Metrology
Metrology
MarForm Software MarWin
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The MarWin Aspheric 3D software package

This package in conjunction with the MarForm MFU 200 measures the topography of optical components such as aspheres.
Measuring principle
For 3D measurements two linear profiles offset by 90° are first measured across the zenith of the lens in a single sequence. Then multiple concentric polar profiles are recorded by rotating the C-axis. These measuring points are used to generate a topography. With the fully positionable probe arm, interrupted surfaces can be measured.
Of course, a quick 2D measurement can also be recorded with a profile across the zenith of the lens.
Using the measuring station in a vibration-cushioned cabinet keeps external interference such as vibration and dirt away from the measuring objects.

Measuring procedure
Before starting the measurement, choose the nominal form type and set the parameters for the expected reference lens. In the next step the measuring data is recorded and compared with the nominal data for the lens.
The RMS value, PV value and slope error are shown as parameters.
In the software the individual parameters for the aspheres, such as the radius of curvature R0, conical constant k and the aspheric coefficients Ai, can be adjusted to the measuring results when adjusting the nominal asphere to the fit asphere.
The differential topography between the measured values and the nominal lens is displayed as a color-coded line chart. The 2D profiles and the differential topography can then be exported in known formats for correction for the machine tool.
In addition to measuring spheres and aspheres as described above, other rotationally symmetrical objects can also be measured and evaluated using the nominal form as a conical profile or Sagitta description of a 3D scatter plot.