My MK3S+ Extruder motor keeps skipping backward and clicking  

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

@obsessed

Cleaning filament is meant to be extruded to “clean”out the hotend of particles and partial clogs.  It works.  It is not work well for cold pulls. 

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

Posted by: @cwbullet

Cleaning filament is meant to be extruded to “clean”out the hotend of particles and partial clogs.  It works.  It is not work well for cold pulls. 

What brand are you using? I get good pulls at 140C with eSun cleaning filament. Just stretchy enough and translucent enough to show any trapped crud. There are a lot of formulations though. I use it for both. Extrude at 265C to push out anything, then let it cool inside the hotend and do a pull at 140C. I do this before removing any nozzle. 

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

@bobstro

I have several brands.  I have some eSun.  I just have not tried a cold pull with it.  I have just found the brands (including Dynapurge)  I have to work better with extrusion than cold pulls.  

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

Posted by: @cwbullet

@bobstro

I have several brands.  I have some eSun.  I just have not tried a cold pull with it.  I have just found the brands (including Dynapurge)  I have to work better with extrusion than cold pulls.  

I have also used Monoprice and Novamaker.

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

Hi everyone,

I wanted to hop on this thread because I am having similar issues-if that's ok.

I got my MK3s a few months ago and it was working great until I tried a semi-complex print with PLA+ and there was a clog. I got the initial clog out but now when I load the filament, it tends to push through well until it gets near the nozzle and appears to catch on something. At this point, the gears turn slower, and filament either slightly comes out or none at all. I tried doing simple first layer calibration prints and nothing.

What I've tried so far.

1. Cleaned out the nozzle and hot end with 0.4 mm cleaning needle and also needle provided by PRUSA (in most cases, it comes out clean)

2. Heated up nozzle to 260 C+ which can clean out any PLA gunk, but the same problem tends to perpetuate

3. Replaced PTFE tube for hot end and cleaned any melted material that may have been present around the hot end

4. Tried various idler screw tensions

5. Tried different PLA filaments (Hatchbox and PRUSA provided). I've printed multiple objects in the past with both filaments, and they typically work very well, but neither filament seems to extrude well now.

6. Also updated firmware.

7. A few cold pulls, although looking at what is considered ideal in this thread, not sure I'm getting that.

Filament above is a pretty good example of what I'm getting when I unload it (which usually is no problem using the printer function).

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

This is out there -- but who knows.

I sometimes wonder if PTFE can be ground or shaved by the sharp new Bondtech gears and gets pushed into the heat break and nozzle. Especially the cases where the PTFE isn't secured and it can ride up into the teeth along with filament being unloaded.  Even cleaning filament will be mostly useless. Cold pulls may dislodge the bits, but they'd just as easily flake off the pull and drop back down, perhaps giving a few minutes respite.

A way to resolve this would be to do a proper high temp nozzle removal, then using a 2mm rod push down through the filament path to clear the PTFE and heat break of any remaining pieces.  Way back when, I did something similar a few times - instead of a rod I used canned air, and did have dust clouds greet me. But at the time I wasn't thinking PTFE - just the dust and debris the teeth created from filament grinding.

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

@tim-2

Tim, I use both cleaning filament and a tungsten welding rod that is 1.7mm.  It works.  Although not 2mm, it will help me clear a clog,  

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

Posted by: @cwbullet

@tim-2

Tim, I use both cleaning filament and a tungsten welding rod that is 1.7mm.  It works.  Although not 2mm, it will help me clear a clog,  

This is how I do it:

I also use it for cold pulls but I have found that purging in combination with cold pulls works better for me.  Often, purging will work by itself.  

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

It seems some use cleaning filament for cold pulls.  If it works, I'm all for it. I've read tid bits that is is a bit stretchy and hard to gauge how much pull is enough. Then again - I do cold pulls so infrequently these days I probably shouldn't be making suggestions. The last one I did (six or nine months ago?) I started at 100c; but I honestly can't recall if I didn't have to tweak the nozzle temp up to get the filament to release.

Bob says he's using cleaning filament at 140c. Bob is usually spot on.

Please read my signature ... lol.

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

@tim-2

I use it for cold pulls at 140 also and the temp of the stuck filaments for purging.  

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

The advantage of cleaning filament is that it will extrude cleanly over a wide range of temperatures, so you can extrude it at 265C to push out any ABS or PETG, but know that if any cleaning filament is left behind, it will also extrude out at 190C if you print PLA next.

It was a happy day when I realized I could shove a length of 1.5mm polished brass rod down through the extruder to clear most jams rather than tearing apart the extruder. It's also a handy way to verify that your filament feed path is aligned and not snagging.

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

Thanks for all the continued support.

I'm actually pretty disappointed in Prusa. Maybe my expectations are too high, but I still haven't heard from them. Maybe tonight I'll hear something.

Otherwise, I'll get my extruder motor fan on Friday. I opted for a 40x10 Noctua 5V; I'll likely tie it into the heat break fan so they are on at the same time. Some people wire it direct I've seen, so it's always on when the printer is on, but I don't really care for that approach. I know the motor can handle the heat but at this point the motor is just an available heat sink to try to pull heat away from the extruder as a whole. I'm at a loss otherwise.

Unless my motor is faulty or has a propensity to behave erratically; I won't know until Prusa responds.

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

@obsessed

A perfectionist will never be happy with 3D printing.  You just have to understand that nothing is perfect when it is extruded.  

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

@obsessed

Yeah - some of this shouldn't be the black magic it appears to be. Hopefully Prusa won't ignore you because you installed the titanium heat break. Also hope they actually have a solution rather than have you jump through more hoops.

My current guess is the motor is bad ... its about the only thing left in the chain of events you've described.  I seriously doubt heat is an issue - but a tape on heat sink will be as good a fix for that as a fan.  Adding a heatsink dropped the motor temp by about 10c, it never helped the clogs I was having. This photo is an attempt to print using the heat sink as a fix. The print failed at the same place earlier prints were failing: 22mm up right where all the small crenellations started. I later replaced the Prusa heat break out of desperation, and that fixed my clogging problem. Still running strong and clog free nearly three years later.

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

Posted by: @cwbullet

@obsessed

A perfectionist will never be happy with 3D printing.  You just have to understand that nothing is perfect when it is extruded.  

Well I'm certainly not a perfectionist.

I just expect to have less than 90% of my prints fail. I don't think I'm being unreasonable. I also understand tinkering is needed. I just need to actually receive help from the manufacturer. A brand new printer should not have issues like this, but I also understand a small company is not working towards six sigma manufacturing. But I would expect some level of support from said manufacturer.

That's all. 

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

@obsessed

90% is a decent expectation.  It is attainable.  

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

Posted by: @cwbullet

@obsessed

90% is a decent expectation.  It is attainable.  

I'd be happy with 90% success. Right now it's 90% failure. 😆 

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

@obsessed

If that is happening to that degree, you are doing something wrong or you have a lemon.  In 3 years, I have yet to see a Prusa Lemon.  That doe not mean it can't happen.  I have 12 - 4 minis and 8 MK3s.  7 of them were lemons purchased by someone else that were not lemons.  Keep trying.  

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

Posted by: @cwbullet

@obsessed

If that is happening to that degree, you are doing something wrong or you have a lemon.  In 3 years, I have yet to see a Prusa Lemon.  That doe not mean it can't happen.  I have 12 - 4 minis and 8 MK3s.  7 of them were lemons purchased by someone else that were not lemons.  Keep trying.  

I mean, I'm willing to listen to suggestions. I've done everything suggested, shared settings, shared detailed info on environment, and nothing has helped. Had another print fail last night, 5 hours in. Then I did another and it failed 90 minutes in.

There was another user that had his extruder motor replaced as it was faulty; not saying that's what is wrong with mine, but is what I am saying is Prusas are not perfect. I just find it hard to fathom it is anything I'm doing when I'm following instructions EXACTLY, using default slicer settings, and it's happening with 4 different types of filament.

Prusa still hasn't responded. I've had others on different forums warn me their CS via email was lacking; guess they were correct.

I'm swapping heat break fans next I guess. Only thing I can assume it is, is heat creep. It never does it right away.

RE: My MK3S+ Extruder motor keeps skipping backward and clicking

@obsessed

When you say failed - stopped extruding or broke award from the plate?