31. Micro-dimple Array Fabrication by Through Mask Electrochemical Micromachining

Micro-dimple arrays are a common mechanical structure in engineering components. Surface texturing is an attractive approach for improving the friction and tribological performance of mechanical components. Through-mask electrochemical micromachining (TMEMM) has shown good feasibility in the field of machining difficult-to-cut metal parts with micro-patterned arrays. Experiments have been carried out utilizing mask thickness of 16 µm to search out for the respective contributions of principle input parameters, viz. input voltage, pulse frequency and duty ratio in controlling the machining performances, such as undercut (U_c) and dimple depth (D_d) of the fabricated micro-dimples. An experimental plan designed based on the standard L₉ orthogonal array have been incorporated to recognize the best possible combination of machining parameters of TMEMM using Taguchi Methodology. By applying Taguchi design, the time required for experimental investigation can be significantly reduced, as it is effective in investigating the effects of multiple factors on performance. In this study, the best possible parametric combinations have been found with the help of signal-to-noise (S/N) ratio and ANOVA analyses that minimize the undercut and maximize the dimple depth respectively. Input voltage has been varied from 8 to 12 V whereas the machining frequency and the duty ratio has been altered from 2 to 10 kHz and 20 to 40% respectively during experimentation. Confirmation experiments under most favorable parametric combination are carried out to certify the certainty in the enrichment in quality characteristics of TMEMM process. Both the performance characteristics are found to be mostly influenced by Duty Ratio followed by Machining Frequency and Input Voltage.