After some great advice we changed infill type to gyroid, tightened the belts and ran a flow dynamics calibration. Off the back of this we were able to successfully print a 15+ hour print without a single issue.
The top surface of any full print is flawless, it’s the perfect consistency and is really smooth. The bottom layer however is full of gaps which is only cosmetic on normal prints but on single layer calibration prints it’s that bad the print breaks into pieces.
The first image is 0.96 flow rate, the second image is 0.98 flow rate and the third image is 1.028 flow rate.
The first number was obtained by running an automatic flow rate calibration. The second number was obtained by running a manual flow rate calibration and choosing the best print from the coarse and fine samples. The third number was obtained by eyeballing the print and guessing.
1.028 seems way too high for PLA filament on the cool plate and is also higher than what Bambu Lab recommend for their own filament.
Not only that but all of this is supposed to be easy and automatic and we’ve now spent hours (10+) trying to get the bottom and top layers perfect.
How do we sort this and how do we go back to the last 7+ months of the printer just working without any of this calibration.
That’s a lot to unpack but you’re definitely following the right path.
In my experience, there is no “perfect” setting but rather a Goldilocks zone between compromises in smoothness, layer adhesion, bond strength… yada, yada, yada. The point is, if you’re seeking that “Goldeness” of filament tuning… well… you would be the first person to actually achieve that. But you are much further than most because of your approach.
The single layer sheet test print that you’re showing is definitely one of my favorites since it is so easy to reliably reproduce and as you’ve seen, it exposes many sins that may lurk in the build plate and/or filament settings.
Having said that though, my general go-to is to use the Temp Tower first - often a controversy if one doesn’t know how to use it but if you have really good filament, then all a temp tower will tell you is that there is a broad range of temps that look pretty close to one another which if you trust the lettering on the box, you could skip this step. I like to do it as a first step for first use of a new Filament maker to see how close they come to what’s printed on the side of the box. Only once was I completely disappointed and that was with Fremover PLA+ which should have been call PLA- because it didn’t survive the temp tower before falling apart and that was with both their red and black filaments.
Then I go to Max Flow rate before anything else as this will tell me how far off my default flow rate is from what I can actually measure.
Then I do Pressure Advance. I use PA Pattern which is still fairly new test if you haven’t tried it yet but if you have the time, PA Tower takes 4X longer but is more accurate in my view.
After that, it really comes down to tuning for the individual model in my view. As an example, there are certain print-in-place articulating models that simply won’t print using Silk unless I change the X-Y compensation to a ridiculous 1.5mm to 2.0mm adjustment. I’ve sworn off Silk as a result and only use it for when I want “pretty” not functional or strong.
Note that all these tests above are baked into Orca and you won’t find these menus in Bambu Studio.
not functional or strong.