The study of measurement of micro gears with a touch-trigger probe

The measurement of micro gears with a touch-trigger probe will be introduced in this paper. Due to the small size and complex geometry of micro gears, it is difficult to measure them by traditional instruments like coordinate measuring machines (CMM) or laser displacement sensors. This study focuses on this topic and proposes an approach to measure the three dimensional profile of micro gears. The methodology is based on coordinate measurement. A special touch-trigger probe which detects the moment of contact is employed in the measuring system. The diameter of the probe tip is smaller than 2 mu m and therefore small enough for measuring micro structures. All the calibration and error compensation for the measuring system are discussed in the view of micro metrology. The comparison of measured profiles from both coordinate and image measurement is discussed. Results of experiments show that the proposed approach is worth of further development in the future.