Very Slow Retraction/Extrusion Movement



  • Hi,
    I have built a printer which uses syringes for printing liquids.
    The syrings in use have a diameter of 30mm and therefore the retraction and extrusion speed and amount needs to be controlled very carefully. This works perfect in conjounction with e.g. a slicer like simpify 3.
    However, problems occur when ventilating the liquid channels, which I solve using macros on the Duet Maestro board. Here it seems to be the case that by default a minimum extruder movement speed is set. If I e.g. use the g code command:
    G1 E20 F0.05
    to very slowly move the extruder stepper motor and vent the liquid channels the extruder stepper moves too fast. This results in very high internal system pressures which lead to leakage at the syringe piston.
    Do I assume right in terms of the default mninimum speed set on the duet wifi and is there any way to tweak it?

    In addition I'd like to either tweak available extrusion speeds of the used 7" PanelDue extrusion interface or completely disable the extrusion button function of the panel. Is there a way to do one of these options?

    Thank you in advance
    Dominik


  • administrators

    The default minimum feedbrate is 0.5mm/s:

    https://duet3d.dozuki.com/Wiki/Gcode?#Section_G0_G1_Move

    For CNC users especially: RRF has a default minimum movement speed of 0.5mm/sec. In firmware 2.03 and later this can be changed using the I ('i') parameter of the M203 command



  • Thank you very much for the fast response!!!
    This will be tested in the upcoming days.

    Will the maximum extrusion speed defined in M203 of the config.g file have an influance on the maximum extrusion speed in the extrusion interface of the PanelDue)


  • Moderator

    @FoxLab said in Very Slow Retraction/Extrusion Movement:

    Will the maximum extrusion speed defined in M203 of the config.g file have an influance on the maximum extrusion speed in the extrusion interface of the PanelDue)

    Yes, the maximum should be respected.



  • Thank you very much for your helpfull answers!!!

    Thus the only remaining question for me is if I can disable the extrusion interface of the panel due somehow or if it is possible to tweak the extrusion speed in this interface?


  • Moderator

    You could edit the PanelDue firmware itself maybe.

    If the extrusion speeds in the PanelDue interface are too high it won't really matter, because if the speed limit is set low in the config.g it won't be able to move it faster.


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