My Thoughts on Our Vastex LED

[alan802]

As I mentioned on another thread yesterday, a few weeks ago we were somewhat forced to make a change with our exposure system.  I'll start by pasting what I wrote yesterday and then go into some additional details on various things.

From the other thread Our Richmond finally bit the dust a few weeks ago when our control panel buttons stopped working.  I knew it was coming but was hoping to get as much out of it as possible and usually when the buttons stopped firing they would only fail for 15 minutes to an hour or so at a time and then would suddenly start working again.  I'll save many of the details for my thread but I knew Kevin at River City had the big Vastex unit and although my research had told me the Starlight was probably the best unit on the market we pulled the trigger on the Vastex.  I won't get into the argument on who makes the best units or who uses the best bulbs but on my thread I'll lay all the facts of our experience with the Vastex, good and bad.  The good far outweighs the bad but it's worth noting everything so that people can use that info to make better decisions. 

I've tried like hell to compare the detail between our old MH and new LED unit and after looking at dozens of stencils at 60X magnification I can say that our MH gives slightly better detail but honestly it's so damn close that depending on my mood I could go either way on the winner and because I don't like ambiguity in this type of comparison I declare the 10K MH unit the winner.   

Our times are slightly faster than a new MH bulb and the best part is it will always stay at this speed.  I wish the control panel was a little more technologically advanced than it is but oh well, it is what it is and it works fine.  My sausage fingers have a tough time setting the correct times and I have to use what little of a fingernail I have to set the time because no way my finger is going to press that button without touching both buttons on either side of the one I want to push. 

I've ran a few hundred screens with HVP and 75-100 of the SP1400 and I much prefer the pure photopolymer because it's extremely fast and the 1400 is not, 40-75 seconds for the 1400 versus 6-20 seconds with the HVP.  I shot a 120/54 with a decent stencil yesterday at 15 seconds and it showed no signs of underexposure.  It was much easier to get underexposed screens with the 1400 and overall I didn't like it versus the HVP and I think we'll stick with the PP emulsions from here on out.  Reclaiming is also much faster with the HVP and it's very noticeable. 

So I'm still testing all mesh counts and right now I'm down to 14 seconds on a 120/54 mesh count coated with the glisten method which is a 1/1 for us with the HVP.  6 seconds on a 305 glisten which is a 2/1 with HVP.  Now, with an emulsion like SP1400 exposure times are a little longer than I expected ranging from 40 seconds on a 305 to about 75 seconds on a regular 110 but a little faster for our thin thread lower mesh counts, 65 seconds or so.  But with the 1400, I wouldn't consider any of those examples as fully cooked, but enough for plastisol.  I've used the Chromaline exposure calculator and then a sample film from the Oyo Techstyler with perfect halftones and great d-min and d-max and as I said in my previous post the detail I've been getting is more than good enough for any shop and I think with some fine-tuning and the right emulsion you can hold anything that a 10K metal halide can hold, or at least a hair under.  I think my doubts about the ability to hold fine detail have been settled and at least for the Vastex unit they seem to have nailed the distance between and from the screen and have a solid performing bulb.  Now is it comparable to the competition?  If you look at the bottom line I'd say it's close.  I've seen a few examples of LED users getting single digit exposures and I'd have to go back and look up all those threads to see what the fastest exposure claim has been but I think I remember a few starlight users saying 6-10 seconds or there about.

Ok, now I'm down to really the only thing I dislike about our unit, and that is vacuum drawdown time.  I looked back at some of the other reviews of other expo units and saw 10 second and less drawdown times.  Our Richmond would draw in about 12-15 seconds when it didn't have holes and I'd love to see a 15 second drawdown with the Vastex.  Right now, I'm at about 35 seconds for a safe time to start exposing but for a fully wrapped screen, 100% drawdown it's closer to 45-50 seconds for two screens.  One screen draws down slightly faster than two and with no screens in the unit it draws down in about 5 seconds.  I thought that maybe when the blanket gets stretched a little bit it would get faster but I haven't noticed much yet.  I have cleaned the areas of contact to make sure there are no obstructions but other than that I haven't tried to troubleshoot it or ask Vastex if that's normal.  I think the expo times are amazing, but I think the vacuum is twice as long as it should be.  Ours is the larger unit with two vacuum motors.  Our Richmond had one motor and it has more volume to draw and it is twice as fast.  10 second exposures are awesome but we're taking a step in the wrong direction with the vacuum time. 

Overall I give the Vastex unit a very high grade and exposure times seem to be very competitive with the other brands so I feel like the quality of the LED's is definitely there.  Had we had more time to make this decision I don't know that I would have made a different one with the fact that Kevin had it in stock and I like to spend our money with them.  I'll continue to gather info on the other LED's and keep on building a nice package of info on our Vastex unit for those that are interested.  Once we get more experience with different emulsions and burn times I'll post those on this thread and any time I get new info on our unit I'll post it here on this thread.

I know I missed a few things on this review and I'll post those as they come to me.  I started typing this thread on Friday morning and with all the stuff we got going on around here I finally got a chance to finish it this morning.  Questions and comments are of course welcomed and encouraged. 

[blue moon]

thanx for the info, I'll throw in a few thoughts as we had a chance to play with the Vastex too.
Vastex did upgrade the motor and it seems you have the earlier version with slower vacuum time.
Also we were doing the 305's with glisten method at 6 seconds, but eventually found out it was not long enough (HV rather than HVP though). In the end we settled on 13 seconds for everything from 110-305.
Last time I talked to Mark (Vastex) he said they upgraded the vacuum, changed the spacing on the LEDs and upgraded the control panel.
Light distribution wise Vastex had a very slight edge over the Starlight. MH unit we use (3140) was holding about 1-2% smaller dot (which could be addressed in the linearization).

pierre

[Sbrem]

Thanks Alan and Pierre, we're pretty much looking at adding this in the spring, and the info really helps a lot.

Steve

[Prosperi-Tees]

Got me thinking about switching to HVP. Anyone know the vacuum time for the single screen 2331 Vastex unit?

[blue moon]

Got me thinking about switching to HVP. Anyone know the vacuum time for the single screen 2331 Vastex unit?

from what I remember, Mark said it was around 10-15 seconds now (with the new pump).

pierre

[alan802]

It would be nice to have the newer pumps.  Maybe I'll jack the one out of the Richmond and put it in and see that that makes a difference.  I don't know if I can live with 30 second vacuum times when I know there is something that can be done about it. 

[ABuffington]

One reason for slow SP-1400 times is 1400 likes a 360 nanometer wavelength while HVP likes the 390-420 that is typical of LED units.  HVP would have better results for time and strength for wb and discharge.  This is why we are interested in Multi-spectral output, some emulsions shoot a little better if there is a spike in the wavelength they use.
Still the new LED's are working well in our test shops on either emulsion and who can complain about the savings in energy as well as lamp life?

[Rockers]

We just installed the Vastex E-2000 4131 yesterday. Will do some screens today and then report our findings.

[Admiral]

Interesting info on the SP-1400, I might have to find a new diazo emulsion for water based printing.

We just installed a Starlight I believe on Monday (I was on vacation until Tuesday) and I dialed in for the most part Ulano Orange emulsion on 110-160 mesh counts.  6 seconds on the 160, up to 9 on the 110 (might be able to go even lower).  Still getting the auto coater settings better then will really try to dial in the exposure times.

These LED exposure units really are awesome, an upgrade that will easily earn a fast ROI.

[ABuffington]

SP-1400 still exposes well on the Starlight, all diazo reacts to similar wavelengths as mentioned.  The starlight in our light meter tests showed wavelengths on the all important light wavelengths.  Our tests on the Starlight show excellent results for SP-1400.  We are in test process on the other light units, but initial results look good for all of them.

Alan

[alan802]

I shot 2 120/54's today at 10 seconds today and they were great.  Maybe not good enough for waterbase or discharge but for plastisol they were just fine.  There was no slime on the squeegee side and it passed all the normal physical tests for proper exposure.  I didn't run these with the expo calculator but I'll see if I can do that at some point in the future.

[alan802]

I wanted to revisit this topic because with most major purchases there is a honeymoon phase and after a few months of use you have a much better feel for how good or bad something is versus after the first few days.  It takes a while sometimes for good and bad things to surface and in the case of our LED unit, unfortunately there hasn't been any good surprises, only bad ones. 

My only concern in my initial review was drawdown time.  I've tried a few things to help it and nothing has worked, it's actually gotten worse.  We're at 35 seconds for a drawdown that's tight enough to expose, but to get a fully locked down screen with just one screen in is about 45 seconds.  Having 2 screens on the unit means drawdown time is over a minute long.  I am not going to lie, I don't like that at all and it makes me wonder if they even beta tested this unit AT ALL before manufacturing them.  None of us are engineers but let's see a show of hands from anyone who would have tested an exposure unit and would have been ok with such long vacuum drawdown times?  Now before I go any further, I've looked at every nook and cranny of this thing and looked for areas that would hurt the vacuum and I've even put on a layer of rubber around the edges of the lid to help with sealing the air so there are no leaks to speak of.  There is some dry-rot in a few areas of the blanket but I can't see any air moving through those areas.  The only other thing I can think of that might affect the vacuum is maybe I don't have enough power coming to the unit.  So I got rid of the extension cord and have plugged it directly into a 110 outlet and it did feel like there was a difference, but only minor.  When making the change to LED I wanted to get ALL of the benefits and with the long vacuum drawdown times, I can't get over the fact that for every screen we expose, I'm leaving about 25-45 seconds on the table that I shouldn't be losing.

Now let's get to the most important part of this more in depth review, actual exposure.  It's good, almost great, but this unit does not penetrate the entire layer of HVP (and other pure photopolymer) emulsions as thoroughly as our MH unit did, even with an old worn out bulb.  It does expose slightly faster now that we've adjusted our burn times than the MH did, according to the exposure calculator.  But here's the problem.  According to the calculator, for example, we can shoot our 150/48's at 18 seconds and there are essentially no physical signs of underexposure.  But on press we see the problem with underexposure.  The same squeegees we've been using for long before we got the LED are now wearing down the emulsion on the edges like most all of us have seen at some point in our screen printing careers.  So after the first week with the LED we were burning at these times:
120/54=20 seconds
150/48=16 seconds
180/48=14 seconds
225/40=11 seconds
280 & 305= 8 seconds
When we saw the emulsion breakdown I simply doubled expo times across the board and then figured we could back off those times slowly and within a few weeks we'd be dialed in.  Well, fast forward to today, we're still getting emulsion breakdown and I'm going to bump everything up another 30%.  But that's going to put us up to burn times that are longer than what we were dealing with on the old MH bulb and nowhere near as good as a fresh MH bulb.  According to all the rules/signs/calculator we're overexposing everything yet it seems like there is incomplete crosslinking which leads me to believe the effectiveness of the bulbs in our unit aren't as good as advertised.  I wonder if these bulbs are the same ones being used in the new units being built.  I know they have upgraded the vacuum system which tells me there was definitely room for improvement in Vastex's mind and they obviously addressed it.

I'm not opposed to trying new emulsions and working on getting a more thorough exposure and overall I'm still on the LED bandwagon.  It's still better than MH but I think that the issues we've had are not exclusive to us but maybe they are exclusive to the first dozen or so Vastex units that were made.  Maybe there are better diodes being used on the new units and those that are from different manufacturers, I don't have that information and I don't have those other units to test side by side with the Vastex.  I know that each manufacturer claims they use better LED's than the competition and as much as I'd like to test those claims I can't go out and buy the Starlight or Anatol or Workhorse so I have to go with what I know.  And it's easy for us to get a new toy and hype it as the greatest thing ever, it happens on every forum and it's human nature.  But I'll go ahead and say that the distance between a strong MH unit and the new LED's isn't as far apart as it may seem.

I still give the Vastex unit a high grade, but like our gone-but-not-forgotten V2000HD manual press, there are some shortcomings that seem to me to be EASILY fixed and should have never been an issue at all.  No manufacturer is perfect, but I just wonder how something that seems so easy (I'm no engineer but vacuum drawdown for expo units isn't a terribly complicated thing) could have been overlooked or perhaps deemed acceptable on any number of pieces built.  Either one of those scenarios puzzles me.

I doubt this will be the last review I do for this piece of equipment but for now it will do.  After re-reading this post it does come off as a negative overall experience with this unit, but that's not exactly right.  I would still take this LED over our old MH unit, but I just want to tap the brakes on the notion that LED is THAT much better than a high level MH unit.  It doesn't change the fact that many shops that have bought new LED's have experienced far better/faster results versus their previous expo unit but unfortunately we haven't had that big of an upgrade.  It's an upgrade though, just not as much as originally thought and compared to what others have gotten.

[Dottonedan]

I haven't looked at their product but my take on it from what you've posted is that it's a good product for the small shop.


In a nut shell, it's a good product for many and I'm sure the price range reflects the quality you get. After all, if it were THE BEST at every test, under every scenario, with every emulsion, with the fastest speeds, then it might be a little more pricey and marketed to the bigger more high end shops. Excuse my ignorance on price but I'd expect it t be designed for sale in the small or new shop market offering decent to good quality with some sacrifices to make it cost efficient for that market. Comparably, to other starter items for new shops, it may be very cost effective with improved quality and speed compared to other older options. Thats from the outside looking in at your educated post.

[blue moon]

few quick thoughts. . .

Vastex adjusted the LED configuration to address the edge breakdown which should not be an issue with the newer units. Early units had a slightly smaller sweet spot and you could potentially under expose the edges of the screen. They rearranged the lights to have better coverage.

As I understand at this point, the LEDs have penetrating power equivalent to a 1kW MH so they are definitely usable, but the 5kW MH (which is what I think you had before) will have more power to penetrate to the other side. This is not related to the number of LEDs, but rather to their power rating.

As you already mentioned, the vacuum has been upgraded too and they mentioned nicer controls (not sure if that was done or not).

To ppl with 5kW or higher units, I have been advising to stick with what they have unless they are looking for the savings in electricity and bulb expenses. Until the power of the individual bulbs gets higher, MH is a better choice for HIGH END WORK (0.1% of the work out there). For the rest of us, LEDs are a better choice.

Between the M&R and Vastex, I give the Vastex a very slight edge. They both have their pluses and minuses, but from what I have seen, Vastex holds a razor thin lead. I should be taking the readings on the Anatol unit this weekend in Long Beach and can confirm or dispute the quality of the light field upon return.

pierre

[blue moon]

I haven't looked at their product but my take on it from what you've posted is that it's a good product for the small shop.


In a nut shell, it's a good product for many and I'm sure the price range reflects the quality you get. After all, if it were THE BEST at every test, under every scenario, with every emulsion, with the fastest speeds, then it might be a little more pricey and marketed to the bigger more high end shops. Excuse my ignorance on price but I'd expect it t be designed for sale in the small or new shop market offering decent to good quality with some sacrifices to make it cost efficient for that market. Comparably, to other starter items for new shops, it may be very cost effective with improved quality and speed compared to other older options. Thats from the outside looking in at your educated post.

Vastex uses less LEDs to generate the price savings. This translates in longer times than the Starlight by several orders of magnitude. The build quality is pretty good, it's on par with M&R from what I've seen. Starlight has an edge in the controls and the lid, Vastex has heavier duty construction (more robust, I mean earthquake proof solid!).

pierre