||Due to the explosive improvement of micro machining technology, many kinds of meso-scale products and parts are developed. There are two techniques, CMM (Coordinate Measuring Machine) and SPM (Scanning Probe Microscopy), commonly used to measure the profile of meso-scale products. However, both of these methods have their own strengths and weaknesses in that scale. The CMM can’t be precise and accurate; while the SPM measurement system will be a time-consuming process. The micro scale CMM measurement system with micro spherical probes would be suitable for measuring meso-scale objects.|
In this study, equipments are built to fabricate the micro spherical probes. The glass optical fiber is selected as the material to fabricate the probes. The heating-pulling method and arc fusion method are selected as the fabrication process. The commercial equipments are available for fabricating micropipette and NSOM (Near-field Scanning Optical Microscopy) probes. However, most of these commercial equipments are expensive, and the heating area is too small to fit our study. In this study, the gas heater is used to replace the laser power as a heat source. A vertical pulling mechanism is developed to pull the optical fiber. Moreover, this study uses Taguchi method to reduce the number of experimental runs and find the suitable parameters for fabrication.
The straight-circular-cone-type probe and the bent-circular-cone-type probe can be fabricated at the same time. The radius of the probe tip can be smaller than 0.5μm for NSOM. In addition, the heating-pulling mechanism can reduce the diameter of optical fiber from φ125μm to less than φ50μm for different purposes. An arc discharge machine is also developed to melt the cleaved end-face of the prob. The heating-pulling mechanism and arc discharge machine developed in this study are successfully applied in fabricating different types of probe ends, φ20~125μm hemispherical end-face and φ50~300μm spherical end-face for example, for different applications.