Frustrated, but still trying...

[Dore Mark]

Well, I took a week off of my makerbot so I could start fresh again.
I took my PTFE off and saw that my previous problem was ABS leaking
all over the barrel threads - so I cleaned it off the threads and the
PTFE (using acetone).

I put the thing back together and I STILL strip filament. I even have
the new MK5 feed pulley. Could it be that my old PTFE just won't work
anymore? I was going to try putting a new PTFE barrier on this week.

If anyone has had this problem before, perhaps you can take a look at
the picture below.

http://www.flickr.com/photos/50872309@N06/4700215644/

You can see that the filament "necks" down before it starts getting
smaller. In other words, there is an hourglass like shape as the
diameter decreases. Does this mean anything?

-Dore

[Andrew Plumb]

If this is happening after rebuilding the nozzle, my first guess would be that you've screwed the brass barrel into the PTFE insulator a little too tightly. Doing so will constrict the passage with an inner ring of PTFE where it meets the brass.

The best fix I've found is to use a 3.2mm or 1/8" drill bit to (carefully) clear out the excess PTFE. As an added bonus, this guarantees that the point at which the PTFE meets the brass will be completely gapless.

Andrew.

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"The future is already here. It's just not very evenly distributed" -- William Gibson

Me: http://clothbot.com/wiki/

[Dore Mark]

Wow, no kidding.... it wasn't tight before - thus the ABS got into
the threads. After I rebuilt, I screwed it on hand tight. You mean I
can screw it on too tight? i thought the limit was breaking the
threads on the PTFE.

-Dore

> > For more options, visit this group athttp://groups.google.com/group/makerbot?hl=en.

[Andrew Plumb]

Yup, it's the non-threaded, smooth end of the brass barrel that's pushing in the thin lip of PTFE.

A.

> For more options, visit this group at http://groups.google.com/group/makerbot?hl=en.

[Dore Mark]

Actually, now that I think of it - not only did I tighten the PTFE on
the barrel, I added a copper sleeve and hose clamp. Could this have
done anything negative?

-Dore

[JohnA.]

We run a similar setup on a few of our nozzles without incident after
bulging a PTFE or two when we first started. We just make sure the
clamp is over the barrel section, and not near the joint between the
two different materials.

JohnA.

[Dore Mark]

What would the symptom be if I had the hose clamp over the joint?

-Dore

[Revar Desmera]

If the PTFE barrel you are using has already failed once, I'd consider it unreliable as the PTFE may have bulged slightly with the ABS pushing into the threads. The copper sleeve and pipe clamp are a good idea, though. I'd just try them with a new PTFE barrel. Also I'd suggest making sure the brass barrel wasn't screwed into the PTFE so tight that it constricted the PTFE channel at the top of the brass barrel. You can fix this up carefully by using a 1/8" or 3.25mm drill bit.

Now, having said all that, if you are still having stripping problems, there are a few more problems it could be:

If your thermistor is badly calibrated, you may be running the barrel too cool to keep the ABS melted. Try raising your temps 5 or 10C.

Otherwise, it's possible that your brass barrel is partly clogged or something. This can happen when foreign materials gets into the barrel, or when the plastic inside is cooked at too high a temperature. I just had this problem myself. The solution that worked for me was to remove the brass barrel, remove the thermistor and nichrome from it, and heat the raw brass barrel up to red hot with a blow torch. That burnt out all the ABS and crap inside and left it easy to clean with alcohol and a pipe cleaner after it cooled. The nichrome wire you unwrapped is a loss, as all the insulation on it was brittle and probably came off when you unwrapped it. Wrap the brass barrel with new nichrome wire, add the thermistor back, and reassemble.

- Revar

[JohnA.]

We were able to salvage one slightly bulged PTFE, but after retiring
it we sliced it down into thin sections for use as PTFE washers
between the M6 nut and the big washer.

JohnA.

[Dore Mark]

I'm running at 225 C, and I'm pretty sure that there's no serious
clog. If I unscrew the idler pulley, I can push really hard on the
filament and get it to extrude.

I'll put all of these things on my list as I try again.....

-Dore

[Dore Mark]

I just took my extruder apart again. Took off the PTFE, which wasn't
on very tight. There was no ABS in between, probably because I
haven't extruded much since the last time I took it apart. I
repositioned the hose clamp above the threads and not at the joint
between the barrel and PTFE.

But then I noticed that the idler wheel had come unglued from the
bearing. I'm gluing it back right now and going to re-run tomorrow
when everything has cured. Hope that solves my problem of having the
filament strip.

-Dore

[Steven Dick]

On Mon, Jun 14, 2010 at 6:51 PM, Dore Mark <dore...@gmail.com> wrote:

I'm running at 225 C, and I'm pretty sure that there's no serious
clog.  If I unscrew the idler pulley, I can push really hard on the
filament and get it to extrude.

If you press a piece of filament into the side of the tip of the hot nozzle, does it melt easily or does it barely mark it and only with a lot of pressure?

[Dore Mark]

When I press the filament next to the nozzle, it melts pretty readily.

I just tried to extrude again, got some extrusion, and stripped
again. I backed it out, cut the filament, tried again, got some more
extrusion, and stripped again. When I manually push the filament
down (without loosening the idler), I can get it to force extrude. I
backed it out again, cut the filament again, and stripped yet again.

I just pushed the calibration rod between the idler and the drive
pulley and things seem pretty tight.

Sigh. if only I could get this to work

-Dore

On Jun 14, 9:19 pm, Steven Dick <kg4...@gmail.com> wrote:

[degroof]

Things that have caused my filament to strip:
- idler too loose
- idler too tight
- idler not centered on guide
- idler cracked
- ptfe barrel leaking
- broken retainer ring
- heater too cold
- 606 bearing (the one on the motor shaft) fell out

At the moment, everything seems to be working OK. I've got things
lined up nicely, a hose clamp around the ptfe, something jammed up
against the bearing to keep it in place...

[Steven Dick]

On Tue, Jun 15, 2010 at 11:41 PM, Dore Mark <dore...@gmail.com> wrote:

When I press the filament next to the nozzle, it melts pretty readily.

so your temp is probably ok
 

 When I manually push the filament
down (without loosening the idler), I can get it to force extrude.

If you have to apply a lot of pressure to make this work, there is probably something wrong with either the insulator (like, the opening is too narrow) or the nozzle tip or something.

It does take a bit of pressure, but not a lot.  If you have to force it hard, that's probably why it is stripping.

 

[ddurant]

> When I manually push the filament
> down (without loosening the idler), I can get it to force extrude

That sounds to me like the idler might be too loose. Can you post a
picture of the backed out filament? Not the bit that's gone into the
thermal barrier - just what's gone through the idler.

> > pressure?- Hide quoted text -
>
> - Show quoted text -

[Andrew Plumb]

How frequently are you flossing between the teeth of the drive pulley?

Every time the filament strips, little slugs of ABS get stuck between the teeth. If you don't clean them out you get exactly these symptoms.

Andrew.

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[neoteric]

As a new user myself, I feel your pain. It is very frustrating. I
have been dealing with exactly the same issues. Here is how I solved
it, although I cant help feeling like it is not the RIGHT solution.

1. Turned up my temperatures in Skeinforge. Its not bubbling,
cracking, or coming out hard, so I think that is ok.
2. Let the extruder get hot, through and through. Dont try to extrude
until you've had the extruder on and hot for a good while, say 15
minutes.
3. Always reverse the filament completely out of the extruder every
time you are done with a build. This clears out the extruder,
especially in the middle. Cut off the extruder filament clean. Let
the extruder get hot. build. repeat.

This seems to be working ok. Also, I ordered a new premade extruder
from Makergear.com. Hopefully, it will eliminate some issues. They
are behind, but I will post my findings when I get it.

> > For more options, visit this group athttp://groups.google.com/group/makerbot?hl=en.

[smonkey]

I had problems like yours and have solved them,
but sadly the answer means spend more money....

I now consider my makerbot "complete" after spending another $150
bucks over kit.

As a makerbot comes they aren't complete.

First, you definately need PEEK thermal barrier from makergear.

I'm not quite sure why they still ship the makerbot cupcake with the
ptfe one when
it fails all the damn time and the PEEK one is only 8 bucks. But
whatever....people do what they do.

And then you need one of those new nifty mk 5 filament drive gears.
They are the bomb and rarely ever strip (well...mine hasn't stripped
yet, but i'm sure one could do it it if one tried).

If you just order the "superkit" from maker gear you get the parts to
make 2 modular heating elements (just screw 'em off and on), one of
those new filament drive gears, an extra wide pinch wheel and the peek
barrel and fat head new extruder tip and barrel and......well...all
kinds of great stuff.

It was totally worth it!

(tho it takes a bit of time for them to get 'em out to you, just be
patient...it will help you so much you will cry...no...really...you
will tear up when you realize how easy it _should_ work).

If you have a little extra cash I'd buy their pre-made extruder that
comes with a sample piece made with it and the like.

That should get you going even faster (to the tune of a couple hundred
bucks, and dont forget the new gear, you still want one of those!).

so, in conclusion,
must haves for the makerbot to run well,

PEEK thermal barrier
new gear bit



there ya go, my 5 cents

n

[Paul Huckabee]

I have to agree with smonkey here. I recently completed the heatcore from my super pack. It is quite nice and well worth the investment. Also the makergear IRC channel is a really good resource for getting help quickly. 

[Pete]

Question: What is the failure mode if you skip letting the extruder
get hot, through and through?

> > Me:http://clothbot.com/wiki/- Hide quoted text -

[Paul Huckabee]

Lack of extruding and stripped filament. My general rule of thumb for printing is to open the control panel, set the temp to 220, wait for it to reach temp or near temp, you will likely see some filament leak out. Start the print. 

[lung fish]

I'm having exactly the same problems that you are, Dore.

I finished my makerbot last week, and have only gotten it to actually
print something once, and the extruder didn't feed for several of the
layers, so even that looks horrible.

To try to stop the filament from stripping, I made my own mk5 style
drive gear. ( http://www.flickr.com/photos/lungofish/4706413917/ )

It worked great. So great it blew out the teflon insulator tube in
about 5 seconds despite the nozzle being at a solid 230 (checked with
a non-contact ir thermometer).

Last night I decided to autopsy my heater core to see if I could
figure out what was going on. The nichrome wire was surprisingly
charred - I guess some of the insulator material doesn't survive the
first heat-up. It had taken some of the klapton tape with it, and left
scorch marks on the insulator fabric. I'm not sure if that's a problem
or not. It wasn't shorting and was getting up to temperature without a
problem. Once unwound, though, it's pretty much wrecked.

The tube was still full so I heated it and pushed most of the plastic
out with a metal rod. As I was doing this I discovered that there was
a tiny ridge inside the heater barrel, about halfway through, all the
way around. It's almost as if the tube was drilled out from one
direction then the other, and the drill bit left a small burr in
there. It's tiny, hard to see even when shining a light down the tube,
but I can easily feel it when pushing a bit of wire in there.

I have the sneaking suspicion that this might be part of the problem.
When assembled, this ridge would be about where the retainer washer
sits. If the nut and washer act as enough of a heatsink, the plastic
there could be cool enough to get caught on the ridge and start
backing things up.

Of course, I had to unwind my nichrome wire to find this out, and I
don't have any more til I get the spare parts kit I ordered yesterday,
so I can't test my theory.

I also need to start trying to track down the interference issues that
I'm having.

- Joe

[Dore Mark]

I floss almost every time it fails

> > For more options, visit this group athttp://groups.google.com/group/makerbot?hl=en.

[Dore Mark]

I'm doing the same. My new stuff from Makergear is coming....

[Dore Mark]

Exactly what I'm doing. I already have the Mk5 gear, now I'm getting
the PEEK

-Dore

[Dore Mark]

Great post mortem. I'm glad I'm not alone here. These problems have
had me going for about 3 months now. I can't spend more than an hour
or two on it at a time with my kids and work, so it's sporadic for
me. Some day I'll get it working. Funny thing is that at my former
job I bought a Stratasys FDM and the thing was a tank. I guess my
expectations were too high...

[peterr]

Please do remember that what comes with the kit works!
The makergear heatercore is a great piece of hardware, but it doesn't
solve your extrusion problems entirely.
PTFE starts to loose it's physical properties at around 250°.
Considering you heat up the nichrome wire to around 270° to reach a
stable 220° at the nozzle - if you position the nichrome wire too high
up the heater barrel you WILL get into trouble with the PTFE.
Important is to use a nut between PTFE parts and the metal retainer.
Not only will it decrease the strain it will also divert some of the
heat that otherwise would travel into the PTFE barrel.

I advise everyone that has problems with the PTFE to add another
thermistor right below the PTFE part to measure the temp that goes
into the barrel.
It should be warmer then around 150° at the entrance of the PTFE part.
I agree that once the PTFE part has been compromised you should throw
it away.
PEEK is a great solution, but not necessary to achieve a decent (long
therm) build.
Warm up your head for atleast 15minutes or longer. Doesn't matter if
the filament oozes... The walls of the standard extruder are approx
1mm thick, and yes they heat up very quick on the surface. But when
you put strain on heat the dispersment of that heat changes. Hence
temperature may flux allot more if you start pushing filament out
after 5minutes. Extrude for atleast 1minute before starting a build -
yes it's a waste - but atleast you'll have filament that behaves like
the entire build.

What goes in, must be able to come out. If your pushing in to much
filament (or to fast) it's all going to back up any one way it can.
Start slow, and work your way up...

i have 4 different heads, three with PTFE and one with PEEK. I see
absolutely no difference between each of them.
three with nichrome wire, one with a heatercore - again no difference
whatsoever...

You are an early adopter, and should consider your machine to be in
beta stage. You WILL take it apart many many MANY more times then you
care for...
but the paradox here is that you NEED to take it apart to understand
what's going wrong. So don't keep messing around with problems trying
to fix them.
Take it apart, clean it, rebuild it - and start over again.

We've all been there, now it's your turn ;-)

Ps: buy lots of nichrome :p

Peter
--------------
makerbotknowledge.blogspot.com

[Paul Huckabee]

I agree with peterr. The makerbot should be considered beta and will likely have to be broken down and rebuilt many times. That is what makes the makergear super pack so nice. It's not that it does some bit of voodoo magic to make your abs turn to shiny golden prints of amazing awesomeness. It's that the whole thing from top to bottom was designed to be taken apart. Every thing is connected via molex to the controller. There are only 2 screws you need to remove to get the barrel and insulator off the block. The heat core never needs to have the nicrome re-wrapped. It is a very well thought out design created by someone who has obviously had to take their MK4 apart from time to time. 

[Andrew Plumb]

Heh. You mean Rick's MK3, not MK4.

...and yes, he's done a lot of experimentation along the way: http://www.flickr.com/photos/makergear/4500989577/

--

[Paul Huckabee]

I think he is on a wade ATM, but who's counting. 

[Dore Mark]

I don't even consider this to be beta. It's proto.

If I released a beta consumer product like this, I'd be fired.

But I did expect to have to work on this alot. I'm just disappointed
that I've only been able to make a few insulator retainers - that's
it.

-Dore

On Jun 17, 6:37 am, Paul Huckabee <krazyl...@google.com> wrote:
> I agree with peterr. The makerbot should be considered beta and will likely
> have to be broken down and rebuilt many times. That is what makes the
> makergear super pack so nice. It's not that it does some bit of voodoo magic
> to make your abs turn to shiny golden prints of amazing awesomeness. It's
> that the whole thing from top to bottom was designed to be taken apart.
> Every thing is connected via molex to the controller. There are only 2
> screws you need to remove to get the barrel and insulator off the block. The
> heat core never needs to have the nicrome re-wrapped. It is a very well
> thought out design created by someone who has obviously had to take their
> MK4 apart from time to time.
>

> > makerbot+u...@googlegroups.com<makerbot%2Bunsu...@googlegroups.com>
> > .

[ddurant]

> http://www.flickr.com/photos/50872309@N06/4700215644/

Maybe it's the lighting or something but the width that's gone through
the pinch wheel but not into the hot zone looks a little inconsistant
to me. (I'd mostly ignore stuff that's been heated.. I get all sorts
of funny shapes on backed out & heated filament)

Have you taken a close look at your idler wheel to make sure it's
centered? If so, it might be worth it to measure your filament stock
to make sure the diameter is consistant.

If your filament isn't a consistant width or the idler wheel/motor
isn't gripping evenly all around, you can run into problems like you
describe. The tolerances between the idler being too tight and causing
the filament to be too wide to fit thru the thermal barrier and being
too loose and not having enough grip on the filament to push it around
is pretty small.


On Jun 14, 11:12 am, Dore Mark <dore.m...@gmail.com> wrote:
> Well, I took a week off of my makerbot so I could start fresh again.
> I took my PTFE off and saw that my previous problem was ABS leaking
> all over the barrel threads - so I cleaned it off the threads and the
> PTFE (using acetone).
>
> I put the thing back together and I STILL strip filament.  I even have
> the new MK5 feed pulley.  Could it be that my old PTFE just won't work
> anymore?  I was going to try putting a new PTFE barrier on this week.
>
> If anyone has had this problem before, perhaps you can take a look at
> the picture below.
>
> http://www.flickr.com/photos/50872309@N06/4700215644/
>
> You can see that the filament "necks" down before it starts getting
> smaller.  In other words, there is an hourglass like shape as the
> diameter decreases.  Does this mean anything?
>
> -Dore

[Dore Mark]

I did have some problems with the idler wheel getting detached from
the bearing, but I check that every time now.

I'll try to run a better picture tonight of the teeth. My still have
the remnants from my last run two nights ago.

-Dore

[ddurant]

> but I check that every time now.

Overkill, IMO.. I took mine apart last week and found that the wheel
wasn't glued to the bearing any more. Since I didn't have any glue
handy and it was a tight fit anyway, I just put it back on without
gluing it and it's been working fine. I'll definitely fix it sometime
soon but it's not a "zomg, that's critical" thing.

If you're even a little suspicious that the filament diameter might
not be consistant, I think that'd be the first thing to check.

> > > -Dore- Hide quoted text -

[Dore Mark]

Problem is that if the idler wheel is unglued, it can walk along the
axial direction of the bearing. When that happens, the idler may not
be aligned to push the filament directly into the drive pulley. This
may have happened to me once or twice, but I'm not sure. That's why
I'm neurotic.

-Dore

[Dore Mark]

My God....I took another week off, and got some parts from
Makergear....

I"m trying to clean out my nozzle/heater barrel for the first time and
like others have mentioned, acetone isn't doing it.

Is there a way of cleaning this out without a blowtorch?

Should I pull the nozzle out of the acetone bath, let it dry, and then
try drilling out as much as I can? Will the abs stay gummy?

Sorry to sound clueless, but I probably am...

[Michael Rule]

I recently cleaned out a barrel using a drill, it seems to have worked
but I will need some new parts to test it. Repeat : drill, acetone,
drill, acetone ? Careful not to drill through the nozzle ? Then it was
still getting clogged in the small end of the nozzle so I took a very
small silicon carbide bit and manually cleaned out the tip while it
was soft with acetone. Even then, it was still clogged. I tried
blowing on the nozzle end when the plastic was still soft and this has
at least succeeded in clearing a visible path though the barrel and
nozzle. I can't seem to get the oxidized ABS to dissolve in anything
though.

--mrule

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[Dore Mark]

I finally got things loose. I used some drill bits to get the gummy
stuff out, and then used a soldering iron to heat up the joint so I
could unscrew the parts.

On Jun 27, 6:36 am, Michael Rule <mrule7...@gmail.com> wrote:
> I recently cleaned out a barrel using a drill, it seems to have worked
> but I will need some new parts to test it. Repeat : drill,acetone,

> drill,acetone? Careful not to drill through the nozzle ? Then it was

> still getting clogged in the small end of the nozzle so I took a very
> small silicon carbide bit and manually cleaned out the tip while it

> was soft withacetone. Even then, it was still clogged. I tried

> blowing on the nozzle end when the plastic was still soft and this has
> at least succeeded in clearing a visible path though the barrel and
> nozzle. I can't seem to get the oxidized ABS to dissolve in anything
> though.
>
> --mrule
>
>
>
> On Sun, Jun 27, 2010 at 12:54 AM, Dore Mark <dore.m...@gmail.com> wrote:
> > My God....I took another week off, and got some parts from
> > Makergear....
>
> > I"m trying to clean out my nozzle/heater barrel for the first time and

> > like others have mentioned,acetoneisn't doing it.

>
> > Is there a way of cleaning this out without a blowtorch?
>

> > Should I pull the nozzle out of theacetonebath, let it dry, and then