Resumen de Vibration characteristics of micro-EDM using variable dielectric media
Vivek Bajpai, Madan Lal Chandravanshi
Micro-electro discharge machine (EDM) is one of the ultra-precision machine used for the production of miniature parts of various sizes in the range of 1–999 ?m. The major sources of vibration induced in the micro-EDM is due to linear motor and sparks between tool and workpice. The study has been carried out to understand the variations in the vibration parameters of the micro-EDM due to the use of the deionized (DI) water in the machining chamber in which tool electrode and workpiece engages during operations. In the present study, the standard level of vibrations in z, y and x axes are measured for confirming the accuracy and repeatability in accordance with prevailing practices. Excitation force from the top frame due to linear motor and transmitted force to the base of micro-EDM were also measured for obtaining the exact values of the transmissibility in terms of force, velocity and displacement units. The variation in transmissibility has been identified due to the change in damping ratio of the EDM by use of dielectric medium as deionized (DI) water in the machining chamber. For this study, a fast Fourier transform analyzer, three accelerometers, a force transducer and the analyzer have been used to acquire the vibration data. The change in operating frequencies were also measured with respect to variations in current supply in micro-EDM with DI water and with air only in the by use of oscilloscope. The results of the study have confirmed that the use of deionized media (air and water) affects the vibration parameters in all the directions of the micro-EDM.
