XL Nextruder Main Plate and Idler Lever - (For Flex Filament)

I was having a lot of trouble printing with flexible materials like Ninja Flex on my XL so I decided to modify the existing parts to try and eliminate the filament jams. Initially i started with reducing the friction from the filament sensors as described in the post here: https://forum.prusa3d.com/forum/original-prusa-xl-tool-changer-user-mods-octoprint-enclosures-nozzles/xl-filament-sensor-mod-for-tpu/?_gl=1*1wbh0eg*_ga*MTQ1MTUxNjYwMC4xNjQ5NDU5NTc3*_ga_3HK7B7RT5V*MTcwNjQxNjcxMS4zMC4xLjE3MDY0MTg0MzUuNjAuMC4w#post-678181

These Nextruder parts have been modified to reduce the amount of space available for the filament to shift around during the extrusion and retraction actions during printing. 

When I first received my XL, I switched the nozzles to steel so I wouldn't need to worry about wear when switching to and from more abrasive materials (just like I have done on my MK3s and MK4). In my testing with the steel nozzles I was able to eliminate the jamming issues with these modified parts, but still had issues getting good extrusion and fill (even with very low max volumetric speeds and higher temps). After switching to a brass nozzle for testing, the results were much better and and everything was working with default temp/fan/and volumetric speed settings. I have also tried lower volumetric speed settings and everything seems to be printing extremely well.

• Lesson here is use a brass nozzle for flex filaments for better stability on the XL

My thought is that the steel nozzle tip was cooling down too much even with the cooling fan turned down to 10%. This is likely what caused problems when there were many retractions occurring in a short time (like when printing text).

I have uploaded the gcode files for reference on the supports used. Settings for the parts are:

• 0.25mm nozzle
• PETG filament (I used Prusament)
• 0.1mm layer height
• Supports used on the overhangs on the main plate

When the parts are done:

• Use a 7/64" (top) and 5/64" (bottom going into the nozzle) drill bit to carefully clear/smooth out the filament path holes in the main plate
• Remove any small plastic blobs that may be in the filament path along the edges of the main plate holes and the guide path of the idler lever parts

For the test prints in the pictures - the first number is the max volumetric speed (mm3/s), second number is the extrusion multiplier, third number is the added nozzle temp above default, the last number is the fan speed (60% was default).

Please let me know how these parts work out for you.

April 17, 2024 - added files with smaller sized holes for the bearing pins to provide a tighter fit in the lever assembly. The model file i downloaded from Prusa had a hole size of 3.25mm which gives a loose fit in the assembly. My pins measured 2.9mm in diameter and the 3mm hole size provided a snug fit. There is also a 3.05mm and 3.1mm hole size depending on the diameter of your pins and the fitment you would like.

May 16, 2024 - added the step file for the nextruder main plate 5. 

Modified the main plate and idler lever parts to help prevent the flexible filaments (like ninja flex tpu) from jamming behind the nextruder gear, under the nextruder gear, and buckling of the filament. Made the spacings smaller that feed and guide the filament into the nozzle tube. also added material to block off access to the area behind the nextruder gear similar to what great_purge_of_mandalore has done with the MK4 main plate model.