MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
I'm somewhat new to 3D printing and trying to learn about this. Purchased the MK3S used (only a few hours on it). I've printed a fair number of items successfully, but recently it started showing me "Crash Detected" and stops the print. I've been trying to dig into the problem, but I'm not finding too much relevant.
What's happening is that there will be a glob of the PLA plastic that is left somewhere, and eventually, the extruder tip (stock) will hit the glob and break the object away from the base, and thus "Crash Detected". I've tried a brand new (sealed) filament.
The Fail Stats show last failure as Crash "X1 Y2". (Power/Fil.runouts =0). Total are "Crash X27 Y40" (Power=0, runouts=1 - not for me though). Some of these will be from when I first bought the printer and the slide bars were dusty/gritty which I had to clean and grease to get it to work the first time...
I went through the Calibration Wizard successfully today, and reset the Live Z back to about where it was before, around -1.90.
I'm trying to print out a box, about 75x90mm. The first complete print went fine (didn't meet my needs) but after that, I haven't been able to successfully print the box. When I print out the base layer (fan is not supposed to be on for the first layer, I learned) but this layer is not really smooth. It has little projections coming up (pretty small though). These recent failures have occurred with in the first hour or so.
I've been babysitting my current print and cut out a couple small globs and stray strings, but obviously I can't do that all the time.
I copied this basic box design from Thingiverse and modified it to my needs using TinkerCad (increased the width, added holes). I did find that some of the printer settings didn't match those from some previous successful prints, which I changed to match, but so far, it doesn't seem to help. Still getting occasional globs.
As a side note, this is an MK3S. The printer came with the "+" modification kit which I haven't put in yet (I did print out the required parts though). I've read that there isn't much difference between the MK3S and the MK3S+, so I haven't installed it yet.
Is there some troubleshooting chart somewhere that might help me? I've found a LOT of hits when searching for "Crash Detected) and they're all over the board. How do I search for the problem where my filament globs (better word???) up.
Mike
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
Pictures might help!
One cause for blobs of filament causing crashes, is incorrectly installed nozzles.
typically this is caused by the heatbreak and the nozzle, not touching intimately inside the heated block of the extruder after a nozzle change.
this allows hot filament to ooze out between the heatbreak and the nozzle, and dribble down the outside of the heater block, before dripping onto the model, (Look at the top of the heat block, there should not be any filament there!)
Often these dribbles are discoloured.
https://help.prusa3d.com/article/changing-or-replacing-the-nozzle-mk2-5-s-mk3-s-mk3-5-s_2069 
another possibility, particularly common with PETG, is slight over extrusion
this can cause the model height to grow, slightly quicker than expected by Prusa slicer (Particularly common on perimeters and solid infill)
as the model grows, the Nozzle, has to plough through the previous layer, causing tiny bits of filament to stick to the outside of the tip of the nozzle
these bits build up to a blob, which typically falls off at the most inconsiderate moment, and stick to the model, then the nozzle catches on the blob on a later layer!
Another cause of collisions is warping where typically a corner of a print lifts off the build plate and catches on the nozzle, looking at the bottom of a print can often show where the model has lifted off the build plate,
this can be a result of build plate contamination, (often finger prints)
this doesnt typically cause blobs
many filaments print better in an enclosure! (ABS, ASA, PC for example!~)
Prusa Knowledge Base is a good place to look!
Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility.Location Halifax UK
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
I'm not sure about the gap in the nozzle theory. The printer has been working fine, unless it has loosened over time. But I do understand what you are talking about. I'll check it soon...
In this case, I'm not using PETG, I'm using PLA. I am sticking to the default temperatures for the extruder and platten.
"Another cause of collisions is warping where typically a corner of a print lifts off the build plate and catches on the nozzle, looking at the bottom of a print can often show where the model has lifted off the build plate, this can be a result of build plate contamination, (often finger prints)"
If you'll check the picture I uploaded, the "Lifting" is prevalent also. Is that due to a problem with the bed temperature?
I've got the print running now, and it seems OK, but this is after I "babysat" it through the start, the first few layers that seem to glob up.
Sir Michael
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
Good Evening Sir Michael,
Looking at your picture I would say that your first layer calibration, is a touch too low (too big a negative Live Z number
when you lay down the first layer, Prusa Slicer estimates the correct amount of filament to fit between the Build plate surface, and the nozzle lower surface.
First layer calibration attempts to ensure that the nozzle is the ideal distance from the build plate, in order to allow space for most of the filament, with the filament bead being compressed into an oval shape, to make it squish into adjacent filament traces, to create a continuous film smoothly across the build plate surface.
What you seem to be getting, is a first layer with ripples in it.
this is caused by the nozzle being too close to the build plate, and squishing the filament wider than expected, this then causes pressure against previously laid strings of filament, pushing them sideways. however when pushed sideways, there is an obstruction from other previously laid strings of filament, causing them to buckle and lift off the build plate, this in turn, reduces adhesion, and creates opportunities for the nozzle to catch on previously laid ripples in lower layers
the Actual Ideal LiveZ value is Unique to every printer and does not necessarily equate to a Live Z number ending in a 0 or a 5
there are many first layer calibration STL's on the various repositories.
the one I remember easiest is 'Life Adjust 'Z' My Way' by Jeff Jordan (largely because it is Mis-Spelled.
https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/
there are test profiles for a 0.4mm nozzle, at the bottom of the first post.
Regards Lady Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility.Location Halifax UK
RE:
Many Thanks Lady Joan,
I'll give it a try in the next few days. I have some (other) projects to attend to for a few days, so playing with the 3D printer may have to wait. I'll read the post (again) and see what transpires. I had found that earlier when I was first got the printer, trying to keep the project stuck on the platen. I do understand about the Live Z adjustment. I may have it too close...
I WILL let you know how it comes out.
Sir Michael
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
Thank You Sir Michael,
I hope the information helps wort your issues.
regards, Lady Joan...
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility.Location Halifax UK
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
Lady Joan,
I did go back through the Z calibration again, reading the post you suggested more carefully. Basically what I picked up was the suggestion of using a caliper to measure the thickness of the layer, expecting it to be 0.20 mm. I do have a caliper that seems to work well. However, I found that when I printed the 75x75 sheet, the middle of the output was bumpy, not smooth. I got my best measurements when measuring the edges.
This one (above) shows the first set (lowest in the picture) at -1.80 "Life" 😉 setting, -1.85 above that, and the very top is -1.90 (which is where I had been running it previously). (I should have used white PLA to allow me to write on it easier.)
I I then tried the -1.85 setting but when did a full printout, you notice that the surface is rough, not smooth (similar to the -1.90 setting also). I'm not sure how or what to adjust to get the surface smooth. At the -1.85 setting, I'm reading 0.18 to 0.19 mm on the printed edges. (Click on the picture to get the full size version.) I'm assuming that this rough texture is abnormal!
I did some further testing with the Live Z, letting it print out the outer band, stopping the print and measuring the thickness. It's not absolutely accurate when I measure the band, but when I'm up at about -1.70, I'm getting an edge thickness reading of between -0.19 and -0.20. This setting does seem to smooth out the surface in the center considerably!
What I'm learning is that if the surface is rough, then you are too thin (at least for my printer)! Measuring the edges (and the outer ring), I'm getting very close to the 0.20 mm, but the center is not quite perfect, and I get measurements of about 0.25 mm when I try to measure that.
With the testing that I've been doing trying to get the Live Z adjusted, there hasn't been too many 'globs' on my work. Not sure what the difference would be! When I "Pause" the print, and restart it, then it tends to tear up the layer that it was working on, but not too bad. I'll have to continue to test and see what happens with some of my new prints.
Thanks for your suggestion!
Sir Michael
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
Hi Sir Michael,
those patches still look a bit too low.
you can adjust live Z as the print progresses,
If you reduce the value of liveZ negative value, during the print the surface should go from lumpy (nozzle too low)
through smooth (Joined strands)(Nozzel about right)
and when the individual strands will start to show gaps between other strands, (Nozzle too high)
if you start to see individual strands your nozzle is too high, increase the Live Z value again a little.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility.Location Halifax UK
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
Lady Joan,
After working with calibrating the Z, I tried a simple print (soap dish), but it failed, as you can see below. The first attempt is at the top, the second attempt in underneath, still on the platen. Both were Crashes. The one on the platen (the latest try) had the edges curled up (though that was from overnight, so I don't know if that was the exact cause.
In between the two, I did try to adjust the Live Z down a bit more, though not much.
Any idea where I can look next?
Sir Michael
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
Please save a copy of the soapdish Project file, Zip Compress it, and attach the zipfile to your next post,
so that I can look at the settings.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility.Location Halifax UK
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
Thanks Joan.
Here is the file, just as I printed it (last night) and also a few weeks ago.
elipsis-soap-holder_0.2mm_PLA_MK3S_3h7m
Sir Michael
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
Hi,
I printed that file, earlier today, and your Mk3/mk3s profile, printed Ok, on my mk3.9.
I am at a loss as to why you are getting tearing effects, the top image seem to have a good first layer, followed by second layer defects.
the other print seems to go loopy at about layer 5... odd...
what happens if you slow the print speed to say 50%
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility.Location Halifax UK
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
I've been reading through some of the troubleshooting pages, , maintenance pages, and doing a lot of digging, but I'm not coming up with much. I've been inspecting for some of the things that other's have had trouble with and so far, I haven't found anything more. I've checked fans, and other things in the "Settings" menu. I did go through the "Calibration Wizard" and everything checks out.
I can try to print it out slower, but that doesn't solve my problem. I think that the next step might be to put in that MK3S to MK3S+ upgrade. (I did print out the pieces that I need earlier.) That will give me a chance to learn a bit more about the printer, and to inspect the bearings, and see I can find anything suspicious.
This is essentially a newer printer, there is only about 11 days on it and it's messing up.
Do you think it would do me any good to do a software reset???
Sir Michael
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
A software reset would invoke a re calibration, which will hopefully sort any hidden gremlins
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility.Location Halifax UK
RE: MK3S Crash Detected, Extruder seems to occasionally leave blobs on the object.
I agree with Dame Joan on the speed. This is PETG ( which brand BTW ? ). Setting 200mm/s for infill speed is a challenge for this filament. I wouldn't go higher than 100mm/s. or even less if that PETG isn't dry. I've got trouble printing some PETG colors from Prusa, no matter what I tried. Switching to another color or brand fixed totally the problems, which weren't related to the printer or the settings but to one specific filament.