Investigation of dimensional deviation in biodegradable dielectric-based powder-mixed electric discharge machining of Ni-based superalloy

Innovations in the manufacturing industries assist to improve machinability of difficult to cut materials, such as nickel superalloys. Critical applications of these materials require improved dimensional accuracy. These requirements justify the use of electric discharge machining (EDM); however, conventional dielectric poses various health concerns, such as breathing issues. Therefore, the potential of powder mixed biodegradable dielectric is comprehensively investigated herein to improve the geometric accuracy of the machined cavity because it is still plagued by overcut/undercut problems. In this work, the performance of four electrode types (ET), namely aluminum, brass, copper, and graphite along with varying powder concentrations (Cp) was deeply examined under canola oil biodegradable dielectric in the context of axial/lateral overcuts (AOC, LOC). The experimentation resulted in minimum AOC (0.279 mm) and LOC (0.276 mm) at [Cp (0.0 g/100 ml), ET1 (Al)], and [Cp (1.0 g/100 ml), ET4 (Cu)]. The composite desirability-based optimized settings including graphite at higher Cp (1.0, 1.5) caused a percent reduction of 9.10 % and 6.89 % for AOC and LOC, respectively.