Yolo Flow Ratio Calibration for Bambu Studio

Enjoying the calibration menu on your Bambu printers? Me too, and I'm happy Bambu merged my Pull Request to enable it.

I just want everyone to be able to calibrate their filament really well, and Auth Control has removed many third party options and convenience. So here's a set of YOLO flow calibrations. 

This'll work on all the printers, but was intended for the H2D because it's the only Bambu printer that couldn't use Orcaslicer to do a YOLO flow calibration.

 

Boost MeI'd super appreciate if you sent a boost my way! It keeps me working with Bambu to make Studio work best for all of us Bambu printer owners. Thanks!

 

All geometry, text, and settings are hand-created/set by me. The idea of using chips similar to this for flow calibration isn't new, though.

How it works

As of 2.2.0 (released August 12 2025) BambuStudio has two flow ratio settings that make this work:

1. “Flow Ratio” in the Filament Profile
2. “Object flow ratio” in the “Quality” Process settings

⚠️ You need to have Developer Mode enabled in Bambu Studio to see the Object flow ratio settings. It'll still print correctly if you don't.

⚠️ Bambu Studio doesn't do per-object Top Surface Flow - when you slice, the preview will have all the top surfaces using the same flow. It still works!

 

The flow ratios work multiplicatively. If you have:

• Filament profile Flow Ratio: Generic PLA = 0.98
• Object flow ratio: 1.05

The effective flow ratio for that object would be: 0.98 × 1.05 = 1.029.

 

This YOLO (you only look once)  calibration is intended to only need 1 pass for the majority of filaments; it focuses on values near the setting you already have for flow rate. 
The 2 step process that's built into Bambu Studio covers a much wider range of flow rate settings. Most of the time it's not necessary, and wastes time and filament by defaulting to two passes.

Which plate to print:

Each Profile has 2 plates:

• YOLO Chords 
  • +.05, -.05 in .01 steps, 11 chips
  • This is the “new” way, and can be easier to see visually which setting is right.
• YOLO Line
  • +.05, -.05 in .01 steps, 11 chips
  • This is the “older” way, and can be harder to pick between to close settings.

Use whichever works best for you / you prefer!

How to apply results

Each chip has a value on it, like “0, -.02, .03”. The formula for setting this in Bambu Studio is:

original_flow_ratio * (1 + chip_value)`

Example:

PLA has a default flow of 0.98. You pick .02 as the best calibrated chip.

.98 * (1 + .02) = 0.9996

So you set 0.9996 as the Flow Ratio for your filament in Studio. 

How to pick the right setting

‼️ We want to ignore the edges and corners of these chips - you want to be testing Pressure Advance / Flow Dynamics to tune those. We're only focused on the inside area of the chips.

Chord Method:

1. We want the smoothest top surface.
   1. ⚠️ NOTE: IGNORE the absolute center where it ‘volcanos’ - Orca doesn't have this because they fill in the circle starting in the center. This model fills in from the outside, and ends up with that effect - I'm researching ways to minimize this in studio.
2. We want to see no gap or ridge where arcs on the outside meet the first full circle line nearer the center.
3. Lines in the circle should be flat, not domed.

Gaps between the lines (normally on the left side) indicate flow is too low

Line Method:

You can tell by looking at some of them that they're wrong. 

 

A lot of the chips are going to look really close to each other. At that point, the best thing to do is scrape across the lines with the back of a fingernail. 

✅ Smoothest surface wins ✅ 

Closing notes

Note: Some filaments (like PLA Matte, or PLA Wood) are really tolerant of different flow rate settings. If you really can't pick a good chip, just go with the filament's “generally good” setting unless that gives you issues.

Don't spend days calibrating filament that doesn't need it - just start printing and see if the defaults get you results you're good with!

 

Happy Flow Rate Calibrating!