Hexagon TESA RUGOSURF 90G Mode D'emploi page 107

TESA-Rugosurf 90 G
b) Altered shape of peaks and valleys
When the diamond passes a peak, the contact point of the stylus on the work piece moves to the probe tip surface so
that the peak tends to become rounder than the true one. This alteration is particularly noticeable with a low Ra value.
The tip radius also reduces the valley depth (c) while rounding the peak (b) whose height (a), however, remains unaffected.
c) Recess cannot be detected
When the stylus passes a recess, it is no longer contacting the surface, thereby levelling it. This mainly happens when
inspecting surfaces of sintered and porous materials.
When the skid doesn't move in phase with the stylus, it can be a cause of error due to its shape, as do some specific surfaces.
Schematic view of a probe with skid (the arrow shows the measuring direction)
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