Notifications
Clear all

Print quality suddenly went from great to bad  

  RSS
Titan
(@titan-2)
Estimable Member
Print quality suddenly went from great to bad

Hi.  Well, my MK3S print quality suddenly took a nose dive from all good to pretty awful.  I thought it could be due to the Priline PETG filament (an old reel - tho dried before use - and that has proven challenging to print with on other Monoprice machines).  It had printed perfectly for days, churning our print after print with no more than a quick wipe of the PEI textured steel sheet, but this morning I had the first failed print and I could hear the Priline PETG skipping every so often against the bondtech gears.  So I increased the temp and used filament floss to clean out the hot end before changing the Priline PETG for an Esun PETG, but the print results were only slightly better.  I thought I'd do a cold pull and assumed it'd be riddled with old filament, but it looked surprisingly clean.  I guessed the nozzle would be obviously damaged but that looks ok too (on the outside at least).

I'd be lying if I said I wasn't confused about what the cause of the sudden drop in print quality was due to.  I'm planning to change the nozzle anyway (and the PTFE tube once my order is delivered) and use the opportunity to give the Prusa a quick service, but I'd really welcome any advice on what the issue is caused by. 

Hopefully some pics might help diagnose too.

Posted : 01/11/2021 3:24 pm
Diem
 Diem
(@diem)
Noble Member

Did you clean out the Bondtech teeth?

Cheerio,

Posted : 01/11/2021 6:01 pm
Titan
(@titan-2)
Estimable Member
Topic starter answered:
-

Hi, I did.  I gave them a clean out when I did the cold pull.  There was a little dust inside the housing (not much really) but the teeth were almost perfectly clear of old residue.  

Posted : 01/11/2021 8:16 pm
Diem
 Diem
(@diem)
Noble Member

From the pictures you filament could do with a little more drying but I don't think that's your underlying cause.  You are planning to try another nozzle, good.  Try tweaking your bondtech idler pressure a little.

It might just be a collision of a few minor adjustments and your general service (look on Prusa Support) might be enough.

Cheerio,

Posted : 01/11/2021 10:03 pm
Titan
(@titan-2)
Estimable Member
Topic starter answered:
-

Thanks for the thoughts Diem, I'll give that a go.

Also, I've just realised I seem to have mistakenly posted this in the prusa mini section rather than the mk3 area. If a moderator reads this is it possible to move it to the correct area please. Thank you!

Posted : 02/11/2021 12:04 am
Antonio
(@antonio)
Moderator

IMHO, sudden underextrusion + skipping(or grinding) gears = stuffed nozzle

you could try to unscrew the nozzle and clean it manually (once unscrewd the nozzle, i used a blow torch to soften the material inside, or replaced it if possible)

 

Parlo italiano...but I'm not an expert.

Posted : 02/11/2021 4:21 pm
Titan
(@titan-2)
Estimable Member
Topic starter answered:
-

The replacement parts were delivered and installed and, after a quick service, it's printing beautifully once again.  I was surprised how quickly the print quality went from great to awful:- within one print.  I've not experienced such a rapid drop off in print quality before due to worn nozzles on my other 3D printers.

It's no surprise that it needed replacing though.  I assumed I'd replaced the Prusa nozzle before, but it turns out it's the original brass E3D nozzle that came supplied with the MK3 build kit... 3.5 years ago!  I can hardly believe one brass nozzle has soldiered on with PLA, PETG, ABS (inc Glow in the Dark) and TPU for hundreds and hundreds of prints without a hiccup. Amazing.

Great to have the Prusa printing well again.  Many thanks for the help everyone.

Posted : 03/11/2021 3:42 pm
Share: