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.

7

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

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?

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.

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