TSB
screen printing => Screen Making => Topic started by: ZooCity on January 08, 2014, 01:16:43 PM
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Is this do-able?
We're testing new emulsions and it looks like the winner is going to be a diazo with a lovely 450 ltu expo time on our AL-53 5k watt halide. We shoot 2up which is part of the longer time of course and testing was done with an Olec brand L1250 lamp.
We just so happen to have a complete 2nd AL-53 setup as a backup. Assuming the reflectors in each unit were the same and photocells were calibrated to each other it seems like it could be an option. My concerns are the light rays crossing over and scattering the actnic light and if you can even run two units off one integrator (could also use two integrators and press the button together I guess). We use an AI 970 integrator.
Just a shot in the dark, we probably need to sell both units and upgrade to more firepower at some point but making a 10kw franken-expo unit out of what's on hand would be kinda rad.
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The trick would be getting them close together.
I bet if they were right next to each other it would burn well because of minimal parallax error, but overheat because half their venting is covered.
There's a lamp head for two al-53/54/56/whatevers. (LT100?) Seen a few go on Ebay for cheap...
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That's a great idea! I saw in my Olec manual that the Al 100 lamphead appears to be setup by daisychaining two 5kw power units. Gonna look into this, thanks Foo.
Also, may be able to work something out by wiring some kind of junction for those DIN cables where it's sending a duplicate signal out, one power and one lamp/shutter to each unit. In the diagram I have for Al 100 it appears that they used a simple Y cable to mirror the signal form the integrator out to each power supply. Seems doable for the lampheads if that's the case ...maybe something like one lamphead runs off the photocell and the other is a slave.
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http://www.ebay.com/itm/OLEC-PRINTING-EXPOSURE-LIGHT-SYSTEM-MAX-2X500W-/261113675044?pt=LH_DefaultDomain_0&hash=item3ccb967d24 (http://www.ebay.com/itm/OLEC-PRINTING-EXPOSURE-LIGHT-SYSTEM-MAX-2X500W-/261113675044?pt=LH_DefaultDomain_0&hash=item3ccb967d24)
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It looks like maybe the 10kw olec is just 2 5kw bulbs nested in front of one reflector. Makes sense since I couldn't find a 10kw bulb.
http://forums.screenprinters.net/viewad/19/75185 (http://forums.screenprinters.net/viewad/19/75185)
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You can also do it the way that douthitt does for it's bigger units.
(http://i.imgur.com/56jJ7KM.jpg)
I think the trick is to not have any overlap, or maybe just the right amount. That way, you could bring the unit closer to the frame and still cover the needed area and slice time off with the inverse square law.
I would think that if you didn't have them as close together as the 10kW unit, it would effectively reduce the amount of uniform radiation. This could probably be overcome if the lampheads are angled in such a way to overlap better than having them face the frame straight forward.
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Is this do-able?
We're testing new emulsions and it looks like the winner is going to be a diazo with a lovely 450 ltu expo time on our AL-53 5k watt halide. We shoot 2up which is part of the longer time of course and testing was done with an Olec brand L1250 lamp.
We just so happen to have a complete 2nd AL-53 setup as a backup. Assuming the reflectors in each unit were the same and photocells were calibrated to each other it seems like it could be an option. My concerns are the light rays crossing over and scattering the actnic light and if you can even run two units off one integrator (could also use two integrators and press the button together I guess). We use an AI 970 integrator.
Just a shot in the dark, we probably need to sell both units and upgrade to more firepower at some point but making a 10kw franken-expo unit out of what's on hand would be kinda rad.
Keep in mind.... you're talking about doubling the size of the branch circuit wiring supplying this unit.
You'd need to have a minimum of 50 amps (at 240 volts).
-or- two 30 amp circuits.
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Yeah Stu, I think that's the rub, getting the two standard reflectors setup to shoot as one standard and not introduce a ton of diffuse light which would be self defeating- faster expo, less detail. I'd definitely prefer to use the double bulb lamp head but those are probably a little hard to find.
Northland, that's correct. Each AL-53/100 power supply has it's own plug so there'd be two outlets on a 60a circuit. Thanks for bringing that up though! We're moving so I'll be sure to size up that wire and the raceway.
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Talked to Douthitt. The double whammy bulb lamp head is obsolete b/c they've come out with a super wide angle reflector. It's abt $300 and comes with some replacement bulb mounts/contacts. The idea is we would go from shooting at ≈55" to ≈33" away from glass for 23x31 2up. Knocks down the effects of the inverse square and knocks down the expo time without using more juice. Probably the way we'll go ultimately.
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I don't know how new these "super wide" angle reflectors but I remember a few years back when Nick (FT Embroidery here, I believe) was very surprised to find that his head unit was designed to be something like 70% of the diagonal distance rather than the 150% rule of thumb standard.
The head units are marked with what reflector was initially installed.
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Yep, I have the original manual for the Olec and it has a table for the different reflectors and the multiplier of the diagonal. Both our units are standard unfortunately.
Another fun fact: the reflectors can wear over time and become more and more refractive v. reflective as they dull. Not sure if that's a sales pitch or a bona fide fact though.
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Another fun fact: the reflectors can wear over time and become more and more refractive v. reflective as they dull. Not sure if that's a sales pitch or a bona fide fact though.
Fact.
They don't wear out, they oxidize. Removing it and carefully polishing it to remove the oxidized layer would restore it to it's full reflective glory.