extruder clicking and hitting prints  

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jacoposquitieri
(@jacoposquitieri)
Active Member

Hi, i recently had to rebuild my whole extruder assembly after an unfortunate blob accident. this morning i was doing some calibration to get back into printing and right away i noticed that while loading filament the extruder started clicking loudly and the extruded filamant came out "in bursts" but if i opened the idler door and pushed the filament in by hand it went down smoothly (the whole hotend was bought new from prusa preassembled). after some research i started trying some fix like the idler axis being inserted correctly, grub screw on the gear tight and filament well aligned, ptfe tube seems correctly in position etc..

now after all this i find the issue is still there only sometimes it doesnt click during the initial wipe before a print ( most of the times it does) but the clicking stops while printing. so i thought it may have been an issue with the "new" 3.9.0 firmware having some speeds for these operations being set too fast. now i started the bed leveling ( im using the textured sheet) and i noticed the z adjustment i had to make to get some adhesion was arount +1.550 which compared to what i had before the new extruder is almost 3 times greater but i just thought it may have been normal. 

so i launch my first print (a 3dbency boat) and after 3 or 4 layers the extruder hits the part , the y axis skips and it loses alignment.

having looked for a few hours on the internet and always finding the same results, i need help ! i cant get this thing working while previously it worked like a charm. 

tldr

extruder clicks on initial wipe and on filament load but not while printing

extruder/pinda probe hits prints dufing first few layers

 

sorry for the wall of text,all the mistakes and weird wording you may find but english is not my first language.

 

Posted : 15/08/2020 5:23 pm
3Delight
(@3delight)
Moderator Moderator

Have you tried adjusting the extruder idler tension screws? So it grips the filament tighter/or looser as it pulls it in?

As for hitting the prints, I'd check the height of the PINDA compared to the nozzle tip first.

Posted : 15/08/2020 6:00 pm
jacoposquitieri
(@jacoposquitieri)
Active Member

@3delight

yeah i dont know how the pinda got lowered but i was stuck on the idea that it was correct and i didnt check until now and it was almost as low as the nozzle. set it correctly and redone the z layer and that seems fixed. the clicking is still there no matter how much or how little tension i put on the idler. i am going to fiddle with it a little for the next hour to check that i didnt have another brainfart.

Posted : 15/08/2020 6:05 pm
3Delight
(@3delight)
Moderator Moderator

You'd be amazed how easy it is to miss something like that, especially as a tiny change can make a huge difference.

Any more brainfarts and we'll have to open the windows 🤣 !!

 

Posted : 15/08/2020 6:30 pm
jacoposquitieri
(@jacoposquitieri)
Active Member

so after a few wasted hours trying to change the tension on the idles, fiddling with the gear, changing filament and running test prints , the issue is still present. while printing i get weird blobs after like 4 layers and the prints fail. i am going to add some pictures and videos asap.

the room in wich i am printing is at around 30°c this time of year but i had no issue last year printing in the same environment

Posted : 16/08/2020 9:06 am
jacoposquitieri
(@jacoposquitieri)
Active Member

some fotos of the failed tests i attempted

Posted : 16/08/2020 10:09 am
jacoposquitieri
(@jacoposquitieri)
Active Member

and here is a video of the extruder in action

Posted : 16/08/2020 10:44 am
peter.m26
(@peter-m26)
Honorable Member

Do a z-calibration.

In settings of printer, set  a 7x7 calibration.

Then do a first layer calibration,

 

Then make a good zoom in picture so we can check the first layer.

Clean bed with dish soap, and a good first layer is most important for 3d printing. Sticking to bed is then at best.

 

Extrude filament by hand, look for bubbles in the filament, it also should extrude in a straight line(partial clog), check thickniss of filament(if not thick enough a partial clog).

 

Posted : 18/08/2020 9:01 am
bobstro
(@bobstro)
Illustrious Member
Posted by: @jacoposquitieri

and here is a video of the extruder in action

That's clearly showing something wrong in the extruder. 1st layer and Live-Z don't enter into it. You were on the right path checking the extruder tension screw. A few more things to check:

  • Open the extruder door and verify that the idler gear can freely rotate. Several users had issues with it coming loose or jamming up and creating a similar problem. 
  • Verify the Bondtech gears are free of debris. Clean with a soft wire brush or toothpick if necessary.
  • Verify the filament is able to feed cleanly and without friction. Verify any bearings on filament stands rotate freely.
  • While you have the extruder door open, unload any filament and try inserting a thin rod or even small hex wrench and verify that the filament path down into the extruder, past the Bondtech extruder gears and into the PTFE tube is smooth and free of obstruction.
  • Try removing the nozzle and extruding some filament. If it still clicks, something is jamming further up. If it doesn't, try a new nozzle.

Those are the easy mechanical checks. Is your extruder motor hot immediately? Confirm you're not printing in an enclosure. 30C ambient should be OK but 40C can cause extruder problems, but usually only after prolonged printing. A lot of people get improvements with heatcreep issues after replacing the Prusa heatbreak with the 2.2-2.0mm step with a standard E3D heatbreak with consistent 2.0mm bore.

Definitely contact support and show them this video. Log into the online store and use the Chat button there.

This post was modified 1 month ago by bobstro
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 : 18/08/2020 2:54 pm
bobstro
(@bobstro)
Illustrious Member

A few other problems previously seen:

  • Open up the extruder, remove the hotend and verify that the PTFE tubing is not deformed. Replacement may be required.
  • Verify the PTFE is not wiggling in the heatsink. Many users found that inserting a collet clip into the coupler helped.
  • Apply some thermal paste at the TOP of the heatbreak where it screws into the heatsink (and NOT the bottom where the heatbreak screws into the heater block).

Consider what you had to clean out to remove the Blob of Doom and see if any leftover filament might be causing a jam.

I notice you're using a MMU2. Not sure what the issues are with that. If you bypass the MMU2, does it still skip?

This post was modified 1 month ago by bobstro
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 : 18/08/2020 3:15 pm
jacoposquitieri
(@jacoposquitieri)
Active Member

I will open up the extruder as soon as I get home. Yeah it is in an enclosure but this time of the year I keep both top and front doors open and a window too so the temp is quite the same in the all room even a bit cooler close to the side of the room with the printer due to it being close to the window. Also yes I have an mmu2 but it has been disconnected for a long time even before the blob and after the big blob I got all new parts for the e axis extruder and heater/hotend ( the hotend assembly I got pre assembled from prusa webshop since I couldn't assemble it myself for the life of me, I just keep having loose hotends and on the last i sheared the nozzle trying to screw it in )

The only thing left to check is the offer tube, I shoud have a couple spare and a locking clip too 

Posted : 18/08/2020 5:07 pm
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