Hot End Bowden tube keeps failing and the hot end keeps plugging - Assembly and first prints troubleshooting

RE: Hot End Bowden tube keeps failing and the hot end keeps plugging

Dirk — Thu, 01 Feb 2024 03:25:51 +0000

Hello there,

Thank you for your feedback, it pointed me in the right direction. It turned out that my hot end cooling fan has died on me which caused the teflon tube to overheat. I got everything up and running now again.

Thanks again.

RE: Hot End Bowden tube keeps failing and the hot end keeps plugging

JoanTabb — Wed, 31 Jan 2024 10:36:44 +0000

the filament should not be hot, in the section of the extruder assembly where the PTFE Tube is (In a Prusa, the PTFE Sticks out a bit further than this at the top!

Where abouts in the heatsink is the filament jamming?
IS the printer inside an enclosure... ?
Is the ambient temperature higher than say 25C?
Is it ONLY PLA, which is Jamming?
Have you tried different rolls?
Is there a tiny gap between the nozzle and the heatblock,
are the nozzle and heatbreak firmly tightened against each other?
Is there a gap of about 4 mm between the Heat Block and the Heat Sink (About the same size as the narrow section in the heatbreak)
Are you using proper E3dv6 Nozzles? Mk8nozzles for instance, are too short!
Is your left hand fan running properly?
when you try a first layer calibration. do you start off with the nozzle high enough for the filament to get out? If you start with the extruder too low, the extruder will be struggling from the start.

Do you have any pictures of the assembled hot end, in the printer?

You appear to be using Capricorn PTFE, is it the thin bore Capricorn? 1.9mm +- 0.05mm? (XS I think)

Have you tried standard PTFE 2mm Bore?

It's hard to diagnose a problem from a distance, when you can't see what's actually going on?

regards Joan

Hot End Bowden tube keeps failing and the hot end keeps plugging

Dirk — Wed, 31 Jan 2024 06:02:23 +0000

Hello Everyone,

I've had my Mk2S and since 2016 now and it has been a workhorse. Recently though the bowden tube in the hot end started failing. From the below picture you can see that there is a section which is thicker than the rest.

It seems like filament is getting stuck which is causing this region to bulge:

Filament after extracting it:

When I pull the hot end apart, then I can see how the filament has broken off in it:

I then have to pretty much disassemble the entire hot end, clean it out, replace the bowden tube and then put everything together. Some photos of the cleaned hot end prior to putting everything together again.

After cleaning it and loading the filament, then it seems to function correctly, but as soon as I try and do a first layer cal., then the extruder motor starts to skip because the filament is getting stuck somehow again in the hot end.

I'm not sure how to solve this as I've cleaned out the hot end multiple times; changed filaments etc.

Any insights would be really appreciated.