How to get yourself out of trouble when this happens!

[Geoff]

Hey guys,

I thought I would share some more tips on some issues you can face, especially once you start getting your hands dirty and change filament alot and generally start to tinker.

One major problem I have found with many many filaments, is what I call the Bastard Bulb. This small bulbous shape forms when the plastic sits inside a very hot chamber and simply expands. I find if a filament is left in the exrtuder for a long time (a long time is a day or two for me) I have problems getting my filament out - it starts to unwind but then jams solid..

What you can't see, is this on the underside of the extruder gear




So you get this problem (which you can't see) where the filament is stuck. You try Feeding the extruder, you try Un-feeding it, nope. its stuck solid..

So you pull a bit harder

and pull a bit more harder and...

SNAP!!!

oh crap..

Now, before proceeding, of course remove the offending piece in the above picture so the path is clear for new filament.


DON'T PANIC!!!

I know I know, I thought the same thing. "How on earth can I fix this?? the filament is past the gear, so there is no way to push this through!!!

Yes, there is.

Reassemble your motor and extruder. Put it all back in.

Select change filament from the menu, wait for it to get hot.

WAIT! Be patient. We don't want to try just yet. Wait for a few minutes , let that annoying piece stuck in the nozzle get nice and squishy.

NOW feed some more filament though the top. You will find the new filament pushes that little piece through! no new nozzle required!

Phew

[ixlr8]

Geoff do you let your machine preheat and sit for a while and that's what causes this? I've noticed some issues trying to print after I let it preheat for, say an hour. It seems to print best if it heats up just before a print for me.

[RobH2]

Did that snap off during use, all of a sudden? If so, I'm not sure how that could happen but if you are messing around with the filament and it bends enough, it will get weak. It doesn't take much to snap it off.

However, when it does happen what I do that works well is to take the tip of an xacto knife blade and put it in the center of that snapped off stub. I spin it slowly and drill a comical shaped hole in the end just deep enough so that you can see it's there. If you go too deep you'll carve out the side. Then I sharpen the end of the new piece of filament coming in, feed that through the extruder feeder and place that sharp tip into the conical hole. That keeps the new filament from slipping off. Then once the head is heated hold that joint and feed about 20mm of filament with the slicer and it pushes the new filament in. It works really well for me.

What this technique does that I like is keep me from moving or messing up my tolerances. If you push that filament in by hand you'll tend to push down on the entire hotend carrier and if you push enough, you'll make something change and might cause you to have to recalibrate the 1st layer gap unnecessarily.

[Geoff]

Did that snap off during use, all of a sudden? If so, I'm not sure how that could happen but if you are messing around with the filament and it bends enough, it will get weak. It doesn't take much to snap it off.

However, when it does happen what I do that works well is to take the tip of an xacto knife blade and put it in the center of that snapped off stub. I spin it slowly and drill a comical shaped hole in the end just deep enough so that you can see it's there. If you go too deep you'll carve out the side. Then I sharpen the end of the new piece of filament coming in, feed that through the extruder feeder and place that sharp tip into the conical hole. That keeps the new filament from slipping off. Then once the head is heated hold that joint and feed about 20mm of filament with the slicer and it pushes the new filament in. It works really well for me.

What this technique does that I like is keep me from moving or messing up my tolerances. If you push that filament in by hand you'll tend to push down on the entire hotend carrier and if you push enough, you'll make something change and might cause you to have to recalibrate the 1st layer gap unnecessarily.

Not a bad idea, can't say i've had to go quite that far yet, I actually did it with the hot end off my machine once, so I could see how melty that cut off piece got, and it pretty much dissolved and didnt require much at all to push it through really.
It's more when you get one of those bulbs and it won't go in or out, no load, no unload and eventually you need to pull it apart and seperate the filament at the bulbous section, or of course heat up the nozzle and pull it out but i've burnt my fingers so many times I do everything cold now lol.