A Reflective Fiber Optic Sensor for Surface Roughness In-Process Measurement

The paper deals with the development of a fiber optic sensor for surface roughness measurement. A new method for the calculation of reflection light intensity is proposed. By numerically counting the amount of reflection light rays from a measured surface, the relationship between the reflection light intensity and the surface roughness can be found. The simulation method is useful in understanding the effects of the sensor probe structure and the component parameters on the performance of the sensor such that an optimum sensor design can be obtained. A fiber optic sensor probe for surface roughness measurement was designed and fabricated using the results obtained by simulation. Experimental results show that the prototype sensor probe has high resolution and sensitivity for ground and milled surfaces with the roughness value (Ra) of $0.1μm∼3.2μm.$ The experimental results also show that the simulation method is accurate, and hence useful in designing fiber optic sensors. The simulation procedure and feasibility of the simulation method as well as the experimental results obtained from the prototype sensor probe are presented in this paper.