Extruder gears jamming

I have iamburnys herringbone gears but they ONLY jam while printing leaving unfilled holes in the model.

I have removed the filament and tested the gears via Web Interface on all speeds (1, 5 and 50mms), rotation (forward/reverse) and length (from 1mm to 400mm) in all possible combinations and not once did the gears jam. The hobbed insert is also clean with no debris.

Did anyone else have this kind of problem? I dont know what to check next ..

Regards,
Antonio

I had this with the standard kit gears using the official reprap firmware. Since then I have updated to DC42'S firmware 078c I think it is and everything works perfect even with the stock gears. I now have the herringbone gears all is fine

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Sardi
Did anyone else have this kind of problem? I dont know what to check next ..

Regards,
Antonio

Could be some tight spots on the gears, maybe you can locate the problem by running a strip of paper in between



...also raising the stepper current could be a Q&D fix - force the gears to adapt and settle in - fireforming with a hotair gun another way but be very very careful, PLA will collapse just like that! (finger snap)

If you think the stepper will get too hot (it wont) you can ad a heatsink (like the one from hotend) to the non-driving end of the stepper - and if you do that you can raise the current up to the stepper/duet max without any problem - trust the force Luke!

One thing you should be careful about if you raise the stepper current - if you change filament by loading the new in the tail of the old - make sure to square of the end of the new (but very lightly sand the edges so not to damage the bowden) before feeding so it has a square surface to push the old filament through, I did fail to do that once, the new filament tried to overtake the old and I ended up with a big bulge on the bowden tube

From my config:
M906 X1000 Y1200 Z800 E1200 ; Set motor currents (mA)

Erik

Also put a couple of drops of 3-in-1 oil on the gears and rotate by hand (with no filament) to get it spread evenly. Other causes of extruder skipping (apart from the first layer of a print where it indicates that the nozzle is too low) are printing too fast (thick layers have a lower max speed than thin layers), and a partially blocked nozzle.

Dave

Thanks guys.

I have just cleaned the nozzle three times following the instructions on RepRap Troubleshooting page.

One thing is for sure - the gears dont start to jam until the filament reaches the nozzle, should I dismantle the hot end and inspect the nozzle for debris by hand?

It stopped jaming all of a sudden. Will try a print and see if the problem is fixed.

Edited 1 time(s). Last edit at 01/17/2015 09:39AM by Sardi.

Are you quite sure the hotend is at the reported temperature/the heating element is all the way in? - I would try raising the temperature, run it on ABS temp. before dismantling and before doing that, would make sure to have a reserve of the special high temperature nozzle inseart ptfe tube as backup

Erik

I dont belive it would be a temperature issue, the jaming is not consistent, it comes and goes randomly.

However, It seems everything is ok now.. I have cleaned the nozzle 6 times by extracting the filament and since then there was no jamming of the gears.

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Sardi
I dont belive it would be a temperature issue, the jaming is not consistent, it comes and goes randomly.

However, It seems everything is ok now.. I have cleaned the nozzle 6 times by extracting the filament and since then there was no jamming of the gears.

Well it seems cleaning the nozzle works randomly too and 6 was your lucky number :-)

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Monty Python and the Holy Grail (sort of)
...Then, shalt thou clean the nozzle six times, no more, no less. six shalt be the number thou shalt clean the nozzle, and the number of the cleaning shalt be six. seven times shalt thou not clean, nor either five, excepting that thou then proceed to six. eight is right out...

Erik (LOL)

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Sardi
Thanks guys.

I have just cleaned the nozzle three times following the instructions on RepRap Troubleshooting page.

One thing is for sure - the gears dont start to jam until the filament reaches the nozzle, should I dismantle the hot end and inspect the nozzle for debris by hand?

It stopped jaming all of a sudden. Will try a print and see if the problem is fixed.

Hi Sardi, it sounds like your nozzle was blocked then.... When you said you had cleared it I was going to suggest you check the bearings in the feeder...
Also after clearing the nozzle, remove the PTFE tube from the hotend... Get it up to temp, then try slowly pushing a bit of filament throu by hand.

I have a theory about the hotend, that when we feed the filament in afresh, that with sharp corners on the edge of the filament, the filament picks up a small bit of the PTFE tubing as it goes from the Bowden tube in to the short length of tubing in the Hotend.... Some times these particles lodge inside the Hotend, and when there is enough, it either blocks the nozzle partially or totally. I noticed a couple of times that the short length of PTFE tubing inside the Hotend had disintegrated. Now when I feed in fresh filament I chamfer the leading edge of the filament, and it stops it.

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Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

My (original kit) extruder gears jammed a lot - took a lot of filing to get to the point where they did not (and even then they did occasionally). I printed out the spring loaded extruder from [www.thingiverse.com] and fitted it with the herringbone gears from [www.thingiverse.com] and have had no problems since.

Richard

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KimBrown
I have a theory about the hotend, that when we feed the filament in afresh, that with sharp corners on the edge of the filament, the filament picks up a small bit of the PTFE tubing as it goes from the Bowden tube in to the short length of tubing in the Hotend.... Some times these particles lodge inside the Hotend, and when there is enough, it either blocks the nozzle partially or totally. I noticed a couple of times that the short length of PTFE tubing inside the Hotend had disintegrated. Now when I feed in fresh filament I chamfer the leading edge of the filament, and it stops it.

My thoughts exactly! After Ive cleaned it twice, I tried printing - jam! Ive cleaned it once more (3rd time) - jam! Then I did it three more times in a row - jamming gone!
But I guess this goes as a part of a regular monthly maintenance

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ormerod168

Quote
Monty Python and the Holy Grail (sort of)
...Then, shalt thou clean the nozzle six times, no more, no less. six shalt be the number thou shalt clean the nozzle, and the number of the cleaning shalt be six. seven times shalt thou not clean, nor either five, excepting that thou then proceed to six. eight is right out...

Erik (LOL)

Laughing my ass off

Hi Sardi

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Sardi
I dont belive it would be a temperature issue, the jaming is not consistent, it comes and goes randomly.

However, It seems everything is ok now.. I have cleaned the nozzle 6 times by extracting the filament and since then there was no jamming of the gears.

It might be a completly different problem. Have you thought about a cable / plug contact problem of the extruder motor. It would at least explain the intermittent problems
the cable contact problem might only occur when on fast moves or so...

Tim

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tstone
...Have you thought about a cable / plug contact problem of the extruder motor...

..and careful about if that should be the problem, the induction might blow the drivers

Erik