Multiple extruder motors simultaneously movement



  • For a pellet extruder, I have a second screw, pushing the pellets towards the main barrel and screw, Sometimes pellets get stuck in the hopper, this motor and screw will prevent this. The thing is I actually need it to always run after startup or to run when the extruder motor is turning.

    Anybody here knows how to pull this off?



  • Is the second screw just an agitator or does it actually have positive pellet movement?



  • just an agitator yes. It isn't tied to the walls of the hopper, just there to stir everything up and push it to the orifice of the pellet extruder, could be turned on permanently after power up



  • In that case why don't you just used a small DC motor which is wired straight into your power supply?



  • @JustinCase said in Multiple extruder motors simultaneously movement:

    agitator

    I have multiple steppers laying around, and some control over the speed would be nice



  • Just off the top of my head maybe you could try specifying another motor for you extruder using the M584 E#,# command. That way when the extruder is driven your agitator will also be driven. This is assuming you have a spare stepper driver available.

    This will not give you speed control though.



  • @stienfromarden said in Multiple extruder motors simultaneously movement:

    For a pellet extruder, I have a second screw, pushing the pellets towards the main barrel and screw, Sometimes pellets get stuck in the hopper, this motor and screw will prevent this. The thing is I actually need it to always run after startup or to run when the extruder motor is turning.

    Anybody here knows how to pull this off?

    Yes, that shouldn't be any problem. It's fundamentally the same as using a mixing hot end where there are multiple inputs but a single output. Your case would be slightly different and more akin to using two extruder motors in a push - pull arrangement.

    Start by adding the second stepper motor but treat it like an extruder

    So M584 Eaa:bb (where aa and bb are the drivers to which the extruder stepper motors are attached.

    Then define the tool to use both extruders e.g.

    M563 P0 D0:1 H1 (in this case D0 is the first extruder which you set up in the M584 and D1 is the second extruder.

    Then you need to set the mixing ratio but in this case, you want both extruders to feed the same amount. So

    M567 P0 E1.00:1.00

    Then whenever you send a G1 extrude command, both motors will turn. You can vary the speed of the second extruder by altering the steps per mm or by adjusting the mixing ratio. But make sure that the mixing ratio for the first extruder is always set to 1.00. So M563 P0 E1.00:0.5 would run the second extruder at half the speed of the first. M563 P0 E1.00:1.5 would run the second extruder 50% faster than the first. (Note that I haven't tested this but it should work in theory).



  • @deckingman, that is a much more thorough explanation than I gave. Thumbs up!



  • @JustinCase said in Multiple extruder motors simultaneously movement:

    @deckingman, that is a much more thorough explanation than I gave. Thumbs up!

    That comes from years of doing crazy things with multiple extruders 🙂



  • Thanks guys will give this a go tomorrow!


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