Linear Advance

[kornshadow097 0]

Alright so this seems to be a big and vastly complicated topic... i have several links to share and a ton of factors I've come across during my time researching all of these things.

 

So I'm using a Tevo Tarantula. I am starting to print PETG and experiment with different nozzle sizes. So far 0.4,0.6,0.8 and 1.0. 1.0 being my favorite and lower numbers in descending order. 

Temps I typically use are 235c initial layer and 230 on the rest. fan speeds go from 40% up to 91%. 

 

So lets begin. I've found the following code and was lead to believe that it is the only way to allow cura to work with Linear Advance. Regardless of machine firmware etc, for some reason the algorithms don't work right in cura if you don't use:

M900 K{material_linear_advance_factor}

M900 W{line_width} H{layer_height} D{material_diameter}  

 

After doing that supposedly it works... I'm not sure what version that applies to or if its been fixed.. if someone can chime in great. I'm going to paste a few sources for lin adv I've found and the first one is the one stating this cura issue. The second one is about creating the above fix and creating a plug in. I personally use Marling and it has the k factor settings in there and i don't really need to input anything else...but if cura screws up the process I'd like to know...3rd link is more info about it from marlin. 4th link is about step 2 of setting up Lin adv and it involves setting up my extrusion multiplier... i tried printing several cubes and none worked for me... not sure why.. they just didn't...gonna post about that later... but if anyone has something other than a cube for calibration then let me know. 5th link is in Russian, just use google translate. What i derives is that longer nozzles work better and since this whole discussion is about equalizing pressure well that's also about that topic and could somehow work together with lin adv in my opinion.

 

So there we have it...  Read, and comment.

 

https://mattshub.com/2017/10/02/linear-advance/

https://community.ultimaker.com/topic/21447-gcode-for-different-filament/

http://marlinfw.org/docs/features/lin_advance.html

https://mattshub.com/2017/04/19/extruder-calibration/

 

http://www.dr-henschke.de/waerme_filament.html

[ahoeben 1,948]

Note that the gcode snippet you quoted only works if you install this plugin:

https://github.com/fieldOfView/LinearAdvanceSettingPlugin

[gr5 2,172]

The version of Marlin that is installed on Ultimaker printers doesn't implement the Linear Advance feature (someone correct me if I am wrong).  It's a pretty cool feature but a bit of a hack (since the shape of the amount of extra filament extruded over time when graphed is not the shape of what is needed) but it is certainly an improvement over no linear advance.

[firepower9966 0]

How do you install that plugin?

[ahoeben 1,948]

The plugin is available via the “Marketplace”, top right of the Cura window

[award0586 0]

Where do i enter that code at in the start gcode? Should it be the very first thing?

 

[ahoeben 1,948]

The plugin will insert the linear advance gcode at the appropriate place(s) in the gcode file for you. You don't need to insert anything in the start gcode (anymore).