Real-time feedrate control for a mortar 3D printer

[MegaGorilla]

Hello everyone,

I am currently working on a 3D printer that utilizes a Duet control board to print objects by layering mortar material extruded from a nozzle. I am facing issues with the line width of the extruded mortar and need help from the forum to address this problem.

The mortar material is pumped through the nozzle, but the flow rate from the pump is not constant, resulting in some fluctuation. To address this issue, I plan to measure the flow rate of the mortar and linearly control the nozzle's movement speed to match the pump's flow rate.

However, I am having trouble achieving this real-time linear control using G-code. For example, with a G-code like:

G1 X0 Y0 Z0 F12000
G1 X100 Y0 Z0 F12000

I cannot linearly control the feedrate between X0 and X100 based on feedback. I am looking for a solution that allows me to adjust the F value with good responsiveness and in real-time. Any suggestions or guidance would be greatly appreciated.

Thank you in advance for your help.

[chrishamm]

@MegaGorilla RRF doesn't support live feedrate updates because moves are computed and finalized before they are executed. You could try to enable segmentation (M669 T parameter) and check if that improves responsiveness of the speed factor.

[MegaGorilla]

@chrishamm Thank you for your response.
I will adapt the T parameter of M669 and see how it works.