Degassing to Remove Bubbles?


I have been having a lot of problems with poor surface finish on certain areas of my parts. See below for an example. Sometimes it’s just a superficial issue that causes a rough surface finish. In worse cases (like in the image below), it ends up creating a flaky thin wall with no structural integrity.

At any rate, I’ve noticed this tends to happen towards the beginning of prints and not so much towards the end. I know that bubbles tend to work themselves out of the resin as the print goes on, so I’m wondering if it’s the bubbles that are causing this issue.

Has anyone tried a vacuum chamber to degass the resin before pouring it into the tray? Seems like this could be very helpful, but wondering if anyone has actually tried this already. I looked through the forum but didn’t see any indication it’s been done. Thoughts?

Interesting, as I have a large chamber. I would have thought though the air bubbles would be pushed out when the platform hits the PDMS? Perhaps someone knows.

Lee - have you had problems with air bubbles? If so, would you mind trying to degass the resin in your vacuum chamber? I am very curious to know if this might mitigate the issue.

I have but I think I’m starting to think about crap on the galvo mirror as I’m getting a lot of part cured resin floating around and its only certain areas that are affected. Let me clean up my mirrors and run some tests.

Oh, if you want to save some prints, I’m doing this: UV laser - filling and curing holes

I know this video seems unrelated, but it’s the technique I used to avoid having bubbles in the resin. It’s called the “bombs away” technique. If you’re impatient, you can fast foward to 4:11 where it explains the technique. Basically, you pour the resin far away from the target to stretch out the cross-section of the flow which removes air from the fluid.

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Hi David. Its what I use it for, I cast and make moulds as part of my business :smile:

I’ve had bubbles in my tank and have never had an issue, They likely are displaced to the side when the platform is pressed against the PDMS as Lee mentioned. Given, the way the machine operates I would check other possibilities. I wonder if offsetting the platform to compress the PDMS more would make a difference. Perhaps your PDMS or platform are not smooth.

More I have printed so far and I am pretty new to this is the material tends to separate too quickly and curing is uneven. Once you start getting artifacts in the resin it only gets worse.

Though I have only used the Gray resin, has anyone noticed if the Clear prints more consistently and the more opaque materials get more troublesome? Wondering if the blockers are too course and don’t suspend long enough during a print.

I noticed I had more blobby issues where the supports attach to an object no matter what angle but the more parallel the surface the worse it is.

Seems bigger the print bigger the problems. I printed out some hinge pins and latch, Longest part was 1/4" at 25 micron. First attempt the supports weren’t touching the part at one end causing them to fail. Manually redid the supports and the parts fit perfectly. All my larger prints have too many random voids, not a void that is repeatable indicating a bad spot on a mirror, bottom of resin tray or in the pdms, Nothing indicating an obstructed beam path or diffused beam but rather all point to the resin and this seems to be a common problem.

Has anyone tried the MadeSolid resins? I see they have a version 2, and curious how compatible it is with the Form1+.

To make a simple degasser for the resin tray you could probably modify the cover and attach something to it. Such a small area it shouldn’t require too much pressure.

Found this pump, never ordered from these people but at least we know the pumps exist:

I think the first thing you should do is filter the resin in the tank and make sure there is no cured resin stuck to the PDMS layer. Once you know you are using clean resin, then you can worry about bubbles.