Cleaning a clogged nozzle - some advice please

[Wingcommander whpthomas]

My extruder nozzle seems to be irreconcilably clogged. So I am planning to remove it tomorrow and see what can be done to remedy the situation. It appears that some deposits have formed on the sides of the nozzle that need removing and these are creating problems for the filament - causing it to jam before it melts properly. So before I start I have a few questions.

Do nozzles ware out over time - when should one purchase a replacement? My printer has done about 600 hours so far.

What are the best options for cleaning gunk out of the nozzle  -  have read a blue flame from a propane torch does a pretty good job - but I also have a lathe though probably not the right sized tool for the job - I am assuming that the hole is 1/32" (1.79mm) - anyone know?

What is the best way to remove the nozzle on a Replicator 2 - I am assuming I pre-heat and unscrew with a spanner - but what do I need  hold with what - so I don't damage anything else while I am unscrewing it? I have unbolted the extruder housing from the gantry and had a look over the underneath - I imagine that one needs to hold the heating block in a large adjustable spanner to stop it unthreading from the barrel while the nozzle is undone - is this correct?

Any other gratuitous advice form people who have done this before is certainly welcome.

[66tbird]

I'm using ABS and the blue flame from a butane pen torch works great. I've seen PLA do the same. No clean up either. The hole size in the nozzle? The small end is 0.40mm, or 0.02 inch or 1/50''.  There is a burr inside as the hole tappers down to the small exit. I've got 8 nozzles, 4@.40 and 4@.35 and all have it and all are different so it's a manufacturing cleanup issue imho. Doesn't seem to make a difference in printing.  I bought my nozzles from China for cheap, like $3each cheap. If I get a curly noddle I swap out and continue on, saving my clogged nozzles for a roast and toast later. btw I don't notice any real difference between the two sizes and use them interchangeably at my .2 layer settings.

You are correct about nozzle removal. grip the block softly and unscrew the nozzle while hot and unloaded.

[Enginwiz]

Hello Henry,

 

I spent this mornig cleaning out my hotend after my extruder started clicking yesterday. I use your filament drive. Great design.

 

Anyway, the extruder started clicking and stopped extruding PLA completely as if the temperature of the hotend would be below the melting point of PLA.

I checked the nozzle temperature with a Pt100 temperature sensor and read 215°C on the flat on the side of the nozzle. The display showed 230°C.

So no temperature problem. My Replicator 2 usually runs around 10°C cooler than indicated on the display.

 

Then I unloaded my black PLA and loaded Makerbots clear natural PLA to be able to see burned residues in the extruded PLA.

I increased the extruder temperature in steps up to 250°C and still had the extruder clicking and stalling.

 

Next I picked up a 0,4 mm drill in my workshop and pushed it gently up in the nozzle. I could feel some resistance about 15 mm

up from the lower end of the nozzle. I tried to push through this blockage and the PLA started flowing again.

 

But the extruder motor still made some clicking noises and the noodle of PLA coming out of the nozzle was not constant in diameter.

I removed the extruder motor and used two M4 nuts to clamp the heatsink and the fan to the extruder mounting block.

The upper end of the hotend should remain cool during cleaning. I preheated the hotend to 230°C.

 

Then I fetched some wooden toothpicks from the kichen. Our toothpicks have a diameter of 1,75 mm. Perfect.

I cut off the tip to prevent the tip from getting stuck in the hotend and reamed out the hotend from the top.

Some nasty looking brown stuff came out of the nozzle and some black residue stuck to the outside of the toothpick.

I repeated this process with 5 or 6 new toothpicks until no PLA rest came out with the toothpick.

 

Then I took the 0,4 mm drill and cleaned out the nozzle from below until I could see through the nozzle hole from above.

 

As a last step I lubricated a toothpick with makerbots PTFE grease and greased the inside of the hotend with it.

 

After this cleaning process the extruder is creating an even flow of PLA at the front of the nozzle without stalling or clicking.

 

A sample print finished without incidents and produced a good surface quality.

 

 

 

 

[Tom Lauerman]

I haven't encountered this problem yet but imagine I will. A friend who works with pricey commercial 3D printers was telling me that often there will be a cleaning routine program built in. The machine heats up to a certain temperature, extrudes a lot of plastic and cools itself down. Would something like an automated cleaning cylce work for the Rep2? Has anyone explored this? Just wondering if soaking at temperature followed by rigorous extrusion might help with at least minor jams.

best,

Tom

[Dan Newman]

On 2 Mar 2013 , at 3:13 AM, Wingcommander whpthomas wrote:

My extruder nozzle seems to be irreconcilably clogged. So I am planning to
remove it tomorrow and see what can be done to remedy the situation. It
appears that some deposits have formed on the sides of the nozzle that need
removing and these are creating problems for the filament - causing it to
jam before it melts properly. So before I start I have a few questions.

Do nozzles ware out over time - when should one purchase a replacement? My
printer has done about 600 hours so far.

Mine haven't, but I also have spares just in case I damage them.

What are the best options for cleaning gunk out of the nozzle  -  have read
a blue flame from a propane torch does a pretty good job - but I also have
a lathe though probably not the right sized tool for the job - I am
assuming that the hole is 1/32" (1.79mm) - anyone know?

See the bottom of this message where I've attached cross sections from the SolidWorks

files for both the Mk7 and Mk8.  I don't know for a stated fact that the Rep2 uses the

Mk8 nozzle, but I suspect that it does.  You should be able to pull the Mk8 SolidWorks

file out of the Replicator 1 Thing at thingiverse.

What is the best way to remove the nozzle on a Replicator 2 - I am assuming
I pre-heat and unscrew with a spanner - but what do I need  hold with what
- so I don't damage anything else while I am unscrewing it?

MBI has a support page on this for the Rep 1 dual should you want to look at that,

http://www.makerbot.com/support/replicator/troubleshooting/nozzle-swap/

Dan

Mk7 image with nozzle orifice on the left.  Mk8 image with the nozzle

orifice on the right.

[bart.s...@ichoosr.com]

Maybe you can get some ideas from:

http://www.youtube.com/watch?v=kNRvXJhpQ_I&list=UUp9k3UHwTonDAi_KSWb7pgQ&index=8

Good luck,

Bart

[Enginwiz]

Hello Henry,

some wood toothpicks with trimmed ends as cleaning tools

pushed downwards the preheated hotend

to push out the clogging stuff out through the nozzle

and upwards by pulling out the toothstick and some adhering residue.

Afterwards cleaning the tip of the nozzle with a 0,4 mm drill

until I could see through the whole hotend

After this 2 hour cleaning procedure my Replicator 2 printed a beautiful astrobot as a test print.

Greetings

Robert

[Kletus VanDamme]

I seem to have a nozzle clog also.

The symptom is the clicking of the extruder stepper.  Also the filament exits the nozzle at a slight angle, as if there is a bit of build up in the nozzle.

I have 2 Reeplicator2 machines side by side and I've swapped everything but the heater block/nozzle, so this is looking like the problem.

Does anyone know a good solvent for cleaning PLA related residue?

I'm hesitant to use a torch in my apartment.

Thanks.

[James McCracken]

Extrusion at an angle or very curly (in thin air) are both signs of a clogged nozzle ...

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[kent faulring]

You might want to use a heat gun, much safer then a torch I would think.

On Saturday, March 2, 2013 3:21:21 PM UTC-8, Kletus VanDamme wrote:

I seem to have a nozzle clog also.

[Adrian Fan]

Is cleaning the tip with a 0.4mm drill a must? 

[Wingcommander whpthomas]

Is cleaning the tip with a 0.4mm drill a must? 

No you can use a sanded down a pin or needle or use a guitar string (if you have one the right size).

Thanks to everyone for their input. I decided to try the toothpick approach but found it a bit fiddly - so I designed and printed a toothpick holder to make the whole cleaning process with toothpicks much easier. I have posted the holder along with instructions on thingiverse here:

http://www.thingiverse.com/thing:56597

[Adrian Fan]

Henry, you have once again done it again. Thanks!

[Adrian Fan]

Thanks to all the others for contributing your solutions as well!

[Wingcommander whpthomas]

Thanks to all the others for contributing your solutions as well!

Yes big thanks to everyone, particularly Enginwiz who I gave an honourable mention for the whole toothpick idea in my thingiverse post.

[David Kessner]

Yesterday I dropped by my local Guitar shop and asked for a single steel guitar string that is 0.015 inches in diameter (0.381 mm).  He went behind the counter and grabbed one.  They only have the packs of 6 strings on display, so you have to ask.  It was US$1.00, including tax. Super quick, super easy.  

The sales guy also said that the diameter will vary, but according to my micrometer the diameter is dead-on.

-DK

[Enginwiz]

Hello Henry,

 

Thank you for designing the toothpick holder. This will speed up nozzle cleaning considerably.

I already printed one just in case.

 

Cleaning out hotend and nozzle on my Rep 2 really improved the constancy of the extruded noodle.

 

 

 

 

[Adrian Fan]

Hi guys, i just bought a new box of toothpicks today. Using a digital caliper, the diameter of each toothpick is about 1.6mm.

And because the tips are so narrow and pointed, when I insert a toothpick into my nozzle, a small portion of the tip will be visible outside the hole of the nozzle (essentially pushing everything out). After cleaning a few more times, I looked thru the hole, and saw that it's clean. Perhaps getting thinner toothpicks with sharp narrower ends can do away the need for a 0.4mm drill bit or a steel guitar string?

On Saturday, 2 March 2013 19:13:39 UTC+8, Wingcommander whpthomas wrote:

[Adrian Fan]

btw, is the brownish thing on your platform bed the paper backing that usually comes with new acrylic?

[Eighty]

Good question, I'm curious about the brown as well.  My replacement acrylic plate had that brown paper, and I thought, "Cool.  A better version of painters tape?"  Sadly, it was not.  The PLA didn't stick to it at all...

[Adrian Fan]

Ah, that was exactly my first thinking too: Will it be better than painter's tape?

Let's wait for Enginwiz's reply.

[Enginwiz]

The brown tape is TESA 4309. It has a stronger glue on the backside.

[Richard]

The brown paper is simply how plexiglass is protected.

[Adrian Fan]

So are you using it to stick your prints or just simply you have not removed it yet?

[Jabu]

I've just started using TESA 4309 and I must say it's better than anything I have tried before for PLA on my Rep2. Highly recommended.

It took me a while to find it in the UK, but eBay came up trumps again. Just look for picture framing tape.

[Enginwiz]

Hello Adrian,

the brown painters tape TESA 4309 on my glass build platform is an industrial masking tape for paint spraying in the car industry.

It has a strong rubber based glue on the back and sticks better to my glass plate than the blue 3M Scotch 2090.

I want to get rid of Scotch Blue 2090 because this painters tape tends to lift off the build plate if I print big parts on it.

To be honest I would like to use no tape at all. But PLA does not stick to my build plate. Maybe I will try to sandblast the glass ...

In the meantime:

TESA 4309 is rated for heat drying up to 120°C and does not lift from the build plate when hot PLA is printed on it.

The "print" surface of TESA 4309 is smoother than 3M Scotch Blue 2090. Nevertheless PLA sticks very well

to TESA 4309, better than to 3M Scotch Blue 2090. And removal of the parts is a bit easier.

I use an alcohol based window cleaning spray (Sidolin Crystal Clear) to clean the tape in between prints.

TESA (www.tesa.com) offers a whole range of high quality masking tapes for applications in the car industry. 

I also might to give TESA 4330 a try because I need to print big parts with minimal warping on my Replicator 2.

My customers simply don't like banana-shaped parts. 

 

[funmakerBart]

So many answers I'm not willing to read... But I have bought very little drills with a 0.4mm diameter on the internet. They come with 10 pieces. And that's good, because one breathe in the wrong direction and they are gone. With a hot extruder and patience you can stickemin.   

Easier to remove the nozzle and use the drill from above (and also heating the nozzle on the stove). But then you have it removed allready; easier to replace with a new one.

So I have bought spare nozzles as well. Really don't want to spent much time to unclog. I simply replace them.

[Dexter Day]

Thank you all for this useful thread. I was able to use the techniques here to unclog my nozzle and now am getting wonderful prints!