New k value?
Hello guys!
I was reading that there is a new k value, is that already in force in firmware version 3.8 firmware?
http://marlinfw.org/docs/features/lin_advance.html
RE: New k value?
I believe the new version is scheduled to be included in 3.9 in November.
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RE: New k value?
Like Bob said, it is not in Prusa's 3.8.0.
You can get LA 1.5 in custom firmware like mine (just comment out the 0.9 degree X & Y motor defines
https://github.com/guykuo/Prusa-Firmware/tree/0.9-Degree-Stepper-Support
or
https://github.com/prusa3d/Prusa-Firmware/tree/MK3_LA15
RE: New k value?
@guy-k2
Thank you very much for that data, how are you doing with the new LA? Do you notice improvements?
RE: New k value?
I'm using Guy's firmware with a Skelestruder and find that the K adjustment is at 0.1 for PETG and PLA, why it can go up to 2.0 is plain daft, it retracts mm's once I set it above 1.0 from the looks of the extruder gear. To be honest 0.1 is too much and it could do with being 0.05
I wonder if there is a scaling bug with the 3.5 gear ratio or something as it seems wrong. In my case all adjustment would be between 0.01 and 0.2 not 0.1 and 2.0.
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.
RE: New k value?
decimal values are OK. Just set up the range and step values to test from 0 to 0.5 when you are making the Marlin test code.
With LA 1.5 values end up 0.075 to 0.1
MUCH lower than with pre- LA 1.5. K is completely redefined in LA15.
If you have not tested with the Marlin code generator, I would leave it off or at 0.1.
RE: New k value?
Thanks Guy,
It was this part from the Marlin documentation that had me thinking the minimum value is 0.1 and must go up in increments of 0.1
Thats great news, going to re run K calibration.
New K value required
As the unit of K has changed, you have to redo the K calibration procedure. See next chapter for details. While old v1 K values for PLA might be between 30-130, you can now expect K to be around 0.1-2.0.
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.
RE: New k value?
marlin has to support bowden fed printers , which will have much higher values the direct drive extruders
RE: New k value?
Wow, I've never used a bowden fed extruder, I had no idea they need squish the filament that amount from what I've seen moving on mine, and the printing speed must have to be so much slower to allow for that amount of filament retraction and de-retraction to print accurately etc.
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.
RE: New k value?
bowden printers have to deal with the flexing of the filament in the bowden tube acting like a spring between the extruder and the hot end and so use larger retraction settings to unload the spring and then retract the filament from the hot end.
one problem with people looking for advice on prusa printers and reading advice for creality printers is the difference between bowden and direct drive