Author Topic: Discharge and Our Vastex LED  (Read 8150 times)

Offline jvanick

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Re: Discharge and Our Vastex LED
« Reply #30 on: October 30, 2015, 06:58:47 PM »
Alan -- what kind of emulsion thicknesses are you guys getting, and how consistent is it?



Offline dirkdiggler

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Re: Discharge and Our Vastex LED
« Reply #31 on: October 30, 2015, 07:11:24 PM »
Richard Greaves will be in my shop all day Monday going over these very issues!  Will post my findings!
If he gets up, we'll all get up, IT'LL BE ANARCHY!-John Bender

Offline brandon

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Re: Discharge and Our Vastex LED
« Reply #32 on: October 30, 2015, 07:16:42 PM »

For comparison, we are now using an entry level SAATI LED unit at 50 second exposure time. Aquasol HV is giving us about 100-200 discharge prints straight out of bucket. If we put it out in the sun, we are getting 500+, even up to 1,000. We are also testing the SAATI PHU and are getting about twice as much on the discharge runs. All of these are without hardener.

pierre

Yup, Saati PHU all the way

Offline Shanarchy

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Re: Discharge and Our Vastex LED
« Reply #33 on: October 30, 2015, 07:16:56 PM »
Different question; what does Vastex have to say about this? They seem to have a pretty good reputation for putting out a solid product. Can they offer you information on why their exposure unit does not work for anything in your shop (one which sounds like you really know what you are doing)?

I went to a trade show a couple years ago intent on buying an LED exposure unit as they just hit the market, I wanted to sell my MSP3140 before it dropped in resale value. A person in this industry (who shall remain nameless) whose opinion on equipment I really respect told me not to. His opinion was all the manufacturers were in such a rush to get their LED to market before/in pace with their competitors that they were still fine tuning and a year later they would more than likely have made a lot of improvements to the product. So I saved my money and have no regrets.

So what this bring me to wonder is you bought the Vastex unit right around when they first came out. Is this an early issue that Vastex has addressed and changed in their unit over the past couple of years? If so it sounds like they should offer a replacement or send the upgraded part(s) for you to swap out. Did you get a lemon from the early batch? If I was in your shoes I'd be looking at Vastex to come up with the solution. You invested your money in their technology as opposed to a competitor's.

I think Vastex is a great company. I'd love to hear their take/resolution on this.

Offline Rockers

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Re: Discharge and Our Vastex LED
« Reply #34 on: October 30, 2015, 09:43:42 PM »
Since buying the Vastex LED we haven't had much need to do any discharge work so I was excited this past week to see 3 new discharge jobs come in but I was apprehensive at the same time with our poor results with most every aspect of our LED unit.  I had this really detailed review of what we've seen, the whole routine we used to make the screens, the emulsions tried, etc, but I just deleted it all and I can sum it all up in one word:  SUCK.  It's my own fault, how in the hell could I have thought that I'd get anything other than poor results?  I still can't believe I thought it would be fine.  So not only can we not produce a good sim process screen above 50lpi, we can't seriously do any waterbased or discharge printing until I jump through so many hoops, do a lot of back flips, hold my finger in the air just right while wearing a tin foil hat, AND PRAY the screen holds up.  I don't like those options.  This shop has steadily progressed over the years into something we're all proud of, and to think that we've had to take a step backwards in our quest to be one of the best doesn't sit right with me.  I know some will think I'm an insane person, that what I'm asking of a piece of equipment isn't reasonable, I need to get over myself and deal with it's capabilities like everyone else because we're not special...I don't see it that way.  Anything less than our best isn't good enough, and over the last year I've tried so hard to keep moving this shop in the right direction and I've finally hit a plateau (actually we've digressed) due to something that did not come with any fine print or disclosures like what we've had to deal with.  It's very bothersome to me.  How could I be the 1st person (that I know of) to have something negative to say publicly about an LED exposure unit?  Were we the first to actually put an exposure calculator on one?  Were we the 1st to fun a few hundred impressions on a screen and have the stencil fail?  Surely not.  Now were we the 1st of active forum members to do those things I asked?   Again, I seriously doubt it.

I can say that if you're seriously looking into this particular LED for your next exposure unit, you still could love the product depending on what you ask it to do.  If you want to do high-end sim process work, it's not for you.  If you want to do virtually any WB or DC work on an auto...probably not for you.  If you use thicker stencils, not for you.  Low mesh counts (thicker stencils)...again, not for you.     

What is it good at?  Doesn't use much energy, the bulbs don't weaken much over time, it doesn't put out much heat, it will do the basic, run of the mill spot color stuff all day long without much problem until you get the screens on press for longer runs, then it really isn't very good at all.

I went further with these DC screens than I thought would be necessary so I wouldn't have to worry much about the screens breaking down on press.  I used a very good water resistant emulsion, a dual cure, tripled the recommended exposure time, blockout, hardener, 10 minute post exposure on the expo unit, sat it out in the sun for an hour, then let them sit for 24 hours before we used them.  The only thing I haven't done with regards to DC screens is test a ton of different emulsions.  I feel confident though since our results were on par with what we're seeing with our plastisol screens and at least 15 different emulsions, I think I'd be wasting my time testing out a bunch of DC emulsions.  And everyone that knows me knows that I didn't just put some emulsion on a screen and shoot them and call it "tested", and to do all of that again for DC ink isn't going to happen any time soon.

Am I out of line to expect this expo unit to be able to consistently produce single digit % halftones of even 50lpi?  What would everyone here expect to be able to get on a standard exposure calculator as far as halftones go?  10% at 65lpi?  5% at 50lpi?  Or am I shooting too high? 

So with ALL of that being said, who wants to buy a used Vastex LED unit?
Totally agree with everything you`ve said. Between not being able to get good sim process screens and extreme undercutting of the image I would not be able to say which is worse. Before we bought the unit we asked the guys at Vastex about exposure times for different emulsions and how halftones hold up, got a .pdf with all the info from Vastex. Based on that we decided to purchase the unit and of course as well the fact that they were able to deliver at the date we needed it while M&R told us they would be 3-4 weeks out before the Starlight could be shipped. In hindsight I really should have waited those 4 weeks and got the better unit instead of wasting a lot of cash on that Vastex tank, build tough but slow as hell.

Offline TCT

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Re: Discharge and Our Vastex LED
« Reply #35 on: October 30, 2015, 09:58:12 PM »
We have tried both the Workhorse led unit and the Saati one, ended up returning both. In Saati's defence the original one they shipped us had a massive hole in it. But neither of them were good. The Workhorse MH 1k unit we had for years worked better.

All ours were on Murakami SP-1400. I refuse to post expose or harden, and I know we probably print with too much pressure in general. So my experiences may be extreme.

We use a MH 5K unit now and don't have issues, it's hard for me to think about switching. Suppose that may change when I need a new bulb though! ;D

The LightSpeed led guy is based up here and is always wanting us to try his, I may have to take him up on it some day and report back!
Alex

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Offline jvanick

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Re: Discharge and Our Vastex LED
« Reply #36 on: October 30, 2015, 10:08:48 PM »
I will tell you that I'm having issues with the starlight exposing Saati PHU-2 emulsion.  The guys from Saati are involved and I'll be testing their 300w light next week.

I believe that part of our issue is that we've been getting almost 40% EOM and that it just may be too thick for the starlight to completely penetrate without over cooking the shirt side of the screen.  I've got a batch of screens that are more around 18-20% EOM that we'll be trying next week as well to see if that's it.

But, between the edge breakdown issues as well as the emulsion softening on longish discharge runs even when exposed to a 7+ on the stouffer strip, I'm not super happy right now.  (This is following all the steps and instructions from Saati)

I can say that halftone detail has been awesome, and that for plastisol jobs, I'd likely be perfectly happy...

SP1400 and the Starlight is not a fun combination... in order to get solid 7's, we were exposing at nearly 2 minutes!

Offline dirkdiggler

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Re: Discharge and Our Vastex LED
« Reply #37 on: October 30, 2015, 10:26:51 PM »
I didn't like phu2 or sp1400 with my starlight, to many issues.  Right now for us, CCI DC plus is giving best results with the starlight.  This may change Monday after I spend the day with Richard Greaves.
If he gets up, we'll all get up, IT'LL BE ANARCHY!-John Bender

Offline Binkspot

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Re: Discharge and Our Vastex LED
« Reply #38 on: October 31, 2015, 07:08:31 AM »
Just some general LED thoughts and opinions. I believe LED is the wave of the future but just not there yet.
LED UV spectrum is a narrow band width. So if your emulsion exposes best at 390nm and the LED puts out 400-420 your not in an optimal UV range.
The LED units expose the bottom layer of emulsion so quickly it may block some of the UV energy from reaching the ink side of the screen acting like a UV filter causing a under exposed condition through the rest of the emulsion.
I do not think LED has for lack of better words enough ass to fully penetrate a thick coating of emulsion.
Eventually I think emulsion mfg will narrow the optimal exposure band with to match a LED standard band width.

Offline jvanick

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Re: Discharge and Our Vastex LED
« Reply #39 on: October 31, 2015, 09:22:03 AM »
Brian nailed it on the emulsion / wavelength sensitivity.

This is one reason why I'm excited to test out Saati's light next week.  They claim their SBQ's are most sensitive at 405nm, and that's what their light is tuned to.

I'm pretty sure there won't be an 'optimal' 'standard' bandwidth for quite some time (if ever). 

Another thought that I had is that ALL led sources are a compromise... in order to expose both SBQ's and Diazo emulsions, the manufacturers have to engineer the wavelength so it sits right in the middle.  My bet is that if I put a diazo screen in front of a 405 nm light source, it would take forever to expose (and probably not expose all the way)... same with a SBQ in front of a 360nm light source.   

A dual wavelength LED unit of say 360/405 seems like it could be perfect (no idea how to engineer that).

Dirk: What kind of exposure times are you running for the CCI DC plus?  -AND- how is the reclaim?  We moved away from Dual Cures due to the hard(er) reclaim than the SBQs.

Alan: When calling Vastex, what do they say that the UV wavelength is of their LED's..

Anybody know what kind of unit we may be able to find to test the ACTUAL wavelength of light being generated from these units?  I'd love to get one and bring it to ISS and do some real testing.

Offline dirkdiggler

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Re: Discharge and Our Vastex LED
« Reply #40 on: October 31, 2015, 09:30:20 AM »
CCI DC Plus 55 sec. on the Starlight, SUPER easy reclaim, CCI micro wash in my dip tank.
If he gets up, we'll all get up, IT'LL BE ANARCHY!-John Bender

Offline ericheartsu

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Re: Discharge and Our Vastex LED
« Reply #41 on: October 31, 2015, 12:03:17 PM »
in case anyone is wondering i've been apart of an email thread about LED and PHU2, with a shop in Chicago, and a couple people from Saati. It's way over my head, but i'll share the details.

I'm not sure what wavelength the STEII/Starlight is, but i do know, we have virtually no screen breakdowns in the shop anymore, with HSA or DC. Here is what they've suggested for PHU 2, adding a Diazo:

Regarding Diazo 11, it's main function is just to sharpen the image detail, as an 'anti-halation additive'.  It's a very light dose of diazo and doesn't contribute a whole lot to cross-linking for added durability.  That said, the sharpening effect does allow for longer exposure without closing out fine details.  The longer exposure results in more curing and thus better durability (encapsulation).  We normally don't recommend adding diazo to SBQ, but for multi-point, or scanning bar, exposure systems that kill resolution it becomes necessary to ensure that finest details can be reproduced in the stencil.  Diazo is more tolerant of light wavelength than SBQ but in any case 405nm is best choice for both.  395nm is ok, but 365nm (UV) is a bust.
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Offline 244

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Re: Discharge and Our Vastex LED
« Reply #42 on: October 31, 2015, 01:10:30 PM »
I will tell you that I'm having issues with the starlight exposing Saati PHU-2 emulsion.  The guys from Saati are involved and I'll be testing their 300w light next week.

I believe that part of our issue is that we've been getting almost 40% EOM and that it just may be too thick for the starlight to completely penetrate without over cooking the shirt side of the screen.  I've got a batch of screens that are more around 18-20% EOM that we'll be trying next week as well to see if that's it.

But, between the edge breakdown issues as well as the emulsion softening on longish discharge runs even when exposed to a 7+ on the stouffer strip, I'm not super happy right now.  (This is following all the steps and instructions from Saati)

I can say that halftone detail has been awesome, and that for plastisol jobs, I'd likely be perfectly happy...

SP1400 and the Starlight is not a fun combination... in order to get solid 7's, we were exposing at nearly 2 minutes!
there are a ton of very good emulsions that work extremely well with the Starlight and provide exceptional screens both in durability and halftones. You are close by. Take the time to see the options in Niles or check with our technical staff.
Rich Hoffman

Offline TCT

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Re: Discharge and Our Vastex LED
« Reply #43 on: October 31, 2015, 06:14:41 PM »



A dual wavelength LED unit of say 360/405 seems like it could be perfect (no idea how to engineer that).


That's what the LightSpeed unit has a patent on from what I understand.
Alex

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Offline Dottonedan

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Re: Discharge and Our Vastex LED
« Reply #44 on: November 01, 2015, 12:43:43 AM »
I never claim to be an expert in emulsion and I can't give any educated information on the wavelength on others or even ours in great detail that would explain any differences. I can only say that the proof is in the pudding. The largest I know of for a fact is 50k while I was there. Another shop does nothing but larger orders of 5k to 30k regularly using LED and dual cure.  I personally have customers using dual cure that do the following,

A, Holds great detail. 7pt times roman (serif font) on 305 mesh for example. 55-65lpi easily down to 3% dots. I haven't looked at edge definition under a high powered mag but the printed results seem able to win awards.

B, Holds long term production runs of 50,000 units in one run with no screen breakdown.

How you get to B, may require a different recipe for different emulsions. Maybe not all dual cures will be able to yield 50k shirts without breaking down but I can tell you it is a fact that there are emulsions out in the market that are doing this. For many shops "is it fully cured?" is not an issue. For anyone having any kind of issues, I would look at the recipe,

Thickness aka EOM. As with any case of curing stencils, there is an optimum EOM ratio (for each mesh) provided by the emulsion manufacturers. Use them. Most overlook this as inconsequential.

Dryness of the emulsion. Have enough screens that you are not starving for dried screens and may use them before they are fully dried.ftp://

So to me there is no question that LED can be well above just "good enough" but it may be true that even the best on the market is not (as strong) as a 5-10k MH. Does it need to be? I say obviously not. It's more than capable of handling everythibg we need it to do.
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