Filament grinding when there is no clog

I had only been using two filament rolls of black and white Inland PLA since I got my printer. After finally feeling comfortable with my configuration I decided to try a few rolls of different colors and types of filament. So I picked up Inland Silver PLA+, Inland Slik Blue Silk PLA, and Inland Translucent blue PETG.

And here is where I ran into some problems. The print would stop extruding filament typically at the point when it got the infill portion on this print using the PLA+ and the Silk PLA. When using my White or Black PLA the print went just fine. The filament would be ground down by the extruder and wasn’t able to move the filament anymore. You can see the piece of filament in the left picture ground down on the far right.

After lots of troubleshooting with esteps, extruder tension, retraction, print temperature, and spool tension. I messaged a friend who has had more experience than me with 3d printing. He said my hot end likely was getting cooled by the fan once it kicked on after the base layers were complete. This is something Cura does and the Ender 3 fan cowling can cool the hot tip and not just the upper portion of the hot end.

His temporary solution was to slow down the print speed so the filament spent more time in the nozzle. This worked great and I was finally able to print with the PLA+ filament by dropping my print speed in Cura from the default 50 for PLA to 25. But I still had an issue with the Silk PLA grinding in the extruder.

Now to fix the actual problem for the PLA+. The nozzle getting cooled by the fan issue can be resolved with a new hot end cowling so it angles the fans differently. I decided on this one due to it supporting BLTouch and having the fans at the angles I think I will need. I printed the pieces with the PETG as it’s much more heat resistant than the PLA’s I have. This went well, I used the same trick of slowing down the print speed by half to 30mm and also raised the temp to the filament recommendation on the PETG box in Cura to 140. My friend also let me know that I should use painter’s tape on my magnetic bed panel as the PETG may bond with it. All this allowed me to print with PETG in acceptable quality for the new hot end shrowd.

Now I can print with my speed up a bit more with the PLA+ but still can’t seem to print with the Silk PLA. I had tried reducing my retraction from the 6.5 default to 4 and 3 early on in my initial troubleshooting to no avail. I later went back to retraction again and tried 1.5, only then did I get a print to complete with the Silk PLA. Some stringing obviously occurred due to the low retraction but not bad and easily cleaned up. No more filament shredding at the extruder occurred.

What seemed like the same issue initially ended up being two different solutions for each filament. The amount I learned due to this issue was significant and really helped me understand more about these printers. It sure did take a while to figure it all out but was well worth it.