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Comment on The Prusa Mk4 has done it again ☹️

Grid infill is crossing, get a decent blob or buildup and you could have nozzle collision, I personally like gyroid but it is slower.

Had a similar failure on the mk3s, what does the belt tension test return? Stealth mode may help or be the cause, anecdotally I’ve seen mention of motor temps, the old rambo board running stock firmware they got toasty when printing in the enclosure in the summer, stealth helped me limp it along until I did a board swap and changed to klipper. I don’t know if this is an issue with the mk4 as that’s not using the older Rambo based boards, but something to consider as well, had it happen even after I did the first abs rebuild.

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ExtremeDullard@lemmy.sdf.org ⁨3⁩ ⁨days⁩ ago
Okay so I’ve readjusted the belts’ tension this morning. The X belt was a bit loose and the Y belt was a bit too tight, strangely enough. Both in the green though. So I set them to the middle of the range. Good thing I checked anyway because all the screws on the X motor mount were so loose they were on the verge of letting go completely.

And since I was at it, I cleaned the entire enclosure and re-lubed the rails and the linear bearings.

However, I don’t think the printer faulted because of any of this: I checked where the hard limit was in X and Y and found that the nozzle came right at the edge of the previous prints that failed on the left and on the top:

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At this point, I’m convinced the printer got lucky twice when it printed that print right, and when it didn’t, it was the result of the carriage hitting the limits when the motor(s) overshot the extreme positions a bit. I re-sliced that print to leave some margin with what PrusaSlicer believes are the limits of the printing area and I came to a perfectly printed set of parts today. And the new set I started 2 hours ago seems fine too.

So I think the lesson here is that PrusaSlicer is a bit too optimistic with how large you can print, both in X and Y. It pays not to believe it too much.

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ExtremeDullard@lemmy.sdf.org ⁨4⁩ ⁨days⁩ ago

Grid infill is crossing, get a decent blob or buildup and you could have nozzle collision, I personally like gyroid but it is slower.

I’ve had the head collide into blob on solid infills (or perimeters) when the filament was too hot - usually TPU or TPE - but never infill. I’ll give gyroid a spin though.

prusa has an article for troubleshooting layer shifting

That’s a great article. Thanks!

I’ll go check everything tomorrow. The thing is, it’s the first time this happens (well, second time now). The only unusual thing I did compared to previous print was fill the bed to the brim, right up to the edges as allowed by PrusaSlicer. I’ve corrected that to make sure this isn’t the issue. Other than that, it’s a printer that’s been printing all day every day for a good year and a half. So yeah, it probably needs some TLC at some point…

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- morbidcactus@lemmy.ca ⁨4⁩ ⁨days⁩ ago
  Says a lot that it can run pretty much maintenance free for a year and a half! I only had issues with my mk3s doing daily enclosed abs prints in the summer, the original petg softened and it ended up killing the idler end of the x axis (idler mount deformed suddenly under tension after like… 1-2 months of that). They may not be the fastest or fanciest but they’re easy to service and in my experience pretty reliable, I repacked the linear bearings after a year or so out of precaution when I did a full rebuild, but I don’t expect needing to do that for a long time.
  
  Here’s another prusa article for infill patterns, the prusa knowledge base is really decent and applicable to a variety of printers, I use my voron a lot but still refer to it.
  
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