Magnetic filament monitor for close loop stepper motor control!

[brunofporto]

The title says it all. Why not use the same board. A small magnet at the stepper axis on the back and a small printed adapter to hold the board in the correct place. Not sure how the firmware would handle it but it can work as a cheap closed loop motor controller for duet

[elmoret]

Already exists, check out Mechaduino.

But what does it get you? If you're missing steps on the extruder, you're already screwed as it means there's a nozzle blockage or some other issue preventing filament feeding. Closing the loop doesn't help, aside from being able to notify the user to intervene.

And if that's the goal, then you actually want a sensor on the filament, as a closed loop stepper motor would have difficulty sensing the hobbed gear slipping, or running out of filament entirely.

[brunofporto]

@elmoret I was not thinking about filament detection but as a closed loop for the other axis.

[dc42]

Possibly even simpler if it works: mount one of our prototype laser filament monitors on the carriage, so that it looks at an aluminium extrusion that it is sliding along. I think that the speckled appearance of plain anodised aluminium extrusion should be a good target for the laser sensor. Does anyone with one of the beta laser filament monitors have time to test the reproducibility of position detection?

[brunofporto]

@dc42 I tough about the sensor at the motor because it is not dependent on the printer structure, cinematics or material But the laser over extrusion would work too - not sure about the precision or repeatability of any of them though.

That really would be a work for the beta testers!

[T3P3Tony]

@brunofporto would you be up for testing the laser over extrusion?

[brunofporto]

@t3p3tony Sure!

But I do not have the sensor... Please, how can I buy it for testing?

[T3P3Tony]

@brunofporto pls send me an email info@duet3d.com

[brunofporto]

@dc42 said in Magnetic filament monitor for close loop stepper motor control!:

Does anyone with one of the beta laser filament monitors have time to test the reproducibility of position detection?

Soon I will

For now, I will be able to test this at the Y direction as my X only havea shiny axis. Please let me know how I could test this to report!

I could also monitor the X by reading the belts at the Y carriage (CoreXY). The belts movement there only happens when the X moves.

[brunofporto]

I can fit both at my Y carriage design with some modifications

One reads the belt for X the other the frame extrusion below!

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[brunofporto]

Another alternative would be having one sensor facing the heated bed to read both X and Y - but it only works as a first calibration reference.....