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Strange dark spots on print  

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Henske01
(@henske01)
New Member
Strange dark spots on print

Hi There,

I'm printing a large project which I started some 8 hours ago. I noticed some dark spots here and there on different layer hights. At some places it was even lying loose on a area that was done printing. when I picked it up I could see that it had a dark, brown, color and the substance was very brittle, easy to break. And one small piece i found even had some pla "embedded" so it must have come out of the nozzle.

I have an MMU2, but this material does not look like residue from previously used PLA.

I've never had this before and the only changes I made (yesterday) was that I oiled the X-axis rods. And today I also noticed a slight "popping" noise during printing which could indicate moist PLA.

Has anyone encountered this before? Does it relate to moist PLA or has it something to do with oiling the rods?

Hope anyone can help me out with this as i'm curious to what it could be!

Thanks!

Veröffentlicht : 02/07/2022 10:38 pm
jsw
 jsw
(@jsw)
Famed Member
RE: Strange dark spots on print

Looks like contamination from something like pieces of scorched filament dropping on the print.

You should probably inspect the nozzle and heatblock assembly to be sure there are no leaks, and, if necessary, heat the nozzle to operating temperature and CAREFULLY use a soft wire brush to remove any filament residue that's there.  Please be careful with the wire brush.  Keep it away from the thermistor wires.

Veröffentlicht : 03/07/2022 6:59 am
fuchsr
(@fuchsr)
Famed Member
RE: Strange dark spots on print

What @jsw said. Most likely debris falling off the heater block or nozzle. 

Veröffentlicht : 03/07/2022 10:18 am
Swiss_Cheese
(@swiss_cheese)
Noble Member
RE: Strange dark spots on print

I agree with both these gentlemen, I would especially look at the top of the heat block, because you shouldn't have any melted filament or burnt residue on the top unless its leaking.

One of the images you posted shows what looks like it could be stringing as you print, and I'm suggesting that if it is stringing while your printing, the strings could be  melting back onto the lower block as the head passes and then burning and falling into the print, This is just a suggestion based on images two and four. My money is on leaking heater block though.

 

Regards

 

Swiss_Cheese

The Filament Whisperer

Veröffentlicht : 03/07/2022 5:24 pm
Diem
 Diem
(@diem)
Famed Member

I agree with the above.  If in doubt show us a picture of your nozzle/hotend assembly from a couple of different angles.

Cheerio,

Veröffentlicht : 03/07/2022 10:06 pm
Henske01
(@henske01)
New Member
Themenstarter answered:
RE: Strange dark spots on print

 

Sorry for the late reply....

Haven't had the time yet to further look into to this but I will certainly check the heathblock assembly for leakage a.s.a.p.!

 

 

Veröffentlicht : 05/07/2022 8:15 pm
Henske01
(@henske01)
New Member
Themenstarter answered:
RE: Strange dark spots on print

Thanks everybody for your replies....i appreciate it!!

Veröffentlicht : 05/07/2022 8:15 pm
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