Success with Shore Hardness A60
For people interested in printing extremely flexible filament this might be usefull.
I was able to print this filament on the MK3: https://flexionextruder.com/shop/x60-ultra-flexible-filament-white/
It has a shore hardness of A60 and is BY FAR the most flexible filament on the market (as far as I know).
There is only one modification I did to the printer:
I changed the PTFE tube to a capricorn PTFE tube and cut it so that it fits perfectly to the extruder gears. You have to cut a v-shape and it should almost touch the bondtech gears.
Extrusion multiplier, retraction and print speed have to be optimized too.
Re: Success with Shore Hardness A60
Only printable with the Flexion Extruder.
Looks like you proved them wrong. Nice work! 🙂
I'm curious, what sort of print speeds were you able to achieve using the replacement tube?
Re: Success with Shore Hardness A60
I print at 30 mm/s.
Funny thing: I have on my second (self build) printer a flexion extruder installed. And with the flexion I encounter the same limitations as on the MK3. E. g. overhangs/bridging are a big problem with that material. I wouldn’t recommend using the flexion on an MK3 because the only thing you would gain is a higher printing speed with extremely flexible materials. With “normal” filaments you gain nothing.
Re: Success with Shore Hardness A60
30mm/s is pretty good! I was expecting it to be under 20mm/s for something that soft.
I had a Flexion on my old Wanhao Di3 and didn't have the greatest luck with it. I was quite a bit less experienced then (i.e. buying it in the first place miiiight have been a mistake, though I did get plenty of use out of it in the long run), but I couldn't quite get it dialed in for PLA. Softer materials printed flawlessly, but it would either slip or grind when I tried PLA. I ended up mostly printing PETG on that printer. I never did have the opportunity to try out any flexible filaments on it before I got my MK3, so it's good to know that the Bondtech setup can handle the same materials without too much fuss.
Re: Success with Shore Hardness A60
I have the dual flexion and use only the HT side for PLA/PETG, … and the standard side for flex.
It was already mentioned in this forum that the (low quality) PTFE tube is too short and the filament path is not exactly straight. It’s a shame that prusa is not recognizing this and updating the parts. It would make the MK3 one of the most versatile printer on the market in my opinion.
Re: Success with Shore Hardness A60
Yeah, when I popped open the idler door I noticed that the PTFE tube was a bit shorter than I was expecting. Considering the one that comes with the Flexion pretty much bumps right up against the gears I think it's safe to say that just shrinking that gap will help tremendously. I'm honestly not sure why PR went with the Bondtech setup considering the extruder doesn't seem to be built to work optimally with flexible filament.
Re: Success with Shore Hardness A60
Extrusion multiplier, retraction and print speed have to be optimized too.
I have some Treed 60 ShoreA filament to test.
Do you use the unusual recommendation of Flexion to print with your filament: "Extrusion width – 90% of nozzle diameter (0.36 for a 0.4mm nozzle)" ?
Re: Success with Shore Hardness A60
I modded my Prusa MK3 for better flexible prints than my RC3 extruder. But now I'm getting X Axis Length calibration errors using this ( https://shop.prusa3d.com/forum/improvements-archive--f85/flexion-extruder-prusa-mk2s-t5169-s10.html ) model. It seems that maybe others are getting it to work. Ive tried all of the basics but Im stuck.
I print primarily TPU for quadcopters and PETG is probably my next most commonly used filament.
Update: TL;DR my post https://shop.prusa3d.com/forum/others-archive--f66/self-test-error-x-axis-length-t13327-s10.html : Use a paper under the PINDA height adjust process when moving the extruder (Step 9, Preflight). Rotate the threaded rods down until it contacts the paper and prevents it from sliding. Then raise it just a little bit so it slides without much/any resistance. Repeat for the right side. Move to the center and use a paper on the bed when also using the PINDA sensor adjustment with the zip tie.
Also consider the tension on the belts, try for 250 (lower number -> tighter). Getting belt tension down to 260 or 250 would be ideal, just dont break something. Support->Belt status. The numbers should be lower and ideally 250 for each. A higher value = looser belts. I didnt change the belt tension (mine were too loose at 270 and 310). Good steps that describe that are here ( https://manual.prusa3d.com/Guide/4.+Z-a ... g=en#s9981 and Y axis belt https://manual.prusa3d.com/Guide/2.+Y-a ... g=en#s8225). Reportedly the Support->Belt status values update after passing the self test. [/b]
See the rest of the discussion and the full thread at: https://shop.prusa3d.com/forum/others-archive--f66/self-test-error-x-axis-length-t13327-s10.html