Study On Key Technology Of Micro Electrochemical Discharge Machining For Glass Microstructures

The non-conductive hard and brittle materials are widely used in a variety of engineering fields due to its excellent performance:high hardness,high strength,good wear resistance,insulation and thermal conductivity.Especially with the vigorous development of MEMS,the micro-structures of the non-conductive hard and brittle materials are used in aerospace,automotive electronics,bio-medical,national defense science and technology and other fields.However,the machining of the micro-structures on the non-conductive hard and brittle materials is very difficult because of its unique properties.The electrochemical discharge machining(ECDM)has been reported as an effective way to fabricate the micro structures of non-conductive hard and brittle materials,which can overcome its hard,brittle and non-conductive properties.In this paper,the typical non-conductive hard and brittle materials glass is selected as the workpiece.A series of experiments were carried out to study the fabrication of glass micro structures in ECDM.The mechanism of ECDM is deeply discussed.The formation mechanism of the gas film and the material removal mechanism are investigated.In this paper,thermal machining and chemical etching are discussed as the most material removal ways.According to the machining principle and experiments requirements,the developed experimental set-up of ECDM is established.For different processing forms,simulation analysis and the experiments are carried out to study the machining performance.The simulation results of flow filed in ECDM drilling and milling show that the rotating helical tool enhances the electrolyte circulation.A mathematical model is proposed to reflect the relationship between the discharge energy and the side gap.The effects of the main process parameters on the machining localization were studied in this paper.The machining localization was characterized by the lateral machining gap.Experimental results show that the machining localization rises with the increase in frequency and feed rate and reduces with the rise in applied voltage and duty factor.Micro hole array and micro groove array are fabricated by the optimized parameters.High aspect ratio micro hole,complex micro channel and 3D micro structures are fabricated successfully.The ultrasonically vibrated electrolyte is utilized to improve the machining performance,which improves the surface quality on entrance.In this paper,the newly developed micro wire electrochemical discharge machining(WECDM)by using a rotary helical tool is proposed.Many experiments are conducted to investigate the machining localization of the WECDM with a rotating helical tool.The present study discusses the effects of machining parameters on the side gap during the slicing of glass workpiece by using the developed WECDM setup.Experimental results demonstrate that the side gap rises with the increase in applied voltage,duty factor and concentration of electrolyte,and reduces with the rise in frequency,spindle speed,and feed rate.Series of micro kerfs are fabricated successfully by the optimized parameters.The complex closed structure,micro glass probe,high aspect ratio kerf,and high aspect ratio pattern structure are obtained by this method.In this paper,the drilling,milling and slicing of ECDM are investigated deeply.Many complex micro structures of glass are fabricated successfully.The experiments results demonstrate that the ECDM is an effective method to fabricate the micro structures of non-conductive hard and brittle materials.