Investigation of Micro Electrical Discharge Drilling on Fabricated Zn/(Fe+Ag+Mg)-MMC for Cardiovascular Stent Application

Abstract

These days, zinc and its composites have attracted significant interest in the field of biomedical engineering due to their bio absorbability. Micro Electrical Discharge Drilling (μ-EDD) was used for making micro perforations in Zn/(Fe+Ag+Mg)- MMC for cardiovascular stent application. The influence of μ-EDD process parameters such as peak current, pulse-off time, pulse-on time, tool rotation, tool material, and electrode polarity were studied with respect To Material Removal Rate (MRR), Drill Overcut (DO), and Tool Wear Rate (TWR) during the micro-drilling of the MMC. Further, Taguchi and GRA based optimization were performed. From the experimental study it was found that MRR, DO and TWR increases with peak current, pulse-on-time and rotation of tool electrode. Optimization improved the MRR, DO and TWR by 111.52%, 20.83% and 76.79% respectively. Peak current and pulse-on-time was found significant for MRR DO and TWR whereas peak current and pulse-off-time was found significant for GRA based analysis. SEM examinations of the micro-drilled hole show that high circularity and a good surface finish was achieved.