Characterization of dimensional features of mesoscale component using capacitive sensor

Current developments in the miniaturization field focused on fabricating smaller and precise geometric features. As the scale of features and machined parts decreases, the resolution of techniques and specifications, used to measure and quantify these parts, increases. In the present work, an attempt has been made for using a high-resolution noncontact capacitive sensor for characterization of mesoscale dimensional features. The dimensional features such as the width and depth of the channel and diameter of the hole/circular feature are measured, and the size of the feature varies from few micrometers to few millimeters. A miniaturized experimental setup has been developed using capacitive sensor and high-precision XYZ linear stage to carry out the measurement. A strategy is proposed to characterize the dimensional features, and it is formulated based on output voltage gain of the sensor while scanning the channel feature. The algorithm is proposed to estimate the position of the edge coordinates and evaluation of the width of the channel and circular feature based on the output voltage gain of the sensor. Two specimens with a channel and circular feature manufactured by using a miniaturized mesoscale machine tool are examined. The evaluated width of the channels and the diameter of the circular features are in good agreement with the results obtained from optical methods. The proposed measurement system effectively determines the dimensional characterization of mesoscale features, and measurement is limited to the width of the channel at 250 μm. Furthermore, the technique can be adopted for online and in situ monitoring and inspection of mesoscale features during machining.