Tank carrier screws (looking for official calibration pdf)

hi guys, my form 2 optical window was cloudy inside, so i decided to clean it. the problem is i unscrew the tank carrier screws also… (i know doomed)

trying to re calibrate now. is there any official PDF for that ?
right now im pretty close with my 10mm high test cubes.
the front screws all the way screwed in, and i playing with the back side screws adjustments, and get this result.

but sadly when i printed the official OpticsTest.form i have got horrible result.

i know, i should not use engineering resin for calibration because it is not optimized for that, but right now i only have that to work with. (trying to get standard resin ASAP)

my question is, could be the failed print because the resin i use, calibration, or something else ?

I’ve just been through the same calibration cycle. But the optical tests show the ‘5’ at the top to be perfectly readable so I would say you still need to do some cleaning of the optical surfaces.

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have you used engineering resin or standard?

well if it would be dirty the other numbers would be bad also arent they ?
just my basic logic.


The optic tests work by scattering the light from the laser. The more the light is scattered, ie the dirtier the optical path is, the lower down the test piece the numbers are distorted.

if you look at the file in preform, you’ll realize it’s made up of several models stacked together. This forces the machine to perform several passes over the same area (effectively printing one geometry within another, if you will), which has the “advantage” of exaggerating the defects of a contamination on the optical path of the laser. These defects are sometimes not visible/easily tested on a standard print which is why this file is useful.

I would say from your first images that you’re not far off in your calibration (although I have never performed this operation so I have little experience), and that the defects in the test print are due to a contamination on the optical path of the laser. If your window is clean, check the main mirror… but it’s usually not the culprit, usually if the window is clean then the galvo mirrors are to blame, Formlabs also has a pdf for this cleaning operation.

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i see, thank you so much. this helped me a lot. i will clean it more both sides and see if it makes any differences.
if not i purchase a new one and check it with that.

still better options then what the support offered me to send it in for 1000euro

do you know any official tolerances ? how accurate should be ?

In an attempt answer your accuracy question, I just re-read your first post and I would make this comment : Don’t measure the height if you’re printing directly on the BP ! At that level of accuracy you’ll measure the flatness of the BP and the accuracy/regularity of the pressure applied on the tank during the first 20 or so layers (for adhesion) more than anything else. It’s not surprising to me that the center part is higher at BPs are either a bit convey or concave.

To calibrate more precisely I would print in Grey or Clear (stiffer so easier to measure, also much more dimensionally stable that Tough), and measure the sides.

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Thanks John

Before buying new glass clean your galvo mirrors. I live in a very dusty area and I have to clean mine about every 2 to 3 months. You will be surprised in the difference.
Also I use to be a heavy smoker (Smoke free now 10 months) but all my smoking actually added a slight film on all my glass surfaces that made the printer print like sh&^.
we seem to forget that this a finely tuned tool and needs to be treated like one.


i did clean the galvo mirrors so as the big mirror, and optical window.

also inserted a brand new tray with fresh resin.
i got same issue. wondering if because the laser giving up and loosing power or because not leveled well the tray carrier.

here is my recent image

anyone know what could be the problem ?

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