INVESTIGATIONS ON ULTRASONIC ASSISTED ELECTROCHEMICAL DISCHARGE MACHINING PROCESS

Abstract

The demand for micro-sized products exists in a good number of application areas due to their technical and economic benefits. Performance, functionalities, and low-cost solutions are required for the manufacturing of micro-sized products. Enabling micro-manufacturing technologies can realize this requirement. Hence, it has created interest in manufacturers, researchers, and academicians across the globe. Micro products need various micro features such as microholes, microchannel, and micro slits, etc. The geometrical accuracy and surface quality of the micro features are essential requirements to produce quality products. The materials required for the microfluidics, MEMS, and medical equipment should be electrically non-conductive and chemically inert. These materials often require precise and crack-free machining without heat-affected zones. Glass is one such material that is suitable for these applications; however, machining on glass is challenging due to its hardness, brittleness, and non-conductive nature. The effective machining of glass with conventional machining processes is limited though several non-conventional processes can be used. Electrochemical discharge machining (ECDM) is one of the most suitable processes for machining glass materials among all non-conventional micromachining processes. The ECDM process is a hybrid micromachining process. It includes hybridization of thermal energy based electric discharge machining (EDM) process and electrochemical energy-based electrochemical machining (ECM) process. It takes advantage of the locally generated thermal energy in the machining zone, which results in the removal of work material by melting and evaporation. The ECDM process can machine the various micro features on work material, making it a simplified machining process. Notwithstanding the benefit of the ECDM process, it provides a low material removal rate (MRR) and has limited high aspect ratio drilling ability. But it is observed that applied voltage is the crucial parameter that governs the amount of thermal energy generated in the machining zone. The intensity of the discharges produced in the machining zone increases with an increase in applied voltage. Higher MRR is achieved at the higher applied voltage at the cost of hole over cut (HOC) and the machined features' accuracy. The ECDM process's drawback with higher discharge energy is higher productivity with precision and accuracy with repeatability. So there is a need for some technical augmentation to improve productivity, accuracy, repeatability during the ECDM process.