Here (image 1), a 3D plot of the grooves cut into a ball bearing which
failed. Optical profiling using interference microscopy produces a high-precision
three dimensional measurement
of the surface character of many materials. A difficulty present in
analyzing the resulting scar is obtaining an accurate calculation of
the volume of material removed, or the depth of the grooves, relative
to the original spherical surface.
- Image 2: Wear scar grooves with spherical shape of ball bearing
removed.
One solution to this difficulty is to "level" the surrounding
surface, and treat it as a flat plane, with the grooves in relative
depth to the flat plane. In Image 2, this groove has been represented
in this condition: notice that the formerly straight grooves now describe
an arc down through the flat plane, reflecting their relative depth
to the spherical surface which had been eroded.
- Image 3: Histogram, 3D volume analysis of ball bearing
wear scar
By calculating the total void area below the theoretical surface plane,
the displacement of materials caused by the wear scar is determined
(Image 3). Features such as leveling, and form removal, are part of
the standard software provided for 3D
analysis of measurements with MicroXAM
non-contact optical 3D profiler. Such calculations derived from
dis-contiguous stylus profilometry is intrinsically speculative, while
the volumes mapped by our 3D optical profiler are precise, and mathematically
sound.
Examples such as this illustrate MicroXAM optical profiler's efficacy
in providing failure analysis,
wear analysis, and volume displacement.
Many different materials can be measured, even composite surfaces of
dissimilar materials. Volume measurements can also be of use in film
thickness measurements, texturing
of materials, and in precision engineering, such as MEMS. Volume
measurements by MicroXAM have assisted researchers in determining the
amount of volume displaced in MEMS actuator motions,
tribology of fluid switches, and deformable mirrors, as well as etch
depth analysis.
