Bob Marley (Jammin') in the heat break
I just put together the MMU and tried printing the "fine positive features" file as my first print to test retraction settings (maybe not the best choice for first print?):
https://www.thingiverse.com/thing:533472/#files
I used the default slic3r settings for PLA (215 first layer then 210, 4mm retraction, etc.)
I'm using just one material to start, and the first layers print ok, but when it gets to the spikes where a lot of retractions are used, I'm getting bad jams in the heat break where the filament gets a buldge on the end and can't retract up into the PTFE tube. When this happens I have to completely disassemble the hotend and remove the PTFE tube from the heatsink to clear it.
I checked that my heat break and PTFE tube are chamfered and as far as I can tell, the PTFE tube was seated all the way down correctly.
One thing to note. With both the installed and the spare PTFE tube that came with it, I couldn't push the Y spliiter down far enough for the screw hole to line up with the extruder adapter. This is mentioned by many people in the comments here (Step 9 - mounting the Y splitter part 2):
http://manual.prusa3d.com/Guide/2.+Multiplexer+assembly/361
Several people mentioned needing to trim the PTFE tube by 2mm so I held my nose and trimmed 2mm off the Y splitter (non-chamfered) side, then used a drill bit to restore the conical entrance, per the instructions. (Note: The trimmed side is not where it is jamming.) The only other option would have been to drill out some plastic from the bottom of the Y splitter to make more room for the PTFE tube to go up into it.
Just my luck, but as I was disassembling the hotend to clear this jam for the 4th time, I removed the trimmed PTFE tube and left it on my desk, it rolled off the back of my desk and down an air vent, probably never to be seen again. 🙁 So now I'm down to the spare PTFE tube. I could trim the remaining tube, but if trimming caused the problem, I don't want to mess up my last PTFE tube. Is there a USA source for replacements?
Any suggestions?
Re: Bob Marley (Jammin') in the heat break
Yeah. Don't trim the PTFE - measure to confirm correct length (41mm). If trimming is really necessary, trim the top end only. Install PTFE properly (it's all here, but to summarise):
Unscrew the heat break from the heat sink by half a turn
Insert the PTFE - tapered and chamfered end first and holding the black locking ring down
With pressure on the top of the PTFE tubing, loft the black locking ring
Maintaining the pressure on the PTFE tube, tighten the heat break into the heat sink (by hand only)
Check that the black locking ring is still up.
Re-assemble.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Bob Marley (Jammin') in the heat break
Thanks Peter, that helped a lot. It was a very tight fit, but I was able to do it. This really should be part of the official instructions. 🙂 From the comments on the Prusa manual page it looks like several people are resorting to trimming it...
Do you know if there any source besides Prusa for getting replacement PTFE tubing?
Re: Bob Marley (Jammin') in the heat break
Thanks Peter, that helped a lot. It was a very tight fit, but I was able to do it. This really should be part of the official instructions. 🙂 From the comments on the Prusa manual page it looks like several people are resorting to trimming it...
Do you know if there any source besides Prusa for getting replacement PTFE tubing?
Apparently it is made by Festo with a nominal inside diameter of 1.9mm.
Capricorn tubing may work, but that is only 1.8mm ID nominal, so is a little small.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Bob Marley (Jammin') in the heat break
Capricorn tubing may work, but that is only 1.8mm ID nominal, so is a little small.
Peter
I did the testing for the Capricorn tubing and the MM setup. It works really well. The actual ID is closer to 1.85mm.
Re: Bob Marley (Jammin') in the heat break
I did the testing for the Capricorn tubing and the MM setup. It works really well. The actual ID is closer to 1.85mm.
I just wish it was more easily available...
Only found one place to purchase (FaceBook) so far and that doesn't work for me.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Bob Marley (Jammin') in the heat break
[url] https://www.tinymachines3d.com/
They sell the Capricorn there. One meter and two meter lengths. Hope that helps and hope I did it correctly. I'm a bit technologically impaired.
Neal
Re: Bob Marley (Jammin') in the heat break
That's great, thank you, but they don't have stock as yet and they are not in the EU.
I will have another look in a week or so.
I would like to use this stuff throughout; it would make the extruder pressure a load more consistent.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…