Originally shared by Mutley3D
Thats a direct drive extruder? Now way…Yes way 
http://www.flex3drive.com
time is 3d…time is now!
If you do like the new site, it would be great if you can share it about. The culmination of a lot of work, and i finally got there.
Now way No way
Yes way 
Good spot! thanks
I was planning a extruder with flexibel drive and relocated stepper when I built my printer but the flexdrive`s I found flexible enough had too much torsional backlash so I went for a regular direct drive at the time
I believe that a lightweight (150-200g) direct drive extruder provides better extrusion control than both bowden and flex drive extruders.
@Jan_erik_Halvorsen I feel perhaps there are a couple of points not considered in your comment. Possibly because these points should be made clearer on the new website as we “fine tune” the presentation of the product.
Our flexible driveshafts are torsionally very rigid, specials custom made - not off the shelf parts from china. No rotational flex when subject to the loads existing within a Flex3Drive. We did a LOT of work and sourcing in this regard specifically for this reason and ended up with shafts made to our specification. (we also give a guarantee with these shafts and the whole driveline for peace of mind to customers)
We use a 40:1 gear ratio allowing for a much greater control resolution. This achieves far smoother sub 50 micron layer heights not achievable with 5:1 or 10:1 ratios.
Due to the control system settings, a much smoother (do not read as “slower”) filament motion curve is present and requires much lower stepper driver currents. This contributes to a reduction/elimination of ringing/ghosting artifacts caused by non-optimal stepper motor control.
There is no real comparison with a traditional direct drive extruder, even a “lightweight” one, and that is why we describe Flex3Drive as a performance extruder upgrade.
One thing I worry about is torque generated on the frame transferred to the effector on a delta, bowden just pushes up or down depending on extrusion or retraction, direct drive contains the torque between the mounts on the effector and the drive gear but doe not transfer to the ball joints except as upward pull if the filament is not feeding well. this remote extruder transfers rotational torque to the ball joints if the filament is not feeding from the spool OR the extrusion is too fast for the hotend. In normal function the resistance of the filament to extrusion as it is pushed through the nozzle is translated as rotation to the effector ball joints and arms.
Does the sleeve resist rotational translation of forces to the mounting points of the drive gear assembly? If so, how much play in that?
I see you have been at it a while and made many prototypes so I would not be surprised if that issue has been overcome, but it’s not mentioned in the info I found so far. Just wondering about the details. The 3q hero shot renders look very nice.
@AlohaMilton Short answer is no noticeable torque is transmitted through the effector.
Typically a bowden arrangement has the full force of extrusion (filament force path) acting upon and spread along the whole bowden tube (akin to a brake bowden cable on a bicycle but in reverse) because the PTFE tubing is rigidly connected to the hotend.
As you already hint at, the filament force path in the Flex3Drive is contained solely between the hobb and hotend.
To directly address the core of your question re rotational forces.The 40:1 gearing within the extruder body requires very little rotational force to drive filament. The torque is contained within the driveshaft assembly with the PTFE tube rigidly clamped to the top of the extruder body and top of motor cap at other end.
