The slicer flow rate settings are often ignored / notr in gcode

[CBX_Micha 0]

Hello community,

 

if I specify flow rates other than 100% in CURA 5.6.0 (often 97% for the first layer, then 95%; depending on the material), this flow rate "M221 Sxxx" is mostly not adopted into the created gcode (searching with np++) so the used print server (Repetier) and so also the printer (Marlin 2) don't know about.
Strangely enough, sometimes it works, but despite intensive searching, I just can't figure out under what circumstances it works and when it doesn't.

Is that just me?

[Slashee_the_Cow 272]

You don't have to use the M221 command to set flow rate - you just calculate it the extruder position.

 

Try making some gcode with flow rate changes, and then one that's 100%, and see what the E value is in the last G1 move on the first layer.

 

All that M221 does is do those calculations for you.

Edited February 6 by Slashee_the_Cow

[CBX_Micha 0]

Hmmm... Ok.
This means that the flow rate setting in CURA is converted to the extrusion rate and does not appear as M221 in the gcode... Did I understand that correctly?
This also means that the print server doesn't notice anything and the flow rate set in the print server of, for example, 100% represents the flow rate of, for example, 90% converted into CURA... Correct?

[Slashee_the_Cow 272]

A print server won't notice the difference, it's just sending the code Cura creates. If your server is set to 100% flow rate then it shouldn't touch the values Cura has calculated, so if you had 100% on the server and 90% in Cura, it will go at 90%.

[CBX_Micha 0]

Are there any settings/circumstances in CURA that still allow an M221 to be integrated into the gcode? Because occasionally when the gcode is transferred from CURA to the server, the previously set 100% on the server is changed. I just haven't been able to figure out in what context and why...

[Slashee_the_Cow 272]

50 minutes ago, CBX_Micha said:

Are there any settings/circumstances in CURA that still allow an M221 to be integrated into the gcode?

It could be changed by a post-processing script, and often startup gcode will contain "M221 S100" to make sure the flow rate is set to 100%, but I just searched literally all my gcode files (gotta love Notepad++) and those are the only instances of M221, never in anything generated by Cura itself.

 

Unfortunately I'm not familiar with your server software so I wouldn't know of any other reasons why it could do that.

[ahoeben 1,951]

The flow as entered in the materials category of the settings is never put in the gcode as a M221 command by Cura. Instead this setting is used to calculate the E steps in extruding moves.

 

The "Tweak at Z" post processing script may be used to insert M221 commands in the gcode at certain heights/layers. This command acts as a "multiplier" on top of the flow as entered in the materials category.

Edited February 6 by ahoeben