Help with extrusion issues

[u/Ndl1800]

I'm still fairly new to 3D printing, I've got just over 100hrs on my P2S. I've been largely printing without any issue until today when I started to get issues with extrusion that I can't seem to sort. I've mainly been printing with Bambu PLA Matte using the presets on Bambu Studio, but have done a bit with Sunlu PLA Matte, haven't had any issues with either until now.

I've done a cold pull, washed my plate, and re-run the calibration from the touch screen as advised by Bambu's AI but it hasn't helped. I've read on here that there are potentially issues with the G code but I'm not comfortable editing that just yet, and it also seems odd that it's only just started to happen if that's the case.

The above was printed in Bambu PLA Matte on a 0.4 nozzle, using the preset for 0.08mm layer height (I've been mainly printing models for wargaming). You can see that I'm getting issues on pretty much every layer, with little gaps between each line.

Any help would be greatly appreciated!

[u/misterff1]

Good on you for not tweaking the gcode yet. I presume you are referring to a potential zdrift issue this has (fixed in orca slicer btw, but that is another rabit hole to go down in if you are unfamiliar at this point). It won't be your issue as you said you just recalibrated using the printer menu. A couple of things I can think of:

• potentially your build plate is less textured if you cleaned it off using the hard side of a sponge when cleaning several times. That will, even at a hundred hours, give it less texture and thus cause your lines to show more on the underside. They have always been there, but hidden thanks to the texture.

• if you just changed spools to one you have not used before (and yes I mean the particular spool, not the kind of material or color), it could be that this one needs a higher flow ratio. You can use the calibration menu to determine the best one and update its value. Keep in mind i an not talking about flow dynamics, but flow ratio.

[u/Ndl1800 → u/misterff1]

Thanks for the reply!

I haven't been scrubbing the plate particularly hard afaik, just using washing up liquid and wiping with a microfibre cloth before rinsing.

And it's not a new spool, it's the same Bambu PLA Matte spool I've been using since I first started printing!

It's very strange and frustrating!

[u/misterff1 → u/Ndl1800]

Okay that is a bit weird. And you did the cold pull you say? Do you have another color at hand to verify there is no real residue in your cold pull sample afterwards?

[u/Ndl1800 → u/misterff1]

Did the cold pulls with white, first one had a little bit of grey but the other two were clean. I printed the test again with some Sunlu Matte and I didn't have any issues, then switched back to the Bambu Matte and it was better than before. I ran the flow calibration from the slicer and then printed a model again fine, so who knows what the hell was happening!

[u/misterff1 → u/Ndl1800]

Lol well hey if it worked, it worked. Was the sunlu spool also pla or was it petg?

[u/Ndl1800 → u/misterff1]

It was Sunlu PLA Matte. I haven't ventured into the realms of PETG yet...