Odd problem with 1 type of PETG
Ok, so this is an odd one because it does not happen all the time (even with the same gcode). I was noticing when I was printing some of my duck models that there appeared to be 'burnt' areas on the build. I thought it might have been black filament, but after cleaning off the nozzle and area, this would still happen once and a while.
I thought I had it under control by reducing the nozzle temp from 230 to 225, mainly becuase I was able to print a few without issues. Now that I need to get something out as a gift, things are hitting the fan again...
I am not 100 % sure of the issue, but it may be over extruding? I was printing last night and it stopped due to a crash. I looked at the model, and in some areas around the back edge, there was a noticeably higher surface on the 2 back corners. I am sure this is what cause the crash. So I am trying to figure out why, just with the Yellow PETG from Polymaker this is happening. I have some translucent blue PETG from Eryone that seems to print fine. PLA has 0 issues. It just seems like this one roll. Unfortunately, its the only Yellow PETG I can find... 🙁
What are the steps to troubleshoot this kind of issue?
Currently I am drying my filament for a day to try and see if that fixes it (I usually dry overnight, but yesterday I only dried for 4 hours). Seems odd that this is a once and a while issue, when visually it seems so drastic....
Please post a picture of the problem and also show us your hotend/nozzle assembly from two different angles.
Cheerio,
RE:
Ok, baked my filament for over 12 hours. I took pictures of the nozzle, then some pics of when the crashes were happening, the final print, and the nozzle after the final print.
A few things to note. After I think the 5th crash, it stopped, those where the last few pics where you can definitely see higher points on the print. What I did, much like I did a few times in the past, was to sand these spots down on the bed, then let the print continue, which it does. Prior to this, it printed with no issues with PLA. In the last printed pic, you can see the trouble areas near the bottom, which are clean and nice on the PLA print.
(sorry, I don't know how to add more than one pic, so I stitched them together)
You can see in the 3rd and 4th images that there are high points on the back corners of the print. I don't see extra 'junk' on/around the nozzle before or after the print.
One more thing that may be of note, I am using a DiamondBack nozzle, if maybe that may make a difference.
Will print another model again tonight with the yellow PETG, and then again tomorrow with the translucent blue PETG (that never gave me issues before).
Your pictures are not quite clear enough to be certain so please check. It looks like you have melted plastic running down from the top of the heatblock. If so, you need to reseat your nozzle, pay particular attention to the diagrams at the bottom of this page:
https://help.prusa3d.com/en/article/changing-or-replacing-the-nozzle-mk2-5s-mk3s-mk3s_2069
This assumes you have either genuine E3dV6 nozzles or close equivalents. The Diamondback v6 compatibles are OK.
Cheerio,
RE: Odd problem with 1 type of PETG
Will check that this weekend. Why would this only be happening with 1 type of filament?
If the nozzle fit was borderline OK then filaments with large amounts of pigment - eg white/pastel might not get through the gap whilst ones with little pigment might *just* ooze through; then like all leaks it gradually worsens and eventualy everything leaks.
Cheerio,
RE: Odd problem with 1 type of PETG
Ok it does seem that this was the issue... maybe I did not tighten enough. I see that there is melted filament around the head (on the threaded side). I am trying to figure out how best to clean this off. I am attempting to wire brush it after heating it up. I will then fully rethread it after... hope this is the right course of action.
Thanks for the find on my issue.
RE:
Ok, I thought I tightened it enough and yet, it is still happening. After the clean up, I can now see the bleed out of the filament. There was a gap after tightening the nozzle, though I did not measure.
So a recap of getting to this point. I got a DiamondBack nozzle (brand name) for Christmas last year. I installed it and printed PLA for several weeks without any issues. I started to create and print some models that I wanted to sit in my car, and found that PLA was melting in the summer heat, so I switch to PETG. Printed several times with Transparent blue and black without any visible issues, but found painting things yellow just plain sucks. Got some yellow PETG and this is where things started to happen.
Is the issue I need to tighten it a bit more? I will remove, and clean of the blobbing, but I would some day like to be able to print again with the yellow PETG....
As long as the face of the heatbreak and the top of the nozzle stem are undamaged a stripdown, cleanup and reassembly should return the machine to a state where all your filaments will print well. Be sure to follow the link above.
Cheerio,