Print Fracturing! Any explanation?!

We’ve been using our Form 1+ for about a month now and we’ve been pretty happy with it! It’s kept in a room that has a fairly steady temperature of 19-21 C. Anyhow, we printed a model that we have made a few times already in the Formlabs Black resin, and the part fractured in two places before we even tried to remove it from the build plate.

What I noticed was that some of the part was warped heavily near the cracks, so could it be just the angle the part was built combined with the strain from the resin vat peeling each layer?

Can anyone explain these cracks?

Any and all help is appreciated!


Hey Richard,

The deformation of the part and the cracking are due to the same issue. It looks like the supports on those flanges are in a straight line, and the part is being build at an angle to them. In later layers, the peel forces are exerting a moment on the parts causing them to rotate around the line of supports. The position the part returns to after this rotation changes slightly for each layer, leading to the bend you see in the parts.

The fracturing occurs when the bendy flange meets the body of the part. Initially they are connected via a single layer of resin (which is not very strong, as you can imagine). This single layer is not strong enough to withstand the peel moment and tears. This continues for the duration of that section, leading to the crack in the part.

And now for the good news: the fix is fairly straightforward. Just make sure angled parts are supported to account for moments. Go into Supports -> Edit Selected, and add a couple supports along the length of that face like I’ve tried to show here with my excellent MSPaint skills. This should reduce the deformation of the flanges and prevent it from tearing.

If at all possible, would you be willing to share the model with Formlabs? We’re always trying to improve our algorithms such that cases like these are caught automatically when supports are being generated.

Hope this helps,

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Thanks very much Steve! That makes a lot of sense. I sent an email back yesterday but wanted to say once more, that you guys are on the ball and very helpful.

I wasn’t thinking that this could have progressed throughout the build, but once more, it makes sense.

We’ll work on better orienting the supports.

Thanks again,