Bumpy Surface

Hello everyone. We’ve had this printer since the end of December and have made about a dozen prints of various sizes.

So far, almost all of our prints have come out great. The surface quality (on areas not touched by supports) using even the lowest resolution has been very impressive. However, the last model we’ve done (and also our largest to date), has had one area that did not come out very smooth. The model is roughly 5" x 5" with a flat surface opposite the supports. That entire surface should be smooth (not counting raised text and several tabs) but one area has a bumpy texture roughly 1" x 3" for some reason. It’s a stippling-like texture. I really couldn’t see it initially, due to the excess resin on the part before putting it into our Form Wash. During finishing, I ended up ruining the part so I printed a second one, thinking whatever caused the bumpy texture was simply a one-time error that wouldn’t be repeated. I was wrong because the second print had the same issue in the same area.

Anyone have any idea why this is happening? I know I could sand it down to smooth out the surface but I’m trying to avoid doing so because there is raised text on several areas of that surface. It’ll be a huge pain and incredibly difficult to avoid the text and make the surface look uniform.

I’ll upload an image later, once I edit some client-related details.

IMG_7447

Hey there @DSMT!

Thanks so much for taking the time to post! I’m glad you’ve been getting good results overall but we definitely don’t like to see rough surfaces like this on the finished products.

Just a couple quick questions for you. What layer height did you print this part at, and what layer height do you typically use? And also how long have you been using this particular resin tank?

Thanks so much for the info!

Hi DKirch.

Layer height was 0.05. For something like this (size and type of part), we would normally print at 0.05 or even 0.1.

This resin tank has been in use since the last week of December. We’ve printed about 0.4L of parts thus far.

Thanks!

I sometimes see this when a few triangles get flipped and face inward. This isn’t always detected and repaired on lettering.

I had this problem a lot with Solidworks and a bit less with Fusion 360 but it happens.

Thanks for the information! This strikes me as probably a little contamination along the optical path somewhere that’s making the laser spot a little messy by the time it gets to the resin.

The best thing to do is to get in touch with our support team at the link below and we’d be more than happy to help you nail down what area needs to be cleaned a bit!

https://support.formlabs.com/s/contact-support?language=en_US

Since we can’t see the supports from the picture, it’s possible the top edges of the holes need more support, without enough support the edges could fall apart and create particles of partially cured resin in the tray and cause flaws in the print. Also, if there’s not enough support to keep it stable that could cause issues as well, but it looks like you might have enough stability overall, I’d just check the top parts of those holes and make sure there’s enough supports when it starts to bridge over.

Thank you Zachary_Brackin. I’ll keep that in mind.

And thank you DKirch. I’ll contact your support team when I get a chance and get this machine cleaned up.

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