Problem printing shelled Heart


I think my printer made my model solid when I imported it and I’m not sure why. Its a 3d heart that I shelled at .1" in solidworks but when I imported the file it said there were errors and asked if I wanted the software to fix it for me. I clicked yes without thinking much of it and came back a few hours to check on it. Everything looks fine so far (about halfway through) but I checked the scroll bar on the right side of the formlabs software to see the progression of the build and noticed that it was solid!

Jeez no wonder it was a 7 hour build! I don’t want to stop it now so I’m going to let it finish but I don’t understand why it would do that. Pretty frustrating…

Heres a visual to give you all an idea of what I’m working on. Fyi, the arrow and the heart are two separate pieces.

This is a typical case of the program trying to be smart. Obviously it doesn’t know what you want it to do when repairing, but apparently it wants to repair the model because it has some errors. The program think it’s a “smart” thing to make your model solid as it’s seen some errors and notices your model is hollow. However, when it doesn’t detect a “drain hole” it thinks that you must have made a mistake and it should be solid.

I don’t know the exact reasons why it does this. It just does. One of the reasons it “would” choose to do this is that you’ll most probably get a blowout if you print a hollow object without a drainage hole. This would then end up as a complete failed print.

Either choose not to repair it and sometimes the print will come out fine. Or use the “Boolean” tool in your 3d modelling program to add a small hole in your print to prevent blowouts and ensure that incured resin can flow away.

Ahh I guess that makes sense. But I just wasted a ton of resin because of that. I’m to blame as well for not investing the error message more but still frustrating :confused:

I’ll add a small drain hole from now on. Is the size of the drain hole important?

Obviously the bigger the drain hole, the less chance of a blowout. However, I’ve managed prints with a 1mm drain hole with a print which was about 5x5cm.

Ok, thanks for your help Alex.

The same thing has happened to me several times.
I always open my models with NetFab and use the auto fix and sometimes it does the same thing but not as much as PreForm.
So I make sure the models are still hollow before printing and sometimes that means printing with errors.
Sometimes its a real error but usually not.

I believe Preform uses the Netfab software so in theory the automatic repair should do the exact same thing in both programs.

PreForm does use NetFabb, and it is absolutely not the same thing. I run a freeware version of NetFabb I started using a few years ago with my Makerbot. I have run in to issues that PreForm cannot correct that the freeware version of NetFabb has no issue with. But then, I’ve also had situations where NetFabb says the part is good and PreForm says it requires repairs (which it then makes).

For complicated objects, you really need a suite of tools. I would recommend the freeware version of NetFabb, as well as MeshMixer and MeshLab (also freeware). I have never tried the NetFabb cloud service, though I would think it would be worth a try, too. So far, I’ve never had a problem I couldn’t fix with a combination of these tools. Typically, I let the tool tell me what’s wrong but then go back to the model and try and fix the problem manually (so I can keep my original geometry “intact”. Having to triple everything before you can process it makes it a lot harder to see what’s going on in the geometry when attempting manual edits.

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Thanks @Randy_Cohen, I didn’t know that. Luckily most of the time in my cases it’s just a flipped poly or a problem converting 4-sided poly’s to 3 when exporting to stl. I shall definitely use Netfabb instead of Preform to repair the issues if they arise.

@Anthony_Huczek, Any luck with the new print? How big did you make the hole? The render of the model looks great, so I’m interested in the actual printed result as well :slight_smile:

Its printing now :slight_smile:

I didn’t have time to print it yesterday but I made a couple of small changes this morning and set it up about an hour ago so it should be ready later this afternoon.

I added two .1" drain holes and it didn’t have any problems/errors importing so we’ll see!

Ok, good and bad. Part of it failed which is bad news but it doesn’t look like it had any problem with the shelling. I ended up with a dime sized hole in one of the upper corners of the heart. I think thats because I let the resin get too low in the tank before pausing and refilling though. I was in a meeting and when I came out there was a little under an hour and I saw there was a tiny hole emerging mid print. The resin in the tank was probably 2-3mm from the bottom. I was surprised by that however because the build was only 78ml I think and the tank is supposed to hold 200ml at the max fill line correct?

Have any of you all had issues with failed prints when the resin is running low?

At any rate, I have a good works like model and I may or may not print again. It was really just a proof of function piece since we don’t fabricate in house here.

Side note: I know you can use resin and a toothpick to repair pin holes but are there any patching options for larger holes besides Bondo?

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