Bed Leveling - Tried Everything!
Hi all, I just wanted to pop in and share my experiences with getting my bed level so far, along with requesting some help from everyone on what my next step(s) should be. For this, I'd like to take you through what I've done since my printer arrived and was built a few weeks ago.
Quick summary: After trying the built-in bed leveling feature (to adjust the front, back, left, and right), manual leveling with screws and nylock nuts, factory resets, P.I.N.D.A. testing, and print-based adjustments, I cannot seem to make my printer extrude a consistently-level first layer, with the front-right areas always higher than the rest of the board.
First Round - Stock build
For this round, I attempted to use the built-in bed leveling feature to adjust my front, back, left, and right Z-calibrations to get a good, consistent first layer. I used a combination of test prints from life adjust Z - my way and running G80 then G81 to see how close I could get my results. In the end, I ended up with something not terrible, but it was the result of pushing every offset to its limit, so I wanted to try something else.
Second Round - Manual Leveling
While I considered going the route of Hyperfine Bed Leveling, I didn't want to mess with firmware just yet, and I was interested in the advantages of a manually-adjustable bed, so I went ahead and tried Bed Leveling without Wave Springs. In the end, I got measurements from G80 and G81 that were incredibly smooth, within 5% variance from the center measurement, but when I went to run test prints, they looked no different from stock, with the nozzle clearly closer to the bed in the front-right areas.
Third Round - Experimentation
At this point, I tried messing with factory resets. No difference. I tried using the Calibrate Z menu option instead of G80, which produced very different numbers, but identical print results when I adjusted my leveling screws to compensate.
Fourth Round - P.I.N.D.A. testing
My conclusion at this point was that the P.I.N.D.A. probe must be faulty, so I went through the steps on P.I.N.D.A. Probe testing to see if maybe there was an issue there. No luck. Everything came back perfect, and the P.I.N.D.A. responded as expected for all heights and X positions. My next attempt was to adjust my leveling screws based on actual print measurements, completely ignoring my G81 outputs. This also didn't make a difference, as it seemed the software compensated for any changes I made.
Current Conclusion
My best guess at this point is that this is either something with the probe or the software's calculations. No matter how I adjust my bed, it seems as if the probe is compensating. It's as if the bed has a different idea of level than me. Has anyone experienced this before? And if so, is there something corrupt in my firmware that I should look into? I'm running 3.5.1. Thanks!
Re: Bed Leveling - Tried Everything!
hey, if it helps. the main thing I noticed is a few of us have to "warm up" the bed and hot end sometimes.
I swear the printer doesn't know how to deal with temps from the pinda while doing its calculations for leveling
don't know if that helps you, but before I preheated,it would be like 2 failed first layers then the 3rd would always work.
I have a Prusa,therefore I research.
Re: Bed Leveling - Tried Everything!
I have seen an increasing number of posts recently about this exact issue, so while it is not help, you are not alone..
There being something in the software doing this seems very plausible, so many posts on this exact issue have recently come up . Have you tried to downgrade to an earlier version? Like 3.4.1? I did not do the 3.5.0 upgrade when it came out because I saw reports of issues, and now the 3.5.1 sure seems to have a lot of people with similar issues with bed leveling and a higher right front from the rest of the bed, which is doubtful it is due to user error with so many reports at the same time...
I hope it is a software issue so it can be fixed more quickly as opposed to an issue with components which are out of spec or something.
Definitely try the bed heating suggestion to see if it helps and make sure to raise the extruder away from the bed while doing so too..
Strange women, laying in ponds, distributing swords, is hardly a basis for a system of governance!
Re: Bed Leveling - Tried Everything!
I've noticed quite a few people with similar complaints recently as well! Here's hoping it's something in the software that can be fixed soon. I have not yet tried downgrading, but it is absolutely next on my list.
As for temperature, I forgot to mention above, but I have tried calibrating at very consistent temperatures, both "always cold" and also at a regulated 35C, using the gcode below:
G28 W ; home all without mesh bed level
G0 X50 Y50 Z70 F1500 ; Raise PINDA in case cooling is needed
M860 S35 ; Wait for PINDA <= 35C
M190 S60; set and wait for bed temp
M104 S170 ; set nozzle temp
G0 X50 Y50 Z0.15 F1500 ; this is a good PINDA heating position
M860 S35 ; wait until PINDA is >= 35C
G80 ; mesh bed leveling
G81 ; check mesh leveling results
G4 ; wait
M104 S0 ; turn off temperature
M140 S0 ; turn off heatbed
G0 X50 Y50 Z70 F1500 ; Raise PINDA back for next iteration
Re: Bed Leveling - Tried Everything!
I preheat with the extruder at 0 z
and about center
I have a Prusa,therefore I research.
Re: Bed Leveling - Tried Everything!
Hi, exact same issues for me, tried almost everything, there is something wrong with the firmware i guess, I'll try to completely disable G80 and see how it works. I also use a start script to wait for PINDA temp > 35c, Im really tired fighting this for a month now... Next step for me would be a careful analysis of the source code of mesh bed leveling.
Re: Bed Leveling - Tried Everything!
Am tired of this as well.
Since most people are just guessing, how about a general test WITHOUT bed leveling, like most cheap printers do? The Prusa should be at least equal, right? Else it would be a mechanical issue.
So, is there a way to get any of the current firmware builds with the Pinda probe completely disabled just for testing?
In theory it should be pretty easy to level the printer manually and then just start the print and see if its still warped.
Re: Bed Leveling - Tried Everything!
There is a temperature calibration for the PINDA. Run it, then ensure PINDA is warm before doing the bed level routine -- easy to add a wait for PINDA temp command M860 (the PINDA is heated by nearby hot parts, not internally):
M104 S185 ; set extruder partial temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
M109 S185 ; wait for extruder temp
M860 S35 ; wait for PINDA temp to stabilize
The other fix was to grab a copy of the user generated firmware that has the 7x7 bed cal.
When printing PLA, my PINDA hits about 37c to 40c max, so letting it warm to 35 before calibrating Z - along with the 7x7 cal matrix - has fixed my layer 1 print to print variation.
fyi: the 7x7 cal method will be in a soon to be released version from Prusa, too. Keep your eyes open for it.
And for those who want to try a print without bed leveling: do that at your own risk, but it's easy to comment out the G80 bed level command in the custom startup gcode.
; G80
Re: Bed Leveling - Tried Everything!
Its not just my printer having this sort of issue then. I've tried to contact Prusa Research several times and they have not responded. Its getting really frustrating.
I took a video of the issue, anyone know how I can upload it here?
Re: Bed Leveling - Tried Everything!
Park it in a zip file and upload the zip. Google share, YouTube share ... etc.
As for a test with the PINDA out of the picture? No. The PINDA sets the home level. It must be operable; but you can turn off the bed level routine. But I really don't know just how the printer will react, if it uses the precision bed cal numbers (L,R,F,B), or if it just prints using the home point as zero (a risk of a bed high spot contacting the nozzle).
Re: Bed Leveling - Tried Everything!
I spent about 2 months getting this right on my MK3. Same issues as described and same troubleshooting steps.
I believe the problem is that either there are slight non-linear variances in bed levels which are not detected by the 3x3 points measured or there is some interference that causes the PINDA to have incorrect measurements in certain areas of the bed. Whatever you do to level the bed better physically is compensated for by the auto bed leveling so the problem persists whatever you do.
The firmware assumes 'linear' interpolation which I don't think is correct given the sparse 3x3 and the micron levels that the printer deals with (especially if adhesion is not quite all there). For instance when you add 50 microns using the manual bed leveling settings to the right, +50 is added to the 3 right points but +25 is added to the 3 center points too. That makes it hard to fine tune things.
What I ended up doing was to modify the firmware. I introduced a new code (G89 was available) that allows me to tweak the 7x7 mesh points individually, after interpolation is done. The offsets seem to be pretty consistent between prints and I've never had to tweak them once I got them right. I also pre-heat the PINDA to 40C before each print which takes a while but has been working well for me for the last month or so.