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Extending DLP print area for large build volume
Posted: Wed Apr 06, 2016 9:04 am
by radi2k
Hi!
On my own DLP printer I have high resolution (50µm) but only limited total build volume (approx 40x65mm) and was thinking about ideas to expand that. One idea is to move the projector on a X/Y table or extended the projection area using mirrors/prisms or any other sort of - I bet this isnt really new!
Do you guys know any private or commercial machine making use of that? I wasnt able to find any single one - probably searched with the wrong keywords. Do you guys have other ideas or thoughts?
I'm currently preparing experiments with multiple exposures in different areas and exposure-overlaps so they can't be seen on the finished object. However, no results yet - software not fully ready yet.
Thanks,
radi2k
Re: Extending DLP print area for large build volume
Posted: Wed Apr 06, 2016 3:42 pm
by SlowSL
Re: Extending DLP print area for large build volume
Posted: Wed Apr 06, 2016 8:34 pm
by Redrichie
I've been looking. But what is the approximate build volume envelope for dlp projection printing in the first place?
Re: Extending DLP print area for large build volume
Posted: Thu Apr 07, 2016 6:30 am
by radi2k
I think you're getting me wrong. I don't want to increase the print area by moving the projector more far away or closer to the reservoir. My plan is to move the projector on a parallel level to the reservoir in X/Y direction. When I move the projector in Z direction we'll loose resolution and probably sharpness, too.
Even the commercial machines only provide poor printing area with DLP based systems. I want to take the benefit of DLP precision but scale build volume up.
Thanks,
radi2k
Re: Extending DLP print area for large build volume
Posted: Thu Apr 07, 2016 8:07 am
by James
Yeah, we've talked about this before. It is a very interesting area to work on because if one can get it to work properly there wouldn't be much limit in the size of the build area one could obtain. I know of one commercial machine that does this and I mentioned it in the forum years ago. Let me find it. Here:
viewtopic.php?f=17&t=57I wonder if Steve (the owner of this forum and the creator of Creation Workshop) has ever had a chance to work on this.
Re: Extending DLP print area for large build volume
Posted: Thu Apr 07, 2016 10:50 am
by radi2k
Perfect James! That's what I was looking for to examine
Let's see if I can contribute some efforts making this home-ready. This evening I'll do some tests...
Thanks,
radi2k
Re: Extending DLP print area for large build volume
Posted: Thu Apr 07, 2016 4:56 pm
by James
Woo! Hoo! Sounds like fun! Looking forward to hearing about any results you obtain!
Re: Extending DLP print area for large build volume
Posted: Thu Apr 07, 2016 11:27 pm
by PacManFan
Yes, It shouldn't be too hard to do it. It's kind of a "Build it and I'll make the mod to the program" kinda deal.
-Steve
Re: Extending DLP print area for large build volume
Posted: Fri Apr 08, 2016 3:20 pm
by radi2k
First test was successful. There really isn't much to do...
First exposed one side and then the other. In the light reflections you can see it but structure is good. Also inspected it under a microscope. Looks like one piece.
Almost forgot it: no special pixel blending on the overlapping area was used to get that result. Probably also because I have very short exposure time of only 150ms (FunToDo Standard black)
However, I didn't move the projector for that. Now after that test I can redesign my whole machine!
Thanks,
radi2k
Re: Extending DLP print area for large build volume
Posted: Fri Apr 08, 2016 4:13 pm
by James
Dang! Nice work! My first thought on problems that could come up were concerning repeatability on the linear moves. Looks like you didn't have a problem with that at all as the boundary looks very good in this regard! What kind of setup did you use for moving the projector? Is it a high dollar setup or just low dollar Asian export linear motion parts.
One idea I thought of while writing this just now is the linear exposure positions could be spaced slightly during the build. Once finished the resin would be held in place by capillary action, which could then be post process cured to "weld" everything together.
Not germane, but that brings up something else. If that worked, one could use that to alleviate shrinkage issues for regular SLA printing, maybe.
That's cool Steve that you're willing to work on this! Definitely a way to get more people interested in CW since a working machine and software combination would generate quite a bit of interest on AM news sites and maker news sites.