Hotend JHead jammed with ABS. Howto clean?

Hi

the extruder motor has not enough power to push the abs trough the nozzel, so i think it is blocked by dust.

i have read about it but dont understand all.

i have to remove the brass part from the rest. than i can use aceton... but what is with the resitor and and so on.

what is with the silicone tape. if i cut it i dont have a new one. do i need it?

have anyone pictures to make it clear?

actually i can not print. it is hard :-(

help me plz.

smuk3d

I just repeat:
Heat to 240C and push the filament in as far as it will go.
Cool to 150C and pull it out.

That will clear most contamination as it is like chewing gum an 150C and pulls out any crap with it.

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[www.hydraraptor.blogspot.com]

hi nophead

should i push manually?

i will try again. the first time i dows not work

best regards
smuk3d

Yes manually.

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[www.hydraraptor.blogspot.com]

good morning,

it is very hard to press manually.

to get 2cm out of the nozzel i have to press about 20 seconds @ 240°C :-(

after 10 times i try with extruder but doesn't work .. the filament i shaped by hobbedbolt :-(
the resistance i to high for it ..

is the hotend defect after 2 weeks? i don't hope .. :-(

thanks for helping ...
smuk3d

Edited 1 time(s). Last edit at 11/09/2013 03:45AM by Smuk3D.

If you extrude at a reasonable speed by hand either the temperature is too low or there is something wrong with the hot end.

With the technique above you should be able to completely empty it. Was that the case?

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[www.hydraraptor.blogspot.com]

No i cant get it empty ...

i tried diferent temperatures from 220 to 250 degree and from 130 to 160 degree for pulling ..
(the printig before the incident had works great by 210 degree)

maybe i had lost now warranty but i have disassabled the jhead because i got crasy without 3d printing :-)
i heat up to 220 degree

so now i have some parts an there is all abs .. the black tube i have allready clean .. but the nozzle looks like it is 20 years old ..

can i put it with resistor in aceton to clean it? .. or should i try to warm up an clean manually without burn my fingers? :-)


thanks for you help again
smuk3d

Edited 2 time(s). Last edit at 11/09/2013 07:55AM by Smuk3D.

Acetone won't affect the resistor, the red wires or the PTFE sleeving but it will destroy the heatshrink and the green thermistor wires.

Did the ABS on the outside leak from above or come from below?

If plastic gets on the thermistor cement it can be absorbed, then it burns and becomes conductive causing the temperature to read higher than it actually is. Does it still read the correct room temperature?

Acetone takes days to dissolve ABS and it won't dissolve burnt ABS. I would heat it to 150C scrape the plastic on the outside off with a penknife or pull it off with pliers while holding the block in pincers. ABS is like chewing gum at 150C and doesn't burn quickly like it does at 240C.

To clean the inside I would heat it to extrusion temperature and dig it out with a 3mm drill (by hand, not it a drill). If there is something blocking the nozzle you might need a 0.4mm drill to unblock it but always do it when hot so the plastic is molten otherwise it may wander sideways and make the hole too big. Other people have recommended hypodermic needles but I haven't tried that.

To reassemble it you need to PTFE plumbers tape to seal the joint. You may also need to loosen and re-tighten the grub screw at the top.

Where did you get the ABS from? 210C seems very low for ABS. I use 240 or 250C.

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[www.hydraraptor.blogspot.com]

hi

i have buy the abs from ebay .. [www.ebay.de]

i think the abs comes from below. had problems with wrapping and so on ..

i will test if the temperature is right ..

thanks for the tips

now i will try cleaning the nozzle.

best regards from germany
smuk

YES we can ....

i got it ..

thanks for the tipps nophead ..

her are some pictures from the stepps of cleaning

best regards from happy smuk



ps here the tools i used


Edited 1 time(s). Last edit at 11/09/2013 02:36PM by Smuk3D.

Well done. Looks like you did a good job there.

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[www.hydraraptor.blogspot.com]

thanks :-)