Filament drive replacement / repair

#1

Hi,
the last days an old problem slowly surfaced again.
With my main printing nozzle right side, the printed surface is not closed anymore and a very few times I can hear a clicking sound from a slipping filament drive gear. I am only using the upper motor and directly feed from a spool on the back of the Zim.
Its clearly a problem with not enough filament coming out of the nozzle.
Using 1.5 as extruder multiplicator partly reduces the problem, but as I normaly use 0.9 its clearly a problem that has to be solved.
I had this problem once before and it magically vanished after I changed the nozzle, repaired my cables and many other things. But now its back, only with the right nozzle and slowly grows.

I checked the motor moving normal, drilled and flushed and cleaned the nozzle several times.
Manual Extrusion works fine and gives a perfect nice and round extrusion, without a slipping gear noise.
But as the surfaces are not closed. its somehow not extruding the full amount needed.

My guess would be the need for filament drive gear replacement. The idea comes from, that there is no visible marks on the filament from the gear.
Just to make sure, there is no way to adjust tension on the upper filament drive?!

So I would need to replace the gear. Its a special piece that I guess can nowhere be bought. Is it even possible to change the gear?

Any ideas what to do now?

#2

One idea might be that your filament is not really 190C (or whatever you heat it to) but something less than that so it’s hard for the extruder to push the filament out, and over time this strips the filament and creates clicking sounds.

Other than using a thermocouple to measure the heater block, I’m not sure how else to verify this temperature.

#3

You can slightly adjust the drive, so maybe yours has moved… If you remove the whole extruder head by removing the two connectors that the flament goes through, you’ll see that the two aluminum pieces that hold the motors are fixed to each other with four screws (They go through the opposing block into the threads of the motor). So, after loosening those screws, the two aluminum pieces can be shifted very slightly. This affects the offset of the filament-gripping wheels inside. Very small movement until the gears will touch, but enough to make a difference between slipping and gripping. I even drilled the holes in the aluminum-blocks a bit bigger to use all of the space.
Also take a look at the lengths of those screws: In my case, three of them had been too long, so that fastening the screws still left some movement in the “gearbox” until screw number four…

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Inconsistent filament extrusion
#4

I agree with @J_Schmidt solution.

The main issue comes from filament that are out of tolerance. I experienced this issue also and finaly I measured the diameter of the filament ->1.58 mm
drilling the aluminum blocks is the soltion :slight_smile:

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#5

Wow, that’s quite out of spec. Is it worth running filament with such a deviation from 1.75mm? Do you get it for free :smile:

#6

Wow, thank you for the great replies.

With my filament I am really happy. Its specs have so far been good.
Its a little too fluid, so occasionally I have minor problems with steep overhangs or faint stringing.
But apart from that I am really happy with it and don’t expect any problems from there.

I took apart my head and it seemed good. There is now a little gear visible on the filament, but problem persists. So I tested further.
It seems mostly related to my nozzle. I swapped the nozzles left and right and now the problem is with the left nozzle.
I did a few extrusion tests and its missing 9mm of 100mm extrusion. So my guess that its somehow not able to fully extrude seems correct. Trying to use more extrusion multiplier seems to not work enough and even though only occasionally I hear a gear slipping, its somehow constantly slipping.
But what causes a partly clogged nozzle that drilling, flushing and cold pull is not able to clear?
The nozzle worked fine for 4 weeks printing time and after a pause of 3-4 weeks it suddenly has this problem.
Now I already have 3 partly clogged nozzles.

I am going to buy new nozzles from Nightmare but that cannot be the solution.
When I receive the new nozzles I will know if its really only the nozzle.

#7

Okay, this sounds a bit like the beginning of the problems that I had… Maybe you should take apart the partly clogged nozzle, taking a close look at the Teflon liner inside the plastic filament guide. In my case, the nozzle was slightly leaking, and a thin part of the Teflon liner went into the nozzle.
So I pulled out the liner and made a new one from the Teflon tube that is used from the cartridge station to the head.

#8

@BDub I had the chance to visit different Filament factories… No comment. you would be really scared :slight_smile: they have a system that controls the thinknes permanently but no one takes care ^^ Factories are really dirty and dusty. workers smoke near the extruder and the humidity is very high. Even if we like some mannufacturers and filament there is many possibilities to have grease dust and other pollution stuff on and IN the filament. :frowning:

@3DPrintEvangelist I agree with @J_Schmidt it looks like a part of liner went into the melting zone.
or some dust came in the nozzle from the filament.

#9

That’s why I chose a local german filament manufacturer that I trust after having seen his production facility :slightly_smiling:
At least so far quality for the price has always been ok.
But of course that can always change.

The last time I tried to dissmantle the nozzle I broke it.
I will give it another try.

#10

Hum you should give me the link of the german manufacturer. Hope he has Nylon PETG material. I love these filaments for my motorbikes :wink: I use Nylon filament for GoPro supports and validated at 300km/h speed on race tracks :stuck_out_tongue: certified Efficient

Without the good tool or a plier modified for this usage you will brake the PEEK tube of the nozzle.