Volumetric Flow Test

Test the maximum printing speed of the extruder. This moves every 2mm to run faster to check your volumetric flow rate. 

Stop the print when you see it starting to unextruded or have inconsistencies in the layers.

Then measure from the bottom to where the last layer that looks perfect with pair of calibers. 

Measure in mm + 10 is what your max volumetric flow is.

So for my test Filamatrix Tough PLA @220c is 18mm + 10 = 28mm3 max flow

Set it slightly lower then this by about 10% in your filament settings for safety so for this would be 25mm3 max flow