Extruder popping (not the typical clicking)  

RE: Extruder popping (not the typical clicking)

Sounds like could be damp filament to me.

How has it been stored.

RE: Extruder popping (not the typical clicking)

Could be moisture in the filament but it sounds too mechanical to me.

It also seems kind of random, so could be noise from pulling filament from the spool, either something catching on the spool as it rotates or the filament has gotten tangled a bit and is clicking as it unspools.  If you ever let go of the end of the filament and it jumps back onto the spool it can get crossed and can eventually tie itself up and not come off the spool causing a print to fail.

RE: Extruder popping (not the typical clicking)

Posted by: @clarmrrsn

Sounds like could be damp filament to me.

How has it been stored.

It is brand new filament. From Prusa. 

RE: Extruder popping (not the typical clicking)

Posted by: @martys

Could be moisture in the filament but it sounds too mechanical to me.

It also seems kind of random, so could be noise from pulling filament from the spool, either something catching on the spool as it rotates or the filament has gotten tangled a bit and is clicking as it unspools.  If you ever let go of the end of the filament and it jumps back onto the spool it can get crossed and can eventually tie itself up and not come off the spool causing a print to fail.

Thanks. Will be careful that it does not unwind. The sound seems to be coming from lower, like the extruder.

It has made a quieter, but I think the same kind of, noise when the extruder was not running and it was preheating.

RE: Extruder popping (not the typical clicking)

Update: the noise occurs with 2 types of Prusament PETG but does not occur with Prusa PLA (using default slicer setting by filament). And, we live 200m from the ocean, so the air is humid.

RE: Extruder popping (not the typical clicking)

I just ordered one of these for filament drying, as not overly keen in sticking it in my brand new bosch oven, I have been guilty of forgetting to put the roll away overnight.

https://www.aliexpress.com/item/1005001854259674.html

You can run the filament from this while printing but clearly would require appropriate placement for the MK3.

There is another similar listing slightly cheaper, they seem to get good reviews

Might be an option if in a very humid climate.

RE: Extruder popping (not the typical clicking)

Gently take hold of the filament above the extruder, when it clicks do you feel it pulse?

If so your extruder idler tension is probably the cause.  Most loud clicks are due to the idler not being tight enough but these quieter clicks are sometimes due to it being too tight.

Cheerio,

RE: Extruder popping (not the typical clicking)

Sounds like Bearings to me.

RE: Extruder popping (not the typical clicking)

I have a similar problem...

 I'm trying to print a bracket I made with TinkerCad sliced with Prusa slicer (generic PETG filament - SUNLU, and 0.15mm quality).

Setup:  PLA prints the model no problem.  Load up PETG and as soon as the print hits 7.0mm in height, the clicking starts.  If I grab gently onto the filament, I feel it pops up (back) when the click happens(every 15-20 seconds) - and only on the faster fill commands.  It will do this until the extruder doesn't extrude enough plastic, and given enough time, the extruder will simply stop extruding filament.

I've paused the print, let it cool down for 10 minutes, then restart.  The clicking still happens.  But then after it gets to 9.0mm in height - it starts working again (very few clicks).  It is completely repeatable.  The filaments (both PETG and ABS) brand new - right out of the vacuum sealed bag.

If I'd venture a guess, it's that after printing to 7.0mm, the extruder gets clogged for some reason and starts kicking back.  The PETG temp is 240, and the ABS is at 255.  The mystery for me is why it prints flawlessly for 7.0mm and then goes south (and PLA works no problem).

I've checked the idler tension and have tried slightly tighter (2 turns), and slightly looser (2 turns) - no effect.  This is the MK3S+ from a kit.  I've printed this same model with PLA with no issues.

Next experiments would be to try to print some of the other supplied models (benchy, frog, gears, etc) and see if they have the same problem.  BTW - they all print flawlessly with PLA.

Any suggestions would be appreciated.

RE: Extruder popping (not the typical clicking)

@glenn-5

This reads like a different problem:  To confirm, repeating the same model the glitches begin in roughly the same place but if allowed to cool normal printing resumes for a little while.  What happens with a different (larger or smaller) model with the same filament?  I'm guessing it's not the layer height but the elapsed printing time that characterises the error...

This is possibly a heatbreak problem with filament melting in the wrong place but one frequent cause is baked-in filament debris constricting the flow so I suggest you try a cold-pull, more than one (until it comes out clean) if you see contaminants.

https://help.prusa3d.com/en/article/cold-pull-mk3s-mk2-5s_2075

Cheerio,

RE: Extruder popping (not the typical clicking)

It wound up that even though the temp readings at room temperature are accurate, readings at print temps were off. Extruded temp was way too high compared to what the sensor read. Have been printing at lower temp and just need to buy a new sensor still

RE: Clicking solved (for me)!

Thanks to both hwmonkey and Diem for responding.  I had two choices, so naturally I started with the easier one...

I put my FLIR camera on the tip and gathered settings to compare programmed temp to measured temp - using the Settings/Temp control.  I set the temp and waited until the info screen showed it was reached.  As it turns out, my thermistor was opposite of hwmonkey - reading high compared to the actual temperature:

Once I adjusted the initial print temp and after-second-layer temp (manual edits to the G-code), I got a flawless print with the PETG.  No clicking at all!  I'm so happy to have this resolved.  It now makes sense - the lower temp was not allowing the filament to melt completely which wouldn't let the extruder push the filament through the nozzle.  Not a problem at the lower flow rates, but once the fill commands started coming in, there just wasn't enough melted filament to push.

Next questions - is there a way to adjust the PrusaSlicer to accommodate the temp error (assuming this is a good thermistor), or is this a bad thermistor, and the temperature readings should be more accurate?  Is there a way to calibrate the tip temp sensor (or put in some offsets)?

BTW - I also included the measurements for the HeatBed (see above).  The heatbed thermistor seems more accurate (but that might be due to the smaller temp range).  I did notice that the heat spectrum is heavy on the front and back Y-axis, and a few degrees less in the middle:

Thanks again for the suggestions (glad it wasn't a heartbreak problem).