Excessive Hotend Jams

Hello, I'm trying to get an E3D v6 Clone working on my Funbot i1. However, the filament keeps jamming/clogging in the hotend the same way every time (pictured in the attachment). I've tried two different filaments to no avail. Now, admittedly they are very old reels so I'm not sure if age is a factor here. They weren't stored in any particular way so I'm thinking moisture got into them and that's why they become brittle and clog in the hotend. Am I on the right track here? Just start with new filament or is there a way to salvage it, or is something else going on?

I'd love to get this thing running, I've been working on it off and on for 4 years now and I'm very close.

Are you running the heatsink fan on the hot-end? The fan should be running any time the thing is hot.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Yes, that's running when its hot. That's why I'm a little stumped.

can you post a photo of the hot-end?

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Here they are, hopefully they can tell you something. Its just an E3D v6 clone from a few years ago. I know there's some ooze on the hotend nozzle, I'll clear that away next time it heats up.

Need any more angles/shots?

Are you attempting to extrude before the hot-end reaches print temperature? What filament material and what temperature are you using?

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Nope, waiting till it hits 185 before extruding. I have cold-extrusion prevention turned on. I even tried to heat it to 230, the ABS preset, and it didn't work either. I have a small reel of old Makerbot Light Grey PLA and a Robo3D Glow in the Dark PLA Kilo roll. Both result in the same type of jam.

Im not familliar with the E3D so happy to be contradicted but:-
Looks like your throat is not in contact with the nozzle. As evident by the rim around your filament in the first picture.
In general i would recomend the nozzle needs to be as far into the hot end as possible and touching the throat.
The heater is heating the block and the heat needs to conduct to the nozzle tip. So you need the maximum contact area for the nozzle.
Its clear in the other picture your nozzle flange is some way from the block.
It seems to me you are heating a lot of material just by the throat and not much by the nozzle tip.
That hot material will then conduct up the throat producing the notories PLA issue with expansion and jamming in the throat.
Other contibutors may be:- Increased mass of filament to heat, exposed Ally block has higher conductivity than the nozzle.

So get the nozzle as far into the block as possible then tighten the throat onto it. However throats are fragile so check the manufacturers assembly proceedure which usually says back the nozzle out a bit then fit the throat, then tighten the nozzle against the throat.

No, that's not how it's done. You screw the heater block onto the heatbreak and then screw the nozzle into the heater block. The nozzle has to butt against the end of the heatbreak to seal it and prevent leaks of molten plastic. You tighten it at print temperature when everything has expanded due to heat by holding the heater block with and open-end wrench (15mm?) and the nozzle with a 7mm wrench. If you screw the nozzle all the way into the heater block you have no way to tighten it against the heatbreak. The nozzle should not be screwed all the way into the heater block. Unfortunately, with this poor design, there's no way to tighten the heatsink to heatbreak connection and it can and will come loose during printing. Locktite may help, but then you'll never get it apart.

I've had problems with the heatbreak coming loose on SoM at the Makerspace and I'm going to replace the hot-end as soon as the parts arrive from China. I've been using an XCR3D hot-end on UMMD for over a year without any trouble. There are a few differences between it and the E3D design that make it better. The crappy fan, the only thing to replace, is mounted on a metal bracket that is securely screwed to the heat sink so it will never swivel around and contact the heater block and melt. The heatbreak is held into the heatsink with set screws instead of being threaded in with no way to tighten it. It does not come loose. The narrowest part of the heatbreak is larger/thicker than the E3D part, and won't bend or break nearly as easily. The XCR3D hotend is several mm longer than the E3D V6, so you'll lose a little vertical print capacity, a fair trade off to gain reliability, I think.

Are you sure the nozzle isn't clogged up with some foreign object?

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Tried to follow the directions here on E3D's wiki and rebuild it and I'm still getting the same result. I'm starting to think I need to spend the money and just get a new nozzle, which sucks. I'm fairly certain it isn't clogged, it oozes a little bit out the end so there's something passing through, just not anywhere near what you need to print. I torqued the nozzle down pretty good, like they said, maybe it needs more on this particular nozzle? If its short that would explain the gap. It is a cheap Chinese clone.

Edited 1 time(s). Last edit at 11/08/2019 09:26AM by Tempest815.

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Tempest815
It is a cheap Chinese clone.

Perhaps that's where the problem lies...

I'm hoping not, and to get this thing working. I don't want to have wasted $20, and I'd like to salvage it if I can. Perhaps a titanium heatbreak and new nozzle?

On the picture you posted above, the nozzle is definitely not far enough into the heater block. The hex part of the nozzle should almost be touching the heater block. Think close to the thickness of a sheet of paper doubled over.

The way I get it right with a new hotend is that I start with a fully disassembled hotend. I then screw the nozzle into the heater block to the distance I described. Then I take the heatsink and screw the heat break into it. Then I screw the heatsink/heatbreak combination into the heater block/nozzle combination as far as it will go. It stops when the heat break butts up against the nozzle. There should be a few threads hanging out the top of the heater block. Then I mount it, wire it and then do the hot tightening of the nozzle.

Edit: you might want to move the fan shroud down a notch too.

Edited 1 time(s). Last edit at 11/08/2019 11:47AM by blt3dp.

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The first thing I'd try is putting on a fresh nozzle. They can get partially blocked by a bur left from the manufacturing process or from other crud that finds its way into the extruder. Nozzles are dirt cheap. Look at amazon - you can buy a 10 pack for about $10. I bought one of those packages recently and inspected each under a microscope- about half of them looked really good and the other half not so good, but not too bad. You should keep spare nozzles handy because they occasionally need to be replaced.

Glow in the dark, glass, carbon, or metal-loaded filaments will destroy brass nozzles quickly. Use steel nozzles for that type of stuff.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

So, I got it to extrude a little! Maybe 2 inches? Then, it jammed again like before. But hey, progress. Is there a chance the Bowden extruder isn't pushing hard enough on the filament?

It's possible that there are bends in the bowden tube could be causing excess friction and preventing smooth extrusion. You could try disconnecting the bowden tube from the hotend and pushing filament through by hand, it shouldn't take very much force.

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The fan shroud is supposed to be down on the lowest heatsink fin. In those hotends, the first 2 fins do 99% of the cooling, the rest seems to be there because the smallest cheap fans they can find are 30mm square.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I agree that the fan should be down on the lowest fin. Also - that extruded filament looks extremely dirty, as though there's a lot of muck being dragged through.

Edited 1 time(s). Last edit at 11/08/2019 04:49PM by David J.

I'll try replacing the nozzle and maybe the heatbreak and see. I think theres a jam in there now anyway. I'm going to get genuine E3D stuff. Is titanium worth it for the heatbreak?

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Tempest815
I'll try replacing the nozzle and maybe the heatbreak and see. I think theres a jam in there now anyway. I'm going to get genuine E3D stuff. Is titanium worth it for the heatbreak?

I have genuine E3D v6 on 2 of my printers, both with the standard heatbreak - the only time I get a jam is when I do something really stupid. I have been known to get stupid in a general sense now and again, but I can't remember the last time I had a jam...

I've come to the conclusion that the nozzle is misdrilled and its getting caught up in the misalignment between aperture and feed section. I'm going to order a new nozzle and install that, see if that works. If not then I really don't know what to do. Unless the thermistor is reporting an incorrect temperature and I'm trying to cold extrude by accident.

Thanks for the help!

Edited 1 time(s). Last edit at 11/12/2019 09:19AM by Tempest815.

I am no expert so do take note of those who know more than me. (Especially DD)
Is the hot end block upside down ?
I see pictures with it the other way up. Which puts the heater nearer the nozzle and with a more direct heat path.

I'll try flipping it, I installed it the direction it came in so I was assuming that at least would be correct.

Flipped it, I can manually push filament through and sometimes get the extruder to push filament through but it seems to jam after a while. I'm thinking its the settings for the speed of the stepper motor on the extruder. Nozzle and heatbreak are clear.

Quote
Tempest815
Here they are, hopefully they can tell you something. Its just an E3D v6 clone from a few years ago. I know there's some ooze on the hotend nozzle, I'll clear that away next time it heats up.

Need any more angles/shots?

Your heat sink fan is upside-down. The bottom of the heat sink needs more cooling that the top. Note, your fan cowling orientation.
Flip it and see if that helps.

DLC

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Yeah its been flipped when I flipped the heatblock. Still getting the same jam every time.

NOW its reading -26 degrees and giving me a fatal error that it failed to heat.

EDIT 11/14/19: Found the problem here, replaced and fixed.

Edited 1 time(s). Last edit at 11/14/2019 09:18AM by Tempest815.