Investigation of through-mask electrochemical machining process using a rib-connected photoresist for microcone array with large height-to-diameter ratio

Abstract

Metal microcone arrays are widely applied in aerospace, medicine, and chemistry, and usually require precision fabrication with a large height-to-diameter ratio and high array consistency. For this purpose, the present paper describes a method of through-mask electrochemical machining (TMECM) using a rib-connected photoresist. A large mask diameter is found to be beneficial for producing microcones with a large height-to-diameter ratio. However, the larger mask is more easily flushed off, which will destroy the consistency of the array. Therefore, a rib-connected photoresist structure for use during TMECM is developed. The improvement in performance offered by this photoresist is verified by simulations and comparative experiments. Finally, the machining parameters of the TMECM using a rib-connected photoresist are further optimized. When the machining time is 46 s, the flushing speed is 4 m/s, and the HCI concentration is 2 mol/L, the microcone array structure with a large height-to-diameter ratio of 10.28 and the standard deviation of 0.22 is obtained.