Flow Rate and Dynamics

What’s the difference?

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Flow Rate/Ratio is about how much filament to extrude per mm in a straight line; It makes surfaces look better in the middle of a layer.

Flow Dynamics¹ controls the amount to extrude during direction/speed changes; makes corners, edges and turn backs look better.

Flow Rate

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On the “Low Flow” above, you can see that there are gaps between the lines.

On the “High Flow” above, you can see a line from the center to top-right that the lines overlap and create a “scallop” effect.

Calibrating Flow Rate

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Bambu Studio’s Flow Rate Calibration isn’t great; I created a calibration model on Makerworld, complete with guide: YOLO Flow Rate Calibration for Bambu Studio.

There are other good options, but I like mine most.

Flow Dynamics

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Dynamics / K / PA is about the edges and corners of a print.

On the “High PA” above, you can see that the edges are “torn”, corners are rounded, and areas near a corner, edge, or feature are underextruded.

On the “Low PA” above, you can see that the corners bulge, and there are issues with too much filament extruded in areas near a corner, edge, or feature.

Calibrating Flow Dynamics

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Bambu Studio’s Flow Dynamics Manual Calibration is good; use the built-in “Patterns” option.

Ellis’ Print Tuning Guide has better guidance and examples for interpreting results than the Bambu Wiki.