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.


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…