PrusaXL probing in mid air on the back side of the build plate - Hardware, firmware and software help

RE: PrusaXL probing in mid air on the back side of the build plate

pw — Mon, 19 May 2025 11:49:12 +0000

That sounds interesting. We got XL at work and we've been having tons of issues. It began to probe mid-air on print starts resulting in failed bed leveling. Then it downright scratched our sheet. Then under warranty got new load cell and sheet. Replaced the load cell and now I don't know, is like a month after I'm getting stuck filament errors mid-print and once again machine began to probe very erratically. I just got so fedup with the printer that were shipping it back to Prusa for warranty repairs. I've spend like I think now 10-16 hours of fiddling around with the machine on company time. Unbelievable junk this XL single tool head has been for us. Just absurd amount of issues. It's so weird as just today it had issues in the morning. I recalibrated load cell and Z-axis. Nothing helped. Then factory reset and it printed first layer test ok. Then change to PETG and for actual work and like within 15mins stuck filament.

I honestly can't recommend XL from my experiences to anyone. I'm now regretting it was me who suggested XL. Should've got Creality's is it K2 Plus or what or like some Bambu. I've had so insanely good experiences with MK3 lineup, with multiple models. But this god damn XL feels like prototype all over. I don't even remember. I think it's something like 7th issue I've reported to customer support. But now I got too fedup with it. It was kit machine, but every single problem has been found from Prusa assembled parts. It's just... Absurd how bad my experience has been.

RE: PrusaXL probing in mid air on the back side of the build plate

Alex Bogdan — Mon, 12 May 2025 08:01:43 +0000

Also, I Have checked the screws that hold the vertical extrusions, I lubed the leadscrews and the z rails. I don't have the option to calibrate the Z-Offset.(Is that feature for the multiple toolhead versions only?). How do I calibrate that since it seems that the offset could be lowered a tad cause the prints don't seem to stick without glue stick.

RE: PrusaXL probing in mid air on the back side of the build plate

Alex Bogdan — Mon, 12 May 2025 04:05:02 +0000

Hello,

I did both the Z axis alignment, Z axis test and everything in between. Is it possible that in the position i mentioned some wire might be touching and the load cell appears as triggere?

Diem — Fri, 09 May 2025 17:15:26 +0000

First run a self test as if a fail had been reported. It may be enough to reset internal parameters.

https://help.prusa3d.com/article/selftest-failed-xl-multi-tool_686941

Come back if problems persist.

Cheerio,

PrusaXL probing in mid air on the back side of the build plate

Alex Bogdan — Fri, 09 May 2025 10:44:44 +0000

I have been assigned to work with the PrusaXL at work and I’m experiencing some issues while probing.

Firmware updated to 6.2.5

Using the latest PrusaSlicer with input shaper profiles

Printed a Benchy and it worked fine

The Problem: I sliced a 320x320x0.2 mm square to test bed leveling. After starting the print, I noticed an issue:

From the left-back corner (X:20, Y:320) to the right corner, along the back edge of the bed,

The printer probes in mid-air, and the gap between the nozzle and the bed increases at each probe point. but only in the back area(last row of heater cells).

When the nozzle returns ti the front area, the build plate comes back up and probes normally.

So when it prints, the printer starts normally and the offset is just fine but when it reaches the problem area, the bed goes down about 4 centimeter and continues printing but in mid air

What might be causing this issue, and what should I do to fix it?