Pneumatic non-contact roughness assessment of moving surfaces

Conventional pneumatic gauging technology is adapted for non-contact roughness estimation by relating the frequency content of the back-pressure signal to the microgeometry of the surface moving lateral to the nozzle. The technique is shown to be capable of rapid areal characterization of surfaces with roughness down to 0.8 μ m Ra, and at speeds as high as 200 m/min. In light of the air jet being inherently impervious to the obscuring influence of machining debris and cutting fluid, the significant potential of the system for in situ application in a machine tool environment is demonstrated.