Analysis of the contact probe mechanism for micro-coordinate measuring machines

High precision contact scanning probes for measuring miniature components on micro- and nano-coordinate measuring machines requires sensitive mechanisms. This paper analyzes the mechanism of a developed contact probe in order to find its optimal dimensions. The contact probe is composed of a fiber stylus with a ball tip, a mechanism with a wire-suspended floating plate, and focus sensors. The wires experience elastic deformation when a contact force is applied. The probe mechanism with a four-wire floating plate is studied. Stiffness analysis is carried out using the theory of elasticity. It is found that, with a proper stylus length, a contact probe with uniform stiffness can be designed.