Trying to resolve deteriorated print quality {Original Prusa i3 "mk1")
 
Notifications
Clear all

Trying to resolve deteriorated print quality {Original Prusa i3 "mk1")  

  RSS
Webdad
(@webdad)
Eminent Member
Trying to resolve deteriorated print quality {Original Prusa i3 "mk1")

I posted this on reddit, and thought I would cross post here for visibility.

Couple weeks ago the quality of my prints started heading south. Have an Original Prusa i3 "mk1", and have been printing great for the last year or so. Probably have close to a thousand hours of printing and have printed over 5000m of PLA. So, not surprising I might need some maintenance.

Filament was printing stringy and inconsistent on just flat areas, so thought I might have a nozzle clog. Tried some cold pulls, didn't seem to help, so swapped the brass nozzle (original nozzle) with a hardened steel nozzle (ordered with my Prusa kit) of same size. Started seeing some blobs of burned filament drop on the print bed.

I was able to stick a pick above the heat block and pull out some melted, partially burnt filament at this point.

After bumping my temp from 210 to 220 it seemed to be okay, but again, the stringy first layers started showing up. At this point I wasn't getting any more burnt filament in the heat block, so I'm thinking that might have been due to the clog.

I use S3D, and adjusted extrusion multiplier from 1.01 to 1.12. Seemed to help with some filaments but not others.

So, based on reading various similar issues, I'm thinking that the clogged nozzle may have resulted in damaging the PTFE tube. (At this point I'm awaiting Amazon to drop off some PTFE tubing so I can replace that.

Any other thoughts or suggestions?

Here are some pictures of various prints:

Sample print: In the below, the gray print was made right after the purple print. The purple first layer is what I'm used to. The gray first layer is stringy and blobby.

This is what has started typically happening with the first layers. The bed adjustment is identical with the purple / gray prints above.

One last anomaly, when unloading the filament, I now get this bulb at the end and typically have to issue the unload command a second time in order for the filament to release. This picture shows what the end is typically looking like:

Welcome the feedback of anyone else that might have some recommendations.

Posted : 09/04/2017 2:44 pm
richard.l
(@richard-l)
Member Moderator
Re: Trying to resolve deteriorated print quality {Original Prusa i3 "mk1")

Looks very much to be a PTFE tube issue. Once replaced you should be good.

Posted : 09/04/2017 11:04 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Trying to resolve deteriorated print quality {Original Prusa i3 "mk1")

I don't think you tightened the nozzle properly.

Before attaching heat break, screw in nozzle and then back off half a turn.

Screw in heat break

Heat to 250 degrees then with correct sized spanners, tighten the nozzle - you may get a quarter of a turn.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 10/04/2017 4:23 pm
Webdad
(@webdad)
Eminent Member
Topic starter answered:
Re: Trying to resolve deteriorated print quality {Original Prusa i3 "mk1")

Thanks guys. Yeah, Houston, we have a problem.....

Here is the PTFE tube once I was finally able to get it out of the heat break. At first it wouldn't come out at all, but after I hit it with the heat gun, it came out looking like this:

And before I got to this point, there was all kinds of burnt filament between the bottom of the heat break and the top of the heat block.

So, Peter, you hit the nail on the head, the nozzle wasn't tightened down correctly. I've been following the Prusa guide for PTFE this time around http://manual.prusa3d.com/Guide/How+to+replace+PTFE+tube , and seeing the error of my ways.

Now i just have to get it all put back to together and I should be set.

Thanks for all the help.

Ray

Posted : 11/04/2017 1:49 am
Share: