Build Your Own SLA/SLS

Some have asked about the Flex bottom VAT that I had been messing around with. The first version worked but not 100% as it was too flexible and would sag with the weight of the resin, I cured this by clamping a piece of glass under the FEP/poly combination which worked but made for a few ripples on the edges.
This is my new prototype I cut on the CNC yesterday, the welding on the VAT walls are not that great as I didn't have the proper gas for what I was doing. :/

Pictures should be pretty self explanatory if you have any questions ask away. It's comprised of 3 pieces the VAT mounting base which has the ring to stretch the FEP, the VAT bottom clamp and the top clamp/walls. The FEP is clamped between the aluminum pieces with a little silicone bead around the edge and screwed in place with 18 6-32 machine screws. Which will then be pulled down over the base ring with 6 1/4" bolts until stretched nice and taunt, the ring was made rather tall so it could be stretched further as the film ages and or stretches out more.

As I say this is a prototype so the base is just MDF coated in Urethane resin to seal it off and make it far stronger, I will be testing how well it works today/tonight once my printer has been completed (rebuilt to remove the mirror) and report back.

Looks good! I've been playing around with a similar design, but so far I've just been using adhesive instead of a clamp.

Wow, Great idea! I tried to stretch some fep but couldn't get it taught enough.
Is there any danger of the fep rupturing and leaking resin resin onto the projector? How thick is the film?

If I may ask, where do you get your FEP from and what thickness?

Thanks for the tips! I had been thinking about making a vat bottom just out of FEP. I have a very thin layer of polycarbonate now with adhesive FEP. The thin layer of poly gives it a good flex during separation.

Tnxs, great writing, I think this thread is the real discussion, where it's all about...
Pacman, how will your FEP-only vat look like?
Not affraid of sharp prints, sticking through the foil?
I'm also dreaming of these kind of solutions... (Getting enough air under the foil, very thin foil so no shadow images, etc etc)

I was also thinking about this, especially after seeing the 'Almetec Master Plus' printer.
That's a very nice solution! Also because of a very thin layer of resin, which will be 'refreshed' after every layer.
And especially that refreshing looks important to me. 'Re-shaking' the resin during building could also be a key factor...
Especially after long builds, it's good the shake te resin. That's what I'm currently trying out.

Since I'm logging all my prints, including photo's, I discover, that the resin is degrading a lot over a couple of days (without refilling the vat).
Maybe stupid and every one knows already... But in my case, the resin will stay in the vat, in an almost dark printer. And ofcourse, I'm shaking/stiring the resin before a new print. Every time these prints with 'older' resin will have worse quality. First I thought my printer was not very good designed, or both mirrors are creating this issue, but now I'm quite confinced that the degradation will be the issue. The resin is shifting and the light liquid on top will faporize and the 'dlp-resin' looses it's quality. (I still need to prove this, I'll let you know when I'm sure...)
What are your idea's about this?

Edge this is a FEP only design unless you accidently wrote Pacman instead of Finhead.

I have let the resin sit for 2 weeks at a time with a stir it's fine for printing. When I was using mirror design it was a issue fie sure, some of the resin that refused yo cure with my folded design Is now curing without iissue.IMO the folded design is limited and complicates the print process too much.