MK3S - Filament ocassionally breaking off/not laying on printbed
 
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NUUDYFIST
(@nuudyfist)
New Member
MK3S - Filament ocassionally breaking off/not laying on printbed

 

I am having a problem with the filament sticking to the plate, as shown in the first picture above. This was created using the first layer calibration and as you can see, the filament occasionally lifts and unsticks from the bed. The following are what I tried:

1) Adjusting the live-z height, which is why I am doing the first-layer calibrations.

2) Replaced the nozzle and cleaned the heat block. Also adjusted the gap between the nozzle and heat block slightly just to check if that was the problem.

3) Cleaned the heat bed as shown in the link (just wiped it with IPA and glue sticks)->

4) Tried the Benchy stock print with 150% flow rate (in case the extruder was not laying the filament onto the bed fast enough).

I tried to upload a video showing the first layer printing process, showing a closeup of the filament being laid down but it may not be the best video (Also I am having trouble uploading it, so it may not even be there). What I observed myself is that, sometimes, the filament doesnt even reach the bed before the extruder moves along. This is only sometimes though, other times I am really not sure what is causing the problem.

Has any faced a similar issue before and/or know how to resolve this problem?

Thanks in advance!

Posted : 02/01/2022 11:59 pm
JoanTabb
(@joantabb)
Moderator
RE: MK3S - Filament ocassionally breaking off/not laying on printbed

is that nozzle designed for a Prusa, it looks like a mk8 extruder nozzle. which is not really suitable for a prusa printer

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

Posted : 03/01/2022 12:24 am
NUUDYFIST
(@nuudyfist)
New Member
Topic starter answered:
RE: MK3S - Filament ocassionally breaking off/not laying on printbed

What nozzle would you recommend? I just need a replacement 0.4mm nozzle to replace the stock one provided.

Moreover, why is this nozzle not compatible with the mk3s? Is it because it leaves too much space inside the nozzle to build up filament?

Posted : 08/01/2022 6:22 pm
JoanTabb
(@joantabb)
Moderator
RE: MK3S - Filament ocassionally breaking off/not laying on printbed

there are many nozzles to choose from, depending upon your requirements, 

I have used cheap Chinese brass nozzles, original e3d brass nozzles, Cheap stainless nozzles and I am currently using a Nozzle Z  (Zaribo Hardened nozzle) and they all worked ok... 

your nozzle 8 probably has 1.5mm less screw thread  than an original or compatible  e3dV6 nozzle. which messes up the relationship between the heater block and the cold end. which in turn undermines the functioning of the heat break.  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

Posted : 08/01/2022 10:44 pm
NUUDYFIST
(@nuudyfist)
New Member
Topic starter answered:
RE:

Hello, since the last time I properly cleaned and reassembled the whole hot end, and I reverted back to my original nozzle from prusa. With a different PLA filament, i was able to print the castle stock print provided with the mk3s. I just finished using that filament and I am back to this black PETG filament and I am again encountering similar issues. In the event that it is this roll of filament that is causing these issues, I have ordered new PLA filament (I realize I should've ordered PETG filament for a better comparison, but it is too late now!).

I also attached a picture of the first layer calibration, and its attempt to do a custom one-layer calibration. What i notice is that the filament constantly balls up at the nozzle and attaches to the nozzle, which later comes off and ruins the print. I also noticed that while the printer is extruding at ~90 degree corners, the filament fails to lay down on the bed appropriately and gets pulled away by the nozzle from where it is supposed to be set. This also occurs when the printer stops extruding and travels over the part. I try to illustrate this with the video (link: https://forum.prusa3d.com/wp-content/uploads/2022/04/video-1648918721.mp4)

 

 

I am quite confident that the issue does not reside among the following, as I have extensively tried to tune/fix these parameters:
1) Bed adhesion (applied a new glue coating as shown in the video at the beginning of this thread)
2) Z-offset (extensively tuned this, it is in a pretty good spot considering the filament that is able to lay flat on the bed lays down well)
3) Bad Nozzle/Hot End (cleaned these parts and reassembled them; worked fine for PLA)
4) Flow rate (Tried increasing the flow rate to 120% and 150%, but experiencing similar issues)
5) Print speed (decreased from 60mm/s to 50mm/s for the standard print speeds and 25mm/s for the specific print speeds (ex. outer wall, inner wall). Travel speed set to 120mm/s when not extruding filament to avoid stringing.
6) Retraction (currently set to 0.8mm, which should be enough)

Does anyone know what the issue could be? Is there a substantially different way to print PETG vs PLA (aside from changing bed/nozzle temps)?

This post was modified 1 month ago 2 times by NUUDYFIST
Posted : 02/04/2022 5:20 pm
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