I tried this small print and got a burned spot. What would cause this?
Nozzle idle in that spot. It’s probably the part in where the nozzle changes layers.
Hey @Adam_Steinmark , from what I can tell from the rest of the print, layer change is located elsewhere. And why would it happen only on that spot and not in every layer? Thanks!
Are you sure? Check the slicer for that spot, also it seems mostly symmetrical so you wouldn’t really be able to tell once you remove the print from the plate.
I had that problem repeating quite a bit on my prints and it got really annoying. In the end I cleaned the hot end both outside (using a brass wire toothbrush) and inside using the cold pull technique (where you let the temp drop just enough so you can pull the filament out and drag all the crap with it) and I never had it again. In my case it was a build up of burnt old filament in the nozzle which was coming out in little bits and ruining my prints. I dont know if its the same problem but it looked identical to what you are seeing.
@Daniel_Bull makes more sense.
@Adam_Steinmark
my thoughts exactly after reading your first comment. However, I picked up the part and I was able to identify the layer change.
@Daniel_Bull Oh you must be right. I did notice that some of the skirt was missing. Now we know where that ended up! I will check it later. Thanks
Yep, almost certainly what @Daniel_Bull said. At some point the burned plastic gets quite runny and can just drip off onto the print.
One other thing to consider is making sure that your nozzle is fully tightened so that you have no leakage, because any plastic that makes its way through the thread area and out to the upper rim of the nozzle will certainly be burned by the time it gets there. Not that I would have any direct experience of that, of course.
Yeah you got a leak from your extruder happened to me too exactly what you pictured. How often do you clean out you hotend?
Thanks for your suggestions. @Dianne_Fontayne1 I haven’t cleaned it yet :). It is printing fine so far so I didn’t want to mess with it.
A more likely source of burned plastic is the surface of the hot end if not cleaned regularly. Once a burned piece stuck to the part, it was likely smeared over a larger region as the nozzle passed over it.
FWIW I got something very like that when my nozzle came loose – the filament was leaking through the nozzle’s thread, going brown over time, then falling into the print.
Turn your head temperature down 5 degrees at a time until it works right. That usually takes care of it.
Burning???
On my prints, I identified the filthy nozzle/heaterblock as the culprit.
Indeed that is the case! I took a look and it is quite messy. Lots of burnt plastic all around the nozzle. Internally I did the cold pull method as suggested and it came out clean. Now I need to figure out how to clean it without removing it. Maybe I will give this a try https://www.youtube.com/watch?v=kNRvXJhpQ_I
A Kim-wipe on a hot nozzle works well for keeping things clean. A needle nose pliers works well to hang on to the kim-wipe to keep from inadvertently cooking your finger. If it really needs a cleaning, a fine grit emery cloth does a pretty good job too.
Yep, any kind of decent paper towel or equivalent. But DO NOT dampen it, because steam and heat conduction and the things you’re wiping aren’t that soluble in water anyway.
Good news Demetris, especially the cold pull results. Internal carbon can be tough to deal with. Keep an eye on any recurrence that might indicate you’ve got a slow leak, they only get worse. And if it’s exposed metal plastic is sticking to and burning, if you can get a wrap of kapton tape around it securely that will help. Good luck.