screen printing > DIY - From master engineered marvels to cobbled together jury-rigged or Jerry-built junk!
My DIY LED "Expansion" Board
blue moon:
--- Quote from: IntegrityShirts on June 18, 2014, 08:13:54 AM ---
--- Quote from: abchung on June 18, 2014, 07:03:15 AM ---That is so cool.
What is your LPI in the photo?
Unbelievable.
--- End quote ---
That's the 65LPI row of the kiwo exposure calculator.
Thanks Pierre. It could be better in a Version 2. I was hoping for Starlight level results, but in the end it's about the same as my 5k Olec. UV meter is probably not a bad idea. If it were accurate enough to see if my row spacing is correct. Still thinking a lower UV range LED might be the ticket to a hotter exposure. Or maybe even a blend of two different UV range strips in an alternating row setup.
I think I'm at about $250 investment. The goal here, worst case, was to have a usable backup in case the 5k Olec breaks. Best case it would replace the Olec. Right now I'm using it for all screens and will continue to play with timing and see how the screens hold up to waterbased with the SP1400 and no other treatment/hardeners. I don't typically do long run WB/discharge, largest is around 250 pieces coming up next week, but I'll give it a go and should at least be able to see some break down or softness at the end if it's a bad exposure.
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most LEDs come with a 120 degree lens. Assuming light distribution is conical round rather than elliptical, spacing between the rows should match the spacing between the elements on the strips. Otherwise you'd have hot spots. With a meter you should be able to change the distance up and down until you get even light readings. If you are hot above the LED the glass needs to be further and if you are hot between the element move the glass closer.
here's a nice timer for anybody looking to try building one of these:
http://www.auberins.com/index.php?main_page=product_info&cPath=16&products_id=368
(sorry, just found this last night)
I think alternating strips of different wavelengths would introduce the effects similar to hot spots as you would have different penetrating and crosslinking ability between the strips. It might be worth contacting a manufacturer in China and asking them to make strips with three different wavelengths on them (5050 strips have LEDs with three sources in each LED and can be made with RGB so it might be possible to put three different wavelengths in each unit. The problem is, all the lower nm LEDs I've seen are significantly lower Wattage than the 395-405nm).
from what I can tell, PhotoPolymer emulsions are really liking 340 or so for exposure, so chances are your times would be significantly lower with lower wavelength. See chart from Ulano below:
pierre
jvanick:
those are some awesome results... very impressed... kinda glad I didn't see this before I bought our new unit here, as i'm happy to have at least one part of the shop that i'm not continually tinkering with. :)
I highly doubt that we'll see any price reduction in the LED units for a while.. heck, the Starlight 2331 costs less than a 3140 MH unit...
I was under the impression that M&R did testing to understand the light diffusion pattern from the led strips and then matched the height of the glass so that it was perfect coverage with as minimal of undercutting as you can get having multiple lights.
I can tell you that looking at the strips on our uniit, there's a perfect square between each and every 4 lights...
TCT:
Now keep in mind, your hero status with me is good for a period of 1 week. That being said, in my most intelligent and influential Pierre voice/post- "it would be nearly impossible and unlikely someone could make a D.I.Y. DTS unit." Now some may call that a challenge.....:D;)
inkman996:
--- Quote from: TCT on June 18, 2014, 09:09:10 AM ---Now keep in mind, your hero status with me is good for a period of 1 week. That being said, in my most intelligent and influential Pierre voice/post- "it would be nearly impossible and unlikely someone could make a D.I.Y. DTS unit." Now some may call that a challenge.....:D;)
--- End quote ---
In the first couple years of DTG the same challenge was issued and many "experts" explained why it was impossible for a DIY DTG. Sure enough people started making them and some were pretty decent to boot.
blue moon:
--- Quote from: Inkman996 on June 18, 2014, 09:28:59 AM ---
--- Quote from: TCT on June 18, 2014, 09:09:10 AM ---Now keep in mind, your hero status with me is good for a period of 1 week. That being said, in my most intelligent and influential Pierre voice/post- "it would be nearly impossible and unlikely someone could make a D.I.Y. DTS unit." Now some may call that a challenge.....:D;)
--- End quote ---
In the first couple years of DTG the same challenge was issued and many "experts" explained why it was impossible for a DIY DTG. Sure enough people started making them and some were pretty decent to boot.
--- End quote ---
just for the record, I am not an expert (hell, 99% of the ppl here have more printing experience than I do) and I did not say it could not be done, just that I would not recommend it (due to proper light alignment being so critical). UV light meter turns out to be a lot cheaper than expected and easier to get. It will still take patience, steady hand and some basic geometry to get it done right. My assumption is that most ppl would just put the strips down and consider it done which can lead to some rather big problems. Unit done here is only few hours away from being a top notch solution.
Here's the link to the UV meter I picked up:
http://www.ebay.com/sch/i.html?_sacat=0&_from=R40&_sop=15&_nkw=UV513AB&rt=nc&LH_BIN=1
pierre
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