need help how to remove the struck ABS in the barrel MK7

[happyman]

Hi, I have encountered a problem for my TOM MK7 after switching to a
new abs filament color. It appears that the hot end can't melt this
plastic filament well and it get struck in the barrel now. Usually, I
can just use some metal to help push it down the barrel by hand but
this time, it won't get through as though it get struck somewhere. I
tried to raise to the maximum recommended temperature 260c but what I
can see at the nozzle is just like a drop of plastic and that's all. I
then tried to disassemble everything and realize that there seem to be
a leak around the barrel connect to the chamber resulting in a big
chunk of hard-to-remove black residue. I managed to use acetone
together with some sanding to remove most of it . However, I can not
remove the barrel or the nozzle as they are very tight. I tried to use
someone suggestion in this group that to heat it up first and then
attempt to remove while it is hot. I am only dare to do it around 120c
because lack of proper equipments and fail to remove them.

So can anyone give me the best procedure or the approximate
temperature that enable to remove these 2 parts from the chamber?

http://i.minus.com/jAUIIqIiObN14.jpg

http://i.minus.com/jUv6IrdM5VrhA.jpg

http://i.minus.com/jbmxa4acfEppD1.jpg

Thanks!

[Achilles Boiser]

Yup, time to use a hot plate. Be careful with the hot plate and raise
the temp slowly and up to what you need. Plus, do it in a well
ventilated as ABS smoke can be nauseas.

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[Achilles Boiser]

Also, rest it on a sheet of aluminum. You don't what gunk sticking to
the hot plate surface permanently.

[Achilles Boiser]

As for tools. You need one adjustable wrench to grab the block end
and channel lock pliers to grab the tube. The bigger the tools the
better the torque and quicker loosening of these parts while they are
extremely hot.

On Wed, May 23, 2012 at 2:14 PM, Achilles Boiser

[Whosawhatsis]

Grabbing the tube directly with channel locks is a good way to destroy the threads. Turn a couple of nuts onto the tube and tighten them down against each other to lock them, then use them to grip the tube instead.

[Jeffrey Ballard]

Take the stepper off, remove top nut on barrel, loosen bottom nut, in screw the entire assembly,  soak in acetone, or heat tell red with torch be careful of the brass nozzle as it could melt.

[Achilles Boiser]

Good luck finding the right size nuts to screw on the threadless end
of the tube. As far as crushing that stainless tube, unless that's
your ultimate goal you won't. You will definitely leave permanent
scratches. But crushing it while giving a good grip is far from
enough force to destroy that thing.

[Whosawhatsis]

The nuts are M6, and there are already two of them on it, on either side of the mounting block.

[happyman]

Thank you everyone for your advices. Finally I managed to remove the
barrel from the heating chamber by tighten it to the metal block with
2 M6 nut and heated it up in the machine at 235c. At first, I was very
nervous because the nozzle started to release lot of smoke and kind
like bubbles fume flew out. I then tried to use the adjustable wrench
to hold at the heating chamber and a long screwdriver poke into the
small hole on the metal block to turn it anti clockwise. It is
surprise how easy to unscrew the barrel out.

I can see that the nozzle look fine as I can see through the hole but
the barrel look mess up with a lot of black burn plastic.

So the next step, I would just submerge it in the finger nail polisher
till it get soft and push them all out right?

Thank a lot for all of your inputs

http://i.minus.com/j8qywDoVIhOwD.jpg

http://i.minus.com/jVPP8aM8ObCO7.jpg

http://i.minus.com/jbc0pWZKctf6oj.jpg

On May 24, 4:57 am, Whosawhatsis <whosawhat...@gmail.com> wrote:
> The nuts are M6, and there are already two of them on it, on either side of the mounting block.
>
>
>
>
>
>
>
> On Wednesday, May 23, 2012 at 2:55 PM, Achilles Boiser wrote:
> > Good luck finding the right size nuts to screw on the threadless end
> > of the tube. As far as crushing that stainless tube, unless that's
> > your ultimate goal you won't. You will definitely leave permanent
> > scratches. But crushing it while giving a good grip is far from
> > enough force to destroy that thing.
>

> > On Wed, May 23, 2012 at 2:27 PM, Whosawhatsis <whosawhat...@gmail.com (mailto:whosawhat...@gmail.com)> wrote:
> > > Grabbing the tube directly with channel locks is a good way to destroy the
> > > threads. Turn a couple of nuts onto the tube and tighten them down against
> > > each other to lock them, then use them to grip the tube instead.
>
> > > On Wednesday, May 23, 2012 at 2:24 PM, Achilles Boiser wrote:
>
> > > As for tools. You need one adjustable wrench to grab the block end
> > > and channel lock pliers to grab the tube. The bigger the tools the
> > > better the torque and quicker loosening of these parts while they are
> > > extremely hot.
>
> > > On Wed, May 23, 2012 at 2:14 PM, Achilles Boiser
> > > <achillesboi...@gmail.com (mailto:achillesboi...@gmail.com)> wrote:
>
> > > Also, rest it on a sheet of aluminum.  You don't what gunk sticking to
> > > the hot plate surface permanently.
>
> > > On Wed, May 23, 2012 at 2:13 PM, Achilles Boiser
> > > <achillesboi...@gmail.com (mailto:achillesboi...@gmail.com)> wrote:
>
> > > Yup, time to use a hot plate.  Be careful with the hot plate and raise
> > > the temp slowly and up to what you need.  Plus, do it in a well
> > > ventilated as ABS smoke can be nauseas.
>

> > > To post to this group, send email to make...@googlegroups.com (mailto:make...@googlegroups.com).

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[James McCracken]

That's a good thought, but be aware that finger nail polish remover (I assume you're not talking about dipping your hot end in nail polish?) has proteins and scents added to it.  If you can find it, 100% acetone is a better choice (look in the paint supplies aisle at Wal*mart)

 

Keep in mind that acetone needs a little agitation to work properly with these small tubes and nozzles... acetone with ABS in it is MUCH thicker than acetone, so they don't tend to want to mix properly; you end up with a tube that was full of ABS and is now full of ABS with a little acetone dissolved in it (as opposed to what you wanted; acetone with a little ABS dissolved in it) so submerge, shake gently for 5 minutes, then try...

 

Keep your acetone solution around when done, it's handy to paint the bed with before a print to ensure great adhesion.

[happyman]

Yes, I plan to completely place the barrel in Acetone. I will get the
actual Acetone from Paint shop tomorrow.

By the way, do you think if I just use the heater cartridge to touch
with the barrel at 225c, will it cause the ABS inside to melt and
remove easy and quickly? I will just hold the heater cartridge by the
wire with adjustable wrench and using pliers to hold the barrel like
in the pic

http://i.minus.com/jma0wVd3zaXQa.jpg

I haven't tried it yet as not sure if there are any drawbacks on this
method, just curious.

[James McCracken]

My experience as a jeweler is sending warning bells; You'll have a lot of metal in the immediate vicinity of the barrel, it'll take a long time to heat up...

 

You might be better off using a toaster oven or something like that to heat it up... go ahead and heat up your wrench too and use potholders to remove from the oven / work with the plastic.

 

Submerging completely is good.  Shaking while submerged is even better - the dissolved ABS really doesn't want to move out of the barrel even after it dissolves, it needs some persuasion to ensure a flow of fresh acetone through the tube.

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[Peter Leppik]

As long as you have the nozzle removed, another thing to try (carefully!) is an electric drill with a drill bit a little smaller than the barrel bore.

The ABS is much softer than the metal, so the drill will remove a lot of burnt plastic very fast without trying to go through the metal tube. This can also get out material which won't dissolve in acetone (because it's too scorched, or because it's PLA).

-Peter

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[charlestx]

Where did you get this "new abs" from? Sounds like something we may
want to watch out for.

Thanks,

Charles

[Shawn]

I recently had a blockage and needed to go through this process to clear
it. I left the nozzle in acetone over-night. Initially agitating it
periodically and clearing away what crud I could. A little more
clearing out the crud the next morning and it was all set and worked great.

I would use acetone, not fingernail polish remover, though the two are
close.

[happyman]

Ok, just grab a gallon of Acetone. Now I place the barrel in the
acetone with some shake around at the interval like every hour. Do I
need to replace the Acetone at some points as it appears to get muddy
from the dissolve abs? Also what is a proper way to get rid of this
used Acetone - can I pour into the sink?

Thanks

[happyman]

Hi,

I just got another problem after able to thoroughly clean the barrel.
Now after I have reassembled (without the ceramic insulator tape or
kapton tape at the hot end), it will overburn the plastic with black
smoke (at 225c) and it seemed to get struck again. I left the barrel
after pick it up from Acetone to dry in front of the fan for 3-4
hours.

Do I need to do any extra step after done cleaning the part with
Acetone? Does the cause is as a result of no insulator around the hot
end? I can not find any ceramic insulator tape at the shop near my
house, are there other substitutes products that work as well?

Appreciate all the supports on this forum.

[Joseph Chiu]

I suggest removing the stepper drive block and hand feed the abs as it is coming up to temperature and see when it starts to flow. It seems like maybe you have bad temp regulation/measurement and the plastic is cooking from getting too hot.

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[happyman]

I tried to feed it by hand per suggestion, and it extrudes quite well
except that there are smoke with burnt smell coming out with the abs
filament. No matter which temperature range (between 215-230c), it
keeps release smoke from the nozzle as long as I push the plastic
filament down the barrel.

Another thing is that the heat seem to spread up to the barrel,
causing the plastic filament to get soft and unable to continue to
push it in and this might be the cause of my previous problem why it
stop extrudes after a while. I think the heating block need to be
insulated and I will try with carbon fiber tape that use in car
exhaust since I can not get ceramic tape in my area.

I hope the insulation will solve these problems with smoke and heat
spread.

I have uploaded the video showing the issue.

http://youtu.be/XdMNhYu38zk?hd=1

Thank all

On May 27, 12:02 pm, Joseph Chiu <joec...@gmail.com> wrote:
> I suggest removing the stepper drive block and hand feed the abs as it is
> coming up to temperature and see when it starts to flow. It seems like
> maybe you have bad temp regulation/measurement and the plastic is cooking
> from getting too hot.

[Andy]

Just wondering out loud, is this smoke dangerous to inhale? I've read before on this group that certain temperatures cause ABS to release highly toxic fumes. I wouldn't want you to injure yourself!!

-Andy

[jet]

I've had to do the same thing almost a dozen times with my Mk7 and
different colors of plastic. I don't know if the head has a problem or
if there's an alignment issue or what. My Mk.6 Just Always Works so I'm
probably going back to that.

--
J. Eric Townsend, IDSA
design <http://www.allartburns.org>
hacking <http://www.flatline.net>
fabrication <watch this space>

[jet]

two answers:

1) don't breathe ABS fumes, use ventilation/filtration or work in a
space with lots of fresh air.

2) make friends with the Material Safety Data Sheet, or MSDS for ABS or
anything else you're using. I've learned a lot of my "don't be stupid,
stupid" rules from these sheets.

[happyman]

Yes, I open all the windows and place the printer near the door away
from where I usually sit. The smell does get attach to the skin too. I
am not sure if the smoke being release due to overcook abs filament as
extruded plastic look fine (I use white abs filament - it does not
display brown or black color like burn) or damaged nozzle from trying
to unscrew it few time. Another thing is that without insulating
material on the hot end - the temperature will fluctuate by +-5
Celsius so might be another cause of improper heat on plastic, causing
smoke. Just my assumptions.

On May 28, 2:36 am, Andy <ganstad...@gmail.com> wrote:
> Just wondering out loud, is this smoke dangerous to inhale?  I've read before on this group that certain temperatures cause ABS to release highly toxic fumes.  I wouldn't want you to injure yourself!!
>
> -Andy
>

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