Brand new Form 3+ had its first failure, but it seems to be something to do with the mixer. When the mixer moves towards the RIGHT (away from home), it works fine, but when it returns, it detaches from the magnets on one side.
The detachment seems to occur on the same side, in approximately the same place every time I have tried to get it working again. Using the tank tool, Ive inspected the film and I cant find any stuck resin, or particles.
I also tried running the Mixer Calibration, which picks up the mixer just fine, but when it returns to home base, it detaches again.
The printer had been sitting for ~ 7 days since its last print, but it is away from sunshine and is always closed.
Is there something else I should looking for?
Tough 2000 resin. Tank is ~ 45 days into its 75 day lifespan.
Sorry for the late reply to this post, but I wanted to make sure that you were able to get in touch with our Support Team to get this problem looked into. Please do submit a ticket if not and they will be sure to help!
No Worries, I documented most of my updates over at
since it was a more popular post.
In short, the issue occurred ONLY with Tough2000.
CS send me a new tank to try, and I still had failures
Then they sent me a new printer, still had failures.
Then CS sent me different resin to test (Gray V4) along with a new tank, and I also purchased Tough1500 and a new tank.
I have not had a single failure using Gray V4 or Tough1500.
I have this exact problem and it only started when I switched to Tough 2000 a few weeks ago, before that I’ve never had any issues with the mixer arm coming loose. Well almost no issues, but that was several years ago and from memory it was a firmware bug that was corrected.
As I trust my Form3 less than my RatRig FMD machine I always keep an eye on it when the print starts so I’ve managed to catch all issues when they happened.
But the interesting thing is a pattern seams to be emerging or if it’s just a coincident. However when I first start a print with Tough 2000 it mixes the tank and just before the platform is to comedown the arm moves to the left and detaches in the front magnet just before it reaches it’s resting position.
I manually pop it back on and hit retry. This time it always works (this far), platforms comes down but when the arm returns to it’s resting position after the last swipe (with the platform almost fully down) it does not go all the way in but stays like 5mm under the platform, which then can’t go down fully.
First time that happened I hit abort but is still printed the first layer so I had to clean up the tank.
Now when it happens I just unplug the printer, after starting the same print again right after plugging it in again it has started without problems.
This has happened three times now.
I’ve recalibrated the mixer arm with the tank full and also almost empty, but it makes no difference.
If the mixer always seems to decouple on the same side (i.e. front or back), it’s possible there could be an obstruction on one side of the mixer coupler assembly. I would encourage you to create a Support case for this issue (if you have not done so already) so that we can more thoroughly investigate.
Thanks for the clarification. Overall I would still think that a physical obstruction is more likely, but reflashing the firmware certainly wouldn’t hurt. It is odd that the issue seems to clear up after a power cycle though. If you’d like, you can Inspect the Form 3 mixer coupler to determine if any of the coupler magnets are out of place or whether there is any other obstruction preventing the motor from rotating the coupler into place. Aside from that, there may be an issue with either the particular tank or mixer you are using.
Thanks for passing along those photos. The magnets are regular magnets, rather than electromagnets, so their power can’t be adjusted. They are physically rotated into place by the mixer coupler system in the LPU housing. Testing out a different tank or mixer (or both) would be a good next step assuming you have access to spares.
Ahh I was under the impression they were adjustable, I do not have any extra mixer arms or new tanks. The tanks I have are filled with resin. I do have one old (3 years) Durable tank that was decommissioned due to usage and increasing number of failures. Would you recommend I take that mixer and if so, how do I get it clean?
Something tells me what ever resin was left has now solidified in it.
Is there anything else I could try with the parts I have? (read software vice).
The mixer can be cleaned with IPA. It would be worth testing and swapping it out if you’re able to get it clean. If there is resin solidified in the tank and on the mixer, it may not be worth the hassle. Aside from that, I would run through the steps I mentioned previously: reinstall the latest firmware version, and if the issue persists you can check the mixer coupler for any obstructions.
From what I experience, every time I reboot the printer before starting the print, it works. But if I print and then start another print, the 2nd print will fail with the mixer arm detaching. If just put the arm back, reboot and restart the same print it has worked every time this far. It even works for the calibration which also dropped the arm at one point, rebooted and tried again and that time it worked.
I’ve also examined the tank to the best of my knowledge and can’t really find anything obvious that would cause this, no scraping marks or so. Only thing I can see if one area where the black frame doesn’t seam to be fully adhered to the film.
On this picture you can see if as the larger white area on the upper left edge, irl its easier to see there is what looks like an air pocket under the film.
Thanks for sharing the video and photo. Given what you’ve observed and tried so far, I would strongly encourage you to make a support case to get further advice on the issue. Support may want to send you a replacement tank to test with. I believe trying a different tank or inspecting the mixer coupler would be suitable next steps.
I remember in the recent past there was a suggestion to have the mixer moving via maintenance menu, just like the motors and lpu. Any news on that?
Because it’ll help someone test many times the mixer movement without having to start a print.
It’ll also help us mix the resin in the tank better, even before starting a print.
I’ll keep updating with what I find out about this, as I print the same thing, over-and-over again it’s variables are fairly consistent.
This morning I rebooted and started a print, but this time is failed! So my previous conclusion was incorrect, rebooting does not always solve the issue.
Through this time it didn’t fill the tank, it just mixed it. As all other times it dropped the front of the arm.
I reattached the arm, cancelled the print and restarted the same print again (without rebooting) – this time it filled the tank and started the print successfully.
I had the same issue with a Form 3B+ printing dental restorations with the permanent crown restoration resin. I had my first fail issue with an x-axis screw getting dirty and causing issues. I loaded a new resin tray when trouble shooting that issue, got that print issue fixed, and then the decoupling started happening every print with that particular resin. I read this post, tried an older firmware, another new print tray, took out and checked the LPU, still the same decoupling. The thing I noticed most watching the decoupling is how the trailing end of the mixer lifted upwards when it failed to dock on the left side of the unit. After trying all the recommendations I decided to just remove(cut flat) the retentive portion of the mixing arm towards the front of the unit. The next print worked, but the mixer tended to float a bit close to the build plate (I watched closely until the z axis stop point of the build plate was above the mixer). I had the extra mixer from the first tray that didn’t work so I only took off about 1mm (rubber polishing point on a dremel) of the retentive feature, now it seems to work properly without decoupling or floating back from lack of retention. I think something changed in the mixing arm design that is causing the issue. Hope this helps.