Counterweight for "flying extruder".

vapvap

Hi,
Can you please tell us how the counterweight of the "flying extruder" is calculated?
As far as I understand, for the effect of "weightlessness" it must correspond to the weight of the extruder itself. To make his weight close to zero.
But based on the viewed photos and videos, the counterweight on some delta printers look very heavy, and on some printers the counteweight cable length is one and a half / two meters ... Why?
Is there some kind of calculation advice / scheme / formula?

P.S. I am printing on the deeply modified Delta.

oliof

Here's how to do it: Add the weight of motor, extruder, and harness. That should be the weight of the counterweight. The length of the cable is to keep the moving weight out of the way of the printer.

For my Kossel with a print height of 35cm and a bed diameter of 24cm I need about 60cm to clear the inner body of the printer -- and to keep the cable weight as much out of the equation I would want to have the same length outside the printer. Accordingly, the cable can be longer for printers with larger print heights or diameters.

Another way to offset the weight is to install a KeyBak to pull the extruder "up", to avoid sagging of the flying extruder on the effector and risking it to crash into the top of your model at an end-of-print move (for example Haydn Huntley's Kumu 3D printer -- see https://github.com/haydnhuntley/kumu-3d for details).

fcwilt

@vapvap Have you considered a remote-drive extruder like a Nimble?

That's what I use on my deltas.

Frederick

vapvap

@oliof Thank you very much! 5*

vapvap

@fcwilt No, I'm using "Bondtech BMG".

fcwilt

@vapvap said in Counterweight for "flying extruder".:

@fcwilt No, I'm using "Bondtech BMG".

You might want to look into a remote-extruder. Very easy to implement and simpler than a flying-extruder.

Frederick

vapvap

@fcwilt Um ... Could you please tell us more about this?

oliof

Remote extruders move the motor away from the extruder mechanism and connect them via a rigid cable. Two commercial options are the flex3drive and the zesty nimble. The direct extruder you put on the effector can be really light (less than 30 grams), not constraining the speed of a delta effector.

vapvap

@oliof It looks great, but I already have a Bondtech BMG.
But in any case, thanks for the good advice.