Dynamic Measurement Of Oxide Film Thickness In ELID Grinding

In ELID technology, the grinding wheel occur electrolytic reaction to generate oxidation film, and the diamond abrasive grains are wrapped in the oxidation film. In the grinding, when the value of the thickness of the oxidation film is larger than the projecting amount of the grinding wheel abrasive grains, the abrasive grains will not directly grinding the work-piece. Then the abrasive grains height is much smaller than the thickness of the oxidation film, the oxidation film in contact with the work piece carried light grinding. And because of miniaturized abrasive, the work-piece surface is achieving shaping removal, so as to achieve ultra-precision processing. In the grinding process, oxidation film on the constantly generated and shedding, to some extent, which reach a dynamic equilibrium. Therefore, in order to get a high-precision processing surface, oxidation film need to keep a certain range value. The oxidation film is particularly important in ELID, also highlights the importance of the measurement of the thickness of the oxidation film.In this thesis, the relationship between the diamond abrasive grains and the oxide film generated, the compositions of the oxide film are investigated. The existing single sensors, combined sensor measuring method are compared. Then the eddy current sensor is used to measure the inner surface of oxide film, the laser sensor is used for measuring the outer surface of oxide film. The measurement characteristics of oxidation film in the different grinding stage and the expression are summarized.Data measurement systems are created by the integration of sensors, capture card and the virtual instrument technology. The systems of data acquisition procedures, data display and save have been implemented in LabVIEW. The sensor characteristics and site conditions are analyzed, independent sensor mounting bracket is designed to reduce interference caused by a field vibration, and the sensor XYZ three directions to move freely is achieved.The sensor is placed in an independent mounting bracket to calibrate and to determine the linear relationship between the sensor input and output. The static test of measurement system is done to verify the accuracy of the measurement system. Then the surface of the grinding wheel is dynamically measured, experiments show that the laser, eddy current sensor measurement system of the dynamic to measure oxide film is feasible.