LS Mtron — M-1000 P4 vibration measurement with FEI SEM (2014-07-08)

To determine whether the vibration environment after applying the M-1000 P4 vibration isolation platform meets the user's requirements.

Measurement date and time: 2014-07-08 (Tuesday) 16:00. Measurement engineer: Choi Seong-won.

Measurement site: LS Mtron 4th floor.

FEI SEM is installed. Tuning and vibration measurement were performed with some microscope functions operating.

Measurement positions were near a corner of the isolation platform top plate (top) and near the floor at the platform base (base).

Isolation platform intrinsic performance is satisfactory.

With active control, the vibration environment on the isolation platform top is E class or better and satisfactory.

The SEM built-in passive isolator appears to show resonance near 3 Hz vertically and near 1 Hz horizontally, without adverse effect on M1000 operation.

For P and R rotational axes the gains were set stably; because performance measured near the corner was good, rotational control performance is judged sufficient.

Horizontal-axis performance near 25 Hz is not favourable in passive or active state; no anomaly was observed at that frequency in open-loop testing, so the cause is judged to be external to the isolation platform.

A pump nearby exposes the installation to audible/vibration coupling; elevated vibration spectra near 90 Hz and 100 Hz are attributed to that influence. A partition between the pump and the isolation platform is planned.