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UV Ink Cure lights


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At this point I'm kind of planning to make my own that will be much skinnier, and probably have one on each side of the head.  The one on the right will obviously have to turn off when it's over the capping station.


But, it may have to be water cooled as well, so I'm not sure if I want to take that plunge into complexity yet. 


I also haven't taken my printers apart yet, so I don't know if I make it skinner if it will actually make it easier to install/use or not. 

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I don't think there is room on the right side of the printhead. and on the left it would have to be slim so it doesn't hit the Epson from.


If the lights are cheap I wonder if it would be easier to just do a row of them under the front edge of the printer that is the full width.

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Is 1/4" wide and 1/4" thick still too big for the right side?  (can you tell I haven't opened one up yet? :lol: )


I also thought about a strip under the front edge, but I've read that (depending on your substrate) the ink has to be cured right after it's been printed, otherwise the colors would start to run and bleed into each other. 


That's why most will only do one way printing, since the LED will only fit on one side.  So if there is room on the right for a 1/4" strip, we should be able to print both directions, and cut the printing time in half.


I even saw a commercial printer that flickered the LED to be off when the nozzles were on, so it didn't accidently cure the ink on the head. 

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Good to know. 


Now I'm wondering if a lower wattage LED on the left side of the head to do a "pre-cure", then a strip of higher wattage LEDs on the front edge would be enough to work. 

Not a bad idea. Is there such a thing as over curing the inks? I would assume not since they would get UV light naturally after printed but I don't know, never messed with UV inks.

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I don't think it would be possible to over-cure them.  As long as you're not putting enough heat down to actually bake it :lol:


I think the main concern with too much power is just that you have to find a way to keep the LEDs cool.  So, you want just enough power to cure it, without making a headache to keep cool.  Of course this probably changes with the type of ink, how much ink, substrate, and local weather conditions :lol:

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  • 1 month later...

We got 2 UV DTS based on Eps 4880 (AZON). We got lapns mounted on carriage's left side (aluminium box with 2 fans and radiatior + 2 x 50W UV diodes).

Last month we bought 4 new led chips - old had to be replaced.

Remember that diodes must have spectrum 395 nm.

Silvester

PS look at these:

https://www.aliexpress.com/item/100w-UV-395nm-led-100W-LED-driver-heatsink-Lens-with-Reflector-Collimator/32444680208.html?spm=2114.01010208.3.1.ha5Ty4&ws_ab_test=searchweb0_0,searchweb201602_5_10152_10065_10151_10068_5160015_436_10136_10157_10137_10060_10138_10155_10062_10156_10154_10056_10055_10054_10059_100032_100033_9911_100031_10099_5150018_10103_10102_10096_10147_10052_10053_10050_10107_10142_10051_10171_10084_10083_10080_10082_10081_10110_10111_10112_10113_10114_10181_10037_10183_10182_10185_10078_10079_10073_10070_10123,searchweb201603_16,ppcSwitch_4&btsid=be1c955e-3d88-4bab-bd9e-42ccbbe1e052&algo_expid=689fc1ff-6ee3-4f86-97c0-5987b0e64228-0&algo_pvid=689fc1ff-6ee3-4f86-97c0-5987b0e64228


https://www.aliexpress.com/item/150w-uv-led-module-for-uv-led-light-Uv-Flatbed-Printer-uv-ink-uv-glue-curing/32690411573.html?spm=2114.01010208.3.39.U3bRm6&ws_ab_test=searchweb0_0,searchweb201602_5_10152_10065_10151_10068_5160015_436_10136_10157_10137_10060_10138_10155_10062_10156_10154_10056_10055_10054_10059_100032_100033_100031_10099_5150018_10103_10102_10096_10147_10052_10053_10050_10107_10142_10051_10171_10084_10083_10080_10082_10081_10110_10111_10112_10113_10114_10181_10037_10183_10182_10185_10078_10079_10073_10070_10123,searchweb201603_16,ppcSwitch_4&btsid=74d47f97-2d97-4431-a593-85aa0a69eabf&algo_expid=9b5b4bb9-86f5-4ac2-b737-e1b4eb9b736b-5&algo_pvid=9b5b4bb9-86f5-4ac2-b737-e1b4eb9b736b

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Sylwester,

  Thank you for posting about adding a UV curing light to your printer.  I am in the process of making a UV P600.  Would it be possible for you to post some pictures of how you mounted the UV light?  How long has the printer been running?

  Thank You!

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  • 1 month later...
  • 2 weeks later...

I realize this thread is about UV Ink Cure lights, but I found this somewhat technical article on the various ink formulations. 

https://sdgmag.com/features/uv-cure-ink-technology


And now to bring the post on-topic....


Excerpt from the article:


LED curing systems generate UV light around one peak wavelength, ink formulators have had to search out and employ photoinitiators that optimally stimulate at the same exact wavelength as the one the LED curing system generates. Conversely, LED lamp manufacturers have focused on tuning their systems for wavelengths to match those that will stimulate known and readily available photoinitiators. The following light wavelengths will work with certain photoinitiators: UV-A at 365 nm, 375 nm, 385 nm and 395 nm, and into the visible light range 405 nm and at 415 nm. Ink maker INX International reports that 365 nm wavelengths cure dark colors better than 385 nm, while 385 nm cures light colors better. Equipment manufacturers may eventually include multiple LED types with sets tuned to different wavelengths to match the best chemistry for applications. 


--------------------------


So, to design a DIY UV array, I think you have to begin by choosing the ink, then design (or select) the UV array to match the ink formula's range of photoinitiator wavelengths. 



So the basic design process would be something like:

 

  1. Identify UV cure ink recommended for use with Epson inkjet printers
  2. Based on ink cure specs, design or select an LED array that delivers the required energy, in the required wavelength ranges, during the window of time the array (i.e. print head) spends over the freshly-printed uncured ink.  
  3. Ensure the UV array operates within its recommended thermal operating range. Add cooling as needed.   
  4. Ensure the UV cure ink is kept within recommended temperature. Add cooling as needed.
  5. Ensure UV light does NOT reach the print head nozzles by blocking it with a shield or whatever.
  6. Ensure the additional weight of all this stuff does not impact print head ballistics, stability, accuracy, etc.   
  7. ??
  8. profit!!

:-)


p.s.  I'm a total noob at DTG and UV cure inks, so please excuse if my terminology is derpy, or I'm just blithely stating obvious crap that everybody else already knows.    

Edited by Guest
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The aforementioned ink 2W/cm2 requirement is 1366 lumens per cm2. The ebay 50W unit produces 50-60 lumens, and the area is 0.075cm2 (27.5mm2) giving a flux density of 667-800 lumens per cm2, therefore 2x50W should work, at a cost of $32 each. You might have to push them a little hard at a slightly higher forward current.   Forward voltage is 32V, and current is 1000mA.  Be nice to find a real data sheet for these. 


Will the printer's 42V supply handle the additional 2A load?  I'm thinking probably not.


DC 3-38V 1000mA constant current supply:

http://www.ebay.com/itm/Power-Supply-3W-10W-20W-30W-50W-DC12V-24V-to-DC3-38V-Constant-Current-LED-Driver-/122547078334?var=&hash=item1c886004be:m:mnj1ZT3pZgJhXljPOVQhg7g

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I looked at Digi-Key pricing on UV LED chips (thinking full DIY design) and about fell over when I saw the pricing on the higher power units.  20mA LEDs are fairly cheap, but the physical size limits the overall energy density that is achievable. 

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Response from INX regarding their LE UV ink cure spec.  


I asked:

 

Hello,  I need to develop a UV LED cure lamp for a custom inkjet printer for a client of mine.  Could you provide engineering level specs for your LE UV cure inks that are suitable for inkjet printing. Wavelengths, energy, time, viscosity, shear, etc.  Thanks.

 

The product manager relayed the following from engineering. 

 

1. Wavelength - 365nm, 385nm, 395nm lamps are used.

2. Wattage - 2W to 16W with air cool or water-cool are used.

#1  so should I interpret this as requiring all 3 bands simultaneously?  

#2  Response is meaningless. Was looking for energy units per areal units. Apparently the engineer didn't understand the question posed.  


Based on just this response alone, I wouldn't want to even deal with the company, let alone spec their inks.  


WTF is wrong with business people these days.  SMDH

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