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Extruder jam cleaning suggestions

Posted by AnMeX13 
Extruder jam cleaning suggestions
June 07, 2013 01:13PM
Filament isn't moving out of nozzle. Extruder pulls out as much as elasticy allows and then it's stuck. There is no plastic coming out when heated to 200 C.

I tried pulling it out by hand, by motor, no go. I could probably use more force, but i already broke a couple of pieces, so i'm a bit vary.

It happened with white, not sure what exactly was i doing, obviously something that ended with reverse, where my with screw empowered extruder managed to snap filament just as it enters the nozzle. I tried pulling it out as per instructions on wiki, but it didn't move, so i was raising temp up to 220 C, by 5 C, while trying to pull it out.

I have some alternative approaches, but they scare me a bit, so i'd rather ask first.
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Re: Extruder jam cleaning suggestions
June 07, 2013 01:49PM
If you are getting desperate you can burn out the plastic in the metal hot end. If you have something else suck in there you'll need a fine drill bit or similar to dislodge it.

Make sure you do this outside. If you can remove the PTFE tube insert I would as it isn't very pleasant when burnt. I used a gas torch to on mine. If you can't get the brass nut off be careful about over heating it as it will melt!
Re: Extruder jam cleaning suggestions
June 07, 2013 02:11PM
I was thinking in the direction of dislodging the jam, but didn't want to damage the tube inset, as i don't know what to replace it with. I do have some of the bowden tube, which was too long, causing other trouble, so if it's the same material it's no problem, otherwise i need to order whatever that is.

My desperation has not got to the burning stage, yet smiling smiley
Re: Extruder jam cleaning suggestions
June 07, 2013 03:36PM
The PTFE lining tube should be flush with the end of the nozzle, unless I misread something in the instructions. From reprappro the length I received was enough to re-line the nozzle 3 times over. This is the same stuff as the bowden tube is made of (in my case at least), but my tubes have a thicker walls, so I can't cut bits off and use it to line the nozzle.

PLA is soft from 100 degrees upwards, so it'll be far more pliable at those temperatures if you want to have a go at it with the pliers, but it looks like you've already tied that. The PTFE lining is happy until it starts going over 260-ish or so degrees where it'll start to give off nasties.. You'd need to go over 350 degrees to burn it out.

If you have ABS instead of PLA in there, soak the nozzle in acetone to dissolve it a little bit.
Re: Extruder jam cleaning suggestions
June 07, 2013 09:25PM
Thank you, there's plenty of bowden tube to go around smiling smiley
Re: Extruder jam cleaning suggestions
June 08, 2013 12:30AM
Ok, here's the dirt :
- there was a remainder of white in the hotend, with a nasty feature of being much wider at the top.
- bowden tube widened above extruder too and that was blocking it going back

I managed to get it out by using a single thread of metalic brush, while having hotend at 190 C. I managed to pull filament out for about 2 cm, then i had to dissasemble hotend and cut away widened part of bowden tube.

Inset luckily survived undamaged, because it's much thiner than the bowden tube and couldn't have been replaced with cutoffs.

If i were to speculate as for the reasons for this trouble, i blame it on my shortening the bowden tube. I must've loosened connection between the hotend and the brass union, which filled with plastic and cooled. I most likely did that while putting brass union on the extruder drive end.

Faulty ventilator didn't help and was a reason why i started with shortening of the bowden tube in the first place.

Anyway, it's out now, thanks again.

Edited 2 time(s). Last edit at 06/08/2013 12:33AM by AnMeX13.
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