Marlin: linear advance slow prntng

Created on 12 May 2020 · 12Comments · Source: MarlinFirmware/Marlin

Marlin 2,0 bugfix when linear advance 1.5 is compiled printng is very slow

Attached are the configurations
Configuration_adv.zip

Marlin 2,0 bugfix using TMC2209

Compile with linear advance activated the printer runs very slow and the stepper motors heat up.
Compile without linear advance print speed normal.

Expected behavior: [Printer operates with new marlin 2.0 bugfix linear advance 1.5]

Actual behavior: [Printer does not operate correctly very slow print speed steppes heat up too hot to touch]

Source

Crunch69

Most helpful comment

It's not clear to me, what "very slow" means in this context. Can you quantify this? Also, looking at your configs, there's a couple of potential problems:

Your default extruder jerk of 5 is too low for LA in my experience. I run 15 on an Ender 3 Pro, which should have the same extruder. If the extruder jerk is too low, LA will reduce printing speeds to respect it.
You are running Junction Deviation with a value of 0.02. If your print is mostly slow in corners and curves: That's why. Try 0.04, maybe even up to 0.08, depending on how stiff your frame is and how much ringing you are willing to accept.
You are using S-Curve Acceleration with LA. That is not recommended and officially not supported, as far as I know. Deactivate it and check again.

If these config changes do not fix it, please let us know at which release it was still running fine for you (with the exact same config).

XDA-Bam on 12 May 2020

👍2

All 12 comments

It's not clear to me, what "very slow" means in this context. Can you quantify this? Also, looking at your configs, there's a couple of potential problems:

Your default extruder jerk of 5 is too low for LA in my experience. I run 15 on an Ender 3 Pro, which should have the same extruder. If the extruder jerk is too low, LA will reduce printing speeds to respect it.
You are running Junction Deviation with a value of 0.02. If your print is mostly slow in corners and curves: That's why. Try 0.04, maybe even up to 0.08, depending on how stiff your frame is and how much ringing you are willing to accept.
You are using S-Curve Acceleration with LA. That is not recommended and officially not supported, as far as I know. Deactivate it and check again.

If these config changes do not fix it, please let us know at which release it was still running fine for you (with the exact same config).

XDA-Bam on 12 May 2020

👍2

Sorry to jump in, but why is scurve acceleration incompatible with LA? I've been using these both settings for a long time now, just asking thou.

margaale on 13 May 2020

LA don't account for SCurve correction, so result is quite unpredictable.

EvilGremlin on 13 May 2020

LA don't account for SCurve correction, so result is quite unpredictable.

maybe needs sanitycheck ?

rado79 on 13 May 2020

maybe needs sanitycheck ?

It has.

qwewer0 on 13 May 2020

i have/had both enabled, never saw a warning - or do i misunderstand sanity check?

rado79 on 13 May 2020

Check is not in stable version yet, only bugfix-2.0.x

daleckystepan on 13 May 2020

👍1

ok, but i do bugfix-2.0.x update once a week. no sanity check warnings in VSCode.

Configuration.zip

rado79 on 13 May 2020

😕1

ok, but i do bugfix-2.0.x update once a week. no sanity check warnings in VSCode.

Configuration.zip

This is what you should see if you try to compile it with both LA & S-C enabled and EXPERIMENTAL_SCURVE is disabled:
#error "LIN_ADVANCE and S_CURVE_ACCELERATION may not play well together! Enable EXPERIMENTAL_SCURVE to continue."

qwewer0 on 14 May 2020

@qwewer0 yes, disabling EXPERIMENTAL_SCURVE shows the warning. thanks for enlightening me.

rado79 on 14 May 2020

XDA-Bam thank you deactivated S-Curve Acceleration changed default extruder jerk to 15

Crunch69 on 16 May 2020

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.