Measurement of extremely long microbores by application of laser metrology

Abstract

The measurement information contained in a very narrow laser beam penetrating a microbore is distorted depending on the microbore geometry. The presented research is composed of three stages: design and experiments on the single lens and double lens laser beam shaping system, the measurement of trough bores and interferometric measurement of blind bores with reflective bottom. The samples were prepared from glass–resin laminate (some of metal plates) with microbore diameter ranging from 25 μm to 200 μm and set coaxially in piles. The paper describes the properties (power loss and phase distortion) of a focused laser beam penetrating long microbores. As a reference a microbore of diameter d=100 μm was taken and all comparative results presented without close description refer to this value. The experiments proved the advantage of a single lens laser beam shaping system and confirmed the possibility of application of interferometric measurement of blind bores.