E3D V6 jamming

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knabo
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E3D V6 jamming

Post by knabo » Tue May 02, 2017 9:07 am

In a nutshell this is my issue:

I have a Max V2 and it has always been a workhorse. I have done numerous hours of production printing with no problem. The printer is about a year old. I upgraded to an E3D V6 fairly soon after building and it had always performed flawlessly, until recently.

My EZR extruder will grind filament randomly. The prints will sometimes come out ok but more and more often the filament will jam and the print is trashed.

I have replaced almost everything in the filament path. New nozzles and heatbreak. I even tried the cleantip versions. I went back to my EZ extruder and had the same issue. I changed Bowden tube, tried the clips (never had to use them before). Some of these I performed several times.

After extensive reading on the forum, it seems the most likely cause is a gap between the Bowden tube and the heat break. It is literally the only thing, but I can seat the Bowden tube very precisely and I still get the issue. Before this I was using 5mm retraction with no issues but I reduced this to 2mm and still had the problem.

So the only thing left is the heatsink. I never considered the heatsink a possibility because its job is kind of passive and it never touches the filament, or its not supposed to anyway. But then it occurred to me that the fitting on the top of the heatsink might be slipping. It seems to lock the Bowden but maybe it is shifting just enough.

I don't know what else could be causing the problem after a year of nearly flawless operation.

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Re: E3D V6 jamming

Post by mhackney » Tue May 02, 2017 11:55 am

It sounds like you should completely disassemble and look at everything under magnification - especially the heat sink internals. With 5mm retract, you were pulling filament up into the heat break. Not that this is your issue but 5mm is a lot of retract for this hot end on a typical Rostock Max Bowden length.

I have multiple V6s with 1000s of hours on them and they just keep going. Something changed. g-code can lead to odd behaviors like this too, especially when you have something "on the edge" like the 5mm retract. Any rapid succession of retracts could cause a jam. What filament do print? Can you correlate the problem to a change in filament, types of things you print or the way you slice them?

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Re: E3D V6 jamming

Post by mhackney » Tue May 02, 2017 11:59 am

One thing you can try is to feed the filament by hand and try to determine if you feel anything odd or if it takes excessive force. This is usually a good approach if you've routinely fed by hand to test so you have a feel for the force required but it's still worth doing if not.

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Re: E3D V6 jamming

Post by Dionysus480 » Tue May 02, 2017 1:29 pm

OK - so this behavior is what I experience every time I try to print PLA on my E3Dv6. However ABS and PETG give me no problems at all. I do find that rapid succession retracts makes it worse, but essentially I can't get PLA to print more than about 20-30 layers before it jams. It is very weird to me that the other filaments print so well. I've got spools of PLA laying around. My extruder is a Titan. However, the "push test" and other steps seem to check out.

I have watched the print occur (heh, 20 - 30 layers - mostly awake) and I'm certain the jam occurs at the hotend, as it is always jammed at that level before I hear the missed steps and filament grinding at the extruder. (It was also a problem before the Titan was installed.)

Every few weeks I get some new ideas to try, but I've not successfully figured this one out. I'm ordering better temperature sensors to figure out if I'm printing at temps much higher than my system it currently reporting. Perhaps heat creep is causing the issue for me? I'll post if I get it figured out.
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Re: E3D V6 jamming

Post by mhackney » Tue May 02, 2017 1:56 pm

Its a strange one. Probably some little thing causing all the fuss.

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Re: E3D V6 jamming

Post by knabo » Tue May 02, 2017 3:03 pm

I don't print much ABS or PET, so this started occurring with PLA. I found some colors, like black, have less of a problem. Some high temp PLAs have more issue.

But, that being said, I have more like several hundreds of hours on this setup, even with 5mm retraction. Something changed, I just don't know what.

When a jam does occur, it is hard to push the filament in but also hard to pull it out. After a short time at temperature, the jam will mostly clear itself and I can push filament again. Then I will extrude 100mm with the motor. Sometimes it pushes through, sometimes it has trouble. This is through the hot end but into open space.

One thing that led me to suspect the heat sink, or rather the bowden tube fitting, is the marks on the bowden tube. Normally the fitting makes a nice sharp indent around the tube. From the heat sink fitting I see a band that is about 1/8 inch wide on the bowden tube. I am hoping this is a sign that the tube was slipping.

New heat sink arriving soon.

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Re: E3D V6 jamming

Post by KAS » Tue May 02, 2017 3:21 pm

I never had luck with large amounts of retract on the E3D-v6. Even their own troubleshooting guide states "Retractions of 5mm or more are troublesome as they pull hot filament up into the cold areas of the hotend where they can freeze, adhere and jam."

One thing you can try is to chamfer the outer part of the bowden tube to further seat into the heat-break. When the bowden tube is cut flat it could have a tendency to leave a small gap at the base of the heat-break. Also just cut off that section of the bowden tube to see if it holds better.

Google image "E3D Jam" and you'll probably see the typical PLA filament jam with the bulbous tip :)

Image

https://wiki.e3d-online.com/wiki/E3D-v6 ... _Blockages

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Re: E3D V6 jamming

Post by knabo » Thu May 04, 2017 2:33 am

So I tried a different heat sink. After some initial good extrusion the skipping and clogging started again.

Everything in the extrusion part of the printer has been replaced at this point. From the motor down to the hot end.
I even put a fan blowing on the controller, did not seem to make a difference.

Since this is not making any sense, I know I need to look at some different data. But for the record, I have made sure the Bowden is seated against the heat break and clipped the one-touch fitting. I changed the hot end fan to a different E3D fan. I have SeeMeCnC Bowden tube installed.

I have 2mm retraction. I am printing a test pattern that is only 3 layers tall so the part cooling fan does not turn on. I am running the latest E3D heater (changed from the previous revision) All genuine parts. I am using the EZR extruder, a new one. I have also used the EZ and a different EZR.
I am cooling the Rambo board front and back.

What usually happens is after some wait time I will start the print. The outline usually looks good, but during the initial infill layer the extruder will start skipping. I am printing at 40mm/s and infill speed is 80% of that.

I usually use older, end of the roll filament for the test prints, so one might say the filament is the problem. That is fair, I switched to some newer filament I usually have good results with (black Hatchbox PLA) so far so good.

When the print does finish without a clog the extrusion is inconsistent. In some places the part will be solid and in others under extruded. It almost seems like the Bowden tube is bending causing a restriction but the line is almost fully extended so no significant bending that I can see. The under extrusion on the part is in alternating bands with ok extrusion but it is not in any particular area or direction of the print.

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Re: E3D V6 jamming

Post by Dionysus480 » Fri May 05, 2017 12:49 am

Do you have any way to measure the actual hotend temperature to compare it to the reported temp? How much variation in temperature are you seeing as you print. And what temp are you printing at (it worked so well for so long I'm not thinking its a problem, just curious.) Does the top of the heatsink get at all warm when the hotend is at temp?
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Re: E3D V6 jamming

Post by knabo » Fri May 05, 2017 8:30 am

I have an IR temp meter but it has never been accurate when I use it on the hot end. I have tried it on several printers heated up to 200c or more and the IR probe reads around 150 at most. It works great for the bed I think. I am only about 5 degrees off setpoint. I need to get a thermocouple probe or other contact type.

I usually print from 200 to 210 for PLA. The top of the heatsink stays cool. I swapped out the hot end fan just to be thorough.

To complete the story, one last detail, I had also bumped up current to 140. I usually run at 130 on all the steppers to keep the heat down.

I seem to have painted an impossible picture. Everything in the extrusion path has been replaced, even parts that rarely fail or have issues. The Rambo board is working and cooled. A system that once worked reliably is now failing randomly but often. It doesn't make sense, I know.

I ran a few test prints using the Hatchbox black PLA and I don't have the jamming problem as much. There are a few places in the print where it looks like it is under extruding slightly, but it finishes and the print is solid.

I am starting to think I just have a weak extruder. Maybe my temperature is off, but I changed from the previous version E3D heater block to the new one with the cartridge thermistor and the problem did not go away. Maybe my filament was old or fat, I have not tried every roll in my collection.

I have a titan that I can try.

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Re: E3D V6 jamming

Post by mhackney » Fri May 05, 2017 9:23 am

I don't think you have problems with filament being old or fat. You are experiencing something systemic that is not right. IR thermometers are not helpful and usually just make things worse since they are so inaccurate in this application. I think you can trust your thermistor and heater given that you've swapped both and still have this problem.

"Just in case" can you take a few photos of your hot end - complete side view showing heater and het exchanger - and as much detail as you can for the extruder please. Sometimes something obvious to use might pop up.

Meanwhile, have you cleaned the plastic out of the extruder drive gear? Is the gear firmly fastened and aligned properly?

Lastly, what state are you in? Maybe some local help is available.

I'm sure we'll get this sorted out. Usually when a problem moves into this "perplexing mode" it almost always turns out to be something incredibly simple.

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Re: E3D V6 jamming

Post by knabo » Fri May 05, 2017 9:40 am

This is a print that did not jam completely, pics of the printer parts coming soon...

IMG_1974.JPG

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Re: E3D V6 jamming

Post by mhackney » Fri May 05, 2017 9:51 am

This shows serious under extrusion so it was a jam waiting to happen.

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Re: E3D V6 jamming

Post by Outsider » Sat May 06, 2017 10:41 am

I just ran into a similar problem on my machine. It would start the print perfectly for the first few layers and then go south. I traced my problem back to wiring. I had one wire that was broken and would break connection only in one quadrant of the bed. I fixed the wire problem and things are back to normal.

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Re: E3D V6 jamming

Post by knabo » Sat May 06, 2017 4:43 pm

Which wire?

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Re: E3D V6 jamming

Post by Outsider » Sat May 06, 2017 7:39 pm

Mine was one of the wires that went to the hot end heater. It broke above the connector. I would start printing and the first 5 or 6 layers were great. then the temps would start to drop off and the print failed every time. That might be something else to check into.

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Re: E3D V6 jamming

Post by knabo » Sat May 06, 2017 9:10 pm

I did a close watch on an aggressive print (lost of short back and forth movement)

The temp was stable, the cooling fan stayed on the entire time. I moved the wiring around to see if I could cause a problem but nothing changed.

Here are some pictures:

I think my extruder is aligned properly

IMG_1975.JPG


Hot end

IMG_1980.JPG
IMG_1979.JPG


Just for the record this is what the black PLA looks like:

IMG_1982.JPG


Not perfect, but it doesn't jam

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Re: E3D V6 jamming

Post by mhackney » Sun May 07, 2017 9:03 am

Yeah but those regular bands in the first layer are an early indication of the pain to come! Something is not right.

Can you take a side view photo of your hot end so I can see the complete outline of the heater block and nozzle.

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Re: E3D V6 jamming

Post by knabo » Sun May 07, 2017 10:45 pm

IMG_1984.JPG
IMG_1985.JPG

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Re: E3D V6 jamming

Post by nebbian » Sun May 07, 2017 11:17 pm

KAS wrote:
One thing you can try is to chamfer the outer part of the bowden tube to further seat into the heat-break. When the bowden tube is cut flat it could have a tendency to leave a small gap at the base of the heat-break. Also just cut off that section of the bowden tube to see if it holds better.


I've been doing lots of experiments with my hotend, and the best way I've found to chamfer the bowden is to make up a tool to do it.

Start with an old heat break, or M6 bolt. Drill this so that there is a 4mm hole in one end, but stop drilling halfway so that it then steps down to 2mm. You now have the exact angle on the inside of the step that matches the inside of your heatbreak. Use a dremel to flare out the entry to the 4mm section. This stops the hard edge of the entry from cutting your bowden when you're chamfering it (later).
Now use a dremel with a cutoff wheel to cut a slot lengthways into your tool, so that you can see the step through the slot.

Once this is done, put your tool into a drill, insert your bowden tube, and spin the drill. This will shave off the end of your bowden to the perfect drill angle (is it 118 degrees?) and the shavings will come out the slot.

Now that I have the tool made up, I can get perfect chamfers in seconds, with no mucking about. I never got a good result when using scalpels.

Image

Note the polished bore inside the hot section, and the slight taper in the transition zone. The more I experiment, the more I appreciate the good design that's gone into this part!

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Re: E3D V6 jamming

Post by nebbian » Sun May 07, 2017 11:25 pm

Well there's your problem. See the dark bands in this picture, that are fat on the spoke, and thin on the rim?

Image

This normally means that you have a cyclical problem with your extruder gear. Looking at this picture:

knabo wrote:
Image



It seems as if the extruder gear isn't square on the shaft, or the shaft itself is bent. Note how the dark discolouration on the drive gear is close to the edge on one side, and pushed away on the other side?

I'd have a good hard look at your extruder gear, while you manually command a 20mm extrusion (no filament loaded). See if the gear is wobbling as the shaft spins. Also, the filament should be seated right in the middle of the extruder gear teeth, not riding right up on the lip of the teeth.

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Re: E3D V6 jamming

Post by knabo » Mon May 08, 2017 10:24 am

I checked the rotation of the extruder gear / shaft, no wobble. I think the dark area in the picture is just a shadow, when I shine a light on it there is no obvious mark. I did a small adjustment anyway, moving the gear out a bit. Ultimately no change.

Back to the filament that clogs so well, high temp PLA.

Initially it seems to extrude ok, then gets thin until it finally clogs. I measure the filament width that I extrude and it measures an average of .3mm. This is out of a .4 nozzle. Verified its a .4 nozzle (3 dots)

After a full clog I can not pull the filament out of the heat sink by hand. I can use the extruder to work it in and out to free it.

There is no blob of filament at the end of the Bowden when I pull it from the heat sink. I usually get a half inch of filament or so out the end of the Bowden indicating it is in the heat break.

The behavior is pretty consistent. After a clog, I can manually extrude and seemingly clear it. During the next print I get some extrusion for a while then it clogs.

It almost seems line I am getting a legitimate nozzle clog but all the time. Like my filament is covered in dirt. I don't think it is BTW, I keep it in a desiccant box. And this does not happen on my other printer. (direct feed Cartesian)

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Re: E3D V6 jamming

Post by nebbian » Mon May 08, 2017 10:38 am

The behaviour you mention. Ah that one. Yep I'm very familiar with that one.

In my case it was because of a combination of:
1) Cheap clone hotend components
2) Long transition zone (distance between heatbreak and heat block)
3) Weak hotend fan
4) Unpolished heat break bore

What happens is that the heat creeps up the PLA / heatbreak, and softens the PLA above where the surrounding throat is hot enough to melt it. When the PLA is soft, the pressure from the extruder then causes it to bulge out and grip the walls of the heat break.
It happens more often when using lots of retractions, and also a nozzle temperature that is too high. I could even cause it to happen just by leaving the printer to preheat for 5 minutes, at 190 degrees it would just jam as soon as it started printing.

How you solve it is up to you, I tried several methods of bore polishing, the one that seemed to do the best job was to run a pipe cleaner through the heat break and put a good amount of abrasive metal polish on the pipe cleaner, hold the pipe cleaner tight at both ends, and run the heat break up and down for a couple of minutes. If you have a genuine E3DV6 heat break then polishing won't help, as those are already polished.
A beefier hot end fan also really helped me.
I also made the transition zone really short (2mm), this won't apply to you though, as you're probably not designing your own hotend layout.
I also seasoned the heatbreak with linseed oil and a blowtorch, make of that what you will.

My hotend now can sit for a while at 220 degrees, with no clogs. I do get clogs if I leave it at 250 degrees for a while, but hey that's pretty extreme for PLA and I was just seeing what would happen.

Good luck with sorting it out, I hope this gives you some clues to try.

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Re: E3D V6 jamming

Post by knabo » Wed May 10, 2017 11:44 am

OK, so let's review.

I installed the original E3D V6 and enjoyed months of printing. Then something occurred that started causing jams.

All extruder parts were replaced and still the problem persisted. These were E3D parts, not clones. I did find out that not all bowden tubing is the same but ended up using stock SeeMeCNC parts. Still jamming continued.

The jamming would occur sooner on higher temperatures.

Based on everyone's input it seems obvious now that I had a heat creep issue. The filament seemed to be binding in the upper, not polished, portion of the heat break. So this is a cooling problem.

I checked my fan and its wiring with no results.

Then I went back and was reviewing the E3D assembly documentation and I realized the problem. Thermal paste, or the lack thereof.

When I first assembled my E3D I used the paste that came with the hot end. Then I think I had a legitimate blockage or things got dirty. But in any case I changed out the heat brake and the nozzle. I did not have any thermal paste for the reassembly. The E3D assembly documentation says it's used in "marginal cases."

My problem started then but I think I was printing a lot of PLA and so maybe did not notice so much. It is also possible that this is not a problem with other materials.

In any case I took the heat break out and gave it a good coat of thermal paste (arctic silver). I was able to print with the high temp PLA after that. Numerous thin wall calibration cubes just to prove to myself it was working. I returned my motor currents down to 130 to minimize heating. This improved the extrusion a bit I think due to the extruder getting warm enough to soften the PLA.

Now I am back to fine tuning my print bed leveling and retesting my retraction.

Thanks for letting me jabber on the forum till I figured it out.

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Re: E3D V6 jamming

Post by nebbian » Wed May 10, 2017 8:39 pm

I'm glad to hear that it's all working for you Knabo! Nice troubleshooting.

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