Skew does not have a positive effect

General Discussion
1

Basic Information:

Printer Model: Voron Trident 250
MCU / Printerboard: Octopus Pro 1.01

Describe your issue:

I used the Califlower Calibration STL Tool. So there was a Skew. I did all what was supposed to be, like SET_SKEW XY=101,99.5,70 – saved it, and it was also loaded at the end of PRINT_START.

After 3 test-prints, it’s still not better, actually even slightly worse.

Any idea, why that could be? Or in other words - IF Klipper gets the proper skew-information, will it improve it about always? (meaning the fault is still on my part. Or are there cases, where it just does not unskew even with proper ‘skew-repair informations’?

cheers and thanks

PS: printer does not work right now (for a week or two) - so no klippy-log :frowning:
…

2

Hello @calmar !

With what command?

Don’t you think getting the printer running again and then fix the skew issue would be the proper way?

3

Please attach your klippy.log.
I printed the latest califlower yesterday but did not proceed yet.
Last time I used it it worked flawlessly.

Edit:
Did you put the [skew_correction] into your printer.cfg?

Screenshot_20240203_215012_Acrobat for Samsung
Screenshot_20240203_215012_Acrobat for Samsung986×226 51.2 KB

4

SET_SKEW XY=101,99.5,70
SKEW_PROFILE SAVE=my_skew_profile
#end of PRINT_START macro:
SKEW_PROFILE LOAD=my_skew_profile

and: GET_CURRENT_SKEW reported a degree or something what needs to be corrected.

But all right, I will wait until I get the part I need for the printer, and do all over again - even so I printed 4 of those califlowers already. Left me a little bit sad … :slight_smile: Maybe I just print a big cross in the future for that purpose instead of the califlower

so thanks a lot! either way.

5

What I miss is the SAVE_CONFIG

https://www.klipper3d.org/Skew_Correction.html#configure-your-skew

6

All that would be visible in the klippy.log if I’m not wrong.

1 Like
7

Yes, I forgot that to mention sorry… It was saved in the config. At the end.

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8

I will provide it, once the printer runs again. All right thx.
And yes, I have that in the config: [skew_correction]

I guess it’s more complex, but basically the skew in klipper will just calculate the corrected G Moves on each G-Move-Command on the fly or similar?

1 Like
9

Maybe i’ll get this done tomorrow and can test it with latest Klipper version.
On my v0 it works fine.

10

I still don’t understand, how and what function gets called/issued during printing here, klipper/klippy/extras/skew_correction.py at master · Klipper3d/klipper · GitHub , to apply the correction :slight_smile:

11

So I had some time to measure the new CaliFlower version.
I was expecting a bigger skew for X and Y but the Excel sheet and the measurements for step 9 and 10 resulted in -0.01° only… :sunglasses:
Good for me but does not help you.

When following the instructions at least its saves the profile and if loaded reports back the right skew.
As I have to discover and fix some other problems on my upgraded printer I do not have time to play with skew yet.
Will just print the flower again as I have to scale it to 100.16% for the current filament.

As to your last question, I think the whole calculation is hidden in the Klipper core and just fed with the passed skew parameters.

1 Like
12

Now it does work. According to the log, it was not loaded.
(I will still try to fix it physically, but klipper is all right obviously).
Assuming I made some stupid stuff, I will chip-in some bucks as an excuse at least :slight_smile:
thanks all

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13

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