Metrology

Metrology
MarForm MFU 200 Aspheric 3D Precision 3D measuring station
EN
Mahr developed the MarForm MFU 200 Aspheric 3D to enable optical components to be tested in 2D / 3D quickly and close to the production area. MarForm measuring machines have been recognized for decades for their accuracy and stability.
With the MarForm MFU 200 Aspheric 3D this experience has now been made available to the optical industry.

Accuracy
The MarForm MFU 200 Aspheric 3D is a precision measuring instrument which with its very low measurement uncertainty is ideally suited to your process optimization requirements.

Measuring principle
The MarForm MFU 200 Aspheric 3D measures the topography of optical components. Of course, a quick 2D measurement can also be recorded with a profile across the zenith of the lens. 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. Interrupted surfaces can be measured with the fully positionable probe arm.
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.
  • Technical data

Roundness deviation (µm+µm/mm measuring height) *
0,01 + 0,0002
Roundness deviation (µm+µm/mm measuring height) **
0,02 + 0,0004
Axial run-out deviation (µm+µm/mm measuring radius) *
0,02 + 0,0002
Axial run-out deviation (µm+µm/mm measuring radius) **
0,04 + 0,0004
Centering and tilting table
automatic
Table diameter (mm)
180
Table load capacity, centered (N)
200
Speed (rpm) 50 Hz / 60 Hz
0.1 to 200
Straightness deviation / 100 mm measuring path (µm)**, Z-axis
0.1
Straightness deviation / total measuring path (µm)**, Z-axis
0.3
Parallelism deviation Z-/C-axis in tracing direction, measuring path (µm)
0.6
Measuring speed (mm/s), Z-axis
0.1 to 50
Positioning speed (mm/s), Z-axis
0.1 to 50
Straightness deviation / total measuring path (µm)**, X-axis
0.3
Perpendicularity X-/C-axis, measuring path (µm)
0.3
Positioning speed (mm/s), X-axis
0.1 to 50
Measuring speed (mm/s), X-axis
0.1 to 50