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Loud clicking sound and check mixer error



I am trying to start my first print, the print loads into the printer and gets to “filling tank”. The laser moves all the way to the left, and the tank gets pushed up and locked in. Then it makes a really loud “CLICK CLICK CLICK CLICK” sound and an error message pops up telling me to push the mixer all the way to the left.

As far as I can tell the mixer is properly positioned: it arms are facing left and clicked into the little notched on the tank. It seems to have locked onto the magnets.

The sound is like a CNC hitting the ends of it’s rails, but the LPU seems to be able to move back and forth freely.


I am having the exact same problem. It really started happening after the most recent software update. Not sure what it’s causing the clicking sound and its not affecting my prints. It doesn’t happen all the time, only 3 or 4 times during a 24 hour print cycle. I would like to know what is causing this clicking sound and how to avoid it.


I think it’s a similar, but different issue: mine would not print at all and the clicking noise was constant and during the priming phase. I contacted support and as soon as they replied asking for a video or recording the problem went away, and has not come back in about 5 months.

That sort of clicking noise is likely a servo hitting the end of it’s track. Probably the one moving the light processing unit around. It should not damage anything (based on experience with zeroing CNC routers, I don’t know for sure with the form) but it is annoying and should not be happening. If you can get a video, send it to support so they can get a better idea what is going on.


I just encountered this for the first time today. I aborted the run and attempted to restart a print several times. Each time during initializing & filling, it would click when trying to pickup the mixer.

I presume there is a mechanism inside the LPU which rotates to engage the magnets on the mixing arm and this is clicking for some reason.

I power cycled my machine and it seemed to work now…hopefully will continue to work for the duration of my next print.


I have had this same horrible clicking noise during the heating process on 2 different form 3’s. Still prints perfect.
Any insight on what this could be?
How to eliminate.


I am having the same problem, but ratchet / clicking sound happens about once every 20 minutes after the tank sweeper completes a cycle


The standard response from Support to these clicking sounds is to re-grease the lead screws. This works fine for the X and Z lead screws since they are easily accessible. However there is also a mechanism that attaches the mixer to the LPU via magnets. This seems to be the source of many of these noises. Unfortunately I can’t see how to access this mechanism, I presume it is inside the LPU which would mean that the unit would, at least, have to be remove to apply the grease.


There is a rotating mechanism inside the lpu that engages the mixer magnets as @billb said.

This was causing problems for me. Strangely it seemed to happen only on a specific resin tank, once I changed tanks it stopped happening. It would solve itself after a power cycle which was weird.


Same problem after last firmware update to rc-1.9.5-629.
was long printing, at morning that printing finished and when i come to office i saw on the printer display message like “new firmware available, update?”. Yes, update. After that routine finished and printer reboot, i starts new printing. In start sequence, after build platform move down, from mixer side appear very loud clicking, like jammed gear. Printing was susses, but almost one months i listen this loud clicking each start of printing.

some video, clicking at begin and end of video

If need some maintenance, what need to do? if it bug of latest firmware i think reasonable fix it.

Form 3 Loud Clicking sounds

We are experiencing a clicking sound that seems similar to the ones described here. It is several quick clicks for a period of about a second. It happens intermittently, perhaps once every several hours of printing. It seems to always happen at just the end or beginning of the layer cycle (I can’t be sure because I can’t stand over it for several hours waiting for it to happen to see exactly whether it starts at the very end of one layer or just at the beginning of the next).

I did not have this problem until this week. We received some Tough 2000 resin and a new resin tank. I updated the printer and Pre-form software. Then the intermittent clicking happened on the first test print.


I have also been having the same issue. My printer was new in December and I have only been running Tough 2000 material.
Note, am only having the clicking issue, like a gear jumping, I am not having any other errors displayed.
Will be following with interest for an explanation / solution…


Hello! I have also the same problem since Dec. 20 with my Form 3 bought in March 2020. I only use Tought 2000.
I tried to print with the room at +30ºC (+86ºF), just in case it’s because of the mixer being stucked by the density of the cold resin, but not, still doing the same.
Sometimes the clack-clack-clack sound takes 0,5 seconds and others around 2-3 seconds, just after the film is tensed (platform go up 10cm–>mixer moves–>film is tensed–>clack clack clack–>next layer). Print is ok.
I will keep you updated, I am checking this with the support.


I’m also having this same issue. It does the exact same click from the posted video during the mixing cycle.

When I print using the Flexible 80A or white resin it only clicks 3 or 4 times and then it’s done.

With the Tough 2000 on the other hand, which I just started experimenting with, it does it every single mixing cycle and it’s 6 or 7 times each time it mixes. Has this been solved through Formlabs yet? Or is it still an issue?


Also having the exact same issue. Happens with multiple tanks and different resins. I’m also having real problems with lines randomly appearing in my prints and trying to correlate whether the 2 are related. Anyone having the same?


I filed a case with Formlabs. When they got back to me after having sent them a video they came up with the fix that they needed to turn the electromagnet strength down and it would solve the issue. This was after having me check my pre-form firmware update to make sure it was all update. Also had me check the firmware on the printer to make sure they matched.

After having done this they remoted in to my printer, turned down the strength of the magnet. After that I needed to reboot the printer for it take affect.

This fix worked for 3 prints. Then it came back and it has been there ever since. It is not quite as prominent as it was before but is still there nonetheless.

Form 3 Loud Clicking sounds

We have three formlab 3 and all started clicking around the same time. ~ Mid Nov. All at the same time. We did a firmware and software update around that time so we thought that. We also wondered if it was the resin we have started to use Tough2000 as it is thicker. Would be interesting to hear others resin use?


I caught two distinct clicking sounds on video, one rapid and one slow:



They started happening right after I installed a new v2.1 tank and did my first print in Elastic 50A. I cleaned and regreased my X lead screw but it didn’t help.


i have the same problem with the clicking anyone have the answer it started with tough 1500


Hi @pitchuk the clicking noise it also happens to me with Tough2000. I haven’t solved the issue yet.


Unfortunately, I encountered the same Clicking issue, highlighted by @rkagerer in video #1 .
At the time it was using Tough2000 and it happened at the same time as in the video.
I will reach out to support and see whether they offered a solution