SOLVED: Taz 6 auto leveling is >0.5mm off (NOW PERFECT TO 0.01mm!)

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ritmopat
Posts: 100
Joined: Wed Feb 13, 2019 9:22 am

Re: SOLVED: Taz 6 auto leveling is >0.5mm off (NOW PERFECT TO 0.01mm!)

Post by ritmopat » Wed Feb 20, 2019 9:33 pm

I just finished getting my bed level here’s how i did it.... found out how much i was out front left corner apx .6mm had to raise the other three... i had a old ‘feeler’ gauge set and cut the correct size thicknesses i needed for each corner... the trick was to cut three for each pad so as to to distribute the load evenly when you tighten the two allen bolts or the pad will distort and set crooked . took off the washer took shims (3) and placed them under the printed pad and tightened the two screws that hold the pad to the alum plate ... then i noticed that when i now tighted the washer it was a little cocked so i made one more shim and placed it on the backside of the screw under the washer and tighted the screw so the washer is now flat (screw - allen bolt ). got all my corners to within .05-.1mm..... didn’t know about having to do the ‘z’ offset afterwards support helped out with that now i just have to tweek my z offset a little more ... but i’m happy for now ... i can post pictures if anyone needs

JoeBowler300
Posts: 63
Joined: Thu Apr 28, 2016 12:20 am

Re: SOLVED: Taz 6 auto leveling is >0.5mm off (NOW PERFECT TO 0.01mm!)

Post by JoeBowler300 » Sun Feb 24, 2019 12:00 am

First off, kudos to cmidgley for this exceptionally informative post! I ran the tests and found my tolerance differences to be .542 max between the largest and smallest reading. I printed off the shim leveling corner.stl files with a layer height of .05 and added them where needed. Two in the right corners and one in the back left. I then ran multiple 10 tests varying times over several days. My average tolerance is .130 And now after the new firmware release v1.1.9.34 I'm getting readings within .101 and .107 (only ran 2 tests so far with the new firmware).

These are the commands I run:
M420 S0 ; shut off auto-leveling
G28 X Y ; home the X & Y axis
G28 Z ; home the Z axis
G29 V4 ; Perform Auto Leveling Test, verbose output

@ritmopat
..... didn’t know about having to do the ‘z’ offset afterwards support helped out with that
I don't understand why you would have to re-adjust your z-offset?
If you placed shims under the supports that hold the glass bed and then secured it back with the washers, you effectively raised the bed and your z-offset the exact same height in parallel, thus which means your z-offset was raised 0 height and remained exactly the same as it was before.
z-offset is measured from the top of the washer to the bed. So the top of the washer is the 0 reference point, move down in a negative direction towards the bed, the height between your bed and the top of the washer is the z-offset.
https://www.lulzbot.com/learn/tutorials/Z-axis-offset

Secondly the screw should not go in crooked or slightly cocked, that would've been your fault not screwing it in correctly and started cross threading the screw. I experienced the same problem, screw was going in a bit crookedly, I backed it off, re-adjusted and screwed it back in. It went in straight and flush with the top of the washer.

ritmopat
Posts: 100
Joined: Wed Feb 13, 2019 9:22 am

Re: SOLVED: Taz 6 auto leveling is >0.5mm off (NOW PERFECT TO 0.01mm!)

Post by ritmopat » Tue Feb 26, 2019 10:16 pm

hey joe i’m not the only one that has noticed cocked washers. here’s the real problem! see video https://youtu.be/k7jnekVjxw0 also notice the picture without the back support screws the washer will tilt every time do you notice the ‘gap’ under the washer....
Attachments
64E3A681-4376-44F5-B6F7-3C0B33CC84B3.jpeg

joshdanielsjr
Posts: 1
Joined: Fri Apr 05, 2019 2:43 pm

Re: Taz 6 auto leveling is >0.5mm off on two opposite corners

Post by joshdanielsjr » Fri Apr 05, 2019 2:50 pm

cmidgley wrote:
Fri Oct 19, 2018 8:20 am
I think (hope...?) I have solved this problem! TL;DR? Bed has to be physically leveled to far better than 0.5mm in order to automatic leveling to work.

It became clear that my bed was out-of-level enough physically that the auto-leveling was just plain messing up - it was off by more than 0.5mm. To fix this on the Taz 6, I had to come up with some trick to level the bed physically. I made a very simple one-layer model of soft corner mounts, so I could place them under the pads but above the aluminum bed - thereby raising the heated plate and the washer (on the standoff).

To determine how much to offset each corner, I used the following commands:

Code: Select all

M420 S0		; turn off bed leveling
G28			; level X/Y/Z
G29 V4		; level bed, with full diagnostics
This would come back with a report something like this:

Code: Select all

...
Recv: G29 Auto Bed Leveling
Recv: Bed X: -9.000 Y: -9.000 Z: 0.209
Recv: Bed X: 288.000 Y: -9.000 Z: 0.174
Recv: Bed X: 288.000 Y: 289.000 Z: 0.026
Recv: Bed X: -9.000 Y: 289.000 Z: 0.541
...
From the above, you can see I was off by more than 0.5mm (comparing the Z values for each corner). The highest corner in my case was the back left corner at 0.541, so I needed to raise the other corners (since it's much harder to lower a corner).

What I did is design a simple one-layer shim that matched the corner gaskets (that hold the standoff to the washer and the two screws), and printed about 10 of them. I inserted them above the aluminum plate but below the gasket - thereby raising the standard and the heated bed. After each attempt, I would run the g-code sequence again looking at the Z numbers. As I got close, I took a flat blade and scraped some of the shims to get back a tad of space.

Once I did this, I got all corners physically within 0.07mm!

Code: Select all

...
Recv: G29 Auto Bed Leveling
Recv: Bed X: -9.000 Y: -9.000 Z: 0.484
Recv: Bed X: 288.000 Y: -9.000 Z: 0.473
Recv: Bed X: 288.000 Y: 289.000 Z: 0.459
Recv: Bed X: -9.000 Y: 289.000 Z: 0.523
...
Now when I run automatic leveling - looking at the Z distance at each washer (and using the M119 command to verify z_probe accuracy down to 0.01mm) - I am now level at all four corners within 0.01mm!

I'm going to run a series of print tests, but it sure feels like I've at least nailed the basic leveling problem.

Big shout-out to b-morgan for helping! His pointing out the usage of M119 with G29 V4, and running a test to show his printer had similar (but far less) alignment issues helped big time to figure this out. And ... @b-morgan ... consider adding a .2 shim to your back left washer! That should nail your alignment...

Chris

MY GAWD! Thank you! I tried everything up until I found you post. Come to find out my deviation was .7mm. The shim idea worked beautifully and I was able to physically level my build plate up to a .08mm deviation between the washers. I do have one question however, how do I take this down to .01mm as you did using the M119 command. Could you please elaborate on this?

Thanks for your contribution

cmidgley
Posts: 9
Joined: Wed Nov 22, 2017 6:13 am

Re: SOLVED: Taz 6 auto leveling is >0.5mm off (NOW PERFECT TO 0.01mm!)

Post by cmidgley » Fri Apr 05, 2019 3:06 pm

joshdanielsjr wrote:
Fri Apr 05, 2019 2:50 pm
Come to find out my deviation was .7mm. The shim idea worked beautifully and I was able to physically level my build plate up to a .08mm deviation between the washers. I do have one question however, how do I take this down to .01mm as you did using the M119 command. Could you please elaborate on this?
No real magic here, and if you are at .08mm you are set! M119 just lets you know EXACTLY when the probe senses the disc, so you can slowly lower Z until it touches (tedious because you need to move it just a bit, and check M119) but you can then know how far off you are and either adjust the spacers, or change your z-probe height. But I've found since writing this that it isn't that important, at least for me, as I adjust z-probe a fair amount based on filament type and print head being used. Get the table (mostly) level is the key to success. Also the newer firmware does a much better job of leveling (smarter about how it lefts off the probes to get an accurate read) and that helps.

Glad this was able to help you. My table has remained level ever since doing this and I'm doing edge-to-edge prints (massive) with great success.

pops
Posts: 26
Joined: Thu Jan 25, 2018 7:28 am

Re: SOLVED: Taz 6 auto leveling is >0.5mm off (NOW PERFECT TO 0.01mm!)

Post by pops » Thu Apr 11, 2019 12:07 pm

I would like to thank all who have contributed to this thread. My bed was way off and I did not know what to do about it until this thread came along. Now, after printing and placing several shims and understanding the leveling commands, I now have my TAZ 6 dialed in pretty well.

Once again, thanks!

aggie6801
Posts: 1
Joined: Fri Apr 12, 2019 10:35 pm

Re: SOLVED: Taz 6 auto leveling is >0.5mm off (NOW PERFECT TO 0.01mm!)

Post by aggie6801 » Sun Apr 14, 2019 7:30 am

I want to add my thanks to all involved in this discussion! Thank you for the explanations and ultimately the solution!

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