This study develops micromanufacturing techniques to fabricate extremely smooth surface finish, high aspect ratio, and complex microchannel patterns. Computer controlled micromilling on a high speed machine system with minimum quantity lubrication is used to remove most materials and define a channel pattern. Assessment of microchannel is performed with optical microscopy, scanning electron microscopy, atomic force microscopy, and white light interferometry. Meso-scale milling confirms the validity of theoretical surface finish of ball-end milling, but surface finish in micro-scale milling is measured to be few orders of magnitude higher. Build-up-edge is reduced with optimally coated tool and milling in minimum quantity lubrication. The surfaces of milled microchannels are then further enhanced by subsequent electrochemical polishing process. When applying to 304, 316L stainless steel alloys and NiTi alloy, this hybrid technique can repeatedly produce microchannels with average surface finish in the range of 100-300 nm.

This research aims to understand flushing of by-products in electrochemical machining (ECM) by modeling and experimentally verifying mechanism of particle transport in inter-electrode gap under low frequency vibration. A series of hole were drilled on steel plates to evaluate the effect of vibration on material removal rate and hole quality. Infinite focus optical technique was used to capture and analyze the three-dimensional images of ECM'ed features. Experimental results showed that maximum machining depth and minimum taper angle can be achieved when vibrating the workpiece at 40 Hz and 10 µm amplitude. Simulation results showed that the highest average flushing speed of 0.4 m/s was obtained at this vibration frequency and amplitude. Machining depth and material removal rate has a positive correlation with the average flushing speed. Sharper ECM’ed profile is obtained since the taper angle is favorably reduced at high average flushing speed.

This research studies how particles transport between low frequency vibrating electrodes during electrochemical machining (ECM). The ANSYS Fluent software was used to study the particle speed while the Star CCM+ software was utilized to study particle interactions during vibration-assisted ECM process. A series of simulations were conducted to calculate the particle average flushing speed. Collided particles either gained momentum or deflected their trajectories to accelerate in the flow of electrolyte. Simulation results showed that the highest average flushing speed of 0.4 m/s was obtained at 40 Hz vibration frequency and 10 µm vibration amplitude. Such higher flushing speed of particles improved machining depth (material removal rate) and produced a sharper machined profile. Experiment results confirmed that the maximum machining depth and minimum taper angle were obtained when vibrating the anodic workpiece at 40 Hz and 10 µm amplitude. Machining depth and ECM material removal rate had a positive correlation with the average flushing speed. A sharper ECM’ed profile was achieved since the taper angle was favorably reduced at high average flushing speed.