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Inconsistent filament flow after first print  

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CodeMalfunction
(@codemalfunction)
New Member
Inconsistent filament flow after first print

I've recently built my Mini+ kit and while the first print was fine, most of the prints(all except for 1 or 2) I've done afterwards have seemed to suffer from inconsistent filament flows with Prusament PLA. The first layer of the print is usually fine (although I've had 1 or 2 cases where the filament on the first layer is inconsistent as well), but then afterwards, the filament seems to get thinner during printing or even stop completely. Sometimes the issue resolves itself, leading to odd gaps in the layers, but usually I find the nozzle printing nothing a few centimeters above the print after leaving the Mini unattended for a while. 

I've reran the first layer calibration, but this seems to be fine. I've added a picture of my attempt to print the whistle that was on the USB-stick bundled with the printer. This started printing OK, but halfway through, some minor gaps started to show in the layers, but by the end, no filament was coming out of the nozzle at all anymore.

What could be the cause of this issue?

Respondido : 02/11/2021 1:42 pm
BogdanH
(@bogdanh)
Honorable Member

Based on info you gave, I think your hotend is clogged. If that's the case, then you should have heard famous "clicks" from extruder -however, you don't mention that to be the case.
Normally that (clogged hotend) shouldn't happen on new Mini in first month of use (especially not with PLA), so I assume hotend wasn't assembled properly.

[Mini+] [MK3S+BEAR]

Respondido : 02/11/2021 4:41 pm
CodeMalfunction
(@codemalfunction)
New Member
Topic starter answered:
RE: Narrowed problem down to extruder

Thank you. I went to check the clicking just in case, but I found an issue with the extruder. The extruder screw shot loose from the extruder idler while I was doing a test print and ended up on my desk. It turned out that the nut supposed to hold the screw in place wasn't fully in the right place, which allowed the screw to come loose.

 

However, after pushing the nut in and adjusting the screw so that it was flush with the plastic as the instructions said, the issue I had still persisted. I've done a few test prints, but from what I've seen every time is that at some point, the extruder just stops turning. I don't hear any clicking when this happens. Loading and unloading filament work fine and I can also turn it from the menu when no filament is loaded, but during printing the extruder just stops at random points. I've checked the connectors on the mainboard and they seem to be pushed in properly and I've also tried adjusting the extruder idler screw both looser and tighter, but this does not seemed to have helped. I'll take the extruder apart later today to see if there are any issues with the pulley on the motor or if I see anything else wrong.

Is there anything else I should check for that could be causing this?

 

Esta publicación ha sido modificada el hace 3 years por CodeMalfunction
Respondido : 03/11/2021 1:17 pm
BogdanH
(@bogdanh)
Honorable Member

You say, extruder motor stops randomly... well, during print, motor doesn't spin all the time -it only rotates when there's the need for filament. Anyway, the only thing that comes to my mind, is the pulley on the motor -which you're about to check. Let us now what you find there.

[Mini+] [MK3S+BEAR]

Respondido : 03/11/2021 6:43 pm
CodeMalfunction
(@codemalfunction)
New Member
Topic starter answered:
Finally found the culprit

I finally found (and fixed) the issue. The screw holding the pulley on the extruder motor had come completely loose for some reason. I tightened it again and this fixed the issue. I'm not sure how it could have come loose at it was fully tightened when I assembled the extruder over the weekend. 

Thank you for your help!

Respondido : 04/11/2021 7:11 am
glowe
(@glowe)
New Member
RE: Inconsistent filament flow after first print

Hi,

My Prusa Mini+ has almost exactly the same symptoms, however, for me it isn't the screw on my extruder. I assembled my Prusa kit, it passed the self-diagnostic and I completed the first layer test. Then half-way through the first print it stopped extruding. I could load, unload and purge filament but all that it prints are hair-like strings of PLA. I adjusted the screw and checked for notched filament, no change. I ried cleaning the nozzle but the same thing happened and I couldn't find a blockage. The extruder gear moves during load/unload but irregularly during printing. I un-plugged and re-plugged-in the extruder motor to check the connection, updated the firmware, and now the self-diagnostic fails on the X-axis. Has anyone had anything like this?

Thanks and all the best

Respondido : 11/11/2021 8:34 pm
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