Optical Fiber Curvature Sensor Used to Measure the Surface Profile of 3-D Printing Objects

A contact stylus profilometer based on an intensity-modulated optical fiber curvature sensor is proposed and demonstrated. The sensor head consists of a multimode-coreless-multimode (MCM) fiber structure, very sensitive curvature, clamped to a metal beam. The 3-D printing stylus was glued to the center of the metal beam. The displacement of the stylus, during the surface scan of the 3-D printing pieces, bends the metal beam, which, in turn, induces a change in the curvature of the MCM producing a decrement of the losses of the characteristic attenuation notch. The profile generated with this simple-to-implement optical fiber sensor was compared with that obtained with a commercial stylus profilometer, observing a very good coincidence between both the profiles.