DIY LED exposure unit update....

[Northland]

I'd like to update some content about DYI LED exposure units I posted about 2 years ago.

First:
-I don't sell these
-I don't think this unit functions well with Dual Cure (I've switched to Chromolime pp emulsion)
-I suspect halftone dot exposure is restricted to modest parameters (maybe 20% to 80%)
-I acknowledge this design modification probably only makes sense for a user looking to upgrade from a Blacklight fluorescent unit

Second:
-I did backtrack and replace 50% of the LED strips I originally installed (due to poor LED quality, which can be seen in the video as dimmer output)
-I raised the LED mounting to 2" below the glass
-The unit has instant start-up and uses about 300 watts of power and modification would cost about $200 in materials (EBAY)
- It works great for my business (mostly 1-3 spot color designs, with limited halftone requirements)

The unit now operates as follows:
225 S mesh exposes at 12 seconds  (180 at 13 seconds, 150 at 14 seconds)
Shorter exposure time is possible but hampers reclaim

https://www.youtube.com/watch?v=RQTXNp4U6pE&feature=youtu.be

[Prōdigium]

The unit now operates as follows:
225 S mesh exposes at 12 seconds  (180 at 13 seconds, 150 at 14 seconds)
Shorter exposure time is possible but hampers reclaim

Seems fine to me, why would you need any faster exposure when it most likely takes 3 times that long to simply draw the vacuum blanket down...lol

Curious as to what your LED's are in watts per meter? Usually rated when you bought them. I have found some here in China that are rated @ 24 Watts per meter...which is not too bad.

[Northland]

This is the supplier I last purchased from:
http://www.ebay.com/itm/10M-2X-5M-5050-UV-LED-Strip-Ultra-Violet-Light-395-405nm-300Leds-NP-DC12V-/321496786580?hash=item4adab3a694:g:M0gAAOSw8lBTrUxe

Theses are 5 meter strips with 60 LED's per meter. I have a total of 30 meters (1800 diodes) and last time I checked it was running a little less than 300 watts.... which would be 10 watts/meter.

[Prōdigium]

Still respectable exposure times given that 10 watts per meter gives each LED only about 0.16 watts each....pretty weak actually.

Whats interesting is that you think it does NOT work well with a dual cure, which should react well to 395nm. PP emulsions actually prefer ranges in the 360~390 range...at least according to an industry expert.

[Orion]

Whats interesting is that you think it does NOT work well with a dual cure, which should react well to 395nm. PP emulsions actually prefer ranges in the 360~390 range...at least according to an industry expert.

This does not seem to be what I recall as the correct spectrums for those two emulsion types. I'll have to come back later and provide the data to prove it. Seems backwards to me.

[Prōdigium]

Yep, I thought the same until a few months ago. Its easy to get confused about it, when you consider reaction vs sensitivity.

Its all here... http://www.screenweb.com/content/taking-control-screen-exposure#.V5J31aIl2Q8