Filament blockage in heatbreak?
I have a factory assembled Mk3, and this has now happened twice...
During a print, the extruder starts clicking, so there's a blockage somewhere. I try to clear it with the acupuncture needle, no good. Try a cold pull, nope. Replace the nozzle... still blocked. Dismantle hot end and remove heat sink etc, and find the heatbreak is filled with filament.
I've drilled it out with a 1.5mm drill bit, followed with a 2mm bit, and it's clear again. Last time it happened was about 3 weeks ago, and the printer gets lots of use, so it's not happening a lot, but today it happened a second time, can anyone shed some light on what could cause this to happen mid-print?
Re: Filament blockage in heatbreak?
Search the forum for "filament blob". This happened to me until it got so blocked I couldn't unblock it. The two main symtoms of this problem other than filament getting stuck is a blob that forms at the end of your filament when you remove it to change filament
The other indication is the PTFE tube in your extruder starts to rise above the printed part. Open the idler door and you can see where the entry point is for the filament to go down into the extruder. If you see the PTFE tube pulled up and deforming this leaves a gap inside the hotend where the bulb can form and cool.
In the below link you can see how high the PTFE tube is. My picture is more out of focus, but you can see what I'm talking about. The tube should be inside that part and not outside.
In my case which had multiple issues with the hotend I received a replacement. I just need to get it installed.
Re: Filament blockage in heatbreak?
In my case it's not happening during a filament change, it's happening in the middle of a print. I start with an unblocked nozzle and part way into the print, it's blocked. It's almost like the heat is creeping up the heat break and causing the filament to melt too early. The noctua fan is working just fine though and the whole hot end is clean, so I don't know what to change...
Re: Filament blockage in heatbreak?
Sounds like a heat creep. Happens to me on high temp PLA and objects with a lot of retractions.
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