Originally shared by Stephen Baird
After about six months of playing with my printer and slowly assembling my thoughts and summarizing what I’ve learned about resin printers I thought it was finally time to put it all down in one place for the benefit of the community.
Photoresin printing is the next great frontier for open source hobbyist 3D printers, and that frontier is getting easier to reach every day.
https://bairdlabs.wordpress.com/2017/02/10/how-to-diy-a-resin-printer/
Wow very informative- nice prints!
Nice write up kind of what I was talking about in my post.
Now for the first of many questions DLP projectors is there one specification or a list of projectors that do work or will annoying over a certain lumens output work?
There are a number of options and considerations when it comes to DLP projectors. The first is ability to focus - For most setups you’re going to be trying to focus your projector over a very short throw distance and at a very small screen size, and neither of those things is what it was designed for.
You can add additional optics in front of the main lens to help with this, but some projectors can be slightly modified to allow for this super short throw focus to work.
Unfortunately there isn’t a good overall list of which projectors require what, the best solution I ever found was to find other people’s experiences and go from there.
My own printer uses an Acer x152H which can be modified for this sort of short throw projection by removing the lens assembly, adding two M3 nuts as spacers to hold the lens a little farther out, and replacing the lens assembly. Some projectors require small modifications like that to work while others will work without modification and still others will only work with extra optics.
Beyond the question of focus, you also want to have very even light output across the entire field. All projectors will have a hot spot of some kind, but some models will have less of a difference between their hot spot and their cold spots, and this is important for a resin printer. Control software allows you to use an image mask to compensate for the different amounts of curing time needed by the differently lit area, but this compensation will add time to your prints because each layer will have to cure for as long as it takes for the dimmest (so, slowest) portions to cure.
Finally there’s the total UV output consideration, which is somewhat a function of total lumens, but is more a function of projector design.
It’s hard to know a lot about the design choices that will affect UV output without opening up the projector to look inside, but some of them you can learn about from spec sheets.
Some projectors have a color wheel that includes a clear section, used to generate additional brightness for white, and this will normally allows for increased UV output as well when displaying black and white images (as we do while printing). The x152H that I use has a color wheel like this.
But you can also modify your projector to increase UV output. You can replace the glass heat break between the bulb and the rest of the printer with a quartz window which will pass UV. You can remove or modify the color wheel to remove another source of loss (but you need to be careful, because some projectors have sense circuits to check if the wheel is there).
What I’m getting at is you can’t really say “a projector of X lumens will work best”.
As total light output goes up, total UV output should go up. But the design of the projector will have a serious effect on that, and as total light output goes up so will the heat output, and eventually that can become an issue. Especially if you orient your projector pointing up, which isn’t the orientation its cooling system was built to expect.
Really, the best solution is to find other people’s projector experiences and decide on your own based on that.
Good article, I want to build a LCD printer, which LCD do you recommend I use?
I don’t have any personal experience with LCD printers (yet, I plan on buying a YHD-101 relatively soon here) but the YHD-101/KLD LCD1260/Duplicator 7 (which are all the same design with different names) all use this LCD panel:
All the aliexpress sellers I have found seem to sell it with the backlight attached, and you would need to remove it to get a bare panel to use which can be a delicate operation. If you ask they may have some without backlights to sell, or they may be willing to remove it for you before sending, but I’m not sure.
That LCD is at least known to work, outside of that it will be down to your own experimentation. I know some people have tried iPad screens without real success, at least with UV curing resins, so there’s some evidence that not all panels will actually work.
just amazing your article:+1:
🖒🖒
Amazing and cool