Help with recurring blockage?

[scaramonga]

Hello all you wise people

Every 3 or 4 prints I'm having my extruder stop suddenly with a loud ratcheting noise, aka the filament blocked? It's that bad, that I cant even pull the filament out, after hotend is heated to 215c, without a pair of grips. Tonight it happened again (after a failed 10 hour print (twice)), extruder ratcheting, no filament coming out, print at 8 hour mark. Ripped filament out with grips, and decided to replace tubing, but that would not budge either, as it was welded inside hotend. Managed to rip that out with grips eventually, and cleaned the hotend out, which had black flakes dropping from it whilst doing so. Shoved a new nozzle on also, as that was not worth cleaning.

This is happening every so often now, and surely this can't be right? It's chugging away at the 5 hour mark now, so we will see if I'm successful for the third time on this print?, but it will only be a matter of time before the same happens again I suspect. Done all the usual, different temps, PID Tuning, speeds etc. Prints fine until late in the print?

Extruder is Creality all metal upgraded (the grey one), with a Noctua 40x10 fan cooling hotend, the part fan is stock. Capricorn tubing, which I'm suspicious about, as this seems to have started since using it?. BTT sensor (deactivated) just before Extruder (a worthless piece of nonsense which is getting removed when I can be bothered to do so, so a fancy filament guide ATM).

Marlin firmware, latest, and BLTouch fitted, and working great. 4.2.7 board, fans on PSU and mainboard upgraded to Noctuas also.

Any ideas guys?

[Gambo]

It sound like you have a leak of filament from between the end of the Bowden tube and the nozzle. Make sure the end of the Bowden tube is really cut square and pushed down hard onto the back of the nozzle. Both of these processes are harder than they sound, get a raelly square cut with knife is very difficult and even a small error can cause leak in the same way getting the tube seated well needs a quite large amount of force to be sure.

[curious aardvark]

what he said :-)

OR
You don't say what the printer is (the nmore info you give, the better the chance we can help you)
As i understand it the capricorn tubing is simply made to a higher tolearance and thus has a smaller internal diameter than standard teflon tubing.
It could simply be extra friction.
Without knowing what the print looks like or what the printer is, can't say if it';s a bowden tube issue or not.

But My first inclination would be that you haven't pushed the tubing down hard enough.

[scaramonga]

Apologies, thought I had mentioned printer, lol, its an Ender 3 V2. I have always fitted the tubing as per the recommended way of, cutting square (I bought one of they tube cutter things, which does a neat cut), fit connector (upgraded black top type), tighten down, then release one turn back, push tube all the way in hard, then while doing so, re-tighten the connector. Attach clip. Print finished OK last night, but it usually takes a few before it starts again. This is with cheap tubing this time, and not the Capricon stuff.

Just ordered a Swiss DD with hotend, so gonna try that route, although not looking forward to figuring out all the offsets, as I'm pretty clueless that way

Thx for suggestions guys, much appreciated!

[curious aardvark]

well the other alternative is that the capricorn tubing is just too small an internal diameter and your filament is not precis and regular enough in its diameter.

I've never had any tubing issues with 2mm internal diameter tubing.

Not sure why the capricorn stuff has suddenly become so popular - compensating for poorly designed printers maybe ?


Are there capricorn sponsored youtubers saying how amazing the tubing is and how it's changed their lives and they've even won the lottery since they started using it ?
No idea, but then I'm a cynical realist :-)

[Gambo]

Absolutely Right.

If you want to modify something for a specific reason do so if you have no special reason (other than the guy on u tube said it was a great idea!!!!!) DON'T
Remember if you want some thing to keep working - IF IT AIN'T BROKE DON'T FIX IT