Wire electric discharge machining (WEDM) is one of the foremost methods which has been utilized for machining hard-to-cut materials like Titanium alloys. However, there is a need to optimize their important operating parameters to achieve maximum material removal rate (MRR). The present paper investigates the effect of control factors like current, pulse on time (Ton), pulse off time (Toff) on MRR of machining of Ti-6Al-4V alloy. The study showed that, increase in current from 2 A to 6 A results in a significant increase in MRR by 93.27% and increase in Ton from 20 μs to 35 μs improved the MRR by 7.98%, beyond which there was no improvement of MRR. The increase in Toff showed a counterproductive effect. Increase in Toff from 10 μs to 30 μs showed an almost linear decrease in MRR by 52.77%. Morphological study of the machined surface showed that cut surface consists of recast layer on which microcracks were present, and revealed the presence of globules, ridge-structured formations of recast layers and voids. In addition, a regression model was developed to predict the MRR with respect to the control factors, which showed a good prediction with an R2 value of 99.67%.

Present research work is focused on investigation of material removal rate in Wire-ED Machining (EDM) of artificially aged Al-6061/ B 4 C reinforced composites with 2-6 wt.% in peak aged condition. Combined effect of B 4 C and artificial aging at 100°C improved the hardness by 20 -170% under as cast and artificially aged condition. Initially the wire EDM experiments are conducted on Al6061 alloy and then the process parameters such as current, pulse-on time (t on ) and pulse-off time (t off ) are optimized to obtain the high material removal rate (MRR). At optimized conditions test samples with various % of B 4 C are machined to study their influence on MRR. The study revealed that current and t off had a significant influence. MRR increased as current is increased and it decreased as t off is increased. Maximum MRR at optimum settings, current : 5.53 A, T off : 10 µs and T on : 36.46 µs is 2.45 mg/min. Considering the limitation of the experimental set up the modified optimum settings (T off : 10 µs, T on : 30 µs and current : 5 A) resulted in average MRR of 2.39 mg/min with deviation of 0.20 mg/min. The study showed that there is no significant difference in MRR and the morphology of the machined surface with respect to test samples of different % of B 4 C particles as reinforcement in Al6061 composite.

Wire-Electric Discharge (WED) Machining is one of the most suitable machining techniques for machining hard-to-cut materials such as Titanium, with precision. It is of utmost importance to optimize the control parameters to achieve the desired levels of machining performance characteristics. Considering this goal, this research investigates the effects of current, pulse on time (Ton) and pulse off time (Toff) on the material removal rate, surface roughness and kerf width of WED machined Ti-6Al-4V. The results of optimization showed that, current -5.19 A, Ton -20 µs, Toff -30 µs, is the optimized settings for machining of Ti-6Al-4V alloy using molybdenum electrode for the best machining performance. Based on the analysis of grey relational grades, the order of influence of the control parameter is ranked as: Ton -I, Toff -II and Current -III. The efficacy of GRA based approach was evaluated through confirmation experiments wherein the theoretical predictions showed errors < 3%.

Foreign body (FB) aspiration is a serious medical problem that can mimic other respiratory conditions. Isolated pleural effusion is a rare presentation of FB aspiration. We report herein a six years old boy presenting with fever and cough without history of choking and respiratory distress and X-ray chest suggestive of pleural effusion. Although, the child was initially misdiagnosed as pneumonia with sympneumonic effusion, the diagnosis was established only once he coughed out a piece of foreign body. The present case highlights that FB aspiration, even though rare, should be considered as one of the differential diagnosis of pleural effusion.