Universal characterization method for 3D tactile probing systems

Abstract

The method of characterizing three-dimensional tactile probing systems is significant when it comes to determining the accuracy of measurements on coordinate measuring machines. The universal characterization method presented in this paper aims at a mathematical description of the probing behavior of three-dimensional tactile systems. In this way, the model developed is able to help improve the accuracy by properly determining 13 probe parameters. These parameters comprise 9 stiffness values for the probing system laid out in a 3x3 matrix, 3 position vector parameters from the stylus sphere as well as its diameter. These values can be used to compensate linear elastic distortion, which is due to the stiffness of the measurement system, the stiffness of the stylus shaft and the mechanical flattening of the calibrated sphere and the stylus sphere. The presented characterization method can be applied to various types of styli, ranging from macro sizes to micro sizes. An exemplary system based on a silicon micro probing system will be described. It is applied in coordinate metrology for the measurement of outer and inner surfaces of micro structures.