Form 4 user here. Got this printer 2 years ago and it worked great for about 6 months. Then it consistently failed on every single print, it can’t get past checking for debris. The flex build platform is colliding with the mixer on every print no matter what the material. Specifically, it lowers…

Sounds very puzzling indeed. the closest related discussions I was able to find were - [image] Form 4 Issue with sending print jobs to printer on network, printer is aborting and debris messages Form 4/B/L I have been able to send two print jobs to the printe…

I did. They had me run through all the steps in Form 4 and Form 4L generation error messages | Formlabs For both Error 1.1.6: Mixer detected debris and Error 1.1.7: Build platform detected debris. Neither procedure produced any different result. I did submit a support request in Nov 2025 but I n…

Hi @matthew_henry , I’m a Customer Support Manager for Formlabs, and I’d like to discuss how to get your printer working again with you, as well as your previous Service interactions. I’ll be reaching out.

A simple fix is stop using the flex build platform and see if your having the same issue with a regular build platform

I considered that and took the flex plate off the build platform and reran the align build platform. But it did not help, the build platform still crashes into the mixer.

I think I know what your problem is here, I have experienced the same. Check under the rear wear strips in the back of the resin tank. Lift it up and see if there is an accumulation of cured resin. I believe this causes the mixer to “ride” up and pinch itself on the build plate. I chased this issue …

The cause of this seems to be a bad LPU, I replaced the LPU, cleaned the wear strip and it started working.

I checked that out. None of my resin tanks had any cured resin underneath the wear strips.

Formlabs just sent me a mixer rebuild kit. I swapped out the parts and have done a couple of test prints without the mixer crashing. I will test print a few more times by the end of this week to see if the build platform will crash into the mixer still.

Form4 critical mixer failure

Support & Troubleshooting

Ashwini August 22, 2026, 6:15pm 2

Sounds very puzzling indeed.

the closest related discussions I was able to find were -

I know I am stating the obvious but - how about reaching out to Formlabs Support? Have you reached out before in the last 2 years?

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“Debris detected by the mixer” false alarms Support & Troubleshooting	7	528	May 29, 2025
Form 4 Issue with sending print jobs to printer on network, printer is aborting and debris messages Form 4/B/L	5	516	April 11, 2025
Form4 Flex build plate detaching mid print Form 4/B/L	5	156	August 16, 2026
Form 3+ Mixer detaches and jams beneath build platform Form 3/3+	1	785	March 18, 2023
Form 4 Durable V2.1 giving debris on build plate error even after cleaning Form 4/B/L	8	673	May 1, 2025

Form4 critical mixer failure

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