Research On Electrochemical Machining Of Corrugated Micro Structure On Cylindrical Inner Surface

As a typical micro structure,corrugated micro structure on cylindrical inner surface has been proved has been widely used in MEMS.Various methods were adopted to fabricate it,however,with its continuous and micro slots(0.1mm),corrugated micro structure on cylindrical inner surface was hardly machined by traditional processing methods.Electrochemical machining removes or adds material at atom scale,which is a prominent method to fabricate micro structures.This paper proposes electroforming processing to fabricate corrugated micro structure on cylindrical inner surface,and two different methods to process mandrel were proposed with their effects compared by experiments.The main research works are listed as follows:(1)The mandrel for electroforming was fabricated by Wire electrochemical micromachining(WECMM).The electric field model was set to investigate the rule of current density during WECMM process while on cylindrical outer surface.An experimental system was reformed,the control and detect subsystem for the system was set based on LabWindows/CVI platform.The dissolution characteristics of aluminum in WECMM was analyzed.Moreover,The effects of different machining parameters for the process was investigated,namely applied voltage,pulse frequency and rotation speed,and with the optimized parameters,micro annular grooves with good surface quality on cylindrical outer surface in aluminum were fabricated.(2)A combinatorial electrochemical method for mandrel machining was proposed.The mandrel was assembled by micro aluminum rings machined by WECMM and copper rings machined by electroforming,after which the mandrel was used for rotary electroforming.The mass transfer enhancement of micro helical electrode electrochemical machining was investigated.Moreover,the complexing effect of complexing agents during electrochemical machining was analyzed to improve the surface quality.An experimental system was reformed,and the effects of different machining parameters for the process was investigated,namely applied voltage,diameter of micro helical electrode and the concentration of complexing agents.Micro aluminum rings with thickness of 100?m and ring width of 500?m were fabricated with optimized parameters.Moreover,the assembly quality was analyzed.(3)The principle of electroforming was introduced,and the experimental system for fabricating corrugated micro structure on cylindrical inner surface was mounted.The quality of different mandrels for rotary electroforming was compared,and the combinatorial electrochemical method for mandrel machining was adopted as the final method to fabricate corrugated micro structure on cylindrical inner surface.Subsequently,corrugated micro structure on cylindrical inner surface with slot width of 104.8±6.5?m,depth of 476.2±9.2?m was fabricated.