Characteristics of a Micro Quartz Stylus Probe Fabrication by Using the Micro-discharge Plasma Method

Abstract

Micro-stylus probes and tactile sensing structures are key components in high precision micro-coordinate measuring machines. Micro-spherical styli with a diameter of 0.125mm are available in commercial markets. A tungsten micro-spherical stylus with a diameter of less than 0.08 mm has been successfully fabricated by using a hybrid process which combines one pulse electro discharge and wire electro discharge grinding methods. However, the low controllability is still a critical problem and the electric discharge process is not suitable for the fabrication of non-conductive materials such as quartz and glass. In order to fabricate a non-conductive quartz-based micro-stylus probe, a micro-discharge plasma process was proposed in this paper. A micro-quartz pipe was mounted on a V-shaped block with a low rotation speed and feeding to the plasma zone in order to enable a sphere formation. The experimental results show that a spherical quartz stylus with a diameter of 0.12mm is produced by using the micro discharge plasma process. The machining characteristics such as machining time, feeding length, accuracy, and diameter, will be also investigated. It is possible to produce a micro-spherical quartz stylus probe by using the low-cost micro-discharge plasma method.