extruder jammed (abs)

I've seen a lot of threads with PLA jamming the hot end, but I somehow managed to do it with abs (black if it matters). The jam starts a little under an inch from the tip of the hot end. I've tried heating it up to 250C and pushing it out from the top (worked for a PLA jam a few weeks ago), but it didn't seem to help. I also tried an acetone bath for about 15 min, but that didn't help either. Any ideas?

The only time I have known ABS to jam was when I received contaminated filament with black bits in it that did not melt and were two big to fit through the nozzle. Note black plastic has a bad reputation for having crap in it.

The way I unblocked it was to push filament in at 250C, cool it to 150C and pull it out. Repeating this about six times cleared it.

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[www.hydraraptor.blogspot.com]

Been trying that the past few days, but to no avail. Any other ideas before I go buy another hot end? And by the way if I do, would I need to change any settings in the firmware?

I would try drilling out the nozzle with a 0.4mm drill in a pin vice, while hot.

If that failed would unscrew the brass part while hot, using adjustable pliers to hold it while turning the PEEK part. Then I would dig out as much molten ABS as I could and then use acetone to dissolve out the rest.

Yes you will need to change the firmware if you fit another type of hot end. The length affects the Z calibration. The thermal properties affect the PID constants and it may use a different thermistor.

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[www.hydraraptor.blogspot.com]

nophead Wrote:
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> I would try drilling out the nozzle with a 0.4mm
> drill in a pin vice, while hot.

Better take a small injection needle as they don't break off that easily.

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Detlef

Excalibur Hotend

reprapclean32.png

reprapzone.blogspot.de

Can you get them with an OD small enough for a 0.4mm nozzle?

They are difficult to buy with points on in the UK because of junkies.

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[www.hydraraptor.blogspot.com]

Sure. [www.aponeo.de]

I have some with 0.3 mm OD. They are fine.

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Detlef

Excalibur Hotend

reprapclean32.png

reprapzone.blogspot.de

nophead Wrote:
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> If that failed would unscrew the brass part while
> hot, using adjustable pliers to hold it while
> turning the PEEK part. Then I would dig out as
> much molten ABS as I could and then use acetone to
> dissolve out the rest.

ordered a pin vice, but while it's being delivered I think I'll try this. But I thought the PEEK was glued on to the brass..? I've tried removing it already but it wasn't budging so I assumed it wasn't meant to be removed. And by the way, isn't it basically impossible for acetone to not work? Even if there is foreign material stuck in there with the abs, eventually the abs around it would dissolve and the material would just fall out if turned upside down. So it's just a matter of time right? Do you think it'd be worth trying a week long (or longer) abs bath? I just finished another 2 day bath but it still didn't seem to do anything.

I just got an idea...what if I hooked up my vacuum pump to the back of the nozzle? Seems to me like it'd be a lot easier, cleaner, and faster assuming the jam comes out as one piece. Anyone know the type of threads these nozzles have?

The PEEK is screwed into the brass with some plumber's PTFE tape to form a good seal. I have never had much success unscrewing them unless I heat them to extrusion temperature first. When cold the PEEK tends to break.

Acetone will work if the blockage is soluble or only held in place by the ABS but it is very slow. It can take days and will destroy the heater wires and the heatshrink. Only the PTFE wires and sleeving will survive it. Because it is down a deep hole you need to keep swilling it out or is soon becomes locally saturated.

The thread in the top is M8 I think.

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[www.hydraraptor.blogspot.com]