Yeah, using matter control. It’s looking like maybe my filament was the problem…
So the right fix depends on the type of clog. If its low end (near the extruder) you can try heating the hot end and using the atomic method. If its on the high end then I recommend taking it out and cooking the hotend in the oven. 500F for about 15 mins does the trick. Then take something and push the clog out. I normally use a long 1.5 mm Allen wrench from lowes or home depot.
How to tell which?
Basically I’ve got a piece of filament about 3" long that when pushed down is below the level that the gears can push it, and when pulled up won’t come out the last bit. I’m basically at a loss as to how to remove it. Exchanging calls with Robo tech support but it’s slow going.
You need to make sure you turn the heated bed off (set the temperature to zero). That’s what eventually did it for me.This should also be listed in the marvin instructions, at least it was when I printed it.
n23d
25
As for removing the clog. Remove the hot end from the Xaxis Carriage. Turn on the extruder. Once it gets hot Use one wrench/pliers to hold the heater block without crushing the heater cartridge and thermistor and another to remove the extruder tip. Do not apply any torque to the threaded rod coming out of the hot block It will break off.
Once the tip is off see if you can hold the top of the cold end of the extruder with pliers and use another pair to push the filament through the now open hot end. If it comes out reinstall the nozzle and try pushing some filament through to get some flow out of the hot end. If you are getting flow.
Pull the filament back out and reassemble you should be good to go.
If you do not get any flow then push a piece of guitar string in the nozzle until it comes out the cold end of the hot end and pull it on through the assembly. Re test flow.
If you cannot get the wire to feed in or (you have no wire small enough to push in the nozzle) remove the nozzle and heat it with a torch and burn out any plastic. When its clear you will be able to see light through the nozzle hole. Re assemble and retest flow.
If you cannot push the plug out you will need to loosen the locking nut on the threaded rod. Again hold the hot block with one wrench/set of pliers and use another to loosen the nut once its free you can unscrew the threaded rod from the hot block and remove the PTFE liner where the clog is most likely wedged. Now without the support of the threaded rod the PTFE tube is in the PTFE will flex enough to push the plug out. If the PTFE tube is badly distorted or damaged you should replace it.
Put the PTFE tube in the threaded rod.
Screw the threaded rod back into the heater block.
Snug down the locking nut. Do not over torque the nut. The threaded rod will break, mine did the first time I did this.
Re install the extruder nozzle.
Re install the extruder assembly in the carriage.
This can be done with a cold extruder however once it heats up you will need to tighten things or else it will leak.
If you do It with a hot extruder be careful the extruder is very hot use only pliers or wrenches to touch any part of it.
Remember once a part is taken off it takes a while to cool back down.
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Many thanks for the detailed write up! I actually scheduled a tier-2 Skype session for Monday to (hopefully) walk me through all this live. I’m a bit uncomfortable taking all this stuff apart when I’ve only had the printer for a few days.
thormj
27
I kept killing the PTFE tube trying to print ABS (it does work, but it has to go from heating->printing->cooling without delay and my bed was taking its sweet time heating, so heat made it up from the nozzle to the PTFE tube and…), so now I replaced it. You can probably prevent failures by adding a cooling fan like for the all-metal hotends.
E3D - Good, but I got one of the ones from a bad batch. And it’s not fast to get them…
B3 Pico Innovations - Great… but the tube is thin and I snapped it off inadvertently. Also kinda long.
Hexagon - Great and pretty durable. I put the thermistor in and bend it upwards before sliding the silicone boot on so it won’t fall out.
The E3Dv6 has a Teflon tube to make it easier to use with flex (and since the PTFE is in the “actively cooled” part of the hotend, it won’t fail like the Robo3D version), but I’ve found a great pair of solutions for that:
1. Bore out the throat and put a PTFE tube from the hobbed bolt down to the top of the hotend.
2. When the hotend is clear (I made the Nylon Cold Pull thing on Thingiverse… works very well), spray some WS2 or HBN lube down it, insert a cold filament and spin it around. Do that 3 times, and the inside of the hotend will be noticeably slicker (before lube, it takes pliers to do the cold-pull. Afterwards, you can do it by hand – still a tug, but by hand).
The other thing that was problematic with my original Robo3D was the hobbed bolt… mine came in a way that kept filling itself with plastic and would stop extruding (consistently) after 4 hours (grr)… replaced with one from eBay.
Thanks much for all that info. A lot to digest but I will keep it all in mind (and this page bookmarked).
It sounds like you might have pulled molten plastic into the upper portion of your extruder when you tried to pull it out. This might have caused the plastic to cool down inside the plastic portion on your extruder. If this is the case you might have to take it apart and drill it out “carefully!” This happened to me once, so now I pull it out slowly at the plastics lower transition temperature so that it doesn’t solidify inside the upper extruder. All I did was pull the cover off and removed the idler arm and drilled it out. Then I took a round tapered file and smoothed it out. Adding an oiler to your filament feed will help prevent this from happening again, or what I do is just occasionally wide some virgin olive oil onto the filament once in a while when I am extruding a lot of plastic to clean out the hot end during a change over. Hope this helps and good luck!
Thanks for the info!
I did my Skype session with them yesterday and we manage to clear it by removing the hot end, heating it up, cutting the stuck filament flush with the top of the hot-end, then pushing it through the bottom using the small wrench.
Interestingly though, after my successful test print that followed, while the extruder was hot I tried to remove the filament so that I could change it and it won’t come out. Doesn’t move AT ALL when I tug on it.
So, while I’ve cleared my clog, I seem to be unable to remove filament, and that worries me…
Q: Do I need a different tube in order to print with PETG? The tech on the phone yesterday said something about that…
Are you releasing the idler arm by pulling it back while pulling up on the filament?
I’m not sure what the idler arm means, but I’m not doing anything but pulling up on the filament (per Robo3D’s instructions).
The idler arm is the spring loaded arm that applies pressure to the filament against the hobble bolt that drives it into the extruder.
Ah, okay. No, I’m not using that trying to remove, only when I load. Is that the correct method?
To remove I’m just heating the extruder to print temp, then tugging straight up on the filament. It doesn’t move at all.
Is it possible the screws are too tight on the idler arm?
No, your not doing it right! Take one hand and put your middle and index fingers on the spring screws, while with your thumb pulling back on the arm. Then you are releasing the pressure allowing you to use your other hand to pull the filament slowly up and out, so as to not pull molten plastic out with it!
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Gah, seriously!? I asked both techs I talked to what the proper procedure was, and specifically asked if I should be pushing the latch back like I do when loading, and they both said “no, just heat the extruder and gently pull up on the filament”.
Sigh.
Lol! There is the alt method of reversing your extruder stepper motor, but this would be more awkward and possibly pull molten plastic up with it!
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Okay, well… I will try changing filament again when this next print finishes. Thanks for the tips!
It’s the weirdest thing. I push that tab back, and yeah the filament pulls out nice and easy UNTIL I’ve pulled about a 3" length or so out and then it just stops and refuses to go any farther.
Any thoughts appreciated!
