A vibrating micro-scale CMM probe for measuring high aspect ratio structures

This paper describes the development and initial testing of a novel three-axis vibrating micro-scale co-ordinate measuring machine (micro-CMM) probe. The vibrating micro-CMM probe is designed to address the needs of micro-manufacturing industry, in particular the requirement to measure high aspect ratio micrometre sized features to nanometre accuracy. The vibrating micro-CMM probe was also designed to address the problems inherent with micrometre and nanometre scale co-ordinate measurements caused by surface interaction forces. The initial concepts were first developed using extensive computational modelling and materials analysis. Production techniques were also investigated. The result was a micro-CMM probe consisting of three flexures, instrumented with piezoelectric actuators and sensors. The micro-CMM probe is capable of controlled vibrations in three axes; an essential feature of the design that directly addresses the problems inherent with tactile CMM probe interactions with measurement surfaces on the micrometre and nanometre scale. The ability of this micro-CMM probe to accurately measure high aspect ratio features will be dependant on the aspect ratio of the stylus. Investigations have been conducted to determine the optimum dimensions of the stylus.