Quantitatively measuring nozzle wear Are there quantitive means of measuring nozzle wear? What steps do you perform to measure this, if so?
I have some digital callipers, but don't have much confidence in measurements taken, as it's almost impossible to ensure the nozzle aperture is completely free of filament residue.
The context here is I've recently been trying out some carbon-fibre infused PLA filament, but would like to keep an eye on how much it wears the nozzle, and get an idea of nozzle wear rates. I can then work out if the mechanical and aesthetic qualities of the CF filament are worthwhile.
Based on CNC Kitchen measurements,

                
            
the wear can be initially estimated by judging the overall length of the nozzle. Abrasive particles wear the nozzle very little on the channel (so the diameter doesn't change, for a while) but they wear out the outer surface in contact with the printed part, resulting in a shortening.
Of course, once the shortening gets severe, the diameter will increase because you reach the inner chamber.