The Attack of the Giant Flake

Thanks for the input, everyone.
I’ll post a photo of the tall crosses after IPA bath later tonight.

They’re fairly illuminating in that peel and hinge sides are perfectly clean, yet the front and back are horribly flakey. The flakiness also seems to change depending on position (it’s a bit worse nearer the hinge) which does sound like it might be an issue with one of the mirrors (were it the laser or the laser optics, it likely would’ve been exactly the same all over).

I’ll contact support and ask about the galvo block removal instructions / small mirror and galvo mirror cleaning instructions.

@Ante_Vukorepa I wanted to share how my day went:

  • This AM I opened a support ticket detailing my flake/jello issues that I was having.
  • I cleaned my main mirror according to the mirror cleaning guide.
  • Support got back to me and included the Galvo mirror cleaning guide. They are also sending a new main mirror. I said that I do not think that is the issue, because I can see that mirror and it is clean…but they wanted to send out a new main mirror to be on the safe side and also ensure my uptime.
  • I performed what I would call a partial Galvo cleaning, I did not use any IPA but simply dusted with a PEC-PAD and air bulb.

After my cleaning I filtered my resin (I have had good success with these guys HERE)
I fired up a print:

and here are my results

Still not 100% perfect, but about 80% better then before, and I have little to no jello in the tank after the print.

All said and done, there is hope, and support has been amazing.

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I’m seeing the same issues plus some; jello resin, a slug of solid material on the bottom of the tank, huge flakes and fracturing, and a rough surface. Plus of a sudden the prints are welded to the base. I have to chisel them off (and then throw them out). All this showed up suddenly.

Fresh tank, fresh resin, freshly cleaned main mirror, to no good effect.

How big a deal was cleaning the galvos?

Here are my cross prints in black, as promised:

Hing Side Print - Hinge-facing
That looks sooo weird…almost like there were giant flakes in the resin that got cured into a layer.

I did not remove the Galvo block, just removed the back cover and using a PEC*PAD lightly dusted the assembly along with some air from the air bulb.
IMO it was easier then cleaning the main mirror because of size and location, but I would contact support before you go for it so you have it on record with them. Also they do have a helpful PDF detailing the process.

That’s pretty much what they are.
The flakes accumulate on the PDMS at the very edge of the print area, until enough piles up for the print perimeter to lift it off the PDMS. Then the process begins anew.

Anywho, got the instructions from the support (they were VERY quick, hats off to Formlabs), cleaned the galvo mirrors (yes, there was some dust on them and a few smudges too), gonna print another test print and see where that got me.

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good luck, Ante! Let us know how it goes

Here are the results:

There are still some oddities (like the streaks on the back side of one of the prints - sorry, not sure which one was which, i was in a hurry and didn’t label them), but it’s a marked improvement. There were some boogers on the print, but they were quite likely from the leftover jello in the tank (i haven’t strained it).

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By the way, in case anyone was curious, this…

… turned out to be almost exactly what it looked like - scratches on the back side of the mirror. I.e. the non-silvered side, likely that way from the factory. As it turns out, the silvering is transparent to deep red/infrared part of the spectrum, so shining a sufficiently bright light through the front will make it appear like there are red scratches / defects beneath the surface (because the transmitted part of the spectrum reflects off the scratches and back through the silvering).

Inconsequential for the actual printer functions. Lesson learned - if the mirror seems speckled or scratched, check the back side before repeatedly attempting to clean it. You might be seeing stuff that’s on the back, not the front side.

@Ante_Vukorepa - so it looks like your printer is fine now?

You say you found some smudges on the galvo mirrors - any idea what they were?

I mean - this post: What is this and should I be concerned? and this one: Mis-formed parts in fine detail resin made me wonder if there’s some route for the z-axis lubricant to the galvo mirrors …

If not that - then what did happen?

I’ve been wondering if condensation may be the cause fore some of these unexplained smudges?

I have learned that air in a can IS NOT YOUR FRIEND!
I was using it to blow off my main mirror for months, I recently got a tactical flashlight (for another toy) I was playing with…I used it to look at my main mirror and look what i found. Apparently the wavelength of that light found things that my other spot/flash lights could not.

This picture was taken before my through cleaning above^^

I believe @JoshK warned us for that in sep’14 ;). Actually that was before you joined this forum…

But in your last post you said you used an “air bulb” which is not air in a can… I don’t think the air bulb should do any harm, but obviously wiping it with IPA and PEC-pads is the proper way to go.

Though it’s never a bad thing to remind readers that air can’s shouldn’t be used to clean the mirrors! They might have missed Josh’s topic like you have.

Yes I did miss that post.
I (and i suspect all new customers) are working off of the Formlabs “Checking the mirror” process.

Now i am a full time air bulb user :wink:

Well, it’s at least back or close to how it was at the beginning, yes.
I still have to verify if the undercuring i’ve experienced since the beginning, on flat top/bottom surfaces (i.e. in the infill), has been fixed as well (as suggested by the support, that might’ve been due to the residue on the galvos as well).

I’ve got absolutely no clue.
Some were dust-like, except they couldn’t be blown off with a bulb. And the biggest issue (i think) was a smudge in the middle of one of the galvo mirrors, that didn’t look greasy and wasn’t very visible straight on, but would get very visible when lit sideways. If i had to guess, i’d say it looks like the mineral residue (limescale) you get from water droplets, but that makes no sense, as there’s nowhere the water might come from. And if it were condensation - there would be no residue.

I don’t see how it could be z-axis lubricant. There’s no access to the Z axis from the rear of the galvo block. The only thing that might get some lube on it would be the small mirror. Besides, what i’ve seen didn’t look like lubricant at all.

So, yeah… no idea what happened there.

I’ve gone back to the tank and resin this all started with to make a more direct comparison. This is the result:

Much clearer, right? :smile:
No flakes, really, but i did find some ribbons (long and thin booger-strips of semi-cured resin) on the front.

Also, one part of the back side was noticeably rougher than the rest:

Shots after the IPA bath… Front looks good:

Back is rough on one side, but not on the other as i’ve said:

Now, i think the part that’s rough coincides with the highest amount of ghosting on the PDMS layer, so that might be it. It’s either that or there’s still some residue in some spot of the mirrors - it’s too localized to be anything else.

If it helps, I had a similar issue with prints last month. Print quality deteriorated to the point that I started getting flaking like what you’ve shown over a short period.

I contacted support, got the galvo cleaning doc and cleaned the galvos and larger mirrors as instructed.
Pec-pads on a stick, IPA, etc.

The results were immediate, which was a good thing because i was in a hurry to get good parts for a project. Compressed air will not do the trick for the galvos.

As for the question about how the galvos could get dusty/dirty…it doesn’t take much. There is an open path between the main chamber and the galvos. Not to mention the fact that every time you use compressed air on the big mirrors you’re stirring things up.

No mater how fast the mirrors are vibrating, they are not going to shake off small dust particles thanks to a little thing called static electricity.

I think the puzzling part was more - how the non-dust residue ended up on the galvo mirrors. Regular dust does seem like it can get there very easily, but there is no direct route from any place in the case that might produce anything that would leave residue.

Interesting you’d mention that, i was just thinking how DSLRs have been fighting the same issue for years, until a sequence of innovations brought about (somewhat) self cleaning sensors. They mostly use vibrations to get the dust off (either sonic or ultrasonic) in combination with layers that reduce (not eliminate) electrostatic cling.

@Ante_Vukorepa - Once I thought about it I realised that of course the galvos must have bearings of their own - and perhaps lubricant from that bearing could be a “smudge” source. Looking at a galvo I had leftover from repairing my old F1 (galvo control board failed - replaced with off-shelf kit - F1+ has new bespoke control board) before I upgraded- they do.

The one below has been lying on it’s side in a draw for over a year - I’m not sure what the glossy area on the left is, I couldn’t rub it off with paper towel, and I’m not sure it matches the side it was lying on. Regardless, the bearing itself is clearly visible - and that has to be lubricated.

Which mirror had the smudge? was it the X-axis galvo - the one hanging vertically?

It was the horizontal one, i.e. the X galvo (the vertical one is the Y galvo, AFAIK - it’s marked as such if i remember correctly, and the Y axis is the one running from the hinge to the peel mechanism), at least if memory serves me correctly. I might be wrong.

Even if it were the vertical one, there should still be no “dripping” from the bearings. They appear to be sealed, and the lube used in bearings is rarely that free-flowing. Plus, the spot on the mirror was in the very center and fairly regular.

Anything’s possible, though.

Re: glossy area - seen that on mine too, but it seemed solid. There were some strands of hotglue on the side of one of the galvo casings, i’m thinking the glossy area might be either hotglue, or possibly the remains of whatever is used to attach the mirror to the shaft (epoxy?)