I’m dialing in PETG-HF and discovered a few things. I increased the temp to 255-265c for better layer adhesion and ran the flow calibration.
One thing I started doing in addition to figuring out what looks best, is bending the flow rate squares to try to break them to see how the layers hold up. Big difference even only 1 number can make!
You can see how on one of the pics the layers separate and the other they stay together.
The correct flow ratio is achieved when a single-walled hollow cube has wall thickness exactly equal to the line width.
Print a 20×20×20 mm hollow cube with no top or bottom layers and 0% infill.
Measure the wall thickness and calculate the correct flow ratio using the following formula:
Correct flow ratio = (expected thickness / measured thickness) × current flow ratio
I would not totally agree with this theory, and for the following reason:
The cross section of a layer is not an exact rectangular shape, but more one with rounded ends. Schematic section and SEM images of the cross-section of (a) the… | Download Scientific Diagram
Therefore the math is not a 100% correct value.
But it definitely gets you quite close.
I print mainly PETG.
I also set the chamber temperature always between 40 and 45 °C and keep the part fan off unless absolutely necessary (bridges / overhangs / short layer times). From my experience PETG likes it warm for good layer adhesion.
Yeah… please bambu turn off the default chamber cooling for PETG under 40C chamber temp… @SupportAssistant
