Investigating nozzle-wear in 3D printers (with excellent cross-sections!)
CNC Kitchen's 18-minute video on nozzle wear in 3D printing involves sending abrasive filaments (the abrasiveness comes from pigments and additives like carbon fiber, etc) through a variety of nozzles (mostly cheap ones from China), then measuring the results with a micrometer and by taking castings of their interiors -- but the best part is when the nozzles are clamped to the business end of a CNC mill and milled down into cross-sections. Man, I love cross-sections. (via Four Short Links)