PLA clogging my nozzle :(

[Quyzi]

I've got a ToM MK7, and I'm using RepG 0034 with skeinforge 47. I got my filament from protoparadigm and I used their temperature settings (205*C extruder and 55*C hbp). I don't hear any audible clicking and there aren't any sounds that tell me that something is gone wrong, it just stops extruding. The extruder stepper keeps spinning, but the filament isn't being fed. I did clean the extruder of powder or anything that might be making it lose grip.  When it stops, is a variable. It seems to happen half way through prints, sometimes. It just stops feeding. I can't figure out why it's doing this. It's very annoying. ABS works fine though. 

[Dan Newman]

On 13 May 2012 , at 6:52 PM, Quyzi wrote:

> I've got a ToM MK7, and I'm using RepG 0034 with skeinforge 47. I got my
> filament from protoparadigm and I used their temperature settings (205*C
> extruder and 55*C hbp).

Try a lower extruder temps such as 190 C. When the temp is too high, a common
problem is exactly as you describe. The heat slowly travels up the filament
making it such that the extruder's pinch gear can no longer feed the filament.
Indeed, there was a recent thread about this a couple of weeks back: same problem,
same solution (decrease extruder temp). You might look back a few weeks to read
the thread to see what temp ended up working for that ToM Mk7 owner.

Dan

[Travis]

Is it the white PLA from protoparadigm?  I've been printing with that for a couple of weeks, and now I'm starting to have feeding failures along with audible clicking.  When I went to clean the feeder gear, there was nothing to remove.  I blew it out anyway, and I still get the clicking.

It should be noted that I'm printing with a layer height of 0.1 mm, which seems to worsen things.

[John D'Ausilio]

It also depends on the plastic, and the speed at which you're printing ...

I have good luck with natural PLA at 225 printing at 100mm/s, and 215
at 50mm/s. The gold PLA I have wants temps 5 or 10 degrees higher. And
the relationship between thermocouple indicated temp and actual nozzle
temp is not the same from bot to bot .. you may be setting 205 but
your nozzle can be +/- tens of degrees from that. What temp do you
successfully print ABS at?
You don't want to leave PLA in a hot extruder without pushing some
through regularly (one of the spring drives for MK7 makes this easy)
Pulling the PLA from the hot extruder after the last print of the day
seems to keep the accumulated crud down.

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[Travis]

I've been on a PLA printing binge lately and have been slowly dropping the temp from 220 to 210, then 205, 200 and 190 this morning, which some recommended.  I did find it odd that the said optimal welding temp for PLA was below it's melting temp, but I guess the internal temp being higher than what the thermistor reads puts that in the realm of possibility.  For ABS, I go with the default (replicator) which was 220.

Are you recommending withdrawing the PLA backward out of the hot extruder after the last print and leaving the extruder empty and hot for a while, or pushing a sizable quantity through forward to clear it?  I often go through the "load filament" script and let it coil for about 1-5 minutes periodically in an attempt to flush the system.  I seems to offer some relief... in my imaginings.

If the issue is stemming from PLA stagnating in the extruder, I think the layer heights I've been doing lately (0.1mm) are at least aggravating the problem.

Though I think the fact that both Quyzi are both using PLA from protoparadigm might be pretty significant.  That would be a pity, because I like them and the end product of their white-white opaque PLA is like porcelain.  ..aand it seems to have now stopped clicking for the time being, so I cannot measure the filament diameter as it has taken on awesome figurine form.

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[Quyzi]

It's the natural PLA from protoparadigm. I don't get an audible click though. I printed a new extruder not long ago when I had problems with filament with large deviations in its diameter. 

I've been successfully printing ABS at 225*C. I don't have a reliable way to measure the temperature of my extruder other than what repG reports. I'll try a lower temperature tomorrow morning, see hwo that works.

[Dan Newman]

On 13 May 2012 , at 8:47 PM, Travis wrote:

> I've been on a PLA printing binge lately and have been slowly dropping the
> temp from 220 to 210, then 205, 200 and 190 this morning, which some
> recommended. I did find it odd that the said optimal welding temp for PLA
> was below it's melting temp,

The melting point of most PLA is 180C or below. Indeed, 170C or below
is fairly common.

Dan

[alex e]

I found that the fan on my TOM was stopping on long prints
(replicatorg bug?), allowing the extruder temp to go up, causing the
PLA to overheat and the extruder to strip. I modified like some
others, and just run the extruder fan constantly by wiring it to 12v.

[Dan Newman]

On 15 May 2012 , at 5:22 AM, alex e wrote:

> I found that the fan on my TOM was stopping on long prints
> (replicatorg bug?), allowing the extruder temp to go up, causing the
> PLA to overheat and the extruder to strip. I modified like some
> others, and just run the extruder fan constantly by wiring it to 12v.

There's a known issue with fan control and the extruder controller (EC).
You need to go to the machine's onboard preferences (in RepG), select the
"extruder 0" tab, enable the automatic fan control, and set a temperature.
Then save the settings in the EC board. Things should then work much better.
For further details, refer to the 7 March 2012 thread entitled, "Extruder
motor fan shuts down during print".

Regards,
Dan

[alex e]

Thanks Dan!

[Quyzi]

I think this has everything to do with my problem. It seems that when I just turn the machine on, I've got no problems with PLA printing. It only shows up later. My extruder gets kinda hot. It seems odd the way the heatsink attaches. It doesn't come in contact with the extruder stepper at all, just mounts onto the block. The fan doesn't stop though. 

[Jack.Wu]

I write a technical support file that discribe how to solve printing
problem with PLA, share with everyone,
you can download here:https://skydrive.live.com/redir?
resid=CC8709D15BB78AA4!506&authkey=!AJrNhQC1vCR6vfw,
why PLA will block nozzle original from its natural propeties
different with ABS, and how to operate printing step with PLA, it is
easy method following up.
I also took some videos here printing with makerbot:http://i.youku.com/
reprapPLA

[Jamie]

I found that putting some thermal paste between the heat sink and the Aluminum block and on the threads for

the extruder nozzle where it screws into the Al block made a world of difference.  The heat works its way up the

extruder and starts to soften up the PLA.

Cheers

Jamie

[Quyzi]

I'm not convinced of what my problem with it is yet. I tried again just now to print with PLA at 180*, 60*hbp. It went fine for about 15 minutes, then stopped pushing. The heat barrier was slightly warm, but not hot. This is really bothering me, as I'm out of abs now and can't get pla to print. When it does print, it seems most of the extruded material is clear but there are some spots that are a cloudy white; could this have anything to do with it? I may disassemble my hot end soon and try applying some thermal paste between the barrel and the block, to see if that helps.

[Shawn]

I haven't printed with PLA yet, but... From what I've seen the cloudy
output is usually a result of moisture absorbed by the filament. You
need to dehumidfy the filament to clear that up. I think.

I've seen the plastic stop pushing occasionally with ABS. This is
usually because I had my nozzle to close to the bed for to long -
plastic couldn't get out, and eventually it just stripped the filament.
Sometimes when this happens I don't see a clear reason. In either
case, I'm fine if I just apply some pressure to the filament to help
encourage it to flow again - it normally does and doesn't give me a
problem for quite some time after that (days or weeks).

If I had to guess though, I think your PLA is getting warm right where
the gears push on it, softening it just enough that the gears are
ineffective. Either less heat on the nozzle, or you may need to cool
the area above the nozzle. Your idea of adding thermal paste may solve
this too.

(wow - that almost sounds like I know what I'm doing. And only 3ish
months of experience too!! lol)

Hope that helps some.

Shawn

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[B_Fraser]

I've got a few replicators and have spent the last month wrestling with PLA trying to get large prints (7-12 hours) to run without fail. I've run al least 10 kilos of PLA at this point and I'm still working on it but here are some thoughts so far...

1) Your heat sink is just fine. It's designed to draw heat away from the tube so that soft PLA doesn't reach the drive motor and cause a loss of traction. It is meant to be attached to the AL block.

2) PLA does indeed absorb moisture. Air bubbles in the extrusion can be a result of small water molecules converting to steam as they hit the nozzle. I recommend trying a new SEALED roll of PLA.

3) Not sure about this, but in my recent tests (still running right now) is seems that the MakerBot brand natural PLA does a little better than the Protoparidigm version. I have plenty of both, they are definitely different, and worth experiments with both.

4) Buy a few replacement nozzles, and replace the one on your machine. After repeated failures, they are not the same. Especially if the failed nozzle was allowed to stay hot for a long time. And unlike ABS, there is no solvent to remove the crud inside.

5) On two of my machines, I just installed .65mm nozzles (drilled out from .4mm nozzles). They run MUCH better. I've only benn running them for one day, but so far, NO failures. My prints are all parts of a much larger object so there is not much super fine detail so I also doubled the layer height to .5mm. Right now my prints are running at twice the speed and I've done 5 prints without failure (As opposed to 50-70% failure before that).

I'll try to think of anything else, but that's all I got for now...

Ben

[Quyzi]

Does it sound like my PLA has absorbed some moisture? I don't live in a particularly humid area (central NJ). I didn't think it was something i needed to be overly concerned with. 

I just replaced my nozzle not long ago. I was using the MK7 nozzle that came with my ToM, but I bought a Mk8 nozzle after an incident. It's no older than a month. 

Trying to eliminate some other variables. Could it be my SF profile settings? I'm using SF47 on jetty firmware. I'm not sure which settings could cause a problem, but I've changed many of them. Mostly in the Speed plugin. I was having trouble with really bad prints, they would crumble in your hand with almost no effort. I changed the flow rate to 3.15, and it's been working fine since; my feed rate is 100.0. For the most part, the rest is standard. I copied the Replicator profile, since there wasn't a SF47 profile for my ToM. 

Thank you for your help, this has been irritating me. 

[Shawn]

I live in a dry climate as well, but still am seeing symptoms of
moisture absorbed in my ABS. (periodic pops/cracks as it extrudes and
brittle prints that delaminate between layers with little effort,
whereas newer spools fresh from their sealed packages do not exhibit
this behavior.

I'm building a box this weekend to put the plastic into and try to
control the humidity. I'm hoping it will clear up some of the (minor)
issues I'm seeing.

> are _definitely different_, and worth experiments with both.

>
> 4) Buy a few replacement nozzles, and replace the one on your
> machine. After repeated failures, they are not the same. Especially
> if the failed nozzle was allowed to stay hot for a long time. And
> unlike ABS, there is no solvent to remove the crud inside.
>
> 5) On two of my machines, I just installed .65mm nozzles (drilled
> out from .4mm nozzles). They run MUCH better. I've only benn running
> them for one day, but so far, NO failures. My prints are all parts
> of a much larger object so there is not much super fine detail so I
> also doubled the layer height to .5mm. Right now my prints are
> running at twice the speed and I've done 5 prints without failure
> (As opposed to 50-70% failure before that).
>
> I'll try to think of anything else, but that's all I got for now...
>
> Ben
>

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[Z LeHericy]

a trick i use is to save the silica gel packets that come with new electronics, or to cut open diapers and get the silica powder which works just as well, and put it in a box with the filament on a spool holder that lets it rotate. Then i punch a 1/4 inch hole in the side of the box, and put a tube from that to the extruder, passing the filament through it, bonus is that it also prevents tangles!!

-Zeno LeHericy

//((=:Z:=))\\
INVENTIONS
Technologies
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[Shawn]

this is similar to what I have planned. I hear rock salt works great
too, but you may need to worry about it discharging it's moisture at
some point. Being in Canada with the snow, rock salt is pretty common.

On 12-06-13 08:45 PM, Z LeHericy wrote:
> a trick i use is to save the silica gel packets that come with new
> electronics, or to cut open diapers and get the silica powder which
> works just as well, and put it in a box with the filament on a spool
> holder that lets it rotate. Then i punch a 1/4 inch hole in the side of
> the box, and put a tube from that to the extruder, passing the filament
> through it, bonus is that it also prevents tangles!!
>
> -Zeno LeHericy
>
> //((=:Z:=))\\
> INVENTIONS
> Technologies

> zinventions.com <http://zinventions.com>

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[Travis]

Ak.  I knew I should have bought a new 0.4mm mk8 nozzle when I had the chance.  Now they're sold out.

My left extruder is now putting out feeble and inconsistent threads.  I random intervals I hear a pop at the extruder and see the filament jerk.  I opened the extruder, and the feeder gear is totally clean.  

I've been printing with protoparadigm PLA with layer heights of 0.1mm with the left extruder for some time, with probably put too little clearance between the HBP and the nozzle.  I guess I'll disassemble the whole thing and perhaps drill out the nozzle if I find it hopelessly gummed up.

[Cymon]

Clogging nozzles that you can't unclog? Printing on glass? As much as I want to take the plunge into bioplastics... I think I'm gonna stick with ABS for a while longer.

[Herón Ordóñez Guillén]

just take the filament out and heat up to 220-230 to help the plastic flow. if it's just plastic it will ooze and get out. 

if that does not work, lower the temperature to 170-190 then take a piece of filament and push it all the way down and back it all up again real quick. 

the melted plastic should stick to the "fresh" and when you pull it out it should come up. you do this at a lower temperature so the plastic inside the nozzle is thick enough to pull it but soft enough to stick.

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[Quyzi]

I think I have it working. Not sure what exactly fixed it, probably a combination of several changes I made

1. my flow rate in my SF47 settings was set to 3.5. I set this to the default of 210 

2. I'm printing the PLA at 200*F. I read an article (  http://www.protoparadigm.com/blog/2012/04/thing-o-matic-mk7-pla-set-up-and-troubleshooting-mk8 ), which said the MK7/8 extruder has an easier time printing PLA at higher temps than lower. 

3. I stopped pre-heating my extruder before prints.

4. I printed out a new extruder from thingiverse that uses a ball bearing instead of a plunger, and a screw to adjust tension. 

Some combination of those seems to have solved the clogging problem. I hope this might be of help to someone else.