Failed PLA Prints Troubleshooting - Possible Layer Adhesion Issue

[ewanjanderson]

Hoping the community can help troubleshoot why my prints keep failing. I’m having an issue where multiple prints have been making it past a couple of layers, then turning into spaghetti. Bed adhesion doesn’t seem to be the problem, as prints are still stuck to the bed, so thinking it’s a layer adhesion problem?

For background, the printer was working flawlessly, then I swapped out the stock 0.4 Hot End assembly for a new 0.8 Hot End assembly, ran a couple of PLA prints using Bambu Dual Color Silk, swapped back to the 0.4 assembly, ran a print using Bambu Transparent PETG which failed, swapped back to PLA Tough and have been getting inconsistent results since.

Here’s what I’ve tried to fix the problem so far:

Bed Adhesion
Tried both Textured and Smooth PEI plates
Washed both thoroughly by scrubbing with Dawn, then IPA

Printer / Toolhead
Checked all connections to extruder board
Pushed pin into Nozzle end to clear clog
Performed Cold Pull with eSun cleaning filament
Kept top glass propped open for venting with a Topprop
Recalibrated the machine after nozzle swaps and cleaning

Maintenance
Cleaned Carbon Rods
Cleaned and regreased Z-Rods

Bambu Studio
Confirmed that the correct plate and filament were selected
Confirmed that correct filament is selected on Device screen
Using Gyroid Sparce Infill, not Grid
Turned Aux fan off
Tried Aux fan at 30%
Tried slowing down speed settings for inner / outer walls and infill
Confirmed correct nozzle size is selected

Filament
Using Bambu Labs Tough Grey
Dried at 50c for 6 hours
Manually calibrated Flow Rate and Dynamics in Bambu Studios: k-value

Next steps
Try replacing stock 0.4 Stainless Steel nozzle Complete Hotend Assembly with 0.4 Hardened Steel nozzle Complete Hotend Assembly (will probably replace the Extruder Gear with the Hardened Steel one while I’m in there)

[RandomKhaos]

You’ve tried a lot, but I didn’t see mention of verifying that the correct nozzle is selected in Bambu Studio. I’ve had that one bite me once, so it’s something I look for first when I start seeing odd behavior like this.

[ewanjanderson]

Ah, good catch! I did check that - I’ll add to the list. Thanks!

[RandomKhaos]

Are those pictures from using the 0.8 or the 0.4 nozzle? Outside of the gyroid infill, aux fan, and speed settings, what other settings are you using? Are you able to show a picture of the sliced model you tried to print in the picture?

[ewanjanderson]

Pictures are from using the 0.4 nozzle.

Other than the update mentioned, I’m using the 0.16 Optimal settings, which I’ve always had success with in the past.

Here’s what I was printing in the pictures, but I’ve tried other models and had about a 50/50 success rate.

[GenericUser]

Looks like there may be lifting on that long section which is throwing it out. That overhang is probably needing a better raft possibly to hold it down. Also try slowing down the acceleration/travel speeds or use silent mode initially to nurse it past the first dozen layers.

[RandomKhaos]

I agree with @GenericUser here. You can see on your first pictures that the thinner sections I circled are completely missing from your print. Guessing those are the hanging bits of filament that lifted from the plate.

[ewanjanderson]

Got it! I’ll try this and some of the other prints that have been failing with increased brims.

Appreciate the help from you both!

[Beste]

you might have to adjust the first layer with a test program.
Advanced flow pressure and flow rate is calibrated?

would a skirt also might help to stabilize the support?
Glue on the plate is also good!

best wishes

[ewanjanderson]

Beste, thanks for bumping the thread and for your insight.

RandomKhaos & GenericUser, thanks for your help - I increased the brim and used Silent mode for the first 20 layers or so and it printed out beautifully. No issues since!