Discoloration.... So I fix several problems only to encounter another...what causes this kinda discoloration?


So I fix several problems only to encounter another…what causes this kinda discoloration? I’m printing PLA between 185 and 200 and it’s never done THIS before…but now it does.

I am not experienced with PLA, but are you overheating it?

Looks like burnt residue from the surface of the extruder. Probably got wiped off when going over three raised portion of the print. Try cleaning your nozzle with a wire brush and see if it happens again.

There could be some leakage? Fluid PLA is dripping off somewhere and running down the hot end.

@Marcus_Guin_Klutmann I’ve seen this before with cheap j-head clones. Also burnt leakage from previous prints seemed to sometimes seep back into the barrel to combine with the new filament.

Though this looks like an e3d so you shouldn’t see this, is there crap in that bundle of Kapton that could be leaking onto the print?

@Liam_Jackson I have an e3d too, and have experienced this. In my case the heat-break wasn’t screwed tight enough into the heated part. Additionally I have wrapped my hot-end with some isolation (like here). After a while I saw small brown dots in my prints. But almost no burned PLA outside the nozzle. In my case it dripped off the isolation from time to time. Now all my connections are tightened and I also removed the isolation.

I had a ‘catastrophic’ failure event a few weeks back that left the e3d sitting in a big blob of filament. Thought I’d cleaned it well enough. I guess I haven’t.

I’ll re-dis-assemble and re-clean at the weekend.

@Marcus_Guin_Klutmann isn’t that why you do the tightening the Nozzle while hot thing (the do not skip instruction in the manual)? Did it come loose after that?

I find it difficult to get the heartbreak tight enough in the heatsink (so it doesn’t come loose) without breaking the heartbreak!

Whelp, the printer’s down…I suspect I didn’t get the nozzle tight enough (I’ll run it up to 300C this next time.) Everything was greasy with filament, so much so that the thermistor pulled out. I caught it in time, but it’ll take some TLC to clean up. (and I might just use the opportunity to use the screw and washer retainer method.

@Liam_Jackson I happend to me after a quick nozzle change. It will never happen again.

@Mike_Miller I heat up my system to 200°C for nozzle change. 300°C sounds a little bit too high for me. Maybe there was something between your connections (burned filament, or hard/sharp edges?), so you couldn’t tighten it.

Certainly possible…the 300C was the original temp they mentioned in the documentation for initial assembly.