Papers by Keyword: Powder Mixed EDM

Abstract: Electrical discharge machining (EDM) is a non-conventional machining technique that is well-known for use in fabricating dies and molds owing to machinability of high hardness materials. Although the electro-thermal mechanism of EDM offers many advantages over other available machining methods, its sluggish nature limits the wide application of such machines for mass production. In this research, adding graphite powder to dielectric is proposed to improve EDM performance factors. Material removal rate (MRR) and average surface roughness (Ra) have been monitored and evaluated after addition of graphite powder to dielectric in electrical discharge milling and sinking. It is found that the presence of powder particles in dielectric fluid enhances the MRR steadily up to ~11 and ~17% for milling and sinking process, respectively. Moreover, the highest enhancement if Ra is ~31% at 1g/l graphite powder concentration for electrical discharge milling and up to ~11% for sinking process. Field emission scanning electron microscopy (FESEM) is used to inspect the machined surfaces. The surfaces machined with graphite powder mixed appear significantly unlike the surfaces machined in pure dielectric. Adding powder to dielectric is found to increase the machined surface hardness by ~26%, from 240 to 302 HV.

Abstract: To Acompany the novel technology advancement demands for advance materials. Beryllium copper is such solitary material which has conspicuous material properties, to be pricise good wear resistance, corrosion resistance and high fatigue strength. But the concern with this is machining by treditional machining processes. To defeat this problem Powder Mixed Electric Discharge Machining(PMEDM) is a surrogate technology, which is acquiring much importance in machining such materials. As compared to convenctional electric discharge machining the powder mixed electric discharge machining has delivered much efficiency because of the addition of fine powder particles in dielectric media. It increases the steadiness and concentrated sparking on the work piece material. This study aims at machining beryllium copper alloys using powder mixed electric discharge machining. The electric parameters namely pulse on time, pulse off time, and gap voltage are retained constant throughout the experimentation. Copper electrode of 3 mm square tip was used for machining of beryllium copper work piece. Gap current is varied as 8 A, 10 A, 12 A and 14 A whereas powder concentration is varied as 2 gm/litre, 4 gm/litre and 6 gm/litre. Material removal rate (MRR) and tool wear rate (TWR) were considered as electric discharge machining output measures for the study. It was observed that the efficiency of powder mixed electric discharge machining improved by using powder mixed dielectric. It was found that the MRR improves as the gap current is increased by the increament of 2A. One more obeservation found was the improvement in the both MRR and TWR with the increase in the powder concentration . Tool wear rate increases due to the truth that as the depth of machining increases the efficiency of flushing reduces hence leading to higher tool wear rate.