Direct drive extruder and Bowden extruder on one machine?

theruttmeister

Nifty.

I'd be worried about the long term durability of what looks like printed gears in that gearbox...
But I've bought enough LDO motors over the years to trust them (even if I would plan for those gears wearing away...)

3D printing really has made custom gears the easiest thing in the world!

Marco_76

@deckingman Impressive, I've seen your videos on your channel. I finally made my two flex3Drive working but I will take it as next generation, when I want to modify again my COREXYU

deckingman

@Marco_76 said in Direct drive extruder and Bowden extruder on one machine?:

@deckingman Impressive, ...........................

Most people say "crazy" - (and they are probably right)

dragonn

It does make sense, I am using it right now.
I have a light Nema 14 direct drive and a large nema 17 bowden.
The whole point of that bowden is to feed the filament inside the printer enclose so the small direct drive doesn't have to work so hard to get the filament.
They is one big problem with that, it is hard to get the ratio perfectly, a slight amount to low on the bowden extruder and after some hours of printing it will span the filament bowden the bowden and direct drive. A small amount to much and it will tangle inside the printer enclose.

T3P3Tony

@dragonn said in Direct drive extruder and Bowden extruder on one machine?:

They is one big problem with that, it is hard to get the ratio perfectly, a slight amount to low on the bowden extruder and after some hours of printing it will span the filament bowden the bowden and direct drive. A small amount to much and it will tangle inside the printer enclose.

Presumably the way to fix that is to use a trigger or two setup to measure the filament tension and then as the tension increases, feed a bit more filament. This can either be adjusting a constant feed from the pusher (ie. M220 + 0.1% ) or a simpler option is a loop of filament that as the loop reduces to a certain amount the pusher pushes until the loop increases past a certain amount. AFAIK thats how (some) filament extruders manage the spooling function.

Anything that relies on perfectly aligning extrusion rates of long print time is bound to be very difficult to calibrate.

dragonn

@T3P3Tony what kind of trigger do you have in mind?

I was something like that but didn't found yet how to actually do that.