Flow Ratio Calibration Boxes

Setting the filament flow ratio correctly for each different brand and type of filament that you use is crucial to good quality prints. These boxes make that quick and easy to do, as long as you also have a digital vernier caliper (an essential tool for 3D printing)!

If you have a printer with an AMS or MMU or similar multi-filament capability then you can print several calibration boxes with different filaments in one go (change the print sequence from “By layer” to “By object”), significantly reducing the time that it takes to calibrate a bunch of different spools. An example of this is shown in the photos.

Usage:

1. Load the STL into your slicer
2. Set the filament flow ratio in the slicer to 1.00
3. Print the box
4. Remove the printed box from the print plate and then use a digital vernier caliper to measure the width of the walls. We'll call the measured value “W”. When the flow ratio is correct, the width of the walls will be 0.8mm.
5. Divide the measured width “W” into 0.8mm. The result is what the flow ratio should be - we'll call this “R”.   So…  R = 0.8 / W
6. Put the value of “R” into the filament flow ratio setting in the slicer
7. Print the box again
8. Measure the width of the walls - they should now be 0.8mm (or very close to it).

I've uploaded stl's for different types of filaments. There's no difference in the walls etc, they just print with a label on the base of the box to indicate the type of filament, which is useful if you want to keep the boxes for later measurement or just seeing what the filament looks like in a print.