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David
(@david-41)
Eminent Member
Blobs, Blobs, Blobs

Hey all. I've been printing pretty reliably with my Mk3S for quite some time but now I am getting blobs of molten plastic. I tightened everything up, inspected and replaced worn parts but nothing seems to help. Prints first layer fine but at some point enough builds up that it causes a crash. Every print no matter the material.

Posted : 04/11/2020 5:11 am
nighthawk
(@nighthawk)
Active Member
RE: Blobs, Blobs, Blobs

I was also dealing with blobs. I tightened everything and installed a silicone sock. Took care of it. 👍 

Posted : 04/11/2020 9:57 am
David
(@david-41)
Eminent Member
Topic starter answered:
RE: Blobs, Blobs, Blobs

@dmiller2564

I was thinking of a sock. thanks

Posted : 04/11/2020 1:10 pm
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(@)
Illustrious Member
RE: Blobs, Blobs, Blobs

If you recently changed nozzles, and now are having leaks and dripping blobs, the common cause is not assembling the hot end properly.

Posted : 04/11/2020 4:22 pm
David
(@david-41)
Eminent Member
Topic starter answered:
RE: Blobs, Blobs, Blobs

@tim-m30

Thanks Tim. If the sock doesn't work I will take it apart and maybe even look at instructions 😉

Posted : 04/11/2020 9:05 pm
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 --
(@)
Illustrious Member
RE: Blobs, Blobs, Blobs

Be careful you aren't just putting on a bandaid that hides a problem, A leaky hot end will appear to not leak for a while, but once the gaps between the and block sock are full, you'll start seeing the same issue.  Do a simple inspection: if you see any melt coming down from the top of the heater block, or melt in the visible nozzle threads (should have a turn or so visible above the hex and below the heater block), you've got an assembly issue. 

Posted : 04/11/2020 11:08 pm
David
(@david-41)
Eminent Member
Topic starter answered:
RE: Blobs, Blobs, Blobs

@tim-m30

I just preheated the nozzle with filament in the extruder and a fine line of filament was passively falling from the nozzle. Is that "leaking"? Is it normal? I never looked that closely before.

Posted : 04/11/2020 11:19 pm
David
(@david-41)
Eminent Member
Topic starter answered:
RE: Blobs, Blobs, Blobs

@tim-m30

The heat break was a half turn loose causing plastic to ooze out and flow over the heat block. Tightened and Fixed 🙂

Since I had already bought them I am trying the "bandaids" anyway but I don't think I needed it.

Posted : 06/11/2020 10:00 am
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(@)
Illustrious Member
RE: Blobs, Blobs, Blobs

You need to torque the nozzle to the heat break when the nozzle is heated to 285c - per the E3D-v6 assembly instructions. Anything less leads to leaks and other printing problems. 

Posted : 06/11/2020 8:32 pm
Henk
 Henk
(@henk)
Active Member
RE: Blobs, Blobs, Blobs

I also had/have blobs printing PETG.

First measure is to dry my filaments: this improved the situation dramatically.

I also installed a silicone sock: again improvement.

When I start a print I wipe the nozzle with a copper brush, just before calibration starts, again improvement less blobs.

Still I have sometimes blobs. Especially when I have a big first layer surface. Somehow material collects around the nozzle (where it is not covered by the silicone sock). This blob at sometime falls off. When I am lucky I can pause the print and remove the blob with a knife etc. or on the next layer the nozzle kicks off the blob without damaging (too much) the whole print.

Does anyone have more suggestions on how to prevent this. Could it be over extrusion? (my first layer and other layers look pretty good...)

Posted : 07/05/2021 5:59 pm
cwbullet
(@cwbullet)
Illustrious Member
RE: Blobs, Blobs, Blobs

@henk

I have had the same experience with wet filament.  Wet filament and the nozzle being a touch loose can do it for me.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 07/05/2021 6:36 pm
Henk
 Henk
(@henk)
Active Member
RE: Blobs, Blobs, Blobs

@cwbullet

Thanks for your answer. I am also thinking maybe my first layer is a bit to low, scraping off material, I have the same issue when I use "ironing" on the top layer. I will try to adjust my Z a bit.

Posted : 07/05/2021 6:42 pm
cwbullet
(@cwbullet)
Illustrious Member
RE: Blobs, Blobs, Blobs

@henk

I think that could also be a cause.  I have not seen it much, but sounds plausible.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 07/05/2021 7:53 pm
Lize
 Lize
(@lize)
Estimable Member
RE: Blobs, Blobs, Blobs

Also have a look at @bobstro excellent page about start up code:

https://projects.ttlexceeded.com/3dprinting_prusaslicer_start_gcode_mk3.html

You can use custom g-code at so it sets the temp to 175 during calibration to avoid oozing, then it heats up to printing temp and the wipe line does a scribble type purge which is very effective at cleaning the nozzle.  Since implementing this I don't even need to watch the first layer go down whereas before I had to watch whether wiping bits off the nozzle was needed.

Theres also notes about pre-heating the PINDA before calibration, I tried this but it didn't seem to make a difference for me so I removed it, not because it took a little longer to warm up but because it took quite a while for it to cool down when doing successive ABS prints in a warm cabinet.

Posted : 07/05/2021 8:09 pm
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