Very Rough Finish on My Parts

Just wanted to add that I’ve been seeing this kind of bubbling too on various prints I am doing with grey resin at 0.05. It is usually (but not always) within 2-4 cms of the base and seems to “hit” in a limited horizontal region. But sometimes on thin-walled stuff, it continues throughout the wall.

I just saw it on a tiki print I did and posted in the prints section. Now I am seeing it on another print that I am doing of a reasonably good stl (not too thick, clean topology, etc).

I have tried all the best practices (shake bottle, scrape tank), start with auto-generated supports, no horizontal surfaces, etc with extreme focus.

Also, though I was printing with grey resin in a tank that had been used for many prints, I just last night switched to a brand new tank with black resin and did the exact same print (no changes to the form file except the resin change). And though the black resin clearly has some different characteristics, the print exhibited the SAME bubbling in the SAME spot on the print - despite new tank and new resin (and I shook the resin in the bottle vigorously for a good 2 minutes before pouring.)

What is really interesting is that other parts of the print have stunning accuracy to the original model. And in fact, a parallel section of the part with that is almost identical prints fine in the same slice region with no bubbles. It almost seems as if the location of the part on the build platform may be related to the bubbles? (I am following guidance btw to place tall support regions near the hinge).

So I am running yet another test where I will simply rotate the last print and see if the bubbles persist. That last test should seem to rule out “dust on the mirror” if the bubbles persist in the same location - since it would seem unlikely that specific dust particles would have such a universal effect on a specific region of the model. Does this approach make sense as a way to isolate mirror-dust as a cause?

Sorry to go on, but maybe we are all seeing the same problem? (I really would like to find a way to get consistent quality throughout a single print.)


You know, I bought an air blower for photo lenses and I plan to inspect my mirror when the tool arrives.
When I first got my printer I noticed some particles on it from shipping and packaging. I am thinking that “cleaning” the mirror should be a semi-regular scheduled maintenance item ?

Here is what I bought to maintain the mirror.

I agree Cesar that dust particles would not cause uniform problems. I think he just wants to do maintenance.

I don’t know how much it would impact your prints, but after using the compressed air duster on my mirror today, I did notice some improvement with regard to roughness. Take a look below (old part on the left, new on the right):

Though the final finish isn’t perfect, it will work for my application.

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Awesome, glad to hear!

looks much better. have you changed orientation? I am starting to think the flat areas tilted at 45 degs or I should day not perpendicular to the build plate seems to get artifacts.

Wow. Same form file? That’s quite a difference. I did a retest on mine to rotate only by 180 and The bad area ‘disappeared’. I am starting to believe dust could be the cause. Bums me out tho - I have been pretty careful in my print environment. If true, this thing needs a clean room.

It’s actually the same orientation as the original. There was a decent amount of dust to remove since it was my first cleaning of the new printer’s mirror.

From now on, I’m certainly going to clean the mirror more regularly. However, I think the bulk of the debris I had to remove came from manufacturing and shipping. Nonetheless, I think it’s a good idea to include mirror cleaning with regular maintenance of the printer.

You don’t happen to have a picture of how bad the dust was to give that result do you?

Unfortunately I don’t. However, I can at least say it was similar’–if not a little better–than the one in picture 2 on Only in my case there was only dust–no resin drops.

Mirror cleaning can sometimes be necessary, but I just want to warn that the mirrors in the Form 1+ are “first surface” mirrors and should not be cleaned with direct contact unless absolutely necessary. Even a microfiber cloth can create scratches or polish away some of the reflective surface.

If deeper cleaning is needed, you can follow these instructions for direct contact cleaning…but this should only be done as a last resort:

Hope this helps!

I want to ask this:

Being the mirrors can be easily damaged etc. Is it possible to purchase replacements that can be user installed?
I haven’t taken a look inside there yet so please forgive the question if it does not make sense.

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Man, it would be awesome if the mirror assembly popped out for cleaning or replacing, this should be a feature request!

okay ill do it, you need to back me up lol

Id like to echo the “dirty mirror” from the factory.

I just took a close look at my printer and here is the mirror. The machine has been printing well with this amount of dust (yes little surface rashing here and there but no failed prints)

I think that we need to create a bit of awareness (or formlabs should) and advise used to dust off their mirrors as part of the setup.

Explore C R

Now regarding the wet looking spot by the back window, I have no clue what that is but I am going to contact support and ask, as I can also see some marking on the glass in the smaller rectangular opening.

The blower I bought and suggested earlier works pretty good to remove the dust particles, but does not replace a can of compressed air.

Matt, I know this is an old conversation, but it is worth mentioning:

  1. Don’t use canned air - the propellant will “grease” the mirrors.

  2. I have seen similar results (not smooth) when I print parts that have a lot of sharp edges. I think that small parts of cured resin end up floating around because it’s trying to create an infinitely sharp edge and can’t do it. The culprit to the rough finish is the particulate floating around in the resin. I have fixed the issue by filleting all corners (I use .01").

Thanks for the advice! I’ll try adding small fillets to my parts. I used a can of compressed air, since Formlabs seems to endorse it ( What do you mean by “grease the mirrors”?

There’s a propellant in some of the canned air that may impart a film on the mirrors. I think Mongor had a post about it…

Here is the article…