[Solved] Clicking noises, uneven extrusion  

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ulf.o
(@ulf-o)
Active Member

After ~3000 print hours, my MK3 suddenly started having the problem described here:
https://www.prusa3d.com/under-over-extrusion/

The first layer is always fine, but then the extruder starts making clicking noises and under-extrudes, making the print spongy and useless.

A few of the fixes I've tried:
- Updated to latest firmware (3.7.1)
- Cleaned the nozzle with a needle.
- Dismantled and cleaned the hotend.
- Replaced both PTFE tubes with new ones.
- Tried every possible tension on the idler door screws.
- Heated the nozzle to 260 deg and let it sit for a few minutes.
- Cleaned the bondtech gears from debris.
- The "Cold pull" method.
- A brand new spool of PLA, to make sure moisture wasn't the problem.
- A little grease on the bondtech gear.
- Lots of other things that I can't remember.

I've had this problem once before and solved it easily (with the overheating trick), but now I'm completely lost. There are tons of suggestions online, but none of them helps.

Best Answer by --:

This is the MK2 forum ... ??

Using a needle on an Olssen nozzle is not recommended - the ruby will chip and you might have done that and now have a ruby chip inside jamming things up.

What cold pull method did you use?

The act of extruding plastic is pretty simple: heat the nozzle until it can melt plastic, push the filament through the nozzle.  Clicking means the extruder is trying to push, but is slipping.  If the feed gear is tensioned properly, then something between the gear and the nozzle is jamming, or the nozzle is clogged.

Open the gear door, see if pushing the filament manually will extrude anything.  

Do a few cold pulls to clean the nozzle.

Remove the nozzle and verify filament can slip up and down the filament path without any resistance.  If you do feel drag, try blowing the path out with canned air.  If still having drag, probably need new PTFE, and check the collet and add a clip when rebuilding.  

Replace the nozzle to verify it isn't the problem.

 

Posted : 18/06/2019 10:46 pm
ulf.o
(@ulf-o)
Active Member

Forgot to mention: I'm using a standard MK3 with an Olsson nozzle and a textured powder-coated build sheet. And PrusaSlicer 2.0.0

Posted : 18/06/2019 10:53 pm
--
 -2
(@-2)
Illustrious Member

This is the MK2 forum ... ??

Using a needle on an Olssen nozzle is not recommended - the ruby will chip and you might have done that and now have a ruby chip inside jamming things up.

What cold pull method did you use?

The act of extruding plastic is pretty simple: heat the nozzle until it can melt plastic, push the filament through the nozzle.  Clicking means the extruder is trying to push, but is slipping.  If the feed gear is tensioned properly, then something between the gear and the nozzle is jamming, or the nozzle is clogged.

Open the gear door, see if pushing the filament manually will extrude anything.  

Do a few cold pulls to clean the nozzle.

Remove the nozzle and verify filament can slip up and down the filament path without any resistance.  If you do feel drag, try blowing the path out with canned air.  If still having drag, probably need new PTFE, and check the collet and add a clip when rebuilding.  

Replace the nozzle to verify it isn't the problem.

 

This post was modified 2 years ago by --
It is always wise to get more than one opinion... as for trusting Prusa? No way man....
Posted : 19/06/2019 1:39 am
ulf.o
(@ulf-o)
Active Member

Oops, wrong forum, sorry. Can a mod move the thread, please?

Anyway, thanks Tim. I'll replace the nozzle and see if that helps.

I used the cold pull method described in the pusa3d.com link above. The filament came out clean.

Pushing filament manually seems to work fine. Don't know how much force you're supposed to need.

Adding a collet clip was a nice idea; the collet doesn't feel very secure.

Posted : 19/06/2019 7:40 am
ulf.o
(@ulf-o)
Active Member

Ok, I switched to a regular brass nozzle, and that fixed the problem, so something seems to be wrong with the Olsson. Didn't have to change PTFE tubes again. Also didn't need to make a collet clip.

Oh well, no more BronzeFill prints for a while 😐.

Posted : 19/06/2019 11:56 am
bobstro
(@bobstro)
Illustrious Member
Posted by: ulf.o

[...] Oh well, no more BronzeFill prints for a while 😐.

Get a hardened steel nozzle. They work quite well for filled abrasive materials.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 19/06/2019 12:39 pm
ulf.o
(@ulf-o)
Active Member
Posted by: bobstro
Posted by: ulf.o

[...] Oh well, no more BronzeFill prints for a while 😐.

Get a hardened steel nozzle. They work quite well for filled abrasive materials.

Yes, it's worth a try. They're a lot cheaper than the ruby.

Posted : 19/06/2019 2:13 pm
--
 -2
(@-2)
Illustrious Member

I'm swagging here, but you might have cracked the ruby while cleaning with the needle: and cracks don't propagate heat very well.  A thorough cleaning and inspection may give an answer.

It is always wise to get more than one opinion... as for trusting Prusa? No way man....
Posted : 19/06/2019 8:06 pm
ulf.o
(@ulf-o)
Active Member
Posted by: Tim

I'm swagging here, but you might have cracked the ruby while cleaning with the needle: and cracks don't propagate heat very well.  A thorough cleaning and inspection may give an answer.

Maybe, but the problem started before I tried the needle. The tip could have cracked/chipped for some other reason, though. Probably need a microscope to diagnose this properly.

Posted : 19/06/2019 9:53 pm
ulf.o
(@ulf-o)
Active Member

If anyone has the same problem, I think I figured it out, maybe. Installed a new nozzle and had the same annoying underextrusion issue. Found this video and realized I forgot to loosen the heater block first. So I reinstalled the nozzle and haven't seen any underextrusion since.

Of course, underextrusion can have a thousand different causes, but it seems this can be one of them.

 

This post was modified 1 year ago by ulf.o
Posted : 25/09/2019 1:42 pm
ulf.o
(@ulf-o)
Active Member

Nevermind, ignore my last post. Problem came back and I'm as lost as ever. 😥 

Almost desperate enough to replace the entire hotend. 

This post was modified 1 year ago by ulf.o
Posted : 30/09/2019 11:31 am
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 -2
(@-2)
Illustrious Member

Ouch - there are Tungsten Carbide nozzle now; better heat than steel - as good as brass, and not quite as expensive as ruby.  From what others have reported, they are bullet proof.

What are you printing?  It seems like something I should avoid. lol.

ps: one last trick: after a jam, unload the filament and post a photo of the melted end.  The shape can be informative.

 

This post was modified 1 year ago by --
It is always wise to get more than one opinion... as for trusting Prusa? No way man....
Posted : 30/09/2019 8:32 pm
ulf.o
(@ulf-o)
Active Member
Posted by: @tim-m30

Ouch - there are Tungsten Carbide nozzle now; better heat than steel - as good as brass, and not quite as expensive as ruby.  From what others have reported, they are bullet proof.

What are you printing?  It seems like something I should avoid. lol.

ps: one last trick: after a jam, unload the filament and post a photo of the melted end.  The shape can be informative.

 

Hello Tim. I really appreciate your help trying to solve this mystery.

The green PLA in the photo is from a regular filament unloading. The white PLA came out of my latest cold pull attempt. Does it say anything useful?

I'd get a tungsten carbide nozzle if that alloy wasn't kind of toxic. Lately I've been on a personal mission to print the perfect snuff box (insides with PETG and outsides in polished Copperfill). It's an obsession at this point, really. Snuff isn't food, but it still goes in your mouth. Better not risk it. I give these prints away to friends, and they'd no longer be friends if I gave them fibrosis;-)

Anyway, I'm debating the problem with the technical support people. Prusa has excellent customer support.

Posted : 03/10/2019 11:53 am
ulf.o
(@ulf-o)
Active Member

Well, I give up. Nothing works, and nothing will ever work. I just wonder what would give the most value for money: Sell the printer at 40% or so and let somebody else suffer. Or smash the damned thing to scraps, Office Space style.

Posted : 03/10/2019 5:44 pm
--
 -2
(@-2)
Illustrious Member

Here's the numbers for the filament diameters in your post: the normal unload must not have been at a jam, but the cold pull was at a jam. The 2.18 mm section is evidence the heat break is involved.  The table is diameter in mm, pixels, pixels per mm. 

Minor variations in the nozzle/heat break seem to make a difference between jamming and not jamming. There is no method or madness to it, it seems almost random; but the effect exists.   As a last ditch effort: try replacing your heat break with a stock E3D-V6 model.  Just be sure you use the E3D-V6 assembly guide when putting things back together.

It is always wise to get more than one opinion... as for trusting Prusa? No way man....
Posted : 04/10/2019 1:19 am
ulf.o
(@ulf-o)
Active Member

Thanks, Tim. Yes, I also suspected something's wrong with the heatbreak. Support said it shouldn't be nessecary to replace it, but this situation is completely insane, so why not.

Is there a difference between the stock E3D-V6 heatbreak and the one that comes with a Prusa?

Posted : 04/10/2019 7:49 am
--
 -2
(@-2)
Illustrious Member

Yes - Prusa has E3D modify the heat break by adding a 2.2 mm bore down  to the neck.  This step will cause jams when melt backflows up into the cold zone when printing with lots of retraction.  And it can cause jams without a lot of retraction, but that is less common.  

Prusa -V6

Stock E3D-V6

Jamming filament sections:

It is always wise to get more than one opinion... as for trusting Prusa? No way man....
Posted : 04/10/2019 8:54 am
ulf.o
(@ulf-o)
Active Member

Aaah... that might actually explain a lot. Interesting.

Posted : 04/10/2019 8:57 am
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