min for the 110 mesh to get no slime on the back.

pierre

[Maxie]

What emulsion were you testing?
I have a problem, my unit works well but I have flouresent tubes and have to improve on this.
All the alternatives are really expensive, I was looking into putting rows of LEDS into my unit but this lamp looks like a great option.
Greg from Saati said the 300W unit can expose Textel PHU in under 1 min at a distance of 36".
This works well for me and at $500 it's a reasonably priced solution.
My son is coming back to Israel on the 11th June and can bring one with him so I have about a week to decide.

[blue moon]

What emulsion were you testing?
I have a problem, my unit works well but I have flouresent tubes and have to improve on this.
All the alternatives are really expensive, I was looking into putting rows of LEDS into my unit but this lamp looks like a great option.
Greg from Saati said the 300W unit can expose Textel PHU in under 1 min at a distance of 36".
This works well for me and at $500 it's a reasonably priced solution.
My son is coming back to Israel on the 11th June and can bring one with him so I have about a week to decide.

Aquasol HV.

My suggestion would be to buy it as long as you can send it back if it does not work out. 'worst case scenario is you are out of shipping money. I doubt I can have and decision quality information in the next few days. . .

pierre

[Dottonedan]

What emulsion were you testing?
I have a problem, my unit works well but I have flouresent tubes and have to improve on this.
All the alternatives are really expensive, I was looking into putting rows of LEDS into my unit but this lamp looks like a great option.
Greg from Saati said the 300W unit can expose Textel PHU in under 1 min at a distance of 36".
This works well for me and at $500 it's a reasonably priced solution.
My son is coming back to Israel on the 11th June and can bring one with him so I have about a week to decide.

Pardon me for my lack of knowledge about your business/shop, but It seems out of place. You have at least one auto (with a DGT printer in one station) and you want a $500.00 exp unit?  Seems like for the cost, it would be under purchasing for your shop. I don't know. Could be very wrong.

[Frog]

What emulsion were you testing?
I have a problem, my unit works well but I have flouresent tubes and have to improve on this.
All the alternatives are really expensive, I was looking into putting rows of LEDS into my unit but this lamp looks like a great option.
Greg from Saati said the 300W unit can expose Textel PHU in under 1 min at a distance of 36".
This works well for me and at $500 it's a reasonably priced solution.
My son is coming back to Israel on the 11th June and can bring one with him so I have about a week to decide.

Pardon me for my lack of knowledge about your business/shop, but It seems out of place. You have at least one auto (with a DGT printer in one station) and you want a $500.00 exp unit?  Seems like for the cost, it would be under purchasing for your shop. I don't know. Could be very wrong.

Dan, $500 is a lot less than an M&R, VASTEX, or any other brand exposure unit, this is just for the light source, and even a powerful single point light should cost less than an entire bank of small ones.
Does anyone else even have an LED light source that can be used at different  distances from a wall mounted vacuum frame?

[TCT]

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.

I have two of their units here and we are testing them. One is the 300W prototype and the other is the 450W water cooled single point light source. Give me few weeks to get some results. We  burned few (3) screens with the 300W unit, but that was just preliminary testing. We were at 2 min for the 110 mesh to get no slime on the back.

pierre

I had one of the 300watt ones. It didn't live up to the claims they had made to me about exposure times. On the SP-1400 it was worse than our 1k MH unit I've had since we opened. That was a annoying sticking point from them, they said I'd be better off switching to their newer hybrid H-something. Then we thought maybe the unit I got was damaged..... All in all I ended up returning it. It performed below our 1k Workhorse we have had for 10 years.

Important to note though, ALL the use and screens we did with it were for DC, WB or HSA inks. Didn't try it on anything for plastisol.

[blue moon]

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.

I have two of their units here and we are testing them. One is the 300W prototype and the other is the 450W water cooled single point light source. Give me few weeks to get some results. We  burned few (3) screens with the 300W unit, but that was just preliminary testing. We were at 2 min for the 110 mesh to get no slime on the back.

pierre

I had one of the 300watt ones. It didn't live up to the claims they had made to me about exposure times. On the SP-1400 it was worse than our 1k MH unit I've had since we opened. That was a annoying sticking point from them, they said I'd be better off switching to their newer hybrid H-something. Then we thought maybe the unit I got was damaged..... All in all I ended up returning it. It performed below our 1k Workhorse we have had for 10 years.

Important to note though, ALL the use and screens we did with it were for DC, WB or HSA inks. Didn't try it on anything for plastisol.

we are on a 1.2kW MH and I am expecting the times to go  up with the 300W and be around the same with the 450W units. This is not a time saving excersize for us. . .

pierre

[Dottonedan]

What emulsion were you testing?
I have a problem, my unit works well but I have flouresent tubes and have to improve on this.
All the alternatives are really expensive, I was looking into putting rows of LEDS into my unit but this lamp looks like a great option.
Greg from Saati said the 300W unit can expose Textel PHU in under 1 min at a distance of 36".
This works well for me and at $500 it's a reasonably priced solution.
My son is coming back to Israel on the 11th June and can bring one with him so I have about a week to decide.

Pardon me for my lack of knowledge about your business/shop, but It seems out of place. You have at least one auto (with a DGT printer in one station) and you want a $500.00 exp unit?  Seems like for the cost, it would be under purchasing for your shop. I don't know. Could be very wrong.

Dan, $500 is a lot less than an M&R, VASTEX, or any other brand exposure unit, this is just for the light source, and even a powerful single point light should cost less than an entire bank of small ones.
Does anyone else even have an LED light source that can be used at different  distances from a wall mounted vacuum frame?

I digress. I'ts none of my business why people make the decisions they do.

[GraphicDisorder]

I would be suspect that as every manufacture is producing LED units that cost thousands that any unit that cost $500 bucks can't be much to write home about. Comes off to me like a late night TV advert... but wait there is more....act now and we will throw in a brand new 12 color auto with your purchase.....just pay processing, shipping and handling. 

[Frog]

I would be suspect that as every manufacture is producing LED units that cost thousands that any unit that cost $500 bucks can't be much to write home about. Comes off to me like a late night TV advert... but wait there is more....act now and we will throw in a brand new 12 color auto with your purchase.....just pay processing, shipping and handling.

We are not comparing apples to apples here. This is just the core. This is not an exposure unit, just the light source.
http://www.theshirtboard.com/index.php?action=dlattach;topic=13347.0;attach=13534

[mk162]

honestly, our 7.5k lights run about $250-300...so that's not bad for a bulb you should never have to replace.

[GraphicDisorder]

I would be suspect that as every manufacture is producing LED units that cost thousands that any unit that cost $500 bucks can't be much to write home about. Comes off to me like a late night TV advert... but wait there is more....act now and we will throw in a brand new 12 color auto with your purchase.....just pay processing, shipping and handling.

We are not comparing apples to apples here. This is just the core. This is not an exposure unit, just the light source.
http://www.theshirtboard.com/index.php?action=dlattach;topic=13347.0;attach=13534

My bad, his post didn't come off as if it was just the bulb. 

[alan802]

A few things I'd like to add here before it gets covered up.  Let's get my points out in the open more clearly with what I know for sure.  We are having tons of issues with different emulsions with the LED.  With the MH we had ZERO issues with any emulsion at any time and even when we were shooting a new emulsion for the first time we rarely had a screen that we couldn't use on press.  The fact is our LED is much more picky about the emulsion it can work with, and the HVP is the only emulsion out of about 6 that it has been able to cross-link all the way through.  To eliminate the possibility of our films being the problem, I've got a few older imagesetter pieces of film I'm using to test on the bottom of every screen we shoot.  This film I'm using to test is of the highest quality there is when it comes to film so I'm not concerned with the issue being our film any longer.

I haven't called or emailed them about our issues and don't plan on it.  They've read this thread, and the others, and with my past conversations and comms with them yielding absolutely nothing but frustration and insinuations that we didn't know what we were doing around here, that's why I haven't reached out to them directly.  Now that I have more time on my hands I may change my tune on that but my lack of confidence that a conversation with them directly would help us get durable stencils and fine detail on our screens is warranted in my opinion.  I can go into detail on each of those issues if anyone wants to know that badly.  It's something that I'm sure most everyone here would feel the same way had they been handled that way.  I think the main issue I had with the first problem was it was a fairly well known issue that I had heard from several other users so when I was told that this was the first they had heard about a pallet rubber issue and WE were overflashing we didn't get started on the right footing.  But almost identical insinuations with other problems we had have kept that relationship very strained.

[ABuffington]

Let's look at 2 things:

How many milli watts of light on the squeegee side during exposure?  This is the area that will break down first.  So what lamp or light is going to have the most power to reach this side of the emulsion?  5k/8k MH or any other lamp of your chosing?  No doubt in my mind and in my observations, the MH 5k and 8k systems expose the squeegee side better.  LED and fluo tubes use shorter distance from emulsion to light to overcome this.  But if you give the exposure enough time to expose the inside of the screen you can wind up with under cutting of details.  Getting an image on the screen is easy.  Getting it fully exposed is another issue and can vary by manufacturer with LED units.  Plastisol?  no problems, Discharge and HSA inks?  Takes a bit of fine tuning of the coating method, opacity of film/image, pushing the time as much as possible and using my emulsion of course.  I sell it cause I have used it with great success in my business.  Just the facts, try it, you'll like it, or I'll help you find the magic if you need it.

Second what is the spectral output of the light?  MH = multi spectral, has all possible wavelengths from white light to 405/420 UV.  Emulsions like multi-spectral light with lots of amplitude.  So a multi spectral LED?  usually this is spill over wavelengths, or spikes in just a few wavelengths, or a single spike with some wavelengths to either side, but so far it isn't the amplitude or multi spectral output that MH provides and emulsions like for complete exposure.  It's not like the sensitizer has changed, it's that the new light has changed and causing failure.  6-9 second exposures?  These are images, for plastisol only.   What I have found is that your old coating techiques can be part of the problem.  While you may have coated 2:2 or 2:3 and achieved good exposure on your MH unit, the same coating may be too thick for the weak LED or fluo light to penetrate the entire emulsion thickness.  The inside is soft.  Any post exposure or hardening is a band aid on a weak exposure.  I have found that coating less can help get stronger exposures.  Try a 1:2 sharp on these systems.  Should still yield 7-10% EOM.    DTS with LED uses stronger light, Film and LED uses a weaker light on the same system since the film and glass cut down the amplitude of the light.  I am still in the Metal Halide camp, especially for large shops.  LED's have significant through put advantages.  Just need to fine tune the process of coating, time.  In most LED exposures the print side is exposed well, the inside can be soft.  Strong film or CTS opaque imagery helps achieve longer times on LED to expose the emulsion.  Try using a little less emulsion, it seems to expose better than 15-20% Eoms.

Bake the Cake, no baker has ever sold bread under cooked.  So why is obtaining the fastest 'cook time' of emulsion so important and like a screen printing merit badge?  I can expose in 9, me? 8? another 6!!! to the point that we hit it with a flash bulb and get a strong screen?  Not possible.  Cook your emulsions up to the point of of overexposure.  It's not how fast you cook it, it's how well you cook it that will give the best results on press, with less breakdown, pinholes and also allows SBQ emulsions to reclaim easier and avoid lock in.  (And for these reasons an MH unit is like a commercial bakers oven and not a small household oven cooking for an entire bakery). Short cut the light energy with lamp choice or time and your exposure will be weaker.  Give emulsion the energy it needs for the right amount of time and the screen will be very durable.

[jvanick]

after having gone through ALL sorts of fun (Alan B can attest to here, I totally agree with the thickness of emulsion playing a MAJOR roll in exposure results.

when we switched from SP1400W back to SP1400 we had a bunch of problems happening, and really couldn't figure out why our results were so different... well it turns out that SP1400 is slightly thinner than SP1400W, so our 1/1 round technique on our 156 and 160S screens was resulting in nearly 30%!!! EOM vs the 17-20% we were getting on SP1400... add to the fact that I was told that SP1400W was a slower exposing emulsion than 1400, we were totally undercooking screens... we've settled back in at around 65-70 seconds on a SP1400 screen to get to 7 solid steps on the stouffer strip, however, even still with 7 or 8 solid steps and 70-80 seconds exposure, if you wipe the back of the screen with a white shirt, you get emulsion color coming off... it's not until you hit 9 or more steps that I'm not seeing the color anymore.

we've got a pretty good running log here that we're recording emulsion, exposure time, eom, stouffer results, coating technique and on-press notes for nearly every screen we burn.

some emulsions we've tested since seem to be far more tolerant of underexposure on press than others, but I can tell you with certainty that 5-10% difference in EOM will result in differing stouffer strip results.

part of me still wonders if it's a color of emulsion situation.. when I have time I'd LOVE to get some undyed emulsions in here and figure out what to dye them with to do my own testing...