Hello 3D printing world,

this is my attempt to improve the already awesome extruder of the Original Prusa i3 MK3 a little bit more. I wanted to print flexible materials more reliable. So I started with importing the original body into Fusion360. In Fusion i did the following:

1. I moved the holes for the stepper mount 0,5mm to one side to straighten the filament path. (Take a look at the pictures) (Because of that there is also a new idler and a new x-carriage with the adjusted holes.)
2. I added a better guide for the filament after the hopped gears to prevent flexible filament like "das Filament TPU" from bending.
3. I added a small support thingi for the new filament guide to print it better.
4. I cut a special fitted PTFE tube for the hotend that goes all the way into the new filament guide. The top end is v shaped. (See pictures) Unfortunately I destroyed mine during some experiments before measuring. (Maybe I add that later)

I uploaded a few renders to better see the new filament guide. Since the extruder is already installed on my printer, to give it a few test prints, there is not much to see on the pictures.

I printed a few things in "das Filament TPU" with 30mm/s and 2mm retraction. I had no issues with under extrusion or bending of the filament.
Also PLA and PETG seems to print like before.

I hope you like it.
Bastian