Worked perfectly straight after build, 2 weeks later I'm struggling.
I bought a MK3S kit in august last year, I didn't get around to building it until a few weeks back. I was amazed that after building it, it worked straight off, I promised myself I wouldn't print a bench....but I guess you know the rest of the story!
Fast forward to Thursday last week, my beautifully working MK3S, suddenly stopped working so beautifully.
I had trouble getting a single print to work, the extruder was producing blobs of filament, sometimes on the purge line where it would get dragged into the print area, or on the skirt or somewhere in the first layer. Although the failure alternated between these, it was consistent in that it happened nearly every time. I was having to spend an inordinate amount of time watching the first layer, hitting cancel when it failed or trying to remove filament or blobs from the print bed as the printer was printing.
Once I got over the first layer it seemed to work ok.
I've been through the "life adjust" procedure, I spent hours getting the first layer right on my prints and up until the failures started coming thick and fast, every first layer was beautiful.
I also noticed that one reel of filament, in particular, was having some other issues, mainly that as it extruded it squeaked (PLA), around this time I also noticed a feint ticking sound during small movements, I searched on the web and found many answers here and on youtube and other pages saying that the gears or the idler were the problem and needed adjusting, I also found descriptions of the symptoms which indicated that the nozzle may be partially blocked.
I tried cold pulls, but that made no difference. This morning I undid the extuder gear hatch and looked at the gears, the grub screw looked like it had come loose and was no longer pinning the gear to the flat part of the motor spindle, instead it was on the round part. I had high hopes that once I rectified this, my problems would go away.
I fixed the position of the gear, and flipped back from using a roll of prusament PETG to PLA and printed a couple of things, they seemed to print well again, the top layer was looking much better than it had with the gear not being fixed to the right place on the spindle. I did a few more prints, and the blob of doom started making a comeback...however, the ticking sound was gone. A small victory.
When this issue first raised, I thought it might be humidity, I dried the reels to no avail and in the end switched to the fresh reel of prusament PETG, the PETG seemed to print better than the PLA did, at least that's how it felt.
When I don't get the blobbing, the printout seems to be great, I've attached a photo of Marvin that I just printed, I am seeing stringing now though which I wasn't last week. (Marvin was printed in PLA).
I'm really at a loss of how to get back to where I was last week, it's getting to the point that I'm considering stripping the hotend down to give it a thorough inspection and then build it back up.
I'm desperate for suggestions on things that I can try to solve this, or at least let me diagnose exactly that the problem is. One other thing is that when printing normally, I get a thin curly noodle of filament extrude itself during heating, I don't remember this happening when the machine was functioning correctly. This noodle on many occasions has been the cause of the first layer failure, either it coming loose in the middle of the print, or it sticking to the skirt or the part, ending in a terminal situation which I stop before the extruder gets caked in filament.
I've tried so many things, but I really don't know where to go now. I've tried many other avenues of support on forums, discord and facebook, but I just can't get reliable prints at the moment.
I realise this is all very vague, but I'm happy to provide any other information that may be relevant to tracking down the source of my current issues.
Thanks
RE: Worked perfectly straight after build, 2 weeks later I'm struggling.
Hi Adrian,
I feel your frustration.
it's difficult to make suggestions, purely on text descriptions. can you show us your first layer prints please, and maybe the bottom of Marvin's feet!?
Marvin looks like the filament was perhaps a tiny bit on the hot side, a little cooler and those stray hairs of strings may disappear...
are your noodles being laid down during the skirt print?
If they are, you could print the skirt say 20mm from the model and give yourself a little more room!
does the blob come first or does the blob appear after a short while?
Sometimes prints do not adhere properly to the build plate, and they end up following the nozzle around and forming an ever enlarging blob.
I clean my build plate in the sink, periodically, with hot water and a touch of dish soap and a clean kitchen sponge. I find it is more effective at removing finger prints and grease, than IPA is. I rinse with hot water, then dry immediately with clean plain paper towels. then without touching the surface with my fingers, I print on it immediately.
For PLA, I find a higher bed temperature works well. I will use 70C for large PLA Models.
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: Worked perfectly straight after build, 2 weeks later I'm struggling.
@joantabb
Many thanks for the comprehensive reply! This is why I went Prusa and not anything else for my first 3D printer.
I'm just printing a Benchy, I will update with pictures of that when it's finished. I'm just using the generic PLA profile that comes with PrusaSlicer, what is strange is that I was using this exact configuration for 2 weeks without any stringing on this very reel, now since the problems have started I'm seeing stringing on it, it's so strange it's like everything at once has decided to go wonky.
When I've done the Z level calibration using the "life adjust" method from this forum, the purge line at the start basically goes the whole width of the print bed, I have yet to see the "life adjust" square have a single blob or print issue. To that end, I took some settings from a post somewhere which did various things like pre-heat the nozzle for Z calibration at the start of the print, but don't raise it to the melting point while doing the bed cal. It then moves the nozzle to almost touch the bed before raising it to the extrusion temperature, this leads to the blobs being purged on the purge line instead of on the bed, in the print, or on the skirt.
This is the purge line from the benchy that is currently printing, you can see the big blob at the start which occurs when the nozzle is bought up to extrusion temperature, you can see why this is a problem when running the stock settings from PrusaSlicer because this blob the majority of the time will cause a first layer failure if I don't either wipe the nozzle in mid-air just before it starts to print, then I'm pretty much guaranteed a failure.
While the "big purge line" and staggered nozzle warm-up helps a lot or fixes the issue, I want to understand why it's doing it now and why the behaviour changed overnight, I went from no failures while printing to pretty much everything failing while printing. If I can't understand why it's behaving this way or what has changed, then I'm never going to trust the printer to do the first layer correctly, I don't want to be in a position where it takes me 10 attempts to get 1 first layer printing properly if that makes sense?
The bod always comes first, but unless the purge is long, then there could be more than one blob lurking in the shadows, ready to pounce on my first layer!
I've cleaned the steel sheet with soapy water, I give it a wipe with isopropanol alcohol after every print and I gave it one wipe over with acetone just to make sure it was clean. (I am definitely not going near the textured sheet with acetone!).
Here's a picture of Marvins feet, it looks like it's ridged, but running my fingers over them it's perfectly smooth, same if I run my nail over it, it's smooth and my nail doesn't get caught in a peak or a trough.
Moving the skirt further away is something I've also considered, but I keep coming back to my initial thought at the start of this, which is why did things suddenly go south so quickly, I'd like to understand what has gone wrong and either take that onboard or fix it, I don't want to paper over the cracks in the wall with wallpaper, because at some point the house will fall down around it!
RE: Worked perfectly straight after build, 2 weeks later I'm struggling.
Could the blobbing and the noodles also be a symptom of the nozzle temp being too high? The Benchy has just finished printing, and there's a 20mm noodle now hanging from the nozzle from after it finished.
RE: Worked perfectly straight after build, 2 weeks later I'm struggling.
@adrian-carpenter
I would mount a new nozzle and start tests on the temptower to find suitable temperature settings (including fan values for cooling). -> https://www.prusaprinters.org/prints/4667-all-in-one-temperature-bridging-tower-pla-petg-gco
wbr,
Karl
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Worked perfectly straight after build, 2 weeks later I'm struggling.
Here's the Benchy, this is not the Prusa fixed version, but a fresh version downloaded from the site and sliced myself, hence the hull line.
RE: Worked perfectly straight after build, 2 weeks later I'm struggling.
@adrian-carpenter
I would mount a new nozzle and start tests on the temptower to find suitable temperature settings (including fan values for cooling). -> https://www.prusaprinters.org/prints/4667-all-in-one-temperature-bridging-tower-pla-petg-gco
wbr,
Karl
Thanks, the thought of replacing the nozzle had crossed my mind given that it would seem that my problems seem to stem from this area, but the rational part of my brain said "Don't be silly, you're clutching at straws here, your nozzle shouldn't be dead after such a short time".
How likely is it to be the nozzle though (I,e does this happen a lot?), the machine has only been running for 2 weeks and in that time there have been less than 48 hours total print time?
It's not a problem replacing it, I have spares, I'll have to go read the manual on exactly how I do this and whether there are any processes I need to go through both before and after the nozzle change, I know that the Z has to be recalibrated for the new nozzle.
RE: Worked perfectly straight after build, 2 weeks later I'm struggling.
Your first layer could usefully go a little lower, more squish.
Two weeks is enough time for filament to absorb enough water for problems to occur if your environment is humid; look for threads on here about filament drying.
Over the first few weeks your printer will run-in and settings will drift a little (every user builds fractionally differently but use shakes things into line). After a while it will settle down and the next maintenance recalibration will leave it much more stable.
Cheerio,
RE: Worked perfectly straight after build, 2 weeks later I'm struggling.
Your first layer could usefully go a little lower, more squish.
Two weeks is enough time for filament to absorb enough water for problems to occur if your environment is humid; look for threads on here about filament drying.
Over the first few weeks your printer will run-in and settings will drift a little (every user builds fractionally differently but use shakes things into line). After a while it will settle down and the next maintenance recalibration will leave it much more stable.
Cheerio,
If I go much lower it starts ripping it up, I'm within 10 or so of it being ok to being too low, I have a stack of the "life adjust" squares with the values all written on them, the bottom is actually like glass on them, I cannot feel any ridges no matter how I try, fingertip, nail, electronics tweezers, it really is very smooth.
I can try lowering it, but I did try that yesterday after the first couple of responses and I ended up ripping up the square as the extruder did its job. I have Mitutoyo callipers, I'm reading about 0.21/0.22 for the layer height on the square.
The filament has been taken out of the wrapper, used, then stuck in a dehydrator for 6-12 hours (with desiccant) and then back into a vacuum-packed pouch, a proper vac pack machine, not a hand pump, I've tried to be very careful with the filament and dealing with it after I've finished printing. I've done a lot of reading! :p
I'm more than willing to try anything, I appreciate your suggestions and the time you've taken to reply.
I've made a couple more adjustments to the start-up g-code, mainly expanding the skirt (which was suggested up the top) and the initial purge line I've made longer, I haven't tried printing yet, I'm just about to go fetch the filament out of the dehydrator.
I can't remember if I mentioned it, but since the problem started happening, I did break into a brand new sealed Prusament reel as an attempt to try and take wet filament out of the equation, I still had the same issue I was having with the 2 PLA rolls I had open.
Even despite the current issues I'm having, I absolutely love this. I'm an embedded software developer, so I tend to tinker with stuff in my spare time and having the ability now to create enclosures or mechanical parts is a game changer for me!
RE: Worked perfectly straight after build, 2 weeks later I'm struggling.
The filament has been taken out of the wrapper, used, then stuck in a dehydrator for 6-12 hours (with desiccant)
OK, but earlier you wrote:
as it extruded it squeaked (PLA),
and one of the symptoms of damp filament is a popping sound that increases to a creaking when very wet and ultimately to groaning and squeaking... another is stringing.
OTOH a little lubricant on the bondtech gears - the cog part not the filament gripper, might be in order - use grease not oil.
I have a stack of the "life adjust" squares with the values all written on them
Don't assume the first layer Z will remain the same as on day one ... it should become stable after few weeks and remain so until the nozzle wears.
I have Mitutoyo callipers, I'm reading about 0.21/0.22 for the layer height on the square.
That only repesents the volume of filament you are extruding within the area, not the height of the nozzle; if the nozzle is too close the excess squidges sideways then wells up making up the thickness.
* * *
I would rate that benchy as good enough for the first month.
Better to settle, temporarily, for a basic working printer and get some useful printing done, make your early mistakes, establish a routine and generally get used to the process. Then when you do your one month service you can take extra care knowing the new settings on your now stable printer are likely to last for several months.
Cheerio