Notifications
Clear all

Overview of troubleshooting my MK3 extrusion issues  

  RSS
Chris
(@chris-21)
Active Member
Overview of troubleshooting my MK3 extrusion issues

Over the last couple of weeks I ran into major issues with extrusion on my MK3. The thing is, I had been printing for months without a problem so I figured it had to be something I caused.

I did a full writeup on my problem and the steps I went through to resolve it in the stack exchange 3D Printer site:

https://3dprinting.stackexchange.com/questions/6183/issues-with-proto-pasta-filament-extruding-on-prusa-mk3#answer-6265

I wanted to repost it here just in case it helped anyone else out or gave anyone ideas/tips on how to troubleshoot the problems they ran into.

---

tl;dr

I had a dragging idler pulley that was causing extrusion issues. Opening the idler pulley door and working it a bit with my finger resolve the issue.

The detailed explanation

So after two weeks or so of troubleshooting, banging my head, taking a break, and coming back to it I'm finally getting good prints again.

I do believe the original problem started with the clogged nozzle due to the bore hole diameter being too small for the glitter filament as mentioned by Axel in the post comments (a bit rude about it, but still probably true), but there were other issues that I ran into.

Troubleshooting steps

General cleaning
After I switched back to inland filament (which had been working fine for months) I was still having extrusion issues. At this point it was due to the clog (I suspect).

I tried several steps to unclog the nozzle including [the steps suggested by prusa support]( https://help.prusa3d.com/l/en/article/WWVRzOY1dX-clogged-nozzle ) and [cleaning techniques suggested by Tom]( ) amongst other places.

I also picked up [a couple of pencil brushes on amazon]( https://www.amazon.com/gp/product/B00CWDO1XU/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 ) including a small brass brush that's perfect for cleaning off the extruder pulley teeth.

Cold pulls
During these steps, I think I introduces the second problem without being aware of it. I perform a bunch of cold pulls (explained by Tom in his video and other videos and posts). During one of these cold pulls I forgot to loosen the MK3's idler pulley door before tugging. Once I noticed it I loosened the door, but I think that tug may have affected the idler pully getting it a bit gritty (I don't know _how_ it would have done that, but it's my current guess).

At this point I was still getting extrusion issues and didn't think about the idler pulley being the issue, so thinking that the nozzle was still the issue I ordered a second E3D nozzle and some Ethyl Acetate which dissolves PLA.

Notes on Nozzles and Ethyl Acetate

E3D nozzles

A couple of helpful points I learned while researching these purchases.

There are a _lot_ of cheap nozzles that say they work on the E3D, but be sure to read the comments from whatever nozzle you're looking at because apparently a lot of them either don't fit or don't print well.

I ended up purchasing a replacement nozzle sold directly from E3D to be safe.

Ethyl acetate

As far as the Ethyl Acetate, I was having a hard time finding it online when looking for it as a solvent without having to purchase the chemical in a giant jar. I didn't want to buy a jug, I only needed a bit.

After doing a bit more research I found out that it's the same chemical that [entomologists use to kill insects for preservation]( https://en.wikipedia.org/wiki/Ethyl_acetate#Entomological_killing_agent ) and when you look for the chemical from that context you can find it sold in much smaller quantities. I was able to find [a small jar of ethyl acetate on amazon for 7 dollars]( https://www.amazon.com/gp/product/B0755JYFJS/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 ). Smaller, safer, and cheaper.

Finding the actual problem

Once the nozzle and ethyl acetate came in I pulled off the old nozzle, dropped it into the ethyl acetate to soak, put the new nozzle on (per the instructions from prusa's website), and reaccelerated the printer just to be safe. I tried printing a test block and it seemed better, so I then tried a larger print and while the printed model seemed better, it was still obviously having extrusion issues and crumpled in my hand.

With the nozzle ruled out, I started looking elsewhere on the printer. After watching [a video from the 3D Printing Nerd on extrusion issues he was having on his MK3]( ) I decided to check the extruder pulleys. When I tried to open my extruder idler pulley door I noticed I couldn't actually get it open; it seemed to be stuck on the bottom. I tried to free the bottom of the door, but couldn't without forcing it past my comfort level. Instead, I unscrewed [the top of the pulley door]( https://manual.prusa3d.com/Guide/5.+E-axis+assembly/510?lang=en#s8310 ) to remove it.

From here I noticed two things, I didn't get the pulley teeth as clean as I though I had before and the idler pulley's mounting rod was extended just a bit (which is what was causing it to stick at the bottom). I adjusted the rod and put the door back on. It was printing better but still had extrusion issues.

I then watched the pulley during the filament loading and notices that while the extruder stepper motor was turning smooth, the idler pulley was stuttering a bit while turning. I imagine those little stops and starts were what was causing the extrusion issue.

I opened the idler door back up and worked the idler pulley a bit with my finger. It started to spin free (maybe there was gunk in it? maybe it was rubbing a bit against the mount? ¯\\_(ツ)_/¯), so I closed the door and screwed it back in tight.

Ran a test print -> perfect.

I've run several prints increasing in complexity and it seems like I'm back to printing well.

How I introduced my own problem

As I noted above in the explanation, I think I introduced the problem during a cold pull where I forgot to loosen the idler pulley door. I know this explanation is super verbose, but when looking around, even after fixing the printer, I haven't really seen many people noting that on the MK3 you should make sure the door isn't screwed down when performing the cold pull. It's def a common sense move, but I don't see it mentioned as a potential for introducing a problem.

Also I didn't see a dragging idler pulley as a possible cause of extrusion issue so I thought I'd note it here as well.

Hopefully if anyone else has a similar problem on the MK3 this will be a source of help.

Posted : 01/07/2018 2:51 pm
gaston.d3
(@gaston-d3)
Reputable Member
Re: Overview of troubleshooting my MK3 extrusion issues

Excellent write up. Happy to see that at the end you figured it out. 3D printing journey is like this: perseverance, frustration, detective work (Columbus) and at the end resolution. Well done.

Posted : 01/07/2018 5:01 pm
bobstro
(@bobstro)
Illustrious Member
Re: Overview of troubleshooting my MK3 extrusion issues

Great info. In researching cold pulls, I also didn't find anything clearly stated on the need to loosen the feed mechanism. I've started doing it simply because it only takes seconds and isn't a precise adjustment to re-tighten it. An official procedure for the Prusa/Mk3 would be a good idea. Thanks for all the detail.

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 : 01/07/2018 6:25 pm
colin.a3
(@colin-a3)
Trusted Member
Re: Overview of troubleshooting my MK3 extrusion issues

If you need help on this I would advise you to phone the milk marketing board, as Prusa are unlikely to be interested.

Posted : 01/07/2018 9:06 pm
bobstro
(@bobstro)
Illustrious Member
Re: Overview of troubleshooting my MK3 extrusion issues

If you need help on this I would advise you to phone the milk marketing board, as Prusa are unlikely to be interested.You realize he was able to fix the problem through maintenance and it's printing well now, right?

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 : 01/07/2018 9:45 pm
colin.a3
(@colin-a3)
Trusted Member
Re: Overview of troubleshooting my MK3 extrusion issues

You seem to be a Prusa plant.

Posted : 01/07/2018 11:26 pm
bobstro
(@bobstro)
Illustrious Member
Re: Overview of troubleshooting my MK3 extrusion issues


You seem to be a Prusa plant.
You seem determined not to contribute anything useful to the conversation.

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 : 02/07/2018 12:11 am
colin.a3
(@colin-a3)
Trusted Member
Re: Overview of troubleshooting my MK3 extrusion issues

that is patently incorrect unless you only have a single point of view.

Posted : 02/07/2018 12:25 am
rob.l6
(@rob-l6)
Honorable Member
Re: Overview of troubleshooting my MK3 extrusion issues

We understand you are not happy with PR, and you feel the need to have a rant. But seriously, going on and on about it here doesn't help you, in fact, probably the opposite.

Address your concerns to PR directly. Go on and on at them until you get the response you wish for. This is a (mostly) self help forum. Calling people fanboys et al just makes you look silly.

Posted : 02/07/2018 4:31 am
Knickohr
(@knickohr)
Moderator
Re: Overview of troubleshooting my MK3 extrusion issues

[moderator mode on]

Guys, please return to the topic !

Thomas

[moderator mode off]

Posted : 02/07/2018 8:40 am
Chris
(@chris-21)
Active Member
Topic starter answered:
Re: Overview of troubleshooting my MK3 extrusion issues

I'm glad you all found it helpful 🙂

It definitely felt like an epic journey while troubleshooting this including some trips to the pits of despair, but I came out better for it in the end 🙂 I definitely feel more confident in my 3D printer knowledge and hardware troubleshooting skills (I'm an app developer by profession so troubleshooting hardware like this is still a bit foreign to me).

Posted : 03/07/2018 12:37 am
nubbyninja
(@nubbyninja)
New Member
Eerily similar issues currently

I'm eyeballing your shots of those bad extrusion areas. They look remarkably similar to my own. Down the rabbit hole I am, almost a year. Will follow your steps and see what's what.

Posted : 07/08/2021 11:06 pm
cwbullet
(@cwbullet)
Approach

@Chris, thank for sharing.  This is very close to my approach.  I will try your next time and compare notes.  

--------------------
Chuck H
3D Printer Review Blog

Posted : 08/08/2021 7:19 pm
Share: