3D measurement of surface structures

As shown on the certificated and traceable surface standard Mahr MSS 3 it is possible to use the smartWLI systems for ISO conform roughness measurements. Even on the expensive high quality standard with an artificial sinus like structure it isn't an easy job. Speed and resolution simplifying the job. Used was an 50x objective. The area scan with 100 Mio. points takes only app. 3 minutes an a small stripe - still with several 100 profiles - and the same resolution can be measured in seconds. Perfect cleaning is necessary as well as an software for correct compensation of the stylus tip geometry and correct filtering processes - after high resolution measurements and an perfect stitching of multiple single scans. After less than 1 year using the standard with optical instruments the standard shows first corrosion holes and scratches.

However the shown surface is optimized for stylus measurements and the reality looks different. It starts with an grind surface:

Fluctuations from the structure height can have a big influence of the functional behavior as for example chatter marks on camshafts (the camshaft rotates and lift the valves - regular height fluctuation cause vibrations...). Even if this isn't the case the measurement results would depending on the measuring position:

Differences from app. 25 ... 50% depending from the parameter and measured position are possible.