Ender 3 V3 SE - Filament not feeding

[Cookeh]

Hiya,

Hopefully this is a quick fix. I have a 4 day old E3V3SE, that's been doing great on Ender PLA. I just changed the filament earlier today to Overture Rock PLA for a print I was hoping to do, and I've set the new filament up as a profile (in Orca Slicer - basically I've just dropped the speed slightly to match Overture's recommendations). I did a bed level and now I'm trying to print some quick calibration prints to dial in the temps, but the filament isnt actually being extruded.

If I press the level back (as if loading or retracting filament) and push it through, I get extruded filament coming out of the nozzle, so there's no blockage. I can hear an almost clicking from the direct drive - could there be a fault there? If so how would I check or resolve that?

Thanks in advance and sorry for the relative lack of information!
Cookeh

 

[gitbags]

Can you extrude manually from the printers UI? I would strip the shroud and check the extruder for damage if not.

 

[Cookeh]

I tried manual extrusion rom the UI, and initially it worked fine. Eventually it stopped behaving. I gave cold pull a try afterwards, but still had issues.

Ended up taking the hot end apart and found a blockage of melted filament between the direct drive and the hot end, actually in the heatbreak itself. Nozzle will be replaced too as that doesn't look too great.

What could cause there to be a blockage in the heatbreak?

 

[gitbags]

Usually molten filament being retracted to far up the hot end but not pulled out, so it cools in the heartbreak. Heat creep is also another possibility if cooling isn't good enough.

 

[Cookeh]

Interesting, thanks. Solution then would be too either drop temp slightly (so its not molten before the hotend), and decrease retraction distance?

 

[gitbags]

Your retraction should be around 1mm on a direct drive anyway so unless that's set wrong you should be good. What temp are you printing? I tend to print pla about 220.

 

[Cookeh]

My retraction was 0.8mm, at 45mm/s. I was at 210 for PLA yesterday, but almost seemed to be burning the filament - the part I cold pulled looked a bit crystalline and off-colour. Trying again now at an ever lower temp of 200 (filament is now extruding even down to 190'c when doing it via the UI or manually).

 

[gitbags]

You shouldn't have problems at those temps. Out of curiosity What's your hot end temp when you switch the printer on from cold? It should be room temp.

 

[Cookeh]

I'll have to check tomorrow night now, but will find out as think I understand your reason for asking and now I'm interested!

Managed to get two prints out today without issue. I cleared the blockage, swapped the nozzle, auto-levelled and set z-offset. That combined with dropping temp and running a much lower speed (60mm/s) seems to have done the trick for now.

Ender PLA was printing at 215-210, and 90mm/s. Wonder if the particles added to make it matte are responsible for the need to run so much slower - perhaps it affects viscosity or fluidity?

 

[Cookeh]

You shouldn't have problems at those temps. Out of curiosity What's your hot end temp when you switch the printer on from cold? It should be room temp.

Sure is room temp, 16'C.

 

[gitbags]

So your thermistor Is probably fine. Is the V3 se a all metal hot end or do you have PTFE to the nozzle like the original ender 3? I wonder if your original nozzle wasn't tightened enough and allowed some filament to build up in the gap, or maybe some debris in the filament itself?

Either way if it's printing ok now, may as well carry on.

 

[Cookeh]

Its all metal, with ptfe lining heatbreak between the hotend and the direct drive extruder.

I'm starting to think it was filament related, had a couple of lengths snap clean off during the print head moving. I cut a metre or so off and arrive then it's largely been behaving.

As you say, combo of lower speed and temp and trimming off that first chunk of filament seems to have done the trick so I'll press on and hope it behaves going forward. Thanks for the help and advice!

 

[Haze]

On my ender 3 I don't print higher than 200 degrees using pla