Extruder feedrates

[greybeard 0]

The extruder feed rate is given for each X,Y,Z LINE movement. Is that the value at the maximum speed rate of the head? Since all axes are moving the head is moving at

sqrt (Xspeed ^2 + Yspeed^2 + Zspeed^2) So shouldn't this be proportional to the Feed rate and also the Edistance? I don't see any correlation of this from the Gcode generated by CURA. Has anyone seen any example firmware code for controlling the Extruder Motor?

The extruder can also be moved when X,Y,Z motion is off independent of them.

[Labern 774]

there will be others who can share a lot more then me on how it all works but In the firmware there is a bowden tube length which is added into the mix.

there is also something which adjusts the extruder while accelerating and decelerating but i'm not sure if this is implemented.

You can adjust coasting before retracts in 2.XX cura though.

[tinkergnome 927]

I don't see any correlation of this from the Gcode generated by CURA. Has anyone seen any example firmware code for controlling the Extruder Motor?

 

I'm not sure if i fully understand your question... but i think you're on the right track.

The generated gcode is only a request to move the axis along a line segment with the specified feedrate. And it's the task of the firmware to decide how to achieve this.

For Marlin firmware all the relevant calculations are done by the planner. There is also a separate documentation project with some basic informations.