HE280 Keeps mysteriously clogging

[sithslayer78]

I've been having the strangest behavior with one of my HE280s recently. No matter what I do, it seems to clog repeatedly, lasting scarcely a print before failing. At temperature, the filament goes through smoothly at first, but clogs quickly and becomes hard to bush through. After a cold pull, the filament is really hard to push through once clear of the extruser, and seems to be wider in diameter as if it had expanded to fill the bowden tube well above the heater block.

Things I have tried:
-Checked for pucks: Haven't seen any since using the PTC tool method.
-Cleaning out nozzle with guitar string: Seems to help get one or two prints out of it before it clogs again.
-Replacing nozzle
-Full Extruder rebuild (cleaned out heat break, new nozzle, flipped heat sink): Did this after I blew a thermal fuse trying to get the filament to flow nicer
-The procedure outlined HEREwith the PTC tool
-Printing at hotter temperatures: Doesnt seem to affect the issue.
-Verified temperatures with thermocouple
-Sliced at 0.4mm, helped a little, but not enough to matter.
-Swapping Extruders: Using another HE280 that belongs to another printer, and printing using the same filament, with the same gCode, the same bowden tube, and the same setup seems to solve the issue, but that extruder is needed elsewhere.
-Retracting at 35 mm/s for 1.8 mm.

Result of Cold Pull (Strongly suspect that the wider diameter shift may be the actual cause of the "clog"):
[img]http://i.imgur.com/eFUsyvo.jpg[/img]
Slicing at 0.5mm
[img]http://i.imgur.com/l9RFwBj.jpg[/img]
Slicing at 0.4mm
[img]http://i.imgur.com/Uum15YV.jpg[/img]
Only "Successful Print". Snapped due to underextrusion.
[img]http://i.imgur.com/Y8Eyksg.jpg[/img]

Things I suspect:
-My PTC retainer may be damaged. It seems to hold the bowden tube in place pretty snugly, and the mark on the tube doesnt seem to move too much when printing.
-I have yet to retrofit to the EZR Extruder, but since a different HE280 worked, I dont think this is the problem.
-I strongly suspect that the barrel fan may be bad. This would be supported by the accumulation of thicker filament above the heater block, and would also explain why the thermal fuse blew despite only being told to heat the printer to 240C. Upon removal and testing, it seems to be vibrating badly.

Thoughts? Any insight anyone can provide would be much appreciated!

[Doug68]

I went through a similar crappy patch of clogging.
I the end a new stainless nozzle fixed it I believe or was part of the solution at least.
Another thing I did similar to the picture below, is wire the PTC connection so it can't move and shove the tube in as far as you can by hand, I think this helps, the symptom being excessive stringing even though there should be enough retract in to stop that, which could be down to free play in the bowden assembly.

Cause or not, if you lock it like this and both ends and sharpie the tube so you can see if it moves then you you'll know if that the issue or not.

[img]https://lh3.googleusercontent.com/76avh ... no-tmp.jpg[/img]

[Dale Eason]

The two most common causes of that are
1. The bowden tube is not seated all the way down inside the hot end.
2. The retract is too big. For the hE280 it must be very small. Good value is 2mm and not much more.

Dale

[geneb]

It's also possible that the nozzle itself is partially clogged by foreign debris. Throw a different nozzle into it and see if the problem goes away.

g.

[sithslayer78]

It's also possible that the nozzle itself is partially clogged by foreign debris. Throw a different nozzle into it and see if the problem goes away.

g.

I've thrown 3 new nozzles on it with no results. It seems like shoving a guitar string through helps it a bit, but it quickly returns to clogging.

I think i'm going to wait for this new Barrel fan to come in and see what that does. The filament buildup in the bowden tube seems to be getting worse everytime I open it up to check it.

thanks!

[geneb]

There shouldn't be any build up in the bowden tube. That's really weird.

g.

[frminio]

Installing the HE280 brought a lot of hassles and clogging I had never experienced before. In the picture you can see my last piece of art. Just last week. Anytime I touch the bowed tube (lately was for the dual kit installation) I experience clogging.

Solution for me was 100% Bowden tube seating.

It must go in 4,6cm from fully seated to the top of the PTC adapter and retainer. Attached picture is not perfect but you can clearly set the notch at 4,6 cm. Sometimes you just can't push it further, chamfer it then, little bit, and it go down much better. This is not stressed enough in upgrade instructions and was even absent from first release.

Anything less that that will result in clogging, straight away.

[djkirkendall]

OP: I'd try a drop of canola oil before every print.

I've noticed with the all-metal hotends (including E3D) the extra lube in the the PTFE tube as well as the buildup in the hotend helps keep things flowing smooth.

Put a drop on your index finger, smear it between index and thumb, and then wipe about 12-18 inches of filament with it before every print for the next 6 or so prints. Then refresh every 10 prints or if you start to see sparse lines again.

Hope this helps!

-Derek

[DeltaCon]

Here we go again...
Micaheals amusing thoughts about using oil (at least in regards of 3d-printing...)
http://www.sublimelayers.com/2017/06/fr ... e-oil.html

[djkirkendall]

That's so weird the author of that article has such utter contempt for using canola oil.

I've found after 30,000 hours with 4 x E3D, I now routinely use it. I have 9 printers now, and sell prints in the order of 100-200 prints per month.

[Xenocrates]

The reason he has contempt for it is because it is a band-aid fix, which has noticeable trade-offs. Running at ABS temps exceeds the smoke point of Canola oil, and others, like PETG or PC, much less PEEK or PEI filaments (You know, the higher temp stuff that's the reason we bought V6's instead of J-heads (Note I mean PETG there, few people print in PEEK)), need options like Avocado Oil, Mustard Oil, or denatured sunflower oil. It also breaks down chemically over time at the lower temperatures, meaning you have an unpredictable, gooey mess to deal with. It attracts dust at every point past the oil introduction, interferes with PEI usage, and produces a greasy looking printer after a long enough period, not to mention the bubbles that can be introduced, and the stench of taking it up to temp for a higher Tg plastic, as all the remaining oil will burn off.

In short, he is so dismissive because chemistry and the oil behaviors easily show why it's a bad idea, and it's suggested as a band-aid to help people who don't want to put effort or thought into troubleshooting, or by the same. No offense to you. If you're happy with PEI not working as well (If at all), degraded structural strength, and being stuck with a lower temp ceiling to prevent major off-gassing, you do you. But don't expect to get to recommend it without someone arguing or bringing up the drawbacks.

[sithslayer78]

Well, It was the barrel fan after all. Upon receiving the new fan, it had a lot less slop and was a lot quieter than the original fan. Once I installed it, it extruded fine (Although I'm still tracking down retraction issues). It was also bought to my attention that the installed fan had had a previous life on a V2 Hotend, so maybe it was just old. Anyway, another thing to keep track of, although much less frequent than pucking or nozzle clogs.

Thanks for the help, learned a lot here!!

EDIT: For the record, this whole thing started when I tried refining retraction parameters in the past. I have a feeling that I may have started the clogging by having my retraction waaay too high, but it seems like I just picked a bad time, namely the time in which the barrel fan was in its death throes. Well, lesson learned. ¯\_(ツ)_/¯

Also, I would NEVER put oil in my hotend, and that was before reading that article, yikes!