Original Prusa MK3S issues
So I have been using my kit-MK3S for some 3-4 months now, with very great results... but now all of a sudden all my prints start failing.
It seems to stop extruding after a certain height, then pick up again (missed layers with just a drip here and there) It started doing this only after I tried printing a large Vanilla White PLA Prusament object, which seems to be a hell to print anyway with having the extruder go up to 230 Celsius as compared to 215 to all the other colours I have (Lipstick Red, Galaxy Black, Aqua Blue and the Prusa Silver PLA that came with the printer)
But it now seems to get worse: the filament doesn't always unload correctly anymore and I have to pull it quite hard to get it out. I seem to get blobs at the end of the filament that prevent it from unloading. I get under extrusion at the very first layer and so on.
I have tried recalibrating, I have tried different filament's, I have tried loosening or tightening the Filament Idler. I tried to relevel the bed. I have read a shitton about what could be causing this. I've (imho) tried everything except taking the whole extruder apart and re-assemble it... or throwing it out of the window, because I'm really close to do that right now, I'm just THAT frustrated.
I'm running PrusaSlicer 2.0 and run Octoprint on my Raspberry Pi 3B+ which is connected directly to the printer. Also using firmware 3.7.2.
Best Answer by Dimensions of Three:
So, after an extensive chat with the troubleshooters at Prusa, I have found and fixed the issue. I had a tiny crack in the Filament Idler Door that prevented the gear that is attached to it to rotate freely. Every now and then it caught ever so slightly, but apparently just enough for the filament to stop moving. I was able to glue the crack to print a new door and replace it, and haven't had any issues whatsoever since. The new prints are even cleaner than I ever have had, so I think it has been an issue since the day that I've assembled the kit. Currently printing a 12 hour print and have never seen such even layers.
So the issue has been solved successfully!
I am now also running the latest and greatest firmware 3.8.0 and am using Prusa Slic3r 2.1.0 RC2.
RE: Original Prusa MK3S issues
More knowledgeable people can comment, but it sounds like heat is moving too far up your heat break,
and you are getting melting in the MK3S "restriction". This would be fixed by replacing it with a stock E3D V6 hot end.
Better question is - why now?
Did your big PLA part cause any parts of the extruder to melt and sag? Fans still aligned and pumping out air?
OK - someone knowledgeable take over.
RE: Original Prusa MK3S issues
Before doing too much else, I'd suggest reading up on cold pulls and doing a few at a temp higher than your highest (white PLA) print temp. A common problem is to print with higher temp material and have some get stuck in the nozzle or hotend. If you subsequently unload the "hot" stuff (PLA, PETG, whatever, it doesn't matter) and load in filament that prints at cooler temps, you can have a partial clog. One way to test for this is to raise Z to max, heat the nozzle up to normal print temps and extrude some filament. Observe the flow of the material out of the nozzle. If it bunches up or skews to one side, you've very likely got a partial clog. Here's an example:
After a few cold pulls, the partial blockage is removed and smooth flow restored:
The "Prusa stepped heatbreak" is a problem that can occur due to a variety of reasons, but often remedied by replacing the heatbreak (not the entire hotend) with a stock E3D V6 heatbreak that doesn't have the 2.2-2.0mm step Prusa has custom manufactured by E3D. That comes into play if you have lots of retractions or other heat issues, and is one of many possible problems in those circumstances.
RE: Original Prusa MK3S issues
So, after an extensive chat with the troubleshooters at Prusa, I have found and fixed the issue. I had a tiny crack in the Filament Idler Door that prevented the gear that is attached to it to rotate freely. Every now and then it caught ever so slightly, but apparently just enough for the filament to stop moving. I was able to glue the crack to print a new door and replace it, and haven't had any issues whatsoever since. The new prints are even cleaner than I ever have had, so I think it has been an issue since the day that I've assembled the kit. Currently printing a 12 hour print and have never seen such even layers.
So the issue has been solved successfully!
I am now also running the latest and greatest firmware 3.8.0 and am using Prusa Slic3r 2.1.0 RC2.
RE: Original Prusa MK3S issues
I am downright amazed! Congratulations to both you and the support folks.
Such a big problem from a tiny crack...