Having trouble with huge layer shifts

Hey all!

I’m pretty new to sla printing so excuse me if I’m making any obvious mistakes.

I’ve been trying to print off some mushrooms models with Formlabs’ flexible resin (the old grey flexible resin, not the 80a resin). It seems like there’s some sort of major layer shifting happening, which I assumed wasn’t really an issue with sla printers. I’ve found a couple forum posts dealing with minor layer shifting, but haven’t been able to find anything documenting anything as severe as mine.

As far as troubleshooting, I did a second print with three mushrooms all at different orientations to see if that affected things, but all three of them turned out real messy. I didn’t hollow out the heads, but I assumed that wouldn’t be a problem with them being so small, and can’t see how something like that would cause these layer shifts. I’ll also say I’m running on a printer that at my workplace that had been beat up pretty bad before my arrival. Lots of spilled resin inside which has lead to a few different parts needing to be replaced.

Before I wasted anymore resin on troubleshooting I thought I’d ask here to see if anyone could point me in the right direction :slight_smile: Cheers

Is the build plate “tight” when locked in position, or does it wiggle (even a tiny bit)?

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Print the mushrooms facing down

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It was! Made extra sure the second time around to give it a tug.

Will give it a shot, thank you!

Also, tall skinny scaffolds tend to "wander’. For features that are long and thin it is often better to orient them more horizontally then vertically. Really tall structures tend to need to be “beefy” or things can deform.

I couldn’t quite tell from your pictures which print was which, though I’m guessing the one with horizontal shifts in the mushroom cap was the one that was oriented horizontally, and the one with the “notch” in the stem was the one oriented vertically. That left the one with only half a cap as the one that was oriented at about 45º. I don’t understand why you only got half a cap on that one. And the one that was horizontal to the build plate should have come out perfectly if the problem was orientation. The fact that it has horizontal layer shifts says the mechanical system is what’s moving.

Oh! I usually go pretty light on the supports because preform has historically done pretty alright doing bigger prints with just that, at least with solid resins. Perhaps because of the small supports and the flexible resin, those skinny supports were able to flex and shift without actually snapping off. I’ve had to jump back to the gray as another project has swept me up, but I’ll add some beefier supports next time I’m printing models off similar to these with the flexible resin!

Thanks for that info Randy, I appreciate it.

I had intended to mention that the supports looked a little “light”, particularly on the 45º one. But I assumed PreForm had generated the supports so they must be OK (mostly). If you placed the supports yourself, and you usually go “light”, that’s definitely the first thing to try. Particularly with the flexible resins, you need more not less. The supports are just as flexible as the print. :slight_smile:

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