FEI SEM LSM M-1000 P4 vibration environment measurement — 2014-07-08
Contents
Vibration environment measurement results (LSM)
Overview
To verify whether the vibration environment after installing the M-1000 P4 isolation platform satisfies the user's requirements.
Measurement date and engineer
Measurement date and time: 8 July 2014 (Tue) 16:00; measurement engineer: 최성원
Measurement site
LSM 4th floor
Measurement conditions and results
With an FEI SEM installed, tuning and vibration measurement were carried out while some tool functions were operating.
Measurement locations were near the top corners of the isolation platform top plate (top) and near the floor beside the isolation platform (base).
Site photograph
Results summary
| Test Direction | Axis | VC-Class (Base) | VC-Class (Top) | Transmissibility [dB@10Hz] |
|---|---|---|---|---|
| ACTIVE | Z | B | E | -27.9 |
| X | D | E | -32.1 | |
| Y | D | G | -31.7 |
Isolation platform intrinsic performance is satisfactory.
With active control engaged, vibration environment on the isolation platform top plate is satisfactory at E Class or better.
The SEM's internal passive isolation appears to show resonance near 3 Hz vertically and near 1 Hz horizontally; operation of the M1000 was not adversely affected.
For the P and R rotational axes, gains were set stably; performance measured near a corner was favorable, so rotational control performance is judged sufficient.
Because pumps are installed nearby and the site is exposed to noise and vibration, elevated vibration spectra around 90 Hz and 100 Hz are attributed to that influence; a partition wall between the pumps and the isolation platform is planned.
