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LCD Based SLA Resin Printer

Discussion in '3D printers' started by evilc66, May 3, 2016.

  1. Oneminde

    Oneminde New
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    Note, UV leds are roughly 50 % efficient, so the 3W successfully converts 3W into 1.5W in lumens energy, which mean that the 3W LED is 54 brighter.
     
  2. evilc66

    evilc66 Journeyman
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    That's probably true for the higher end LEDs, but the junk out of China is more likely around 35-40%. LEDengin has one of the better 365nm LEDs, they only hit 50% efficiency in their top most bin. The only advantage of using the cheaper, less efficient LEDs is that the cost per milliwatt of output is far lower, so you can just brute force it. For the same number of LEDs from LEDengin, it would have cost me over $2K
     
  3. Oneminde

    Oneminde New
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    I understand the cost of things, but are you not happy with the output math I handed you :D

    Also, if the diffusers are in place, why not use fluorescent tubes instead of LED's ? underneath and in close proximity to one another similar to PCB exposure box.
     
  4. evilc66

    evilc66 Journeyman
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    Oh, don't get me wrong. I think you are heading down the right path. 9% might be a little on the high side for the output in 365nm +/-5nm, but you aren't too far off. For bar napkin calculations, it's a great working point.

    I had thought about fluorescents. Small T8 or T5's seem to be available, but CCFL's (cold cathode fluorescents) might be an option and was what I was originally thinking of when it came to fluorescents. The only kicker is that CCFL's overall lifespan sucks when compared to LED. Even the T5's are only rated to about 3000-7000 hours (depends on the size of the bulb). Sure, that's a lot of print time, but LEDs will last virtually indefinitely in this application. Cost might be about the same too once you factor in the number of bulbs required, plus ballasts, sockets, etc...
     
  5. Oneminde

    Oneminde New
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    Right. Valid argument. But lets say the LCD (polarize film) breaks down due to UV exposure and lets say one get 1 year of good prints if you print every day, then the LCD needs to be replaced. 3000 hours for the CCFL's life span is equal to 8,2 hours of useful print time every day. All very speculative atm ofc.

    What I "worry" about is proper diffusion, the point light led's generate bother me, I want as evenly spread as possible - I guess experimentation is in order. But I am onboard for LED's due to lifespan.

    - EDIT -
    My calculations did not account for the other useful wavelengths, but if we include them, up to 460 nm, we are looking at roughly 100mW/cm^2
     
  6. evilc66

    evilc66 Journeyman
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    Another benefit to using LEDs is that you can adjust the brightness easily to suit your needs. There may be certain resins that work a little better with lower intensities. For all we know, we may be some light bleed through the LCD at higher intensities resulting in poor print quality. This is all speculation at this point. LEDs will give us the most flexibility. It will also give is the tightest wavelength output with no wasted energy in longer wavelengths.
     
  7. Oneminde

    Oneminde New
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    True. So glad you are a thinker ... LOL

    I wonder if all UV resins cure at 365 nm or if there is another sweet spot, do you know ?
     
  8. evilc66

    evilc66 Journeyman
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    Seeing as we have been talking about 4K UHD panels recently, I want to use this post as a collection point for the various 15.6" UHD panels that I end up running across. So far I have found the following (I'll add links to free datasheets as I find them):

    LG - LP156UD1-SPB1 (this is the panel that I purchased and is an RGBW panel, for what that's worth)

    Sharp - LQ156D1JX01 (Physically looks almost identical to the LG panel above, but it's RGB from what I can see)

    Samsung - LTN156FL02L01 (RGBW, which is odd considering Samsung's smear campaign against LG, but it has the same pixel arrangement as the LG)

    Edit (10/14/2016) - Looks like all of those panels are electrically equivalent, so they can use the same Displayport adapter board (same connector and pinout). They are also all available for under $100 on eBay.

    Here is the adapter board by itself for those interested

    DP Board for 15.6inch 3840x2160 4K LCD LP156UD1-SPA2 LP156UD1-SPB1 LP156UD1-SPC1
     
    #128 evilc66, Oct 13, 2016
    Last edited: Oct 14, 2016
  9. evilc66

    evilc66 Journeyman
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    So far, I've been using the datasheet for Makerjuice's G+ resin, mainly because it has good reviews, reasonable price, and the datasheet is readily available with the absorption curve :)

    https://cdn.shopify.com/s/files/1/1224/0904/files/GPlus-TDS.pdf?5013488679945133065

    360-385nm sees to have the best reaction. Shorter wavelengths than that seem to perform better, but the price of the light source increases exponentially as the wavelength drops (at least for LEDs). 365nm is a decent point to work from regardless of the light source type, as all arc lamps (metal halide, mercury vapor, fluorescent) utilize mercury, and that produces the 365nm peak that you see in every lamp of this type (regardless of whether it's a UV or daylight type lamp), and 365nm LEDs are getting much easier to find.
     
  10. Oneminde

    Oneminde New
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  11. evilc66

    evilc66 Journeyman
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    You mean, as the wavelength lengthens, the absorbance decreases ;).

    This is what I ordered

    10pcs/lot 1W 3W High Power UV Ultraviolet 365nm 375 395nm 400nm 410nm 420nm LED Lamp Bulb Light-in LED Bulbs & Tubes from Lights & Lighting on Aliexpress.com | Alibaba Group

    I'm not expecting them to be very good for this price, but they will work for now. If we find out that we need far less output than we would get from a 1W LED array, then I can start looking at mid power LEDs like 5050's that will be a lot cheaper.
     
  12. Oneminde

    Oneminde New
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    Yes, as the wavelength lengthens, the absorbance decreases ... :D

    Yeah. Sounds like a good plan.
     
  13. Oneminde

    Oneminde New
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  14. evilc66

    evilc66 Journeyman
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  15. evilc66

    evilc66 Journeyman
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    I updated post #128 with links to datasheets as well as a link to the eDP adapter board
     
  16. Oneminde

    Oneminde New
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    You have the same question as I do. What is the XY resolution of the Forge 1. Time will tell... if it is actually launched that is. Plenty of projects have never been released.
     
  17. Oneminde

    Oneminde New
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    I know which display Forge 1 is using, its the Ipad Pro 12.9". XY print envelope info on home page: 8" x 10.2". The Ipad Pro 12.9" have a resolution of 2732 x 2048 pixels, Display size: 7.74" x 10.32" and 96 microns. Its the only tablet display that makes sense. There is also a 13.3" 1440p display, but the size is off, so can't be that one.
    Which mean yours and mine (since we are the only two working towards 4K) will have a marginally better XY resolution and larger build volume, and that alone is certainly worth a few hundred bux more. $1500 is definitely not a shabby price for this version.
     
  18. evilc66

    evilc66 Journeyman
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    You know, I had a feeling that it was the iPad Pro. Man, what an expensive way to get the job done (comparatively). I wonder where they are getting the LCD from though. I know ebay isn't exactly a reliable source of parts for production, but you only seem to be able to get the LCD with the digitizer bonded to the screen (not good for print definition). I have yet to find the manufacturer or the part number for that display, but there is a pretty good chance it's an LG.

    Similar size and resolution displays would also be the Pixel C and the Surface 4, but those are physically smaller than the iPad Pro with similar resolutions.

    Panelook.com doesn't have any listing for a display with that resolution. What they do have is a listing for a 65" 8K Innolux display (186 micron XY, 56.23"x31.63") :)
     
  19. Oneminde

    Oneminde New
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    I have been unlucky in locating the panel as well and as you say, you can only get the display with the digitizer.

    I'd rather take this SLA than the Forge 1, BUT the Forge 1 is without any doubts a good solution compared to lets say Envisiontec. I wonder if this one can beat the Forge 1 in price.

    Anyway. On hold for the microscope images, extremely interested in seeing the RGBW up close as well as the UV possibility. :)
     
  20. evilc66

    evilc66 Journeyman
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    I really hope it doesn't take too long to get here. I've been feverishly checking the tracking information, but China Post is notorious for not keeping up with the various details until it lands Stateside and USPS takes over.
     
  21. Oneminde

    Oneminde New
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    Shipped from China can take 3-4 weeks, especially if its by sea. The most economical way is combined with other goods in a container. I always get nervous ordering stuff and it takes weeks before I get the item, no no, i get paranoid ... LOL. But in time you'll get there. All you can do is wait, but rest assure, I am waiting with you :)
     
  22. evilc66

    evilc66 Journeyman
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    Woohoo! LCD touched down in Chicago today. Should see it Monday according to USPS.
     
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  23. Oneminde

    Oneminde New
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    Its going to be a looooong weekend... LOL
     
  24. evilc66

    evilc66 Journeyman
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    The LCD fairy came early!

    [​IMG]

    Actually, it came Friday. Just forgot to upload the picture. Everything came perfectly packaged. Hope to get it fired up tomorrow once I find a barrel jack that will fit the adapter board.
     
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  25. Oneminde

    Oneminde New
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    Awesome. I would be super excited if it was mine.
     
  26. Jim S

    Jim S Well-Known
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  27. evilc66

    evilc66 Journeyman
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    I had seen that build before, but it wasn't as far along as this. His print results look great. I'm curious how he is running an iPad display and NanoDLP though.
     
  28. Oneminde

    Oneminde New
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    The prints look good. Going to check both links properly.
     
  29. evilc66

    evilc66 Journeyman
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    In regards to my own printer, I tried firing up the 4K LCD last night. As I kind of expected, it didn't work. The ebay page did caution against using older displayport cables, and to make sure to use UHD Displayport 1.2 compliant cables. As you may have guessed, mine weren't compatible, and it left the backlight blinking randomly with nothing on the display. The other possibility as to why it didn't work was that the video card in the laptops weren't up to outputting a 3840x2160 resolution, so I picked up a USB 3.0 to Displayport 1.2 adapter that's certified for UHD resolutions. It wasn't expensive ($65), so it will be a last resort if the cable that I also picked up today doesn't quite cut it.

    Now, what was interesting about the panel itself was that there isn't really a rigid frame encasing the LCD like the iPad display. With the iPad display, the housing covered the back as well as the sides. The LG panel looks like it was designed to be installed in the lid of the laptop where the lid itself is structural. I guess without getting too long winded about it all, it means that the back reflective white layer is sitting there out in the open. It's entirely possible that you could pull that layer out without too much effort, allowing for an external backlight without a lot of work.
     
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  30. Oneminde

    Oneminde New
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    If you are using an older laptop, the max resolution should be seen in the Display menu if you are using Windows and when the screen is attached, and yes, cable and output is very important. HDMI = 2.0 and DP = 1.2/1.2a for 60 Hz and 1.4 for 120Hz. I know Nvidia 600 series supported 4K which is by now an old card. I am sure you know your way around computers, just helping you along in the way I can.

    I C, it would make sense that the display comes without a frame as the laptop becomes the frame. Also makes sense in relationship to weight and cost, but its not a bad thing actually. More accessible that way.
     

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