Effects Of Magnetic Field On Micro Electrochemical Machining

Micro hard-to-cut metal parts have been widely applied in the industries of aeronautics and astronautics, ordnance and precision devices. However, it’s difficult to machine these parts. Extra material is dissolved from micro metal parts with micro electrochemical machining technology(MECM). Due to this technology, material with high hardness can be machined and the surface quality can be improved. Also, there is no loss in tool electrode. So that it is an ideal machining method for micro hard-to-cut parts. To improve machining accuracy and reduce stray corrosion of MECM, magnetic field assisted MECM technology has been used. The main research work is as follows. Based on the theory of classic mechanics, the influence of charged particles’trajectory under magnetic field was analyzed. The influence of the liquid transport process with magnetic field was analyzed with magnetic fluid dynamics (MHD) theory. Experiments of MECM (micro hole and micro groove) with and without magnetic field were carried out respectively with DC power supply and nanosecond-pulse power supply in the NaNO3 electrolyte with high elasticity nickel iron alloy 3J21 as the machining workpiece. Results show that the hole taper is decreased, and the machining accuracy of micro holes and micro groove structure is increased when the magnetic flux intensity is about 0.1T and the direction of magnetic field is perpendicular to the feed direction. Experiments of MECM (micro hole and micro groove) with and without magnetic field were carried out by using NaCl electrolyte. The results show that quality of workpiece surface is improved, stray corrosion and surface roughness are reduced with magnetic field. A lot of parameter (feeding rate and machining voltage) matching experimental researches were carried out. Results show that faster feeding rate and lower machining voltage can be used with magnetic field, which indicated that the current density has been increased, the removal rate of the workpiece has been sped up and the processing efficiency has been increased.Based on theoretical analyses and a series of orthogonal contrast experiments, it can be concluded that when magnetic field which the magnetic induction intensity is about 0.1T and the direction is perpendicular to the feed direction was added to MECM, machining accuracy and quality of workpiece surface can be improved, and machining efficiency can be also increased. A new method is provided to solve machining problems of micro hard-to-cut metal parts. Meanwhile, theoretical and experimental foundation for the magnetic field assisted MECM technology has been established.