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Build Your Own SLA/SLS • InFocus LP280
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InFocus LP280

Posted: Wed Feb 18, 2015 8:05 am
by jthornton
Is the InFocus LP280 a suitable projector? I've found one on CL.


Re: InFocus LP280

Posted: Wed Feb 18, 2015 12:33 pm
by orangezero

This place lists it as 800x600 native, which isn't the best and will limit either your size or your resolution, or both.

The real problem is that it is an LCD projector, which means the light must pass through the tiny LCD, and this blocks a ton of the wavelength of light needed. So it generally doesn't work well, if at all. You really should be looking for a DLP, as that (I believe) reflects the light off of tiny mirrors in the chip, so more light is transmitted out rather than absorbed.

To some degree, lumen output and all is just a rough idea. You may have lots of output at 800nm or 600nm, but this is essentially worthless for an SLA printer and just adds extra heat. LCDs would also often block most of the UV light (which generally also helps to cure) but constant UV light would also degrade the LCD itself eventually. Not sure if it would take years or months, but it wouldn't be a good solution long term even if you had enough output of light at the proper wavelength.

If you've read about LCD on here, the only successful stuff is using larger monochrome LCDs (which don't block as much of the required wavelengths), or using a regular LCD screen like and ipad retina screen. But then you need to account for a color LCD screen only allowing around 10-12% of the light to go through, which means lots more heat and wasted energy. Not a perfect solution.

Someone correct me if any of this is wrong.

I believe, you want a DLP (1024x768 minimum probably, but 1080p native would be best) that also has a workable lamp bypass (to potentially add UV or 400-420nm LEDs in the future). Or find one that has cheap replaceable lamps. No sense getting a five year old projector if you can't find the bulbs or can't DIY a different light source.

Best of luck.

Re: InFocus LP280

Posted: Thu Apr 30, 2015 3:31 pm
by Cation
You can use it with resins that are sensitive in the 460nm (Blue) range using the mercury lamp provided or if you are handy enough replaced with a 10-100W 460nm LED for use through the Blue LCD.

Most resins are only sensitive from UV up to ~420nm (UV-Violet). You will need to use resins that cure with Blue light UV - 470nm or higher.