| dc.description.abstract | It is well known that by incorporating an appropriate amount of bubbles in
the mixed gas electrochemical jet processing method, the contact area between
the electrolyte and the material during processing can be reduced. This leads to
an increase in the current density per unit area, resulting in advantages such as
reduced characteristic size and decreased surface roughness of machined micro
concave. This technique effectively improves feature accuracy and enhances
surface quality. In this study, a novel mixed gas electrochemical jet processing
technique was adopted. Prior to entering the nozzle, the electrolyte undergoes
electrolytic gas mixing and generation treatment in an electrolytic gas
generation module. After uniform mixing of bubbles and electrolyte, the
mixture is ejected onto the surface of the stainless steel workpiece through a
microelectrode nozzle. By applying an electrolytic voltage, characteristic
microstructures are fabricated. The study investigates the influence of different
electrochemical jet processing parameters and various electrolyte gas mixing
ratios on the processed features.
In the electrolytic gas-liquid mixing machining process, the bubble size and
gas-to-liquid ratio can be precisely controlled by manipulating the current. This
ensures a stable flow field during processing, preventing blockages in the flow
channel due to excessively large gas bubbles. Moreover, controlling the bubble
ratio during processing prevents issues such as insufficient conductivity,
reduced material removal rate, turbulent flow field, and increased surface
roughness caused by an excessive number of bubbles.
In this study, the size of the electrolytic gas bubbles was maintained within
the range of 7 to 13 μm, while the gas-to-liquid ratio was controlled between
III
0.01% and 0.07%. The experimental results revealed that under high current
density, mixing the electrolyte gas reduced the overall current density and led
to improved surface roughness and machining accuracy. Additionally, the
experimental results indicated an inverse relationship between the mixing
current and machining characteristics such as diameter, depth, and material
removal rate. Within the set range of mixing current values in this study, larger
mixing currents corresponded to smaller values of these machining
characteristics.
Regarding surface morphology, at a processing voltage of 200 V, electrolyte
concentration of 12 wt.%, processing gap of 450 μm, mixing current of 0.2 A,
and a processing time of 2 seconds, the surface exhibited better roughness when
compared to characteristics from non-mixed processing. | en_US |